tag:blogger.com,1999:blog-33189306967397972982024-02-07T01:49:21.957-08:00The study of Global Warming.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.comBlogger28125tag:blogger.com,1999:blog-3318930696739797298.post-60230587382116725002011-08-03T18:14:00.000-07:002011-08-04T22:39:57.077-07:00Sea Level RiseI will be discussing this topic in various blog entries over the next several weeks, possibly longer, as I will concentrate on tropical systems affecting my area in other blogs, as warrented.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://ibis.grdl.noaa.gov/SAT/SeaLevelRise/slr/slr_sla_gbl_free_txj1j2_90_500.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="444" width="640" src="http://ibis.grdl.noaa.gov/SAT/SeaLevelRise/slr/slr_sla_gbl_free_txj1j2_90_500.png" /></a></div><br />
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Sea level rise is one effect of anthropogenic global warming that is both complicated and simple. It is complicated by the complexity of ice sheet behavior. Some factors, such as ice sheet lubrication by meltwater penetrating to the interface between ice and rock beneath the ice sheets have only been known about for the past few years (more on this later), changes in the <a href="http://en.wikipedia.org/wiki/Geoid">geoid</a> as ice sheets melt and the mass balance of the Earth changes as a result, <a href="http://en.wikipedia.org/wiki/Isostatic_rebound">isostatic rebound</a> continuing from the prior ice age, and from today's ice sheet melting. Also potential changes in weather patterns--shifts in mean high pressure centers and storm tracks, as well as in the ENSO cycle will probably be significant in augmenting or slowing sea level rise in many areas--unfortunately confident predictions of weather pattern shifts as anthropogenic global warming proceeds are not possible as yet.<br />
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Many laypeople assume that sea level rise will be uniform. After all if you add water to the ocean, it should rise everywhere, shouldn't it? Not so. The ice sheets of Greenland and Antarctica contain quadrillions of tons of mass, and have significant gravitational effects. If, for example, the Greenland Ice Sheet melted completely away tomorrow, global sea level would rise on average 23 feet. However, because gravitational attraction would be reduced near where the Greenland Ice sheet used to be, sea level would rise considerably less near Greenland, and considerably more at the <a href="http://en.wikipedia.org/wiki/Antipodes">antipode</a> relative to Greenland. It could be that sea level rose 18 feet near Greenland, and 28 feet at Greenland's antipode. (Isostatic rebound of the land under the former Greenland Ice sheet would ultimately reduce this effect). Since the West Antarctic Ice sheet is near Greenland's antipode, and contains enough ice to raise sea levels by 16 feet, this gravitational effect would be mostly counterbalanced if it melted simultaneously, and most of the globe would experience sea level rises between 36 and 42 feet. <br />
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A good illustration of the non-uniformity of sea level rise is shown in the map below. It is perhaps unfortunate that sea level rise has been most marked in the western tropical Pacific while the North Atlantic and eastern Pacific which most of the developed world (North America and Europe) have seen sea level rises below the global average. A sea level rise of 10 mm (1 cm)/year on the northeast seaboard would concentrate minds! However, this map shows the ocean we have:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://ibis.grdl.noaa.gov/SAT/SeaLevelRise/slr/map_txj1j2_sst.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="375" width="640" src="http://ibis.grdl.noaa.gov/SAT/SeaLevelRise/slr/map_txj1j2_sst.png" /></a></div><br />
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The simplicity of sea level rise is that it is inevitable. A warmer world is already resulting in temperate and tropical mountain glaciers melting everywhere (q.v.) <br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.uwsp.edu/geo/faculty/lemke/geol370/images/04_glacier_mass_balance_graph.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="486" width="640" src="http://www.uwsp.edu/geo/faculty/lemke/geol370/images/04_glacier_mass_balance_graph.png" /></a></div><br />
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Mountain (alpine) glaciers do not have enough ice to raise sea levels by catastrophic amounts of course. However they do represent a significant fraction of the sea level rise occurring today. Another factor adding to sea level rise is thermal expansion as the oceans absorb heat trapped by rising concentrations of carbon dioxide, methane, and other greenhouse gases. Thermal expansion seems to be the primary driver of sea level rise at present. However, it is likely to be overwhelmed by massive melting in ice sheets during the late 21st and 22nd centuries. <a href="http://www.sciencedaily.com/releases/2011/07/110718092220.htm">Recent work</a> indicates that thermal expansion may not have played a large role in the <a href="http://en.wikipedia.org/wiki/Eemian_interglacial">Eemian interglacial</a> 120,000 years ago compared to meltwater from ice sheets. However an extra few feet will just be another twist in the knife our descendants will have to face.<br />
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Sea level functions as a crude thermometer for the Earth. Sea level is determined by the temperature of the oceans, and the mass of the water the oceans contain. During the next three centuries, much of the more than 30 quadrillion tons of ice on our planet will melt. Even the East Antarctica Ice sheet. The amount of heat required to melt more than 30 quadrillion tons of ice is enormous. Enough to raise the atmospheric temperature to more than 1000 °F! While heat is absorbed by melting ice, global atmospheric and oceanic warming will be slowed. It <i>will</i> be much warmer, but temperatures will be livable in most places while the heat sink of ice melt operates. In 2250, St. Louis may have the average temperature of Phoenix or Miami, but it is perfectly possible to live in those cities (whether agriculture will be possible in the Midwest is another matter). The heat energy absorbed by melting ice and the warming of the oceans will both contribute to sea level rise, even as atmospheric temperatures do not rise by many tens or hundreds of degrees. The ocean depths, mostly between -4°C and 4°C, will also slowly absorb heat as it diffuses from above. (A warming of the ocean depths in future centuries, so that they were 30 °C all the way down would provoke an additional sea level rise of about 15 meters, as can be computed from <a href="http://www2.volstate.edu/CHEM/Density_of_Water.htm">this table</a> but that won't happen as long as ice sheets exist to cool the ocean where they come in contact. In other words, not for many centuries.)<br />
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Is radiative forcing from our greenhouse gas emissions enough to remove all ice sheets from the surface of the earth?<br />
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Well let's see. <a href="http://www.esrl.noaa.gov/gmd/aggi/">Current radiative forcing by antropogenic greenhouse gas emissions is estimated to be 2.77 watts per square meter of the Earth in 2009.</a> The surface area of the Earth is 510,072,000,000,000 square meters. This represents about 1,412,900,000,000,000 watts per second! <br />
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But wait! As MichaelSTL has reminded me, humankind has also increased aerosol emissions into the atmosphere, which reduce radiative forcing. He has generously provided the following two links, <a href="http://data.giss.nasa.gov/modelforce/">here</a> and <a href="http://data.giss.nasa.gov/modelforce/RadF.txt">here</a>.<br />
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So let's recalculate again. Using the figures for 2010 from this <a href="http://data.giss.nasa.gov/modelforce/RadF.txt">link</a> courtesy of MichaelSTL, the net radiative forcing, adding the effect of aerosols, the figure of 2010 is 1.6628 W/m2. This revised figure gives us 850,000,000,000,000 watts per second for the whole surface of the Earth.<br />
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850 trillion watts, wow! But how much heat is that, really? After all, visiting Turkey in 1999, Mike and I were agog at the dollar being worth 650,000 Turkish lira, and spending 10 million Turkish lira for dinner!<br />
Well it does collapse down. Going by this <a href="http://www.unit-conversion.info/energy.html">energy unit conversion table</a>, a watt-hour (3600 watts) represents about .8598 of a kilocalorie, the heat required to increase the temperature of 1 kg of water 1 °C. 4187 watts raises one kg of water 1 °C. A kilogram of water is a liter, and there are 1,000 liters in a cubic meter, and a billion cubic meters in a cubic kilometer. Also, the melting of ice into water takes tremendous energy, as much as raising the temperature of water 80 °C! And ice is not necessarily at 0 °C--I'll assume that the average temperature of all the ice in ice sheets is -20 °C. The specific heat of ice is half that of water, so it takes 90 kcal to melt the typical kg of ice under that assumption.<br />
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So we have 850,000,000,000,000 watts per second to play with. Dividing by 4187 yields 203,000,000,000 kcal per second to play with. Dividing by 90 to melt a kilogram of ice yields enough energy to melt 2,255,000,000 kilograms of ice. Per second. This is 2,255,000 cubic meters of meltwater per second. Which is about 1 cubic kilometer every 7 minutes 23 1/3 seconds, or about 71,160 cubic kilometers of meltwater per year. Enough to melt all the ice on the surface of the Earth in 421 years. Of course this would mean no temperature increases in the atmosphere or oceans. All the heat would be absorbed by melting ice.<br />
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Of course we are not melting enough ice to yield 71,160 cubic kilometers of meltwater per year, even though our greenhouse gas emissions are trapping sufficient radiation to do so. The atmosphere and surface of the land is warming. The oceans are warming. The oceans are now our primary heat sink.<br />
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But the amount of anthropogenic greenhouse radiative forcing is increasing steadily. Current projections show it rising easily to 4, 5, and possibly 6 watts/square meter as the 21st century wears on. As temperatures rise, melting will accelerate on the margins of ice sheets, through the collapse of ice shelves in contact with warmer oceans, and acceleration of glacier movement provided by meltwater on the surface of glaciers and ice sheets working downwards to the ice/rock interface. <br />
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Rigorous scientific examination of the effects of anthropogenic global warming on sea level rise began surprisingly recently, with a paper by J. H. Mercer in 1978 on the possible collapse of the West Antarctic Ice Sheet. It would be very generous to say there was much scientific research into the effects of anthropogenic global warming on sea level in the 1960s and 1970s. If you had asked most qualified scientists back then, I suspect that they would have answered that increased snowfall on polar ice sheets would counteract the effects of melting alpine glaciers and thermal expansion. This 'consensus' was surprisingly long-lasting---after a few papers made a splash in the 1978-1981 period, research into the effects of AGW on sea levels, the hypothesis that AGW would result in major sea level rises fell into disfavor, or more accurately, neglect. This continued through the 1980s, and with some exceptions, through the 1990s. The discovery of outlet glacier acceleration in Greenland during the first years of the 2000s changed this. But that will be for a future blog entry.<br />
<a href="http://junksciencecom.files.wordpress.com/2011/08/science-sea-ice-seesaw.pdf"><br />
Adding an interesting article about arctic sea ice during the Holocene Optimum.</a>StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com19tag:blogger.com,1999:blog-3318930696739797298.post-90367084786516402012011-07-02T11:00:00.000-07:002011-07-02T12:11:05.139-07:00Global warming is here, and soon in an unprecedented way!<a href="http://www.sciencedaily.com/releases/2011/06/110629205053.htm">On June 30, NOAA released the new climate normals for the 1981-2010 period for the USA</a>. Average temperatures were 0.5°F higher in 1981-2010 than in 1971-2000. Since the period 1981-2000 is included in both periods, this means that the 2000s were 1.5°F warmer than the 1970s in the USA! There can be no clearer indication that <b>global warming is here</b>!<br />
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This is a stunning rate of temperature rise. Half a degree per decade. If temperatures continue to rise at this rate, the 2090s will average 4.5°F warmer than the 2000s, and 6°F warmer than the 1970s! And the temperature rise will almost certainly <i>not</i> remain constant. Due to humanity's accelerating consumption of fossil fuels, carbon dioxide concentrations in the atmosphere will accelerate their rise and temperature rises will almost certainly accelerate as well. 0.5°F/decade almost certainly represents an <i>underestimate</i> of how much temperatures will increase during the 21st century.<br />
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Humanity has never lived in such a rapidly warming environment. Ever. Nothing comes close in our planet's history except for the <a href="http://en.wikipedia.org/wiki/Petm">Paleocene–Eocene Thermal Maximum </a>(PETM)<br />
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The PETM was a huge warming triggered by mass releases of carbon dioxide and methane from the oceans 55.8 million years ago. Temperatures soared by more than 5°C from what was already a warmer environment than the present. The average temperature at the North Pole was 73°F, comparable to Miami. For tens of thousands of years there was not one snowflake. Not one floe of ice. No frost. Anywhere.<br />
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So how does our present addition of carbon dioxide to the atmosphere compare to what happened during the PETM? Much research has been done in the last decade, and the scope of carbon releases during the PETM, and their speed compared to our own time has become clear.<br />
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And the comparison is not good.<br />
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Here is a graph showing carbon releases into the atmosphere. Our current additions of carbon to the atmosphere are already more than 5 times greater than during the PETM, and are continuing to accelerate as the developing world industrializes, and the developed world does very little. Projections show that our carbon emissions will nearly triple, to 15 times the carbon emission rates of the PETM.<br />
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Graph of net carbon emissions into the atmosphere from <i>Scientific American</i>:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://climatecrock.files.wordpress.com/2011/06/sciampetm.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="326" width="640" src="http://climatecrock.files.wordpress.com/2011/06/sciampetm.jpg" /></a></div><br />
And a sediment core sample showing the PETM:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://climatecrock.files.wordpress.com/2011/06/sedleftc.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="800" width="83" src="http://climatecrock.files.wordpress.com/2011/06/sedleftc.jpg" /></a></div><a href="http://www3.geosc.psu.edu/~lrk4/">Dr. Lee Kump</a>, one of the most renowned experts in the PETM, has written an article, <i><a href="http://www.scientificamerican.com/article.cfm?id=the-last-great-global-warming ">The Last Great Global Warming</a><i></i></i> for the July 2011 <i>Scientific American</i>. It makes sobering reading.<br />
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Some highlights from Dr. Kump's article:<br />
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<i>Until recently, though, open questions about the event have made predictions speculative at best. <b>New answers provide sobering clarity.</b> They suggest the consequences of the planet’s last great global warming paled in comparison to what lies ahead, and they add new support for predictions that humanity will suffer if our course remains unaltered.</i><br />
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<i>But what surprised us most was that this gas release was spread out over approximately 20,000 years—a time span between twice and 20 times as long as anyone has projected previously. <b>That lengthy duration implies that the rate of injection during the PETM was less than two petagrams a year—a mere fraction of the rate at which the burning of fossil fuels is delivering greenhouse gases into the air today. </b>Indeed, CO2 concentrations are rising probably 10 times faster now than they did during the PETM.</i><br />
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<i>But what surprised us most was that this gas release was spread out over approximately 20,000 years—a time span between twice and 20 times as long as anyone has projected previously. That lengthy duration implies that the rate of injection during the PETM was less than two petagrams a year—a mere fraction of the rate at which the burning of fossil fuels is delivering greenhouse gases into the air today. <b>Indeed, CO2 concentrations are rising probably 10 times faster now than they did during the PETM.</b></i><br />
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<i>Species extinctions are on the rise, and shifting climate zones have already put surviving plants and animals on the move, often with the disease-bearing pests and other invasive species winning out in their new territories. <b>Unlike those of the PETM, modern plants and animals now have roads, railways, dams, cities and towns blocking their migratory paths to more suitable climate. These days most large animals are already penned into tiny areas by surrounding habitat loss; their chances of moving to new latitudes to survive will in many cases be nil.</b></i><br />
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<i>Current global warming is on a path to vastly exceed the PETM, but it may not be too late to avoid <b>the calamity that awaits us</b>. To do so requires immediate action by all the nations of the world to reduce the buildup of atmospheric carbon dioxide—and to ensure that the Paleocene-Eocene Thermal Maximum remains the last great global warming.</i><br />
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I have to disagree with Dr. Kump in the last extract from his article. Calamity <i>does</i> await us. The scientific community has known for almost 50 years that our fossil fuel emissions will warm the atmosphere. And yet next to nothing has been done. During the 1970s we had our best chance of limiting fossil fuel emissions during the first energy crisis. We made some cosmetic changes, but no real reforms. During the 1980s we slept through the soothing lullaby of the Reagan administration's neglect of environmental issues. During the 1990s Clinton triangulated away any meaningful environmental and energy reforms, and failed to provide any leadership on the <a href="http://en.wikipedia.org/wiki/Kyoto_protocol">Kyoto Protocol</a>. The second Bush administration's hostility to environmental and energy reforms has been told in many long accounts, and requires no further comment by me.<br />
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And now we have Tea Party fanatics who would rather send the Earth straight to hell than acknowledge scientific reality, blocking any reforms to increase energy efficiency, or environmental protection. The Tea Party fanatics even want to reduce study and research about Global Warming! <br />
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We've never missed an opportunity to miss an opportunity. <br />
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I don't see how we can avoid calamity. It's not just the USA--cheap, carbon rich coal is powering the development of China--lip service is paid there to global warming, and <a href="http://en.wikipedia.org/wiki/Greenwashing">greenwashing </a>in China may be more prevalent than in any other country. India, South America, and even Africa are expanding their fossil fuel consumption rapidly. Coal is cheap, almost everywhere, and the worst thing we can consume. Short term thinking conquers all. <br />
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It makes me sad. I live on a beautiful barrier island, <a href="http://sherpaguides.com/georgia/coast/southern_coast/st_simons_island.html">St. Simons Island</a> with my partner. It is beautiful, a great place to grow up and a great place to live.<br />
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By 3000 CE, all of this will be gone. My house and island will be under a warm, acid sea, so deep that the sun will be only faintly visible. Rising to the surface, no land will be visible. The same will be true for land where billions of people live now, and where billions get their crops and foodstuffs from. And we're doing nothing to stop it. And with the current trajectory of carbon emissions, and our refusal to face the situation squarely, the remaking of our fair planet into an acidic, hot, steambath of a world seems inevitable.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com26tag:blogger.com,1999:blog-3318930696739797298.post-6295446620891978822011-06-15T16:58:00.000-07:002011-07-02T12:20:11.416-07:00New Maunder Minimum? Don't Count on it!<!-- Place this tag in your head or just before your close body tag --><br />
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There's been a lot of loose talk in the past couple days about a new <a href="http://en.wikipedia.org/wiki/Maunder_minimum">Maunder Minimum</a> that will save us from the consequences of our greenhouse gas emissions. Would that were true. Even if a new Maunder Minimum does happen, the radiative forcing by additional carbon dioxide will overwhelm the effects of a reduction in solar activity, even a prolonged and deep one.<br />
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A NASA image of the Maunder Minimum:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://solarscience.msfc.nasa.gov/images/ssn_yearly.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="226" width="600" src="http://solarscience.msfc.nasa.gov/images/ssn_yearly.jpg" /></a></div><br />
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Andrew Rivkin writes about this latest <i>deus ex machina</i> <a href="http://dotearth.blogs.nytimes.com/2011/06/15/a-solar-scientist-rebuts-a-cool-sunspot-prediction/">here</a>.<br />
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Dr. Doug Biesecker, the head of NOAA's sunspot team, has created a slideshow presentation <a href="http://www.slideshare.net/Revkin/why-there-is-no-evidence-for-a-new-maunder-minimum-8318340">here</a>.<br />
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And Dr. Biesecker has written up a report "<i><a href="https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B88iFXWgVKt-NzU0Y2I3M2QtNGNkNS00ZTcyLWIxN2UtOWEwMzNmOTMzOTAx&hl=en_US">Predicting Solar Cycle 25</a></i>" which goes into further detail.<br />
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An article about the case for a second Maunder Minimum, from <i>The Economist</i>, a source I generally find credible, is <a href="http://www.economist.com/node/18833483?story_id=18833483">here</a>.<br />
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Richard Black of the BBC also has an interesting take on the possibility of a Maunder Minimum II and its effects <a href="http://www.bbc.co.uk/news/science-environment-13792479">here</a>.<br />
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The main issue is that even if a new Maunder Minimum does occur, it will offset only a small part of the radiative forcing of the additional carbon dioxide in the atmosphere. Estimates of the reduction of solar radiation during the Maunder Minimum are on the order of 1 watt/square meter. But the radiative absorption by carbon dioxide and other greenhouse gases is already almost 2 watts/square meter, and will be around 9 watts/square meter by 2100. A Maunder Minimum II would slow global warming slightly, but not stop it.<br />
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I hope Maunder Minimum II does take place. It would be helpful. And give us some breathing room for enacting reforms in energy consumption and protecting the environment in ways to slow down global warming further.<br />
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Unfortunately, our political and business history shows that even if a new Maunder Minimum takes place, we will squander the opportunity and declare the problem solved. Humanity has never faced the global warming problem squarely in the past, and I hardly expect it will do so now. And when the sun resumed its normal radiative output, global warming will quickly become catastrophic.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com5tag:blogger.com,1999:blog-3318930696739797298.post-15177220253585068852011-06-14T11:55:00.000-07:002011-06-14T12:31:43.281-07:00Atmospheric Carbon Dioxide hits new record; the rise's acceleration.Atmospheric carbon dioxide hit a new all time record at the Mauna Loa observation site, as it has in <i>every</i> May since observations began. 394.15 ppm, on track to hit 400 ppm in spring 2014. Recent graph below:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_trend_mlo.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="459" width="594" src="http://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_trend_mlo.png" /></a></div><br />
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Carbon dioxide's rate of increase in the atmosphere has increased during every decade of record, except for the 1990s, when it was slowed by the effects of Mount Pinatubo's eruption in 1991. The 2000s show a continuing acceleration, making up for the slowdown of the 1990s. The rate of acceleration is about 0.3 ppm faster for each year per decade. It is very disturbing. <br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_data_mlo_anngr.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="459" width="594" src="http://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_data_mlo_anngr.png" /></a></div><br />
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Finally, arctic sea ice is melting very rapidly. It is too early to say that it will reach a new record lowest summer minimum this September, but it is behaving as it would were it to reach a new minimum this year.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="504" width="630" src="http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png" /></a></div><br />
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And I love Mike Luckovich's cartoons. Especially this one:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://blogs.ajc.com/mike-luckovich/files/2011/06/mike061220111.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="462" width="600" src="http://blogs.ajc.com/mike-luckovich/files/2011/06/mike061220111.jpg" /></a></div>StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com0tag:blogger.com,1999:blog-3318930696739797298.post-71651707547548488702011-06-11T14:19:00.000-07:002011-06-11T14:19:27.872-07:00Global warming since 1995 'now significant'A story with powerful conclusions in updated data--global warming is REAL. And the trend since 1995 is undeniable (except by the simple-minded and dishonest).<br />
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<a href="http://www.bbc.co.uk/news/science-environment-13719510">The story, with links to relevant reports included:</a>StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com1tag:blogger.com,1999:blog-3318930696739797298.post-45722635642405296232011-05-30T13:06:00.000-07:002011-06-05T12:50:13.379-07:00The Causes of Climate Change conference--Boulder, CO 1965Are human technology and activities forces of geophysical scope, capable of affecting the entire planet Earth? Surely not, thought most earth scientists in 1940. But a quarter century later, the consensus was beginning to shift. Several factors were involved in this shift. First of all, unprecedented economic growth. As I noted previously, during the first half of the 20th century, continuous, exponential economic growth was not a given. Two world wars and the Great Depression had interrupted economic growth in many developed countries. In 1950, industrial output was lower than 1913 in several major economic powers, such as Germany, France, and Japan. The Soviet Union and the United Kingdom were not much better. True, the USA had more than tripled its industrial production during that period. <br />
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Many scientists in the 1940s and 1950s assumed that carbon dioxide emissions would remain relatively constant. Gilbert Plass assumed that humankind's carbon dioxide emissions would be a flat 6 billion tons annually. (The IEA released a report on May 30, 2011 that humankind's carbon dioxide emissions soared past <i>30</i> billion tons for the first time in 2010, <i><a href="http://www.iea.org/index_info.asp?id=1959">q.v.</a></i>).<br />
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By 1965, humankind's carbon dioxide emissions were greater than 12 billion tons annually, and rising by more than half a billion tons per year. The assumption that carbon dioxide emissions would remain relatively low was incorrect.<br />
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Second, the work of Drs. <a href="http://en.wikipedia.org/wiki/Roger_Revelle">Roger Revelle</a> and <a href="http://en.wikipedia.org/wiki/Gilbert_Plass">Gilbert Plass</a> showed that the oceans would not, <b>could not</b>, absorb all of humankind's carbon dioxide emissions, and that additional carbon dioxide <i>would</i> increase absorption of infrared radiation. <br />
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And then, <a href="http://en.wikipedia.org/wiki/Charles_Keeling">Dr. Charles Keeling</a> proved through his meticulous measurements of atmospheric carbon dioxide, and his isotopic analysis, that humankind's activities <i>were</i> increasing carbon dioxide in the atmosphere. During the first couple years of his measurements, it was postulated by some scientists that there could be a natural cycle that causes carbon dioxide concentrations to fluctuate, and it was <i>possible</i> that he was observing the uptrend of a natural cycle. And in fact there is such a natural cycle---the ENSO cycle does cause carbon dioxide concentrations to fluctuate by a few parts per million. But as carbon dioxide concentrations continued to rise each year, by 1962/1963 there was no possible doubt. Atmospheric carbon dioxide concentrations were rising, and humankind was responsible. For the past 50 years, no serious scientist has doubted that.<br />
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This graph shows the Keeling measurements for atmospheric carbon dioxide from 1958-1966. I would have preferred a 1958-1965 graph to dovetail with what the scientists at the "Causes of Climate Change" conference knew, but it is close enough for my blog, and the trend was clear:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.aip.org/history/climate/images/keeling-71-sm.gif" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="564" width="560" src="http://www.aip.org/history/climate/images/keeling-71-sm.gif" /></a></div><br />
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Although the conference was organized by Dr. Revelle, the inspiration for it happened in 1963 Dr. Revelle had a conversation with astrophysicist and atmospheric physicist <a href="http://en.wikipedia.org/wiki/Walter_Orr_Roberts">Dr. Walter Orr Roberts</a>m who founded the <a href="http://en.wikipedia.org/wiki/Walter_Orr_Roberts">National Center for Atmospheric Research</a> in 1960. Dr. Roberts pointed out the aircraft contrails in the sky early one morning, and said that they would be indistinguishable from natural cirrus clouds in a few hours. They had a morning meeting, and when it broke for lunch, Dr. Revelle and Dr. Roberts went outside and could see the contrails from earlier, smearing out. By the time they finished lunch, the contrails looked just like cirrus clouds. Dr. Roberts wondered if adding cirrus clouds to the atmosphere could change the climate. Dr. Revelle wondered too.<br />
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The National Center for Atmospheric Research. The futuristic buildings served as a set for the comedy classic <i>Sleeper</i>, directed and written by <a href="http://en.wikipedia.org/wiki/Woody_Allen">Woody Allen</a>.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/wikipedia/commons/thumb/3/31/National_Center_for_Atmospheric_Research_-_Boulder%2C_Colorado.jpg/800px-National_Center_for_Atmospheric_Research_-_Boulder%2C_Colorado.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="450" width="600" src="http://upload.wikimedia.org/wikipedia/commons/thumb/3/31/National_Center_for_Atmospheric_Research_-_Boulder%2C_Colorado.jpg/800px-National_Center_for_Atmospheric_Research_-_Boulder%2C_Colorado.jpg" /></a></div><br />
Also in 1963, <a href="http://en.wikipedia.org/wiki/Reid_Bryson">Dr. Ried Bryson</a> (1920-2008), meteorologist and geologist, and one of the few scientific opponents to anthropogenic global warming, noticed on a flight across India to a scientific conference noticed that although the sky was cloudless, he could not see the ground, with all the smoke from brush and cooking fires. He noticed similar hazes in Brazil and sub-Saharan Africa. Dr. Bryson thought that <a href="http://en.wikipedia.org/wiki/Global_dimming"><i>global dimming</i></a> would trigger global cooling--and that was the major threat that humankind's activities would have on the environment, a view that influenced <a href="http://en.wikipedia.org/wiki/Issac_Asimov">Dr. Isaac Asimov</a> (1920-1992) during the 1960s and 1970s.<br />
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During the last few years of his life, Dr. Bryson revised his views and concluded that global warming from the greenhouse gases humankind emits are the greater threat.<br />
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An aside on global dimming. It is a legitimate scientific viewpoint, and in fact during the 1950s and 1960s, the rise in global temperatures did pause, and increased pollution in the industrialized countries coupled with increases in tropical haze from cooking fires and brush fires and fires set to clear forest land may have had enough of an impact to blunt the rise in global temperature. Since the 1970s, increased pollution controls in the most advanced countries coupled with the relentless rise in concentrations of atmospheric carbon dioxide have clearly overwhelmed any cooling effect from aerosols in the atmosphere which promote global cooling.<br />
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To save time and effort, I am not going to go into every scientist that attended the conference, or go into everyone's theories or what they said. The main purpose of the Boulder conference, at least officially, was to discuss the mechanisms of natural climate change.<br />
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Until the 1950s, it had been believed that there were four major ice ages over the past 2 million years. And this viewpoint persisted in most of the general scientific community until the 1970s. In fact, the four ice ages are referred to in <a href="http://en.wikipedia.org/wiki/Arthur_C._Clarke">Dr. Arthur C. Clarke's</a> novel <a href="http://en.wikipedia.org/wiki/2001:_A_Space_Odyssey_%28film%29">2001: A Space Odyssey</a> (1968). [There are not many references to the novel, which was released in July 1968. There are many references to the film, of course.] This went with the reassuring <a href="http://en.wikipedia.org/wiki/Uniformitarianism">uniformitarian</a> mindset that typified earth science studies from the time of geologist <a href="http://en.wikipedia.org/wiki/James_Hutton">Dr. James Hutton</a> to the mid 20th century. Over the past 50 years, the realization that changes in the Earth's environment can be sudden and far reaching has led to a more <a href="http://en.wikipedia.org/wiki/Catastrophism">neo-catastrophism</a> mindset, of which the extinction of the dinosaurs by the impact of a comet/asteroid is the most prominent example.<br />
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Discoveries in the 1950s lead to the realization that ice ages and interglacials were far more frequent--more than 20 glaciations were identified by 1965, although this new knowledge took a long time to diffuse into the general scientific community. This work had been done by Drs. Harold Urey and Cesare Emiliani (<a href="http://en.wikipedia.org/wiki/Catastrophism">q.v.</a>) Their discoveries also indicated that climate change could have been rapid, although this discovery was resisted. However, in the early 1960s, work by <a href="http://en.wikipedia.org/wiki/Wallace_Smith_Broecker">Dr. Wallace Smith Broecker (Wally)</a> (1931-) on ancient tropical corals also showed evidence that climate could change rapidly. [Dr. Broecker will be the subject of a forthcoming blog entry.] Also, <a href="http://en.wikipedia.org/wiki/Edward_Lorenz">Dr. Edward Lorenz</a> (1917-2008) discussed his work on computer simulations of weather patterns, which was proving to be chaotic. Dr. Lorenz wondered whether climate states could also prove to be chaotic.<br />
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The implications were becoming clear. Climate had changed more rapidly in the past than had been believed before. Most of the scientists who attended the Boulder Conference on Climate Change were convinced of that by the time the conference was over. But it took a long time for this new consensus to diffuse into the general scientific community. To use an analogy, the discoveries of the 1950s had planted the seed of the possibility of rapid climate change. The 1965 conference was when the seed sprouted.<br />
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The work by Dr. Charles Keeling (<a href="http://stsimonsislandgaguys.blogspot.com/2011/05/charles-david-keeling.html">q.v.</a>) had shown definitively by 1965 that humankind's activities were measurably and significantly increasing the amount of atmospheric carbon dioxide. Dr. Gilbert Plass had overthrown the old belief that increases in atmospheric carbon dioxide would not increase the amount of infrared radiation trapped by the atmosphere---additional atmospheric carbon dioxide clearly would. So would humankind's carbon dioxide emissions trigger a sudden change in the Earth's climate? That question left the attendees of the Boulder conference uneasy.<br />
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The minutes of the conference published in 1966 contain this interesting statement: "We are just now beginning to realize that the atmosphere is not a dump of unlimited capacity but we do not yet know what the atmosphere's capacity is"*<br />
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*National Academy of Sciences, Committee on Atmospheric Sciences Panel on Weather and Climate Modification, <i>Weather and Climate Modification: Problems and Prospects</i>. 2 vols. (Washington, D.C., National Academy of Sciences, 1966), col. 1, p. 10.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com11tag:blogger.com,1999:blog-3318930696739797298.post-82465487419991792402011-05-25T11:53:00.000-07:002011-05-30T13:44:32.773-07:00Charles David Keeling<a href="http://en.wikipedia.org/wiki/Charles_Keeling">Dr. Charles David Keeling</a> (1928-2005) was the giant of the 20th century in atmospheric carbon dioxide studies. It was his single-mindedness that established continuous carbon dioxide monitoring. Without him, it might have been decades more before continuous carbon dioxide monitoring was established.<br />
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Dr. Charles Keeling was born in Scranton, PA on April 20, 1928. A precocious child, he obtained his B.S. in chemistry from the <a href="http://en.wikipedia.org/wiki/University_of_Illinois_at_Urbana-Champaign">University of Illinois</a> in 1948 at age 20, and earned his PhD in chemistry from <a href="http://en.wikipedia.org/wiki/Northwestern_University">Northwestern University</a> in 1954.<br />
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Dr. Keeling had many interests---he was an accomplished piano player and loved hiking and camping in the mountains of California, when he moved he moved after obtaining his doctorate. He was a postdoctorate fellow in geochemistry at the <a href="http://en.wikipedia.org/wiki/California_Institute_of_Technology">California Institute of Technology</a> from 1954-1956, where he developed new instruments which for the first time could measure carbon dioxide in the atmosphere in parts per billion. His instruments were later supplanted by the <a href="http://en.wikipedia.org/wiki/Electron_capture_detector">electron capture dectector</a> invented by <a href="http://en.wikipedia.org/wiki/James_Lovelock">Dr. James Lovelock</a> in 1957, which was adopted worldwide for sampling in the 1960s. <br />
In 1956 he was invited to join the <a href="http://en.wikipedia.org/wiki/Scripps_Institution_of_Oceanography">Scripps Institution of Oceanography</a> by <a href="http://en.wikipedia.org/wiki/Roger_Revelle">Dr. Roger Revelle</a> <a href="http://stsimonsislandgaguys.blogspot.com/2011/04/roger-revelle-work-and-what-it-shows.html">(q.v.)</a><br />
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Dr. Revelle said about Dr. Keeling "He's a peculiar guy. He wants to measure CO2 in his belly...and he wants to measure it with the greatest precision and the greatest accuracy he possibly can.". Keeling had taken his instruments to sites in the Sierra mountains, but there were problems. When the wind shifted so that the sites were downwind of major cities like San Francisco and Sacramento, the concentrations rose sharply. What Dr. Keeling needed was a pristine site, thousands of miles away from large cities and industrial concentrations. <br />
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The 1950s and 1960s were a golden age for scientific research. The impetus of the Cold War, and unprecedented prosperity and rising wealth stimulated large and increasing research budgets. The <a href="http://en.wikipedia.org/wiki/International_Geophysical_Year">International Geophysical Year of 1957-1958</a> (IGY) further augmented research budgets. Climate change, much less anthropogenic global warming, was not a big priority with the IGY, but Dr. Revelle made funds available for Dr. Keeling to make his carbon dioxide observations at the <a href="http://en.wikipedia.org/wiki/Mauna_Loa_Observatory">Mauna Loa Observatory</a>, beginning March 1, 1958. Dr. Keeling also supervised a carbon dioxide sampling program from the new Antarctic bases established during the IGY. <br />
Mauna Loa was an ideal site for Dr. Keeling's measurements. It was far from any population concentration, and the site being over 11,000' in elevation placed it above the inversion in the atmosphere that separates the low level moist trade winds from the middle levels of the atmosphere, reducing anthropogenic influences even further. <br />
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Continuous carbon dioxide monitoring was a new idea. Before discussing it with Dr. Keeling, Dr. Revelle had envisioned sampling carbon dioxide at various pristine sites around the world during the IGY, and then a new sample program comparing the IGY readings to observations made during a subsequent sampling program ~ 20 years later, say in 1980. And the Antarctic observations were dropped in the year or two after the IGY. Scientific research budgets were large and rising, but not unlimited, and atmospheric carbon dioxide measurements were not the highest priority. And as we shall see, there were serious threats to cut off the Mauna Loa measurements in the 1960s, before the importance of the measurements was fully appreciated by the scientific community.<br />
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Dr. Keelings measurements soon showed that carbon dioxide <i>was</i> accumulating in the atmosphere. Dr. Revelle had been proven correct--the buffer mechanism he had proposed that prevented the oceans from absorbing all the CO2 humankind was emitting was making a measurable difference in atmospheric concentrations!<br />
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Dr. Keeling published his preliminary findings in the June 1960 of <i>Tellus</i> in the article "<i><a href="http://docs.google.com/viewer?a=v&q=cache:jAAKtss1zb8J:sio.ucsd.edu/special/Keeling_50th_Anniversary/images/keelling_tellus_1960.pdf+the+concentration+and+isotopic+abundances+of+carbon+dioxide+in+the+atmosphere&hl=en&gl=us&pid=bl&srcid=ADGEESiICEfOaeJ5oE4NY90UZ8NnZaNi8cC6BlSuRQH272-gJ5WOcCKq2cEORkSsMNINAW44zeTdEjgLWmqGzJzf5w_yxSaPV9ddbnB6j3BRkzLAjSimKUPzsIEA7p8-vOXY5TfTaewk&sig=AHIEtbRPzn_JVutv79CCQU2te91m41WSCQ&pli=1">The Concentration and isotopic abundances of carbon dioxide in the atmosphere</a></i>" This article contains the graph I embedded below:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://i609.photobucket.com/albums/tt179/johnttucker/1960.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="251" width="464" src="http://i609.photobucket.com/albums/tt179/johnttucker/1960.png" /></a></div><br />
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Two years wasn't much though. After all, there could be some sort of atmospheric cycle going on. Today we know that is ridiculous, and we can safely dismiss the denier cranks who make that argument, but 50 years ago it was still a reasonable position. Dr. Revelle continued funding Dr. Keeling's carbon dioxide measurement program, but outside events intervened. A stock market 'crash' in the spring of 1962 wiped out more than a quarter of stocks' value---the market soon recovered, but there was a disruption to the Scripps Institution's endowment. Also in the early 1960s there was a sort of pause in the growth of budgets for scientific research, and increasing amounts were being absorbed by NASA. There were waves of growth in scientific research funding in the late 1950s and the mid 1960s, but the early 1960s saw something of a pause. And most important of all, no research agency considered Dr. Keeling's carbon dioxide measurements truly compelling---the measurements were interesting, yes, but not enough for an agency or institution to fund themselves. And the Mauna Loa Observatory was relatively isolated---an advantage in obtaining pristine atmospheric carbon dioxide measurements---but a disadvantage in that it was expensive to supply and operate.<br />
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Dr. Revelle was able to divert some funding to keep Dr. Keeling's measurement program going through 1963, and by late in that year had some promising indications of permanent funding from the <a href="http://www.nsf.gov/">National Science Foundation</a>. (NSF) But in January 1964 the money ran out. Carbon dioxide measurements at Mauna Loa Observatory stopped.<br />
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This triggered a reaction in the scientific community--Dr Keeling's carbon dioxide series was suddenly appreciated much more in its absence!--and the NSF quickly approved permanent funding. After a 3 month hiatus in February, March, and April 1964, the Mauna Loa measurement program was resumed on May 1, 1964, and has continued to the present day.<br />
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As I said before, some scientists looked at the first 2 years of data from the Antarctic stations and Mauna Loa with legitimately skeptical eyes. The <a href="http://en.wikipedia.org/wiki/ENSO">ENSO</a> cycle was not well known 50 years ago (which does affect carbon dioxide concentrations in the atmosphere, particularly in the Pacific), but a cycle was plausible. However, as the measurement program went on, and carbon dioxide continued to increase its concentration in the atmosphere every year, such skepticism, never widely held, fell by the wayside. Since the mid 1960s, no reputable meteorologist, climate scientist, or physicist has denied that humankind's emissions are driving the atmospheric carbon dioxide increase. By the mid 1960s, the increase was undeniable. The following graph shows how carbon dioxide concentrations were increasing through the mid 1960s.<br />
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Note the funding hiatus in 1964. Mind the gap!<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.aip.org/history/climate/images/keeling-71-sm.gif" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="564" width="560" src="http://www.aip.org/history/climate/images/keeling-71-sm.gif" /></a></div><br />
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The importance of Dr. Keeling's measurements of atmospheric carbon dioxide cannot be overstated. Dr. Revelle showed that the oceans would not absorb all the carbon dioxide humankind emitted. Dr. Plass proved that increases in the concentration of carbon dioxide in the atmosphere would increase infrared radiation absorption. And Dr. Keeling proved that carbon dioxide concentrations were increasing, in a measurable and significant amount. As these facts disseminated through the scientific community, the scientific consensus swung decisively to the reality of anthropogenic global warming by the mid 1960s, and has remained so.<br />
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An aside here---it is frequently asserted by deniers that meteorologists and climate scientists believed in global cooling in the 1970s. This is utterly false. <a href="http://www.newscientist.com/blogs/shortsharpscience/2008/10/global-cooling-was-a-myth.html">An analysis of peer-reviewed articles on future climate change from the period 1965-1979 shows that predictions of anthropogenic global warming outnumber predictions of anthropogenic global cooling by more than 6 to 1 (specifically 44 to 7).</a><br />
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Whenever a denier claims that the scientific community was predicting global cooling in the 1970s, that denier is either ignorant, or deliberately lying.<br />
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Dr. Keeling was concerned enough about rising carbon dioxide levels to participate in a panel by the Conservation Foundation on March 12, 1963 "<i><a href="http://openlibrary.org/books/OL5752181M/Implications_of_rising_carbon_dioxide_content_of_the_atmosphere">Implications of Rising Carbon Dioxide Content of the Atmosphere</a></i>", the report issued being among the first to speculate that anthropogenic global warming could be dangerous to the Earth's biological and environmental systems. It includes on page 6: "many life forms would be annihilated" [in the tropics] if emissions continued unchecked in the upcoming centuries. They also projected that carbon dioxide emissions could raise the average surface temperature of the earth by as much as 4°C during the next century (1963-2063)<br />
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Rising concern was also brought forth in 1965 when the President's Science Advisory Committee formed a panel to address environmental issues, including a climate change sub-panel. The 1965 meeting and report of this panel will be the subject of a future blog entry. <br />
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Dr. Keeling did have a monomania concerning carbon dioxide, but it was a <i>productive</i> monomania. Dr. Keeling was made professor of oceanography at the Scripps Institute in 1968, and received many honors for his scientific work. A short list of some of the honors he received:<br />
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Second Half Century Award of the American Meteorological Society, 1981<br />
Maurice Ewing Medal of the American Geophysical Union, 1991<br />
Blue Planet Prize from the Science Council of Japan and the Asahi Foundation, 1993<br />
<a href="http://en.wikipedia.org/wiki/National_Medal_of_Science">National Medal of Science</a>, by George W. Bush in 2002<br />
<a href="http://www.usc.edu/admin/provost/tylerprize/about.html">Tyler Prize for Environmental Achievement</a> in 2005 (shared with <a href="http://en.wikipedia.org/wiki/Lonnie_Thompson">Lonnie Thompson</a>)<br />
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Dr. Keeling married Louise Barthold in 1955, and they had 5 children. One of whom, Dr. Ralph Keeling, is a climatologist at the Scripps Institute himself, following in his father's footsteps. <a href="http://scrippsco2.ucsd.edu/personnel/ralph_keeling.html">Dr. Ralph Keeling is the current director of the Scripps CO2 Program.</a><br />
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Dr. Keeling was a lifelong Republican, of a type we don't see much of anymore--a Republican with a strong concern for the environment and science. Dr. Keeling deeply regretted and was disappointed by the politicization of science, and the abandonment of science by the large parts of the Republican party during the last two decades of his life. When ideology and scientific fact conflict, it should be the ideology that changes--because the facts will not. Dr. Keeling continued his measurements of carbon dioxide until he died of a heart attack on June 20, 2005.<br />
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A picture of Dr. Charles Keeling in 1997:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.esrl.noaa.gov/gmd/obop/mlo/programs/coop/scripps/img/img_scripps_Keeling97.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="404" width="600" src="http://www.esrl.noaa.gov/gmd/obop/mlo/programs/coop/scripps/img/img_scripps_Keeling97.jpg" /></a></div><br />
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Here is the latest Keeling Curve, with the full record of carbon dioxide levels in the atmosphere: <br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_data_mlo.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="612" width="792" src="http://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_data_mlo.png" /></a></div><br />
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A report released today (May 30, 2011) by the IEA <a href="http://www.iea.org/index_info.asp?id=1959">reports that our CO2 emissions reached a new record in 2010, 30.6 billion tons</a>. CO2 emissions in 2010 were 5% higher than the previous record in 2008.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com13tag:blogger.com,1999:blog-3318930696739797298.post-3884070248381102992011-05-17T13:45:00.000-07:002011-05-17T13:49:13.837-07:00A striking image of arctic sea ice concentrations in 2007I thought this deserved it's own entry. I wonder how this year will shape up? Arctic sea ice has been falling <i>very</i> rapidly so far in May, but it's too early to say if arctic sea ice will reach a record low this year.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/wikipedia/commons/2/2e/IICWG_Arctic_Chart_2007_H.gif" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="640" width="631" src="http://upload.wikimedia.org/wikipedia/commons/2/2e/IICWG_Arctic_Chart_2007_H.gif" /></a></div><br />
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Plus a couple of news stories I found interesting:<br />
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<a href="http://www.bbc.co.uk/news/science-environment-13423085">Murky exoplanet 'could host life'</a><br />
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<a href="http://www.bbc.co.uk/news/science-environment-13415890">Human arrival 'wiped out' Hawaii's unique crabs</a>StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com3tag:blogger.com,1999:blog-3318930696739797298.post-23636835618370810772011-05-13T18:30:00.000-07:002011-05-17T18:54:32.303-07:00Gilbert Norman Plass<a href="http://en.wikipedia.org/wiki/Gilbert_Plass">Dr. Gilbert Norman Plass</a> (1920/21/22-2004) was the last scientist before Charles Keeling to make important contributions to the study of global warming. He was a Canadian physicist, who obtained his PhD at John Hopkins, and not a climatologist or meteorologist. But it was the publication of his insight into the the reality that increases in carbon dioxide in the atmosphere <i>would</i> increase infrared radiation absorption and global surface temperatures, along with <a href="http://en.wikipedia.org/wiki/Roger_Revelle">Roger Revelle's</a> work on the oceanic chemistry of carbon dioxide, and Charles Keeling's measurements proving that carbon dioxide was increasing in the atmosphere that established the scientific consensus that humankind's activities could and would warm the climate of the Earth.<br />
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Back at the end of the 19th century, <a href="http://en.wikipedia.org/wiki/Svante_Arrhenius">Svante Arrhenius</a> made his famous proposal of anthropogenic global warming. But although a few lonely scientists believed him and carried on research in anthropogenic global warming, <a href="http://en.wikipedia.org/wiki/Knut_%C3%85ngstr%C3%B6m">Knut Johan Ångström</a> carried out experiments in laboratory conditions that appeared to show that carbon dioxide was saturated as an infrared absorber. These experiments were done near sea level, with the higher temperatures and humidity of sea level air. Dr. Plass wondered about the absorption of infrared radiation by carbon dioxide at greater altitudes in the atmosphere, and what increases in carbon dioxide would mean.<br />
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A huge hint that Ångström's experiments with carbon dioxide's infrared absorption were not correct had been noted as early as 1890---and yet was ignored. <a href="http://en.wikipedia.org/wiki/Frank_Washington_Very">Frank Washington Very</a> and <a href="http://en.wikipedia.org/wiki/Samuel_Pierpont_Langley">Samuel Pierpont Langley</a> had carried out infrared astronomy for the moon beginning in 1890, and noted that more infrared radiation from the moon was observed when it was near its zenith than when it was near the horizon. These observations <b>proved</b> that carbon dioxide was not saturated in terms of absorbing infrared radiation--it it were, then the absorption of infrared radiation would be the same no matter what altitude above the horizon the moon was. Amazingly, Arrhenius and all climate scientists seemed to have remained unaware of Very and Langley's work for more than 60 years!<br />
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Gilbert Plass was either born in1 1920, 1921 or 1922 (my sources disagree) in Toronto and quickly showed strong aptitudes for math and science. After scoring a 168 on an IQ test and having it confirmed, he was allowed to skip years in HS and the government of Canada paid for his education at Harvard where he graduated with a BS in physics in 1941, and earned his doctorate in physics from Princeton in 1947.<br />
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After World War II, as part of the United States' rapidly expanding scientific research, the <a href="http://en.wikipedia.org/wiki/Office_of_Naval_Research">Office of Naval Research</a>. Much of this research was esoteric---who knew what kind of scientific discoveries were to be made, and what impact they could have! The 30 years after World War II were a time when government institutions and Bell Labs supported pure scientific research, and allowed research scientists to follow their own muses, unlike today's more commercial research climate (no pun intended). <br />
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The Office of Naval Research was interested in absorption of infrared radiation in the atmosphere as it related to heat-seeking missiles and other weaponry. Beginning in the late 1940s, observations at the <a href="http://en.wikipedia.org/wiki/Qaanaaq">Thule</a> (now named Qaanaaq) base in the northwest part of Greenland suggested strongly that variations in carbon dioxide strongly changed absorption of infrared radiation by carbon dioxide. Dr. Plass was a physicist, not a climatologist or meteorologist. However, he was aware of the scientific consensus that carbon dioxide was saturated as an infrared radiation absorber. What if this was not the case?<br />
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Dr. Plass was curious about this, and worked on his own time to see if carbon dioxide was really saturated as an infrared absorber. From observations at arctic bases and at high altitude flights were missile tests were conducted, he concluded that it was not. But concluding this was one thing, <i>proving</i> it was another.<br />
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In 1953 Dr. Plass moved from Canada to southern California to work with Lockheed on missile testing and guidance. And for the first time he had access to a computer. As a competent physicist, Dr. Plass knew how to craft programs to analyze the absorption of infrared radiation by carbon dioxide using <a href="http://en.wikipedia.org/wiki/Quantum_mechanics">quantum mechanics</a>. Without a computer, he would never have been able to make the calculations. Dr. Plass felt confident enough in his belief that our carbon dioxide emissions would warm the Earth's climate that in 1953 <a href="http://www.time.com/time/magazine/article/0,9171,890597,00.html?promoid=googlep">he contributed to an article in Time magazine saying so</a>. But the computers of the 1950s were balky and slow, and he had to do his research on his own time. So it took him more than 2 years to mathematically <b>prove</b> that infrared absorption was not saturated at current levels of carbon dioxide in the atmosphere. <br />
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Dr. Plass published his work in the July 1956 issue of <a href="http://www.americanscientist.org/">American Scientist</a>. Dr. Plass made some errors that oddly enough, cancelled each other out. Dr. Plass underestimated the amount of carbon dioxide humankind was emitting into the atmosphere---he gave a figure of 6 billion tons. We now know it was 8.8 billion tons in 1956. Dr. Plass also overestimated the radiative forcing of additional carbon dioxide in the atmosphere. Dr. Plass estimated that a doubling of carbon dioxide in the atmosphere would yield a radiative forcing of 8.3 watts per square meter under clear conditions, and of 5.8 watts per square meter under cloudy conditions. He only had observational from a few arctic bases and brief airborne tests piggybacking on missile testing. The explosion in the earth sciences generated by the <a href="http://en.wikipedia.org/wiki/International_Geophysical_Year">1957-1958 International Geophysical Year</a>, in which high altitude observations were made in the Andes and Antarctica refined this to 4 watts per square meter, under both clear and cloudy conditions. These refinements came quickly---by 1960 all atmospheric physicists knew that a doubling of carbon dioxide would have the correct, 4 watts per square meter warming. And anyone who still goes by the Ångström experiments of 1901-1902 can be dismissed as an ignorant quack (it is amazing how much Ångström's experiments are <i>still</i> cited by deniers).<br />
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Dr. Plass's paper is summarized and discussed <a href="http://www.americanscientist.org/issues/feature/2010/1/carbon-dioxide-and-the-climate/1">here</a>.<br />
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Dr. Plass made several simplifying assumptions. He assumed no change in water vapor, and no change in absorption of carbon dioxide by the oceans---as I said he was not a climatologist or meteorologist, or oceanographer. He simply ignored feedbacks in his paper. He also assumed that humankind's carbon dioxide emissions into the atmosphere would remain constant at 6 billion tons per year (and as we know, it was already 8.8 billion tons in 1956.<br />
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Dr. Plass made some of these simplifying assumptions because of 'known unknowns'--he knew he was not qualified to assume how water vapor and other feedbacks would behave. Also, in the 1950s, while computers were beginning to be used in science, their power was extremely limited by today's standards. <br />
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The assumption that carbon dioxide emissions would remain constant seem more inexplicable. As I have discussed in previous blog entries, in the 1950s long-term economic growth on a planet-wide scale was not a given. Countries such as France, Germany, and Japan had lower industrial output in 1950 than in 1913. The United Kingdom and the Soviet Union were not much better. Yes by the mid 1950s the industrial output of the United States was more than triple its 1913 level, and so were Canada's and Australia's. But among those three, only the United States was emitting carbon dioxide at a globally significant level.<br />
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This seems amazing, when we consider than global carbon dioxide emissions more than doubled over the next 15 years. But scientists had no way to know that was going to happen--wars had set back economic growth on a generational scale twice in the recent past, and there was no reason to suppose that would not happen again. <br />
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Dr. Plass concluded that carbon dioxide could double over a century and raise global temperatures 1.5° C over the next century, a figure that agrees closely with the definitive <a href="http://www.atmos.ucla.edu/~brianpm/download/charney_report.pdf">Charney report of 1979</a>, which gives a 1.2 °C figure. Dr. Plass also concluded that known reserves of carbon-based fossil fuels would add enough CO2 to the atmosphere to warm the surface of the Earth by 7 °C (12.6 °F) by 3000 CE. At such a planetary average surface temperature, the Greenland and West Antarctic ice sheets would be gone, and the East Antarctic ice sheet would be going.<br />
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I must repeat here that Dr. Plass was not a climatologist or meteorologist. He did not try to compute feedbacks such as decreasing albedo or increased water vapor in the atmosphere. He focused on the radiative properties of CO2 only.<br />
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During the 1960s, returning to his work on CO2 and the Earth's climate, he concluded that net feedbacks were positive, and that each doubling of CO2 in the atmosphere would increase surface temperatures by 3.6 °C. <br />
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It has to be said that Dr. Plass did not optimally research and craft his meteorology papers. His lack of some knowledge of meteorology led him to some errors---he tried to compute atmospheric properties and constants that had been solved by others, sometimes decades previously. And he made some mistakes. Today's research on climate feedbacks produce much larger increases in surface temperature.<br />
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But I must also repeat that Dr. Plass's proof that increased CO2 in the atmosphere increases infrared radiation absorption did hold. No meteorologist or climatologist denies that now. Not reputable ones.<br />
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Roger Revelle had shown how oceanic chemistry buffers prevent the oceans from absorbing all our carbon dioxide emissions. Plass had proven that carbon dioxide was not saturated in the atmosphere from an infrared radiation absorption standpoint. But were human activities really causing carbon dioxide to accumulate in the atmosphere? That question still remained.<br />
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And Charles Keeling was to definitively answer it. But that's for the next blog entry. <br />
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Here is a picture of Dr. Gilbert Plass:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://lightbucket.files.wordpress.com/2009/02/gilbertplass.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="602" width="420" src="http://lightbucket.files.wordpress.com/2009/02/gilbertplass.jpg" /></a></div><br />
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Dr. Plass left Lockheed in 1960 to join the research staff of Ford's aeronautical division. Dr. Plass also edited <i><a href="http://www.elsevier.com/wps/find/journaldescription.cws_home/525439/description#description">Infrared Physics and Technology</a></i>, a peer-reviewed scientific publication. Dr. Plass worked there until 1963, when he accepted a position as first professor of atmospheric and space sciences with the University of Texas at Arlington, where he remained for 5 years. In 1968 he joined the faculty of Texas A&M University, ultimately becoming head of the department of physics.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com4tag:blogger.com,1999:blog-3318930696739797298.post-56882972971506845262011-05-10T21:30:00.000-07:002011-05-13T13:19:13.495-07:00More entries soon!Taken a rest from my history of global warming studies blog, been organizing new entries in my head. But more entries are coming soon I promise!<br />
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In the meantime a cartoon by the 2010 Pulitzer prize winner for editorial cartoons, Mike Keefe:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.intoon.com/toons/2011/KeefeM20110508.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="374" width="600" src="http://www.intoon.com/toons/2011/KeefeM20110508.jpg" /></a></div><br />
And I like this new video, adding it back after the outage:<br />
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<iframe width="576" height="394" src="http://www.youtube.com/embed/LiYZxOlCN10?fs=1" frameborder="0" allowFullScreen=""></iframe><br />
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And...for the very first time on record, the concentration of CO2 exceeded 393 ppm at Mauna Loa, during April 2011. <br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_trend_mlo.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="459" width="594" src="http://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_trend_mlo.png" /></a></div><br />
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Which fits well with my new entry about Dr. Charles Keeling, coming soon!StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com6tag:blogger.com,1999:blog-3318930696739797298.post-71613633010762327042011-04-09T14:43:00.000-07:002011-04-23T12:47:39.286-07:00Roger Revelle' work and what it shows about the carbon budget.As we have seen from the previous blog entry, the buffering of the oceans works more efficiently the warmer the Earth is. In other words, the warmer the oceans, the quicker carbon dioxide is returned to the atmosphere.<br />
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An interesting facet of the ice age cycles is that ice age cycles are just as much about where carbon dioxide is stored as where water and ice are stored. During ice ages, a considerable fraction of the Earth's surface water is stored in ice sheets on the continents, and the oceans fall. The amount of water on the surface of the Earth doesn't change, but where the water is changes.<br />
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The same thing happens with carbon dioxide.<br />
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During an ice age, the amount of CO2 in the atmosphere falls by about 100 ppm from the 280-300 ppm in the atmosphere during interglacials to 180-200 ppm during the depths of ice ages. But where does the CO2 go?<br />
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The answer is that it goes into the sea. The oceans absorb it, and become slightly more acid. There is a cycle that slowly changes the <a href="http://en.wikipedia.org/wiki/PH">PH</a> of the oceans by ~0.03 The PH of the oceans is not just controlled by the acidic and alkaline compounds dissolved within it, but also by <a href="http://en.wikipedia.org/wiki/Activity_%28chemistry%29">activity factors</a> that mitigate (or increase) ionic concentrations. The chemistry for activity factors in the oceans is very complicated and I will not be going into it here, but the net effect is to slightly mitigate, or lessen, the swings in ionic concentrations in the oceans as the amount of CO2 increases or decreases. At least in the natural history of our recent ice ages. I will discuss it briefly at the end of this entry<br />
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Some of the results of this carbon cycle are counterintuitive. During ice ages, the atmosphere has less carbon dioxide, but the oceans are more acid. How can this be? <br />
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The answer is that the amount of carbon dioxide in the oceanic/atmospheric system remains broadly the same. At least the carbon does. During ice ages, more carbon remains in methane, which is trapped in methane hydrates in cold continental shelves. The total amount of carbon dioxide in the oceans and atmosphere does fall slightly, with more methane. But the amounts of carbon remain the same.<br />
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Another factor is that colder waters can hold more dissolved oxygen, and colder waters can support more life, if other trace minerals needed are present. Evidence does suggest that oceanic biological productivity was slightly greater during ice ages, and this may also have trapped some more gigatons of carbon.<br />
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But the main thing is that carbon dioxide accumulated in the oceans. <br />
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As I said, the PH of the oceans falling as CO2 concentrations fall in the atmosphere sounds counterintuitive, but it does make sense. The amount of carbon in the oceanic/atmospheric system remains broadly constant. If there is less in the air, there is more in the sea.<br />
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Carbon dioxide was not trapped on land in vegetation. Not only were millions of square miles covered under ice sheets, but today's temperate zones were much colder and drier. Forests are the main way life stores carbon on land, and there was much less forest area during the ice ages. There was increased land areas during ice ages as continental shelves were exposed (the area of ice-free land was about the same during ice ages as today) But it was mostly dry tundra or grasslands, and even in the tropics forests shrank and became patchy in restricted areas or river valleys.<br />
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*note* Tundra can trap large amounts of carbon. If it is <b><i>wet</i></b> tundra. We all know about the thawing tundra bogs bubbling with methane as they thaw. But <b><i>dry</i></b> tundra is different. It's just frozen without much biological productivity and not much buried biological matter to become peat infused with methane. The climate of the Earth was much drier during ice ages---so dry that in many places cold enough to form ice sheets, such as Siberia, they did not form. Dust deposits, or <a href="http://en.wikipedia.org/wiki/Loess">loess</a>, show that at best much of North America, Europe, South America and the remaining temperate parts of Asia were at best semi-arid and most of these areas were true deserts.<br />
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Much of the interior of North America resembled the <a href="http://en.wikipedia.org/wiki/Gobi_Desert">Gobi Desert</a>. The <a href="http://en.wikipedia.org/wiki/Sand_Hills_%28Nebraska%29">Sand Hills of Nebraska</a> were giant sand dunes. When Native Americans first became numerous ~15,000 years ago, the climate was already becoming milder and wetter, supporting more vegetation and life. And I am skipping over the raging question of when mankind arrived in the Americas, but there is not evidence of widespread populations more than 15,000 years ago.<br />
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*end note*<br />
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As the implications of Revelle's worked seeped through the geologic, oceanographic, biologic, and climatologic branches of science during the 1960s and 1970s, there was some thought that there might be a global carbon cycle, driven perhaps by a long cycle in volcanic activity over tens of thousands of years, that injected and withdrew carbon from the oceanic/atmospheric system. But it was never a widespread belief, and no evidence has been found for it.<br />
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The work on the Earth's carbon budget has had two main implications for climate science and global warming, one well grounded in fact, and the other more speculative.<br />
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The first one is that yes, warming out of the ice ages does come before carbon dioxide begins to rise in significant quantities. And it <i>does</i> make sense and <i>doesn't</i> invalidate carbon dioxide as <i>the</i> major driver in climate change.<br />
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The reason is this. The <a href="http://en.wikipedia.org/wiki/Milankovic_cycle">Milanković cycles</a> determine how much solar energy falls in the polar and temperate zones, and the tropics as well. The Milanković cycles trigger a small warming, which then increases the buffering of CO2 by the oceans. The oceans, as they warm slightly, return CO2 more quickly to the atmosphere. This increases the warming, which then increases the rate CO2 is returned to the atmosphere, and it triggers an accelerating feedback. As the climate warms and becomes wetter, tropical forests and wetlands increase, increasing wetlands and methane emissions. More warming. Methane hydrates in marginal areas become unstable and release their methane. More warming. Swamps and wetlands increase in temperate and polar zones and emit more methane--more warming. The methane is quickly oxidized to CO2 and water, but the CO2 is still a warming gas, as we know.<br />
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As ice sheets shrink, the Earth's albedo decreases and the Earth retains more heat. More warming. Less known is the fact that forests are quite dark, while deserts are reflective. Compare the Amazon rain forest to the Sahara Desert in satellite pictures. Or the Siberian taiga to the rocky wastes of northern Canada's islands.<br />
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All these effects produce enough warming to bring the Earth out of an ice age. But the key is that temperatures rise first from the Milanković cycle.<br />
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This is a point that deniers try to exploit. When they do so, you can be sure that they are either ignorant of climate processes or being deliberately dishonest. Usually they are being dishonest.<br />
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Deniers argue that because the temperature began to rise before CO2 began to rise in the atmosphere that means that CO2 is not a greenhouse gas. Or that it doesn't trigger warming. Or some such thing. No. CO2 rises as a feedback to a slight temperature increase, and then vastly increases the temperature rise far beyond what Milanković cycles can do. And the albedo effects from reductions in ice and snow cover and changes in vegetation increase temperatures still further! The Milanković cycle increases temperatures a few tenths of a degree and the feedbacks from CO2 and decreasing albedo trigger the far greater temperature rises.<br />
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Milanković cycles work because the Earth is finely balanced between different climatic states, ice ages and interglacials. Milanković cycles determine how much solar radiation reaches the polar and adjacent temperate zones. Aside from changes in the eccentricity of the orbit of the Earth, Milanković cycles do <b>not</b> change the total amount of solar radiation reaching the earth. When changes in the axial tilt increase solar radiation in polar zones, they decrease solar radiation in tropical zones. The total amount of solar radiation reaching the Earth remains the same. Aside from the changes in the eccentricity of the orbit of the Earth around the sun, Milanković cycles wouldn't change the temperature of the Earth at all if positive feedbacks didn't come into play when more solar radiation reaches polar and adjacent temperate zones.<br />
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The fact that the Earth's climate warms so much from subtle changes in solar radiation in polar zones shows that the positive feedbacks are very strong. And that is why what we are doing to the atmosphere is so dangerous.<br />
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This brings into play <a href="http://en.wikipedia.org/wiki/Climate_sensitivity">climate sensitivity</a>. We know that Milanković cycles, aside from the minor orbital eccentricity effect, can't change the total solar radiation the Earth receives. Jule Gregory Charney (1917-1981) crafted the first definitive report on climate sensitivity in 1979. You can read it <a href="http://www.atmos.ucla.edu/~brianpm/download/charney_report.pdf">here</a>.<br />
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Climate sensitivity compares how much a given increase in a greenhouse gas, carbon dioxide in this care, to what actually happened in the climatic record. Although Charney's report is from 1979, it is definitive. The basic physics of radiation absorption by CO2 have been well understood for decades (As I have said in previous entries, it was believed until the 1940s that CO2 in the atmosphere was saturated as far as infrared radiation absorption is concerned. In other words, that adding more CO2 would not make a difference because it already absorbed all the infrared radiation it could. I will be discussing how that was proved wrong soon in an upcoming blog entry.)<br />
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From the Charney report we know that climate sensitivity greatly increases temperature swings from changes in atmospheric carbon dioxide alone would do. And has done. The question humanity faces is how powerful these positive feedbacks will be in a warming world.<br />
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Revelle's research, and other research by scientists later, is disquieting on several fronts. Back then there was 50 times as much dissolved CO2 in the oceans as in the atmosphere. It is now about 40 times as much, as atmospheric CO2 has increased so quickly. We have added nearly 3 trillion tons of carbon dioxide to the atmospheric/oceanic system. Despite the swings in oceanic chemistry between ice ages and interglacials, the oceans are already far more acid (or less alkaline) than in the ice ages. As temperatures rise, the efficiency of carbon dioxide return to the atmosphere increases. The oceans hold hundreds of trillions of tons of carbon dioxide. Could the large increases in temperature in store turn the oceans into net carbon dioxide emitters?<br />
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We don't know.<br />
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The warmer water becomes, the less gas it can dissolve. That runs counter to what we know in daily life, because we know about how solids behave in water. Cold water doesn't dissolve much sugar, and dissolves it much more slowly than hot water.<br />
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With gases it is different. Molecules vibrate faster and travel faster as temperatures warm. In fact the motion of molecules defines temperature in our daily lives. Solids dissolve more readily in liquids as the temperature rises because the break off from the surface of solids and are incorporated into the liquid.<br />
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For gases, the greater the temperature, the more rapidly the gas molecules travel, and the more easily they can escape the liquid. That is why the warmer water is, the less dissolved gas they can hold. That is why CO2 buffering becomes more efficient as temperatures rise. Rising temperatures will also decrease the amount of oxygen dissolved in water, with impacts on biological productivity. We don't know how oceanic life will adapt to warmer, more acidic conditions. Photosynthetic algae do remove a lot of CO2 and convert it to oxygen. Algae decompose on the surface when they die, and the carbon within them remains part of the open carbon system. But animals feeding on them can sink to the ocean floor when they die, as well as diatom shells. Could the warming and acidification of the oceans decrease biological productivity enough to significantly reduce the amount of carbon that settles to the sea floors? <br />
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We don't know. <br />
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The chemical processes of the Revelle Effect are well known, and assuming no major changes in biological activity, the impact of the Revelle effect is quantifiable. All measurements agree that CO2 buffering and return to the atmosphere increases by 6%-8% for every 1° C. That is a closer agreement than many in science.<br />
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But the possibility of some sort of biological threshold being reached--a cliff--where biological productivity decreases enough to increase the Revelle effect much more than expected is not something we can safely ignore.<br />
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Here are some links to the chemistry of oceanic carbon dioxide buffering:<br />
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<a href="http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch7s7-3-4-2.html">From the IPCC</a><br />
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<a href="http://eesc.columbia.edu/courses/ees/climate/lectures/ocean_co2control.html">Some of the major chemical reactions in oceanic carbon dioxide buffering from Columbia University.</a><br />
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<a href="http://docs.google.com/viewer?a=v&q=cache:-hgW0rq3AxMJ:qcpages.qc.cuny.edu/~cyi/buffer.pdf+carbon+dioxide+buffering+ocean&hl=en&gl=us&pid=bl&srcid=ADGEESifnfT-MMZcDRWNVnany2m2KcKLTwe0lM1LJR0_CxIcFON2RA_NASh9Y-Ujb1Ma1RjJL8BDjbAYQkWa-KqMKFjVALqpE3t__6LxzysSGraTPv6Y3WHyGMkS7Xbn7A44YGPO1me_&sig=AHIEtbTweQqnTezMVv2P_xpV3_OLtC9qpA&pli=1">And a more detailed paper on the chemical reactions of oceanic carbon dioxide buffering by Chuixiang Yi, Peng Gong, Ming Xu and Ye Qi.</a>StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com11tag:blogger.com,1999:blog-3318930696739797298.post-54734963433325959652011-04-03T12:43:00.000-07:002011-04-09T12:53:58.381-07:00Roger RevelleThe investigation into atmospheric CO2 and its interaction with the oceans is a long and complex story. Dozens of oceanographers and chemists contributed in this work, and the chemistry is also very complex. However, <a href="http://en.wikipedia.org/wiki/Roger_Revelle">Roger Revelle</a> is the central figure in this field of research. At least <i>I</i> consider him so. At any rate, he was the first to show that mankind's addition of CO2 to the atmosphere would not be absorbed by the oceans quickly, and was able to work out why.<br />
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This had been a question since Arrhenius. It was known since the Challenger Expedition of the 1870s that the oceans contain large amounts of CO2, and that oceans are alkaline world-wide. The Challenger expedition showed that the oceans contained ~50 times as much CO2 as the atmosphere. One of the main objections to anthropogenic global warming is that the oceans are alkaline---and should therefore absorb CO2 easily. <br />
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But proponents of anthropogenic global warming, such as Arrhenius, Alfred Wallace, and Callendar raised an interesting question. If the oceans really could absorb all the anthropogenic emissions of CO2 easily, why didn't the oceans absorb all the CO2 that is in the air now? In other words, since the oceans hold 50 times as much CO2 as the atmosphere, why didn't the oceans just absorb the 51st molecule, and then have the Earth freeze into a snowball?<br />
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This was a nagging question for oceanographers, but that scientific field was consumed by another controversy. As I wrote in a <a href="http://stsimonsislandgaguys.blogspot.com/2011/03/discourse-on-salinity.html">previous blog entry</a>, the oceans have contained roughly the same salt concentration as today for billions of years. Once it was realized that the Earth was billions of years old, the main question for oceanographers was how do the oceans get rid of their salt? Even now some aspects of that question have not been solved, although we now have a broad picture of how salt can be evaporated and buried under sediments in shallow seas and estuaries. But during much of the 20th century, the salt question was <b>the</b> major question in oceanography.<br />
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<a href="http://en.wikipedia.org/wiki/Roger_Revelle">Roger Revelle </a>(1909-1991) was an oceanographer with the <a href="http://scripps.ucsd.edu/">Scripps Institute of Oceanography</a>. During the mid 1950s he was part of a team studying how fast the oceans 'turn over', the seawater at the surface sinking to the depths and deep ocean waters rising to the surface. This was suddenly an important question. The Japanese were in an uproar over nuclear testing and radioactive pollution of their Pacific fishing grounds.<br />
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There had been rising anxiety in Japan already about nuclear fallout (Japan had great nuclear anxiety in any case from their experience with the atomic bombing of Hiroshima and Nagasaki less than 10 years earlier.) In 1954 two incidents occurred.<br />
The first, and most serious, was the irradiation of the <a href="http://en.wikipedia.org/wiki/Daigo_Fukury%C5%AB_Maru">Daigo Fukuryū Maru</a> (q.v) and later that year, the release of the movie <a href="http://www.imdb.com/title/tt0047034/maindetails">Gojira</a>, which we know as Godzilla, rushed into production after the Daigo Fukuryū Maru incident. <br />
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The United States Navy rushed a study to find out how fast the oceans 'turned over' and carried radioactive fallout to the depths. Revelle and his team determined that the oceans turned over over several hundred years (that is a bit wrong---we no know that the oceans turn over in about 3,000 years). That data showed the oceans turn over fast enough to absorb and remove CO2 from anthropogenic emissions. And yes, 3,000 years is fast enough also to dissolve most CO2 in the oceans and keep atmospheric CO2 from rising much.<br />
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But Revelle went further. The question of why the oceans didn't absorb <i>all</i> CO2 nagged at him. And his research in the field gave him knowledge and access to a tool oceanographers didn't have. The nuclear tests in the Pacific created lots of radioactive carbon isotopes. Carbon isotopes as great as C-22 and as low as C-8 were created. Most of these had a half life of microseconds or less. But C-11 (carbon 11) has a half-life a little over 20 minutes. Revelle didn't use the C-11 created by nuclear explosions---almost all would be gone in a couple days--too quick to visit an explosion site, with lots of other longer-lived radioisotopes around. But C-11 did give him an idea---create CO2 using C-11 and see how it interacted with ocean water. It was radioactive enough to be very easily traceable, but not too fast to decay immediately. And also, in a day or two almost all the C-11 would be gone. So it wasn't a disposal hazard.<br />
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The chemistry he found was amazingly complicated. Seawater is not just salt, it is a complex soup of many thousands of chemicals dissolved within it. And it also has living organisms. So there are thousands of reactions that CO2 can make with the different chemicals in seawater.<br />
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It had been suspected that the oceans had a buffering mechanism. What Revelle found was that in many cases, CO2 combined with chemicals in the seawater and created volatile compounds that promptly evaporated back into the air. Once back in the atmosphere, the CO2 would encounter free oxygen, or be dissociated by ultraviolet light, and create CO2. When he raised CO2 concentrations slightly, to 350 ppm or 400 ppm in the atmospheric samples over the tanks of seawater, molecules containing the radioactive C-11 were returned back to the air in significant amounts, while significantly less C-11 remained in the seawater. C-11 decays too quickly for longer studies, so Revelle switched to C-14, with a half-life of 5,730 years. In 1955-56 he determined that when CO2 in the atmosphere increased, about half of what the oceans absorbed would be evaporated out via volatile organic compounds within a year. <br />
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In a paper he co-authored with <a href="http://en.wikipedia.org/wiki/Hans_Suess">Dr. Hans Seuss</a> (1909-1993) (no, not <b><i>that</i></b> Dr. Seuss) Revelle wrote in a few sentences at the end that assuming that CO2 emissions stayed at 1957 levels, CO2 would rise in the atmosphere about 40% (to 440 ppm) over the next few centuries and stabilize. <br />
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This was mind-blowing. 440 ppm was a big rise! And certainly enough to warm the Earth's climate considerably! Revelle was not a climatologist or meteorologist, and did not realized the implications of what he had written. But others did.<br />
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It created a big scientific controversy. Unlike today, it played out in scientific circles and was largely unreported to the public. Objections were made, and then refuted. Perhaps the C-11 (with a half-life of 20 minutes, it is <i>very</i> radioactive) was killing the seawater microbes and they were releasing volatile organic compounds when they died. But research by others using C-14 quickly showed this was not the case. By 1960 Revelle's work was accepted.<br />
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One of the scientists Revelle worked with was Dr. Charles Keeling. Keeling, whom we all know, was inspired by Revelle to create his famous Mauna Loa carbon dioxide measuring observatory. It also combined with other work that I will be talking about in another blog entry, about how CO2's apparent saturation in its IR bands was not really saturated after all to show that increasing CO2 in the atmosphere would result in global warming. This has been the consensus for the past 50 years, and is the consensus now.<br />
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Revelle's guess about future CO2 concentrations in the atmosphere was a gross underestimate. He assumed that CO2 emissions would remain close to their 1957 levels. At the time, that was not a ridiculous assumption. <br />
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During the previous generation, there had been two terrible world wars. Continuous, progressive, exponential economic growth had not been the reality. In 1950, industrial production in the Soviet Union, Germany, France, Italy and Japan was lower than it was in 1913! There was no real reason to expect that the future would be different from the past. What Revelle didn't realize was that beginning in the mid 1950s the world had entered an unprecedented economic boom---with CO2 emissions more than doubling between 1957 and 1972. From 1973 to the late 1990s, emissions slowed in their rate of increase, but did not stop rising. And the growing boom in China and India has caused CO2 emissions to rise more rapidly in the past 15 years than during the pause from the mid 70s to the mid 90s.<br />
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In short CO2 emissions rose on an annual basis<br />
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1957-1973 6%<br />
1974-1997 2%<br />
1998-2011 3.5% (4%+ 2005-2010, despite the recent recession)<br />
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The combination of unprecedented economic growth, Revelle's CO2 chemistry work, Keeling's Curve, the discovery that IR absorption by CO2 was not saturated led by 1965 to a scientific conference in Boulder, CO about anthropogenic global warming--the first scientific conference with that as the main topic. I'll blog about that soon.<br />
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Revelle's work was also incomplete. He identified some of the main chemical pathways CO2 dissolved in the oceans returns to the atmosphere in volatile compounds. But many other oceanographers and chemists have been working since to identify other pathways--there are tens of thousands of them! Individually, most are trivial, but together they make a significant fraction of carbon dioxide atmospheric return. They vary by differences in temperature, local differences in chemicals dissolved in the oceans, and of course, different organisms present in the surface waters.<br />
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Also, some of the major chemical reactions that return CO2 to the atmosphere had already been discovered during the 1940s and 1930s. But it wasn't realized that they were a major part of the flux of carbon between the atmosphere and oceans. What Revelle largely did was discover that these reactions returned a large amount of carbon to the atmosphere quickly. There is a distinction between discovering a chemical reaction and discovering its magnitude and importance.<br />
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One alarming thing is that this return of carbon dioxide to the atmosphere is a powerful feedback. The warmer surface temperatures rise, the more quickly organic compounds evaporate and return to the atmosphere. Also, as temperatures rise, more compounds become able to evaporate. <br />
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Research shows, and is <b>unanimous</b> in agreement, that for each 1 C° rise in the surface ocean temperature, the return rate of CO2 to the atmosphere increases by 7%. <br />
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When I said unanimous, I was not quite right. All models show an increase from 6-8% per degree Celsius. What's really interesting is that if the increase is closer to 8% then more CO2 will be returned to the atmosphere, warming it faster, and cause more CO2 to be emitted by the oceans. This has big implications on temperature and oceanic acidification. It results in a damned either way situation. A slightly faster CO2 evaporation rate will result in faster warming, but less oceanic acidification. A slower CO2 evaporation rate will result in less warming, but more acidification. A difference between 6.2% and 7.8% is pretty close agreement, but running the calculations out to 2100 and beyond results in quite different states for the atmosphere and the oceans. As always, we need more research!<br />
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Roger Revelle<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.nap.edu/html/biomems/photo/rrevelle.JPG" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="441" width="300" src="http://www.nap.edu/html/biomems/photo/rrevelle.JPG" /></a></div><br />
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I will add further information in this blog entry later on some of the chemical pathways of CO2 return to the atmosphere.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com1tag:blogger.com,1999:blog-3318930696739797298.post-45797284132609116732011-03-27T14:50:00.000-07:002011-03-27T15:01:24.591-07:00Harold Urey and Cesare EmilianiThe pause in global warming research continued a surprisingly long time. World War II accounts for part of this--scientists were working on problems directly related to the war effort and not more esoteric research. Afterward, there was the Cold War, in which although funding for scientific research expanded enormously, much continued to be directed towards military applications. This was the case until the International Geophysical Year of 1957-1958, which stimulated much research relevant to anthropogenic global warming, triggering investigations some of which continue to this day. But that's for another entry.<br />
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However, not all was quiet on the anthropogenic global warming front. <a href="http://en.wikipedia.org/wiki/Harold_Urey">Harold Urey</a> (1893-1981) is one of the towering giants of 20th century science. He won the Nobel Prize for chemistry in 1934 for research in isotopes. He discovered <a href="http://en.wikipedia.org/wiki/Deuterium">deuterium</a> in 1931, and was the first to isolate pure liquid deuterium from liquid hydrogen. He did much research on the isotopes of uranium, being a member of the brain trust that helped develop the atom (fission) bomb. He came up with a model for the early atmosphere of the Earth in 1952, speculating it was composed of ammonia, methane, and hydrogen, which he published in his book <i>The Planets: Their Origin and Development</i>. Urey's hypothesis for the composition of the atmosphere of the early Earth has since been shown to be wrong, but it was a good kind of wrong that stimulated a lot of research. Harold Urey was <a href="http://en.wikipedia.org/wiki/Stanley_L._Miller">Stanley Miller's</a> professor and adviser, and together they crafted the <a href="http://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment">Miller-Urey experiment</a>, one of the most famous experiments of 20th century science. This experiment showed that complex organic compounds, including many <a href="http://en.wikipedia.org/wiki/Amino_acid">amino acids</a>, could be generated easily and in large quantities by natural processes.<br />
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Harold Urey was also Isaac Asimov's chemistry professor at Columbia University. <br />
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After World War II, Harold Urey turned his attention to isotopes of oxygen. It was a natural question for him to explore. Urey had used centrifuges to separate deuterium from ordinary hydrogen, and had helped work out how to separate uranium-235 from uranium-238 by creating <a href="http://en.wikipedia.org/wiki/Uranium_hexafluoride">uranium hexafluoride</a> which could be spun in centrifuges to separate the lighter uranium-235 from the heavier uranium-238 (and helped created the more exciting and dangerous world of today)<br />
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Harold Urey realized that evaporation of water and condensing it into glaciers could act as a natural way to separate isotopes. <a href="http://en.wikipedia.org/wiki/Oxygen-18">Oxygen-18</a> is a rare but stable isotope of oxygen. A water molecule containing an atom of oxygen-18 is heavier than water molecules containing oxygen-16, and does not evaporate as easily. This means that during ice ages, when more and more evaporated water is trapped in ice sheets, the remaining water in the oceans is enriched in oxygen-18. Therefore, the more oxygen-18 is concentrated in the oceans, the greater the volume of ice sheets and (presumably) the colder the Earth was!<br />
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Urey wrote in 1947 that we should check coring samples of the ocean for deposits of <a href="http://en.wikipedia.org/wiki/Foraminifera">foraminifera</a> (forams) shells in the sediments, hypothesizing that those living in times of past ice ages would have enriched levels of oxygen-18 in their shells. This was the first time that nuclear science and biology had been combined to solve a scientific problem!<br />
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The problem was taken up by <a href="http://en.wikipedia.org/wiki/Cesare_Emiliani">Cesare Emiliani</a> (1922-1995), a geologist from Italy who was one of Urey's students after the war (Many of Urey's students became scientific giants of their own working on problems suggested by Urey). <br />
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There were many difficult problems. Sediment coring up until that time was not very sophisticated---it was simply dropping a very heavy and dense metal tube into oceanic sediments. This had been done since the 1870s <a href="http://en.wikipedia.org/wiki/Challenger_expedition">Challenger expedition</a>, discussed in a previous blog entry, but it blurred and mixed the core samples too much to provide reliable samples of foram shells inside. This is not to say that these primitive core samples were useless---they did provide much information on sediment layers but they were too crude for the sort of research Emiliani was doing.<br />
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Borge Kullenberg <a href="http://books.google.com/books?id=eSQDAAAAMBAJ&pg=RA2-PA166&lpg=RA2-PA166&dq=%22borge+kullenberg%22&source=bl&ots=syFFcEFlmI&sig=lpmTFi95Bhvc6MTsn8Ud2so1AyA&hl=en&ei=QbGPTZfPMdG2tgeDnLGICQ&sa=X&oi=book_result&ct=result&resnum=2&sqi=2&ved=0CBcQ6AEwAQ#v=onepage&q=%22borge%20kullenberg%22&f=false">saved the day</a>. Working on the Swedish Deep Sea Expedition of 1947, he developed a new coring device that used a piston which deployed when the coring tube hit the ocean floor, enabling core sample tubes to be wider and penetrate far deeper into the ocean floor sediments. The coring samples were much clearer, and were 15 meters long, instead of a couple meters. By 1951 he developed a 20 meter coring apparatus.<br />
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Back in the lab, people could take precise samples of each layer, tease out a few hundred foram shells, which were then ground and roasted in the presence of pure oxygen-16 gas to form carbon dioxide. The oxygen-18 could then be measured by spinning the carbon dioxide in centrifuges, separating the heavy molecules containing oxygen-18 out.<br />
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As Kullenberg's new coring apparatus replaced older coring techniques in a few years, lots of samples became available for inspection. Emiliani used the new technique of <a href="http://en.wikipedia.org/wiki/Carbon_dating">carbon dating</a> on the top layers to determine an average rate of sediment deposition on the ocean floor. (beyond about 40,000 years carbon dating does not work as <a href="http://en.wikipedia.org/wiki/Carbon-14">carbon-14</a> decays). With the new sediment cores of 20 meters, he was able to get samples as much as 300,000 years old.<br />
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Emiliani found several pieces of the climate puzzle.<br />
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He found that the signature of ice ages could be clearly and consistently seen from ocean-floor sediment samples around the globe.<br />
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He also found that the temperature curves generated from these samples matched the <a href="http://en.wikipedia.org/wiki/Milankovitch">Milanković</a> theory very well.<br />
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Milanković had not achieved much scientific recognition up until this point---his chronology for ice ages differed from the scientific consensus developed in the late 19th century. But he lived long enough to see vindication through Emiliani's work.<br />
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Emiliani also found that there were sharp changes in the temperature of the earth---lots of evidence that ice ages were not smooth curves of cooler and warmer temperatures, but lots of sharp jagged swings in temperature, in periods of hundreds of years. Sharp advances and retreats. <br />
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When Emiliani published his research in 1955, it was recognized immediately as groundbreaking. The conclusion that ice ages were driven by <a href="http://en.wikipedia.org/wiki/Milankovitch_cycles">Milanković cycles</a> was accepted. <br />
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But the sharp temperature swings were not. The coring technique was new--perhaps it was affecting the sampling. The idea that the climate could change by large magnitudes in hundreds of years was against the scientific consensus---there was no way that Milanković cycles could explain that. Sampling errors seemed more likely, and the idea of rapid climate change was unsettling.<br />
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Today we know from ice core samples and more sophisticated ocean sediment sampling techniques that rapid changes in the climate have indeed occurred in the past. And not just in hundreds of years. But in a decade. Or less. Emiliani's work was a big clue that climate was not a stable beast. That climate could turn on a dime. But that realization only came much later.<br />
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Harold Urey, 1963:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/wikipedia/commons/2/2e/Harold_Urey.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="436" width="346" src="http://upload.wikimedia.org/wikipedia/commons/2/2e/Harold_Urey.jpg" /></a></div><br />
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Cesare Emiliani 1952 (?)<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/wikipedia/en/5/56/Cesare_Emiliani_in_the_early_1950s.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="706" width="605" src="http://upload.wikimedia.org/wikipedia/en/5/56/Cesare_Emiliani_in_the_early_1950s.jpg" /></a></div>StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com0tag:blogger.com,1999:blog-3318930696739797298.post-90650456832244803592011-03-26T12:54:00.001-07:002011-03-26T12:54:21.223-07:00Best tsunami videoI've seen a lot of tsunami videos on youtube---and many are very impressive. But this is the best one.<br />
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<object width="480" height="390"><param name="movie" value="http://www.youtube.com/v/Ct9GEaWAmJg?fs=1&hl=en_US"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/Ct9GEaWAmJg?fs=1&hl=en_US" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="390"></embed></object>StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com2tag:blogger.com,1999:blog-3318930696739797298.post-84791323687615712011-03-15T23:45:00.000-07:002011-04-23T12:40:08.735-07:00A discourse on salinity, early life and the environment of the ancient Earth.One of the problems with ocean chemistry was that oceanographers were trying to solve the great salinity mystery. And what was that?<br />
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Oceanographers had known for a long time that the salt concentration of the oceans could be accounted for by rivers dissolving salt and depositing it in the seas where it concentrates. At the rate of salt deposition by rivers, the oceans were about 80-90 million years old. This had been known since the late 19th century. <br />
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And in fact there was another factor. There is an old Norse myth that the reason the oceans are salty is that there is a giant salt mill under the sea, forever churning away. The Norse were not far wrong---the spreading centers at the mid-ocean ridges are continuously putting more salt in the sea. We've all seen those hydrothermal vents---they are full of salt dissolved very efficiently from the hot rocks they percolate through. So the actual time it takes to achieve today's ocean salinity is only 60 million years.<br />
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This age for the oceans was supported by <a href="http://en.wikipedia.org/wiki/Lord_Kelvin">Lord Kelvin</a>, who believed that the sun was not much more than 100 million years old, and probably less. <br />
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The young salt oceans were used to support evolution (our blood is about 0.8% salt, and it was supposed that this was the salinity of the ocean when our amphibian ancestors left the sea, with that concentration 'preserved' in our bodies till this day (I read this in my 10th grade biology book as well) It was also used to attack evolution because Charles Darwin thought the world had to be several billion years old. <br />
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Geological evidence by the 1920s with radioactive decay of uranium into lead proved that the world was over 2 billion years old. The question immediately became, why aren't the oceans more salty?<br />
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Equilibrium had long been recognized as the oceans being 15% salt. That's what the salinity would be if there was no way to remove salt from the oceans. That clearly hadn't happened. And had never happened. <br />
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Our cells, animal, fish, plant, cannot tolerate that much salt. Of course a 2% salt concentration would kill us very quickly through osmotic dessication. But even if the concentration is even between cell walls and their surrounding fluid, at 5% the 'pulls' of the sodium and chlorine ions dissolved in the water will pull apart the phospholipids that make up the cell membrane. <br />
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Yes, there are freaky organisms like brine shrimp that are able to keep salt out of their bodies (their internal salt concentration is the same as ours) Life is still possible with salinity over 5%, but all higher forms of life would go extinct faced with such salinity (aside from oddballs like brine shrimp) and the forms of life would have been very different even if salinity had reached 5%--and such life forms are rarely observed in the fossil record. Also, marine organisms that would have gone extinct if salinity <i>had</i> risen above 5% have not.<br />
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This drove oceanographers to distraction. How the hell do oceans get rid of their salt? Salt spray carrying salt back to the land was out. Except for hurricanes, salt spray does not go far inland, and any salt deposited on shore a few yards away washes back in with the next rain. And analysis of rainwater shows that salt is present in the most miniscule amounts. <br />
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It has been recognized that salt can be removed through evaporite deposits and covered with sediment that prevents it redissolving into the sea. When the Mediterranean dried up several times 5-6 million years ago each occurrence removed trillions of tons of salt that were covered by river and wind-borne sediments. Salt domes form in similar circumstances, through evaporation from restricted marine basins and burial under sediment. <br />
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That was worked out gradually in the 1960s and 1970s, but there is still a nagging problem. That can account for the salinity of the oceans staying well below 5%, but it seems a bit weak to most. After all, what happens if due to some continental configuration, there just aren't any restricted marine basins (or enough of them) to form enough salt deposits to keep ocean salinity down? This salt deposition process can account for the average salinity of the oceans, but with varying continental configurations there would be large and lethal salt variations.<br />
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Another mechanism for salt removal is the subduction of oceanic crust, impregnated with salt water in every pore---steam is released in volcanoes, but not much salt (usually---there are a few volcanoes along subduction zones that have very salty magma)<br />
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Proponents of <a href="http://en.wikipedia.org/wiki/Gaia_hypothesis">GAIA theory</a> propose that ocean salinity is under biological control. They propose two main mechanisms---salt being captured/incorporated into diatom and coccolith shells as they drift to the ocean floor after the animals die. The higher the salinity, the more salt they would capture. This hypothesis was tossed around a lot in the 1970s, but has since been found wanting. Diatoms do not capture more salt in their shells when salinity rises---and at much above 4.5% salinity they die. <br />
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The other is that reef building organisms help create restricted basins that trap salt deposits under sediments and marine skeletons. This does have some backing to it--coral atolls do trap layers of salt in lagoons and bury it under coral skeletons, and the Great Barrier Reef could certainly trap many billions of tons of salt. <br />
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But even this hypothesis seems weak. Reef building organisms have existed for several hundred million years, with different types of organisms forming them in different periods. But the oceans formed more than 4 billion years ago. So reef-building organisms cannot account for the stability of the salinity of the oceans for over 3 billion years. (Yes there were <a href="http://en.wikipedia.org/wiki/Stromatolites">stromatolites</a> 3 billion years ago. And they do trap salt, to a degree. Quite avidly, actually. But they live in tidal zones, and not in shallow marine seas, where they could trap salt on a much larger scale. Stromatolites simply can't trap enough salt to keep the salinity stable)<br />
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There are some negative feedbacks that help stabilize the salinity of the oceans in the absence of biological control. During the time of <a href="http://en.wikipedia.org/wiki/Pangaea">Pangaea</a>, all the continents were together, and there were no marginal, enclosed seas, or very few compared to today (The Gulf of Mexico, the Red Sea, the Mediterranean Sea, the Persian Gulf, the Caspian Sea, among other examples). But computer modeling and geologic evidence also shows that most of Pangaea was very arid--far away from the oceans and their moisture bearing winds. Much like the interior of Asia, only more so. And large endorheic basins trapped salt carried by what rivers there were in evaporite deposits in the interior of continents. (although these could get washed out later when exposed to rainfall when the continents separated)<br />
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So, supercontinent---not many marginal seas to form evaporite deposits, but not much salt transport from the land. Continents scattered about--more rainfall on land but more marginal/partially enclosed seas to trap salt.<br />
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But it's still hard to see how there wouldn't be salinity crises occasionally. Until recently, we didn't even know how continents assembled and broke apart very well before Pangaea. But over the last 15 years there has been a revolution in paleocontinent studies---through careful exploration and analysis of isotopes in rocks, geologists believe that they have identified all the prior supercontinents!<br />
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It has to be said that supercontinents have been increasing in size as <a href="http://en.wikipedia.org/wiki/Continental_crust">continental crust</a> increases with time. Before Vallbara, there is no evidence for continents at all. Earth seems to have removed its heat through <a href="http://en.wikipedia.org/wiki/Hot_spot_%28geology%29">hot spots</a>. 4 billion years ago, if we had seen the Earth we would have seen a planet-wide ocean, probably less than 3% coverage of land, but lots of volcanic island chains, and some island arcs as <a href="http://en.wikipedia.org/wiki/Subduction">subduction</a> began. The first "continents" were probably large islands similar in size to Borneo and Madagascar today. That is not to say these were the first "continents"---they were not. <br />
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Continental crust is considerably less dense than oceanic crust, and much less dense than the mantle. Granites and other "light" rocks form from differentiation in subduction zones. Less dense minerals stay on the surface of the Earth, and heavier minerals form oceanic crust or remain in the <a href="http://en.wikipedia.org/wiki/Mantle_%28geology%29">mantle</a>. Continents, including <a href="http://en.wikipedia.org/wiki/Continental_shelf">continental shelves</a>, cover almost 40% of the surface of the Earth. <br />
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This addition of continental crust, currently a few cubic kilometers a year, has some interesting implications. Assuming that the volume of the oceans has been broadly similar for the past 4 billion years, small, isolated subcontinents would not have had marine continental shelves. A few percent of the surface of the earth in elevated continental crust would have let the oceans "fit" around them. As continents took up more and more surface area, oceans would necessarily shrink in area and become deeper. When continental crust reached a large fraction of the surface of the earth, the oceans would not have as much room, and spread over the lower margins of continents. <br />
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Think of it this way. If <b>all</b> the Earth was covered by continental crust, the oceans would still exist and simply cover the lower areas of the continents. There would be less land area than today, with high mountain chains and plateaus like Tibet being the only land areas. <br />
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This helps find the solution to a mystery--why did photosynthetic bacteria "wait" over 1.5 billion years to change the atmosphere, releasing enough oxygen to become a part of the atmosphere (oxygen is a very reactive gas). Fossil bacteria from over 2.5 billion years ago have very similar appearances to modern photosynthetic bacteria today. In fact, some may be the same species! Bacteria multiply very quickly---if we found an earthlike planet, devoid of life, with oceans and continents, a similar climate and enough trace elements and minerals that bacteria need, we could seed the planet with bacteria and they would multiply and become ubiquitous in a few years. So why didn't bacteria do that during the <a href="http://en.wikipedia.org/wiki/Archean">Archean era</a>?<br />
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The answer may be that until the time of the <a href="http://en.wikipedia.org/wiki/Great_Oxygenation_Event">Great Oxygenation Event</a> there were not enough continents--or more properly, continents covering enough of the surface area of the Earth to have continental shelves. Continental shelves are good environments for bacteria---shelf waters receive minerals and other dissolved solids from wind erosion (dust) and more importantly river erosion. The first continental shelves may have formed 2.5 billion years ago, and triggered a population explosion of bacteria---which were finally able to release oxygen fast enough, and in large enough quantities, to fill up the "oxygen sinks". The primary sink seems to have been dissolved iron in the oceans. In the absence of free oxygen, iron compounds are mostly easily soluble in water. The anoxic oceans of the early Earth were a rich soup of dissolved metal compounds. But in the presence of oxygen, iron forms iron oxides (rust) that are <i>not</i> soluble in water.<br />
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The release of large quantities of free oxygen had tremendous effects on the Earth and it's environment. Iron and other metals used by bacteria precipitated out of the oceans to form trillions of tons of <a href="http://en.wikipedia.org/wiki/Banded_iron_formation">banded iron formations</a> that are still important today---most of our iron we mine comes from those formations. Within a brief geological period, minerals precipitated out, and bacteria had to evolve in a new mineral/metal-poor environment, evolving new metabolic pathways to use what iron and other metals they needed more efficiently. <br />
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And also with free oxygen present in the oceans, for the first time <a href="http://en.wikipedia.org/wiki/Eukaryote#Origin_and_evolution">Eukaryotes</a> evolved. These are more complex cells that have <a href="http://en.wikipedia.org/wiki/Organelle">organelles</a>and nuclei--specialized structures better able to deal with the metal-poor seas. It has to be said here that the fossil record of life before large animals and plants evolved is not all we could wish for. Rock formations become increasingly rare beyond 2 billion years ago, and microscopic organisms are difficult to detect. Instead of just looking at a rock outcrop and seeing it packed with <a href="http://en.wikipedia.org/wiki/Trilobites">trilobites</a>, scientists have to pick rock that they hope will contain microscopic fossils, and inspect the rocks very carefully to find them.<br />
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Another difficulty is that almost all old rocks are continental crust. Seafloor subduction eliminates almost all oceanic crust--the oldest oceanic crust on the sea floor is 180 million years old and is about to be subducted under the <a href="http://en.wikipedia.org/wiki/Philippine_Plate">Philippine Plate.</a> Oceanic crust almost as old is present in the Gulf of Mexico, caught and dragged along by the <a href="http://en.wikipedia.org/wiki/North_American_plate">North American Plate</a>. This may last longer than 180 million years, but still is not helpful for seeing how Archean ocean life evolved. <br />
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The earliest eukaryotic organism that we know of is <a href="http://en.wikipedia.org/wiki/Grypania">grypania</a>, a form of algae. <br />
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Note that higher plants and animals evolved from the same eukaryotic root. Plants did not evolve out of photosynthesizing bacteria, and animals did not evolve from other bacteria. The eukaryotic cell evolved only once, with plants, animals, fungi all springing from one eukaryotic ancestor. Pretty much the life we see.<br />
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The differences between eukaryotic cells and prokaryotic cells are fundamental:<br />
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A eukaryotic cell:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://mcdaid-science.wikispaces.com/file/view/EukaryoticCell.jpg/53082064/EukaryoticCell.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="575" width="640" src="http://mcdaid-science.wikispaces.com/file/view/EukaryoticCell.jpg/53082064/EukaryoticCell.jpg" /></a></div><br />
And a prokaryotic cell:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://image.wistatutor.com/content/fundamental-unit-life/prokaryotic-cell.jpeg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="470" width="640" src="http://image.wistatutor.com/content/fundamental-unit-life/prokaryotic-cell.jpeg" /></a></div><br />
Notice how a eukaryotic cell has organelles that specialize in different functions. A prokaryotic cell has its nuclear material scattered about, without a discrete nucleus, and lacks specialized internal structures. <br />
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Remember that almost all Archean life was marine, in the oceans. Their fossils were subducted billions of years ago. What we know of Archean life comes from two sources---bacterial life on continents in wet areas---lakes or rivers where bacteria could survive on land, or in small areas of oceanic crust that were "caught" by continents as they expanded and collided. Those are the sources of our banded iron formations today---the source of most of our iron and steel. <br />
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But with almost all our oceanic crust subducted and long gone in less than 200 million years, what remains of our view of Archean life is very incomplete. Conditions in wetter parts of the early continents were not representative of marine life, and conditions where oceanic crust was about to be caught up and incorporated into continents may not have been representative either. <br />
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An illustration of the current age of the oceanic crust, worldwide:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/wikipedia/commons/4/44/Earth_seafloor_crust_age_1996.gif" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="402" width="640" src="http://upload.wikimedia.org/wikipedia/commons/4/44/Earth_seafloor_crust_age_1996.gif" /></a></div><br />
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The Great Oxygenation Event had other impacts. The presence of free oxygen is incompatible with large amounts of methane in the atmosphere. Our models show that before the mass release of free oxygen, the Earth's atmosphere had significant quantities of methane. By that I mean about 20 times as much, perhaps 4 ppm in an atmosphere 10 times as thick as ours today. (Methane cannot have been much more abundant than that--if it had been much more the Earth would have been brought up to the boiling point, with all the CO2 present as well. That never happened) Methane (CH4) reacts quickly with oxygen. One CH4 molecule combines with 2 O2 molecules to form two molecules of water (H2O) and one of carbon dioxide (CO2) In short, CH4 + 2(O2) = 2(H20) + 1(CO2) Methane, as we know, is a potent greenhouse gas. The sun was significantly dimmer more than 2 billion years ago, dim enough that an Earth with today's atmospheric composition would be a <a href="http://en.wikipedia.org/wiki/Snowball_earth"><i>snowball earth</i></a>. This is known as the <a href="http://en.wikipedia.org/wiki/Faint_young_Sun_paradox">Faint Young Sun Paradox</a>. What seems to have happened is that oxygen accumulated in the seas, precipitating iron and other metals out, until (almost) all metal compounds were precipitated out. What happened next? <br />
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Free oxygen then began diffusing out of the oceans into the atmosphere. And all hell broke loose. The Earth's early atmosphere did not resemble today's. If we could go back in time, we would have to wear pressure suits, well shielded from radiation (radioactivity was thousands of times greater than today in the oceans) and be well insulated. Carbon dioxide was superabundant--so much so that the there was 10 times as much atmosphere as today, 10,000 millibars, with about 92% CO2 and 8% N2. It was very warm--geochemical evidence shows that the Earth was 40°C to 50°C. With a near worldwide ocean, it was very humid. Also in the absence of oxygen to react with chemicals in the atmosphere, it was probably very hazy even when clouds were absent. There were no blue skies. The appearance of the Earth may have resembled <a href="http://en.wikipedia.org/wiki/Titan_%28moon%29">Titan</a>. Ultraviolet radiation hit the atmosphere, generating photochemical smog, and reached the Earth's surface far more strongly than today (However, the faint sun was cooler, and ultraviolet radiation was even more reduced than visible light, being perhaps 1/3 to 1/2 as much as today. Even so, ultraviolet radiation was far stronger on the earth). Ultraviolet radiation, along with far more prevalent radioactivity, would have created and broken apart compounds far more than we see on the Earth today, with some of those compounds being useful to life. Hostile and alien it may seem to us, but 3 billion years ago life was pretty 'easy' for bacteria. Warm temperatures make chemical reactions go faster and there were plenty of metals dissolved in the oceans for them to use. <br />
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The first thing that happened to the early Earth's atmosphere was that as photosynthesis accelerated, carbon dioxide was drawn down. The atmosphere would have become thinner, and temperatures would have begun to fall. Why an ice age wasn't triggered quickly can seem mysterious, but there are two major factors why the early Earth would have been more resistant to ice ages. One was the scarcity of continental land masses, still probably 10% or less of the Earth's surface. There may not have been land masses near the poles to freeze up, accumulate ice, and increase the Earth's albedo. In fact we know there weren't, because otherwise the Earth would have frozen into a <a href="http://en.wikipedia.org/wiki/Snowball_Earth">Snowball Earth</a> more quickly than it did. When oxygen finally began to accumulate in the atmosphere after precipitating out the iron and other metals in the oceans, it then quickly reacted with the photochemical smog in the atmosphere, clearing it out, and reducing the albedo of the Earth. These two negative feedbacks enabled the Earth to remain warm long enough to allow the Great Oxygenation Event to proceed.<br />
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Imagine being on the Earth ~2.5 billion years ago, after millions of years of photosynthesis and when oxygen was just beginning to accumulate. The pressure was down to perhaps 2,000 mb, twice today's pressure, and a mix of roughly equal amounts of CO2 and N2 (nitrogen). Radioactivity in the early oceans was thousands of times greater than today and resembled <a href="http://en.wikipedia.org/wiki/Deinococcus_radiodurans"><i>Deinococcus radiodurans</i></a>. It may be that the the great radioactive cleanup was the most important factor in the evolution of eukaryotes--bacteria before then had to repair themselves from radiation damage--and more complex cells have more things that can go wrong. We would still need pressure suits, with the pressure twice today's level, and oxygen. We could ditch the radiation shielding. <br />
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The Earth still looked very different, under clear skies. The sky was green, not blue (large quantities of CO2 generate a green sky). The Sun was a little smaller, a little more orange. Enough to be recognizably different. But we could see it in good weather. Temperatures were more moderate, perhaps 20°C to 30°C over the Earth. It was a little more like home. <br />
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But finally, the oxygen reacting with the CO2, CH4, and <a href="http://en.wikipedia.org/wiki/Carbonyl_sulfide">carbonyl sulfide</a> (also a potent greenhouse gas) was too much. There were no large continental land masses at the poles, and albedo was decreasing, but the reduction of greenhouse gases finally overcame those negative feedbacks. The Earth descended into the Huronian Glaciation, perhaps the most severe global cooling the Earth ever endured. The global ocean froze from pole to equator, and remained that way for 300 million years, with a few brief breaks.<br />
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(The reason for the occasional breaks is that when the oceans froze, interaction between the oceans and seas was mostly cut off. Even though oxygen reacted slowly in a drier, cooler environment, eventually it would get used up. Aside from a little photosynthesis from bacteria in ice near the surface, and in hot springs and near volcanoes, photosynthesis almost stopped. The ice was at least 1 km thick. CO2 and methane would accumulate in the oceans again, and they would become anoxic again. Once in a while, an asteroid or comet, or massive volcanic activity would break up large areas of ice, and the greenhouse gases would bubble up and thaw the world. Until photosynthesis drew down the greenhouse gases, precipitated out the metals in the sea, and cooled the earth again.)<br />
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This switching back and forth in the environment from cold to hot, oxygen to anoxic must have sped up the evolution of life greatly. Also, each warm break would have been less and less radioactive---precipitated radioactive compounds on the seafloor and subducted away were not returned. This created an environment more favorable to evolve complex, eukaryotic life. <br />
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Finally about 2.1 billion years ago, the snowball earth thawed. Perhaps the slowly brightening sun was enough to thaw the Earth. <br />
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It was still not like our Earth. Oxygen was only about 1-2% of the atmosphere. The sky was still green. But the sun was a little brighter, a little less orange. A little closer to home. <br />
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The timing of the first continental shelves, generating the first population explosions of bacteria that were enough to change the chemistry of the oceans and atmosphere was fortunate. If continental shelves had formed in large areas 3.5 billion years ago, instead of 2.5 billion years ago, with the even fainter sun the oceans would have frozen right to the sea floor. Life would still have been possible around hydrothermal vents. But the Earth would have frozen so deeply that CO2 would have also frozen out. The temperature would have plunged to -200°F. Chemical reactions at such temperatures would be too slow for life as we know it to operatem and there would be no liquid water. Even when ice is frozen to -50°F or -100°F, mineral contaminants and exposure to the sun can create small mircoscopic pores or films of liquid water for bacteria to live in. But not -200°F. Also, with no ocean present under a thick ice sheet, even 1 km thick, recovery would be far more difficult. The reason is this: If an asteroid or comet hit the oceans, like the Chicxulub impact, even if there was a kilometer-thick layer of ice there was still a lot of liquid water underneath. When an impact broke open a million square kilometers of ice, the ocean underneath would fizz and release its greenhouse gases back. Currents would bring more water to release their gases, and so on. The gases released from currents bringing in new water would keep releasing more greenhouse gases. If the ocean is frozen solid, an impact would release the gases from the ice it melted and vaporized, but not from all the oceans away from the local impact. Also, the extreme cold would cause CO2 to quickly refreeze, making its greenhouse effect very brief. Only the largest impacts could have thawed the Earth. An impact by a 100 mile wide asteroid could have done it---but we know there have been none in the past 3.5 billion years. An impact that big on a thawed Earth would have vaporized all the oceans, raising the Earth to beyond the boiling point. That hasn't happened on our Earth. It could happen on an alternate Earth that had mass photosynthesis develop early from faster-growing continents and their accompanying continental shelves. But it's awfully chancy.<br />
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What if the continents had grown more slowly? And the Earth had waited until 1.5 billion years ago to have large continental shelves, and photosynthesis explode? That would have been too late. <br />
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The reason is that by about 2.5 billion years ago, the Earth was getting into trouble. On the verge of breaking out into a fever. Even in the absence of oxygen, weathering does take place on continents. CO2 is an acid, and combines with minerals and is removed from the atmosphere. A little of this carbon would sink to the sea floors and be subducted away, although most was consumed by bacteria that generated methane. So CO2 was, very slowly, falling in the atmosphere. But it was not falling fast enough. Many models, although not all say that between 1 and 2 billion years ago the temperature of the earth would have reached the boiling point. And then we would have a runaway greenhouse. The oceans would have become steam. And there would have been no going back. Eventually, ultraviolet dissociation in the upper atmosphere would have dissociated water molecules, allowing hydrogen to escape. The oxygen would combine with carbon and other elements, leading to an Earth like Venus. Dry. Hot. Dead. A bit 'cooler', 600°F, not 900°F. And with a little lower pressure---most estimates of the Earth's geochemistry show that there would not be quite as much CO2 ~60 bars instead of 90 bars. But close enough to be a twin of Venus, and incompatible with life. <br />
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It is possible to see life recovering from an early snowball Earth. Life could persist in areas of volcanic activity, with hydrothermal vents. The sun would slowly brighten, and maybe eventually an impact of the right size to thaw the Earth instead of boil it would happen. But from a runaway greenhouse, there is no escape.<br />
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And now we go back to the salinity mystery. With the low area for continents and continental shelves absent, how marginal basins could have formed to evaporate water and precipitate salt is a real mystery. The answer is that for before 2.5 billion years ago, we simply don't know how salt was removed. It is very mysterious. If there was an unknown mechanism removing salt <i>then</i>, why isn't this mechanism operating <i>now</i>? Could it be that the oceans were simply very salty back then and salt was gradually drawn down when continental shelves first appeared, along with marginal seas? Maybe, but this hypothesis has strong objections. There are salt loving (or salt-tolerant) bacteria known as <a href="http://en.wikipedia.org/wiki/Halophile">halophiles </a>that can handle very high salt concentrations today. Halophiles live in the Great Salt Lake and the Dead Sea, and other similar places. But in today's world, they seem like oddballs, almost parasitic. These bacteria depend on oxygen and other chemicals generated in vast amounts from other bacteria and other organisms. They expend great amounts of energy to keep salt out of their internal structure. Their cell walls are distinct. That could represent adaptation by bacteria that have evolved to tolerate very salty niches in the environment. In fact it almost certainly does. <br />
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It is very hard to imagine life developing in such saline water. Even if the concentration inside and outside the cell walls is the same, preventing osmotic dessication, the materials cells use to form themselves fall apart because of the strong ionic charges in highly saline water. Phospholipids fall apart. DNA and RNA are pulled apart. So are many amino acids (although not all of them)And these are really fundamental components of life. It is conceivable that there are other molecules besides DNA and RNA that can encode genetic information and be tolerant of salt. But these compounds, if they exist, have not been identified. <br />
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How life would have switched from some non-DNA/RNA genetic architecture to the genetic architecture we know is also mysterious. There is some evidence that genes may have originally developed on RNA molecules and then life switched to DNA. But these are very similar molecules. And how could cells have operated without many of the amino acids our cells use to build proteins and transmit information? And then change to DNA/RNA and amino acids? Such a life form discovered today would be strongly considered to be extraterrestrial.<br />
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Halophile bacteria today use DNA and RNA, and the same complement of amino acids we do. Since continents formed, there have always been some areas that are highly saline, like the Dead Sea that I mentioned before. Why hasn't any of such life built on different building blocks survived? (or hasn't been discovered yet, what a possibility!)<br />
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In short, it is possible that maybe the Archean oceans were far more salty than today, and that life operated using fundamentally different building blocks. But it is hard to see how life could change it's fundamental components so completely. There is no evidence that this has occurred. So I have to say it is highly unlikely. <br />
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It is time to review the supercontinents of the past, and what we know about them.<br />
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<a href="http://en.wikipedia.org/wiki/Vaalbara">Vaalbara</a> formed gradually 3.6 to 3.1 billion years ago, broke up 2.8 billion years ago. This "supercontinent" was probably about the size of Australia. It is probable that for most of its existence there were some other continental islets, like New Zealand, roaming around. Evidence for it is found in compatible rock formations in South Africa and northwest Australia. The Australian size estimate can be regarded as a maximum--it may have been considerably smaller, more like Greenland. But we do think this was the first landmass larger than 1 million square miles. Because of the paucity of data, no generally accepted reconstruction of its shape and position has been made.<br />
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<a href="http://en.wikipedia.org/wiki/Ur_%28continent%29">Ur</a> was a subcontinent that formed ~3 billion years ago, and maintained itself for 2 billion years until it broke up into portions of what is now Asia, South America, Africa and Antarctica ~1 billion years ago. It was not a supercontinent, but deserves a brief mention as a very long lived continental structure. When it joined supercontinents, it broke off as itself without major amputations or additions for 2 billion years. It was originally thought to be the oldest continent until evidence for Vaalbara was discovered and accepted, hence it's name.<br />
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<a href="http://en.wikipedia.org/wiki/Ur_%28continent%29">Kenorland</a> formed ~2.7 billion years ago, broke up ~2.5 billion years ago. It was the first "full size" continent, being about the size of South America. Kenorland is the first continent for which there is evidence of submerged continental shelves. It seems to have not glued together very tightly, with pieces jostling together or a little apart, with large bays or narrow seas between its components. Kenorland played two crucial roles in the development of life. It was the first to have significant areas of shallow seas and bays that supported dense bacterial populations--large enough to oxygenate the oceans and atmosphere. Paleomagnetic studies show that it formed in low latitudes, but that as it was entering its final breakup ~2.5 billion years ago, it moved to a polar region, and possibly helped trigger the first snowball Earth. <br />
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When considering Kenorland, it is important to remember that the Earth was far more geologically active then than it is now. Continents may have moved a foot or more per year, instead of a few inches today. And it seems to have been in large pieces most of the time. Like a group of subcontinents the size of the Arabian Peninsula or Greenland, occasionally welded all together, but mostly traveling together close to each other. Paleomagnetic studies indicate that these subcontinents were close together, and sometimes together. <br />
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The time of Kenorland also represents a shift in the Earth's geological behavior. Before Kenorland, the Earth was dominated by large hot spots---think hundreds of island chains like Hawaii, with some hot spots much bigger than that. Continental crust was generated from the lighter mineral 'scum' staying on the surface. But this is a slow and inefficient method for creating continental crust. During the time of Kenorland, the Earth's behavior shifted as hot spots declined, and sea floor spreading and subduction became prevalent. This is not to say that seafloor spreading and subduction did not exist before Kenorland, and hot spot volcanism continues today. But it was around the time of Kenorland that plate tectonics, as we see it today, became dominant.<br />
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Subduction is a far more efficient and rapid method for generating continental crust than hot spot volcanism. The Earth has also been cooling since its formation, and as a result is becoming, very slowly, less geologically active. This means that until Kenorland, continental crust formed very very slowly. It was also slowly declining in its rate of formation. Someone observing the Earth 3 billion years ago might have concluded that much more continental crust would never be formed.<br />
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However, with the switch to a sea floor spreading/subduction regime, the rate of continental crust formation increased rapidly. There was a major pulse of continental crust formation between ~2.5 billion years ago and ~1.8 billion years ago, with new continental crust forming at ~10 times the rate it had averaged during the previous billion years. Continental crust formation then slowed down considerably (although somewhat faster than before Kenorland) and then there was another pulse of continental crust formation from 700 million years ago to 500 million years ago, along with the continents speeding up to a foot a year or more. The reason for the first pulse of continental crust formation is pretty straightforward. The Earth switched to a predominantly sea floor spreading/subduction mode that was more efficient at creating continental crust. The reason for the second pulse 700 million years ago to 500 million years ago is not clear. There are several different theories, but this blog entry is long enough already. Suffice it to say that there is no one theory that is generally accepted.<br />
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Both of these pulses in continental crust formation are associated with snowball Earth episodes and great advances and diversification of life. There is a general feeling that these are all connected, and many theories. Again, no one theory yet has general acceptance.<br />
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<a href="http://en.wikipedia.org/wiki/Hudsonland"><br />
Columbia / aka Nuna / aka Hudsonland</a> formed 1.9 billion years ago and broke up ~1.5 billion years ago. This was the first real supercontinent, about the size of Eurasia. Columbia is estimated to have been about 12,900 kilometres (8,000 miles) from North to South, and about 4,800 km (3,000 miles) across at its broadest part. The east coast of India was attached to western North America, with southern Australia against western Canada. Most of South America span so that the western edge of modern-day Brazil lined up with eastern North America, forming a continental margin that extended into the southern edge of Scandinavia.<br />
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The Columbia supercontinent was probably the first supercontinent to have large scale deserts. <br />
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Rodinia 1.1 billion years ago to 750 million years ago. This is the first supercontinent for which we have a consensus of how it fit together. This supercontinent had lots of indentations and marginal seas. Its breakup coincided with the second large scale snowball Earth episode, and the beginning of the evolution of animal life visible to the naked eye. (It is possible that animal life was present earlier--there are fossils of 'worm tracks' which may or may not have been formed by worms over 1 billion years old. These worm tracks could have been produced by non-biological causes. No direct fossil evidence of animal life large enough to see, besides some freakishly big one-cell organisms has been found before the <a href="http://en.wikipedia.org/wiki/Ediacaran">Ediacaran period</a>.<br />
Some evidence from <a href="http://en.wikipedia.org/wiki/Molecular_clock">molecular clocks</a> indicates that animal phyla separated as long as 1.5 billion years ago. Others say no, much shorter. It is possible that single-cell or near-microscopic eukaryotic animals separated that long ago, and then a common environmental factor stimulated the growth of animals and plants into larger sizes. We just don't know.<br />
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A reconstruction of Rodinia:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.snowballearth.org/slides/Ch13-4.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="500" width="640" src="http://www.snowballearth.org/slides/Ch13-4.jpg" /></a></div><br />
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Pannotia 600 million years ago (briefly by geologic standards) was a strange supercontinent, that by most reconstructions is shaped like a giant 'V'. For reasons not understood the Earth seems to have had a geological freakout. Continents were flying across the map, bouncing off of each other almost like pinballs, old continental structures that had maintained their integrity through the previous cycles of supercontinental formation and breakup were torn apart, and new continental cores were welded together and remained as one. Continents were moving at 12-18" per year, and the pace of continental crust formation, which had been declining for more than a billion years sped up again. Why all this happened is not clear--there is no consensus yet. Pannotia, which formed the quickest after the breakup of the previous supercontinent, seems to have been almost accidental. The continents whizzing across the Earth happened to meet up, stick together a while, and break apart again. Pannotia only lasted 10-15 million years. After this breakup, with all the reshuffling of the continents, old ones breaking apart and new ones put together we see for the first time some continents that correspond with today's continents.<br />
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Pannotia had an unusual configuration. Usually with supercontinents there is a large reduction in seashore length and continental shelf area, but Pannotia was V-shaped (or crescent shaped) with all the continents next to each other in an arc. They were connected but not pressed together. This unique configuration preserved lots of shallow continental shelf areas, over wide latitude zones, with a wide variety of rapidly changing environments that stimulated evolutionary development. <br />
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Pannotia's appearance:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://jan.ucc.nau.edu/~rcb7/600moll.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="320" width="640" src="http://jan.ucc.nau.edu/~rcb7/600moll.jpg" /></a></div><br />
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For about 50 million years after Pannotia broke up, the continents continued whizzing around. Then around 550 million years ago the continents slowed down and the snowball earth freeze/thaw cycle that operated several times between 750 million years ago and 550 million years ago thawed out decisively. It was almost as if the Earth decided that animal and plant lifeforms had developed, now let them grow! <br />
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Another mechanism that undoubtedly stimulated animal evolution was higher levels of oxygen. Before Rodinia, oxygen levels had been rising gradually, so gradually. Oxygen was 2%-3% of the atmosphere 2 billion years ago, and 4-5% 800 million years ago. The only difference is that we would aphyxiate more slowly. <br />
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But between Rodinia and Pannotia, when the snowball Earth thawed and the oceans turned green, for the first time oxygen climbed above 5%, spiking to 10%-15%. Oxygen fell again when the oceans froze but kept rebounding. When the Earth thawed definitively, oxygen was 12-15% of the atmosphere---enough for the fist time to support large animals. The reason for this was the subduction of large amounts of carbon during the geological freakout. This allowed oxygen to accumulate from being an important constituent of the atmosphere to a major constituent--from then on in second place. CO2 was down to less than 1%, which was good as the Sun continued to warm. There were fluctuations and extinctions, but never again was oxygen scarcity a dominant global condition (although under certain circumstances, <a href="http://www.rochester.edu/news/show.php?id=1395">Canfield oceans</a> did form and cause serious problems, such as during the <a href="http://en.wikipedia.org/wiki/Permian">Permian</a> and <a href="http://en.wikipedia.org/wiki/Cretaceous">Cretaceous</a> periods)<br />
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The concentration of oxygen during prior geologic periods has been been controversial in some respects. During some periods, it appears that there were very high concentrations of oxygen--30% or more. The problem is that is impossible. The intensity of combustion increases by 70% for each 1% that oxygen increases in the atmosphere. In other words, at 22%, an oxygen fire will generate 70% more energy than at 21%. At 25% sopping wet wood will burn, and at 28%-29% wood will spontaneously ignite. The worlds we read of in science fiction stories with bracing, oxygen-rich atmospheres are fiction indeed. The landing of the spacecraft would incinerate the planet! <br />
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This can't be emphasized enough---at 30%, just one lighting strike would trigger a forest fire that would rage across continents. <br />
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But yet we find fossils of giant insects like this 30" dragonfly:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/wikipedia/commons/0/0d/Meganeura_fossil.JPG" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="480" width="640" src="http://upload.wikimedia.org/wikipedia/commons/0/0d/Meganeura_fossil.JPG" /></a></div><br />
These giant insects present a big problem--how could they survive in a 21% oxygen atmosphere like today? They can't. They would asphyxiate almost immediately. The solution is that the atmosphere was 1.5 or 2 times as dense as today---lots of oxygen, in a dense atmosphere for giant insects to metabolize, but with the greater amount of atmosphere keeping oxygen concentrations below 23%.<br />
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The problem with this idea is what would the additional gas be? It can't be nitrogen. Nitrogen is the only element on Earth found predominantly in the atmosphere. There isn't much in the oceans, there isn't much in minerals or in soil. If we took <i>all</i> the nitrogen out of the soils and oceans, it would raise nitrogen levels by less that 40%. And nitrogen is needed by life--a big depletion of nitrogen would have reduced life's prevalence drastically in ways not consistent with the fossil record. The giant insects flew in forests full of life. So nitrogen is out. <br />
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Carbon dioxide? Nope. Suppose we had an atmosphere of 20% oxygen, 40% nitrogen, and 40% carbon dioxide at double today's pressure. That much CO2 would make it impossible for animals to respire it out of their system. And that is also 2,000 times the amount of CO2 in today's atmosphere. The sun was dimmer, but not that much. By 350 million years ago that much CO2 would send the Earth to the boiling point.<br />
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It's hard to see what the mystery gas could be that was added to the atmosphere to dilute oxygen to a non-dangerous level, while keeping oxygen abundant enough for giant insects to thrive. <br />
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It has been suggested by some that giant insects could breathe, and had lungs like we do. But there is no fossil evidence for that--the giant dragonflies had <a href="http://en.wikipedia.org/wiki/Spiracle">spiracles</a>, just like insects today, and received their oxygen by diffusion. There is still a lot of controversy about this!<br />
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Here is a summary of the oxygen concentrations during various geologic periods:<br />
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<a href="http://en.wikipedia.org/wiki/Ediacaran">Ediacaran</a> 8% with many spikes up and down, first occurrence of 10%+<br />
<a href="http://en.wikipedia.org/wiki/Cambrian">Cambrian</a> 12.5%<br />
<a href="http://en.wikipedia.org/wiki/Ordovician">Ordovician</a> 13.5%<br />
<a href="http://en.wikipedia.org/wiki/Silurian">Silurian</a> 14%<br />
<a href="http://en.wikipedia.org/wiki/Devonian">Devonian</a> 15%<br />
<a href="http://en.wikipedia.org/wiki/Carboniferous">Carboniferous</a> 32.5% (controversial as noted)<br />
<a href="http://en.wikipedia.org/wiki/Permian">Permian</a> 23%<br />
<a href="http://en.wikipedia.org/wiki/Triassic">Triassic</a> 16%<br />
<a href="http://en.wikipedia.org/wiki/Jurassic">Jurassic</a> 26% (controversial)<br />
<a href="http://en.wikipedia.org/wiki/Cretaceous">Cretaceous</a> 30% (controversial)<br />
<a href="http://en.wikipedia.org/wiki/Paleogene">Paleogene </a>26% (controversial)<br />
<a href="http://en.wikipedia.org/wiki/Neogene">Neogene</a> 21.5%<br />
<a href="http://en.wikipedia.org/wiki/Quaternary">Quaternary</a> 21%<br />
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Pangaea formed 250 million years ago and began breaking up 180-100 million years ago. Pangaea is well known so I will just provide an illustration:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://wordrogue.com/wp-content/uploads/2010/03/pangaea1.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="400" width="640" src="http://wordrogue.com/wp-content/uploads/2010/03/pangaea1.jpg" /></a></div><br />
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We still don't know about the marginal, partly enclosed seas very well before Pannotia. Salt domes don't last very long by geological standards---they fault, let water in, get subducted, uplifted and eroded--we don't have examples of salt domes or extensive evaporite deposits from billions of years ago.<br />
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It has been bandied around that Earth was just very lucky---that we happened to have a continental configuration that at all times kept ocean salinity within reasonable bounds. I have read estimates that the chance of random continental configurations keeping salinity within acceptable ranges for our marine life at less than 1%. I have seen others say less than one in a thousand. Others say that unknown processes could have removed salt more efficiently during the time of the Hadean era, when it was much warmer--salty ocean crust could have been buried by massive hot-spot volcanic eruptions before subduction became dominant--could this have been more efficient at removing/burying salt? We don't know.<br />
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Could it be that on most earthlike planets, even when life forms, unlucky continental configurations caused lethal changes in ocean salinity and either extinguished life or kept the biosphere very weak, and at a low level, preventing evolution of more advanced forms?<br />
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Nobody knows.<br />
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But it was the salinity question that was a big priority of oceanographers in the 1930s and 1940s---why isn't the ocean more salty? That question was the big problem for oceanographers---not solving the trivial mystery of the behavior of carbon dioxide interactions between the atmosphere and ocean.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com2tag:blogger.com,1999:blog-3318930696739797298.post-80322235767035157562011-03-15T20:12:00.000-07:002011-03-15T21:16:03.192-07:00Guy Stewart CallendarThe pause in the study of anthropogenic global warming continued for a surprisingly long time. After the first decade of the 20th century, it fell out of favor---and anyway seemed like a problem for thousands of years down the road. But there was one who thought differently. <br />
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Guy Stewart Callendar (1898-1964) was not a meteorologist. Or a climatologist. Or a physicist. In fact he was not a scientist of any kind! And a lot of his work was really flimsy. That was not all his fault---there was still no way of measuring carbon dioxide with the sort of pinpoint accuracy that we see today from <a href="http://www.esrl.noaa.gov/gmd/ccgg/trends/">Mauna Loa</a> and other sites. But he was the only one who made any sort of impact at all during the long period of inactivity in greenhouse studies, so he is worth going over.<br />
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Callendar was the son of a prominent British physicist, Hugh Longbourne Callendar, and Victoria Mary Stewart. Hugh Longbourne Callendar specialized in thermodynamics, and held the lead physics chair at <a href="http://www.mcgill.ca/">McGill University</a> from 1893-1898. So Guy Stewart Callendar was born in Montreal. Hugh Callendar did make one innovation outside of thermodynamics---he developed and implemented the idea of using <a href="http://en.wikipedia.org/wiki/X-ray">X-rays</a> to inspect machine parts. He started with aircraft engines in World War I, helping to discover hidden defects and making engine manufacturing more efficient, by revealing how and where defects occurred---enabling manufacturing processes to be revised to lower defects and increase efficiency.<br />
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Back to Guy Callendar. As I said, he was not a scientist---although he stayed in the general field of his father. Guy was a power plant engineer, and he was a good one. From the 1920s on he developed methods to make energy production more efficient--which obviously required a good working knowledge of thermodynamics. He was also an amateur meteorologist. Well, not really. He didn't have a lot of training, although he read a lot of work in meteorology. But he never obtained a degree or took advanced coursework. And he was convinced the world was warming. And he was right about that. He was also convinced that mankind's CO2 emissions were responsible. About that, he was not right. At least not yet.<br />
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[It has to be said here that CO2 emissions, while rising rapidly from the 1870s on, were rising from a very low base, compared to today. By the 1920s and 1930s, CO2 emissions were just enough to have a very slight effect on climate, especially if sustained. However, they were not enough to account for the warming that took place from the 1880s to the 1930s, which must therefore have mostly resulted from natural causes.]<br />
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Whatever the causes, the warming was noticed by the 1920s and 1930s. Arctic ice shrank. Warming was most pronounced over the Arctic (Antarctica had no good weather records---expeditions kept meteorological diaries, but no permanent bases were established until the <a href="http://en.wikipedia.org/wiki/International_Geophysical_Year">1957-1958 International Geophysical Year</a>, and there was only the testimony of the whalers who talked of "good ice years" and "bad ice years" and almost NEVER braved the Antarctic winter.<br />
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The warming was also most noted in continental interiors and less in the oceans--exactly what Arrhenius had predicted!<br />
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[This is also questionable. Callendar was basing this on the Dust Bowl drought of the 1930s, with the record heat waves in 1934 and 1936. Stalin's Soviet Union was not cooperating with other countries in releasing meteorological information. There was also political pressure on climate statistics there. Stalin and the <a href="http://en.wikipedia.org/wiki/Lysenkoism">Lysenko clique</a> believed that the development of Siberia---the growth of cities and the leveling of the forests would result in a warmer climate. The point was made when meteorologists were executed when their records showed that the temperature had dropped from one year to the next. Temperature records therefore showed steady rises from year to year. This data was not released to the world, being a 'state secret'. Mongolia of course did not have regular meteorological observations that could be used to determine climate well. Republican China had a few places with reliable observations--Beijing, Shangghai, Hong Kong. But the Chinese did not have reliable climatic records for the interior.]<br />
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So on the basis of temperature records in Spitsbergen, Greendland, the Canadian Arctic, and the United States, Callendar concluded that anthropogenic global warming was occuring---and was occuring NOW (in the 1930s)<br />
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Callendar researched the levels of carbon dioxide in the atmosphere. The method for determining atmospheric CO2 concentrations was primitive, and not very accurate. What one did was get a dilute alkaline solution, and bubble air though it at a fixed temperature and rate and determined how much air flowed through before it neutralized the alkaline solution (CO2 being an acid compound). But this was fraught with difficulty. First of all, it assumed that all the CO2 in the air bubbling through the alkaline solution was interacting with it--what if some made it through? Second, observers did not always use the same alkaline compound---and we now know that CO2 reacts more easily with some basic compounds than others. Absorption of CO2, like all gases, varies according to temperature. The colder it is, the more easily the gas dissolves. And the apparatuses scientists used were not the same--each one tended to build his own apparatus (scientists being almost all male in those days--as far as I can tell, none of the pre-World War II observations were made by a woman)<br />
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There were also problems with local effects. The level of CO2 varies measurably between night and day. Downwind of herds of farm animals it was elevated. And observed CO2 levels in cities were very high--some of the observations in London during "pea soup" smogs when pollution was trapped under inversions were over 550 ppm! And those figures were probably correct. Greenwich Observatory reports figures over well over 500 ppm now during inversions. <br />
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Callendar was convinced that atmospheric CO2 was rising but it was almost impossible to prove. In fact, it was impossible, unless he made some arbitrary assumptions. First, he eliminated urban observations. Then he went over rural observations---and took out some downwind of large herds or in a couple of cases, power plants. After that, his decisions on what CO2 observations to include, and what not to include, seem mostly arbitrary. Callendar did include observations from ocean islands, like the Azores and Bermuda---and those were probably the best sites to observe what he was looking for. But his methodology was questionable. However in fairness, these primitive observations were all he had to work with.<br />
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Callendar wrote articles for science journals until the early 1960s, and here is his data reproduced from a late article. The observations he included when he made his presentation to the Royal Meteorological Society in 1938 are circled in the graph below.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://doctorbulldog.files.wordpress.com/2008/12/ball1210.jpg?w=390&h=284" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="426" width="585" src="http://doctorbulldog.files.wordpress.com/2008/12/ball1210.jpg?w=390&h=284" /></a></div><br />
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As you can see, the observations Callendar chose do show a rising trend. And no one believed that the observations above 400 ppm were representative of the atmosphere of the Earth. But you can also see how there were a lot of observations Callendar excluded that seem like 'reasonable figures'.<br />
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Callendar was nervous as he addressed the Royal Meteorological Society. They listened politely. They did ask some questions about his choice of data. There was a little scattered applause when he finished. <br />
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And that was pretty much it. Callender published his work later in 1938 in the Journal of the Royal Meteorological Society. <a href="http://www.rmets.org/pdf/qjcallender38.pdf">Callendar, G.S. (1938). "The Artificial Production of Carbon Dioxide and Its Influence on Climate." Quarterly J. Royal Meteorological Society 64: 223-40</a><br />
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After the questions about 'cherry picking' data and some correspondence with meteorologists, he omitted the graph above. His article contains some interesting statements, such as the one below: <br />
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"By fuel combustion, man has added about 150,000 million tons of carbon dioxide to the air during the past half century. The author estimates from the best available data that approximately three quarters of this has remained in the atmosphere."<br />
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n.b. At present we add that amount in 4 years.<br />
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Callendar believed that global warming would proceed at about 0.5C per century.<br />
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He believed that the concentration of CO2 in the atmosphere was 274 ppm before industrial activities began.<br />
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He believed that CO2 in 1936 was about 296 ppm.<br />
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Unlike Arrhenius, Callendar took into account economic growth. He believed that CO2 emissions were rising over time. So CO2 concentrations would go up faster and faster! But his estimates for the future seem quaint.<br />
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2000 AD 335 ppm<br />
2100 AD 396 ppm (will probably be reached in 2012)<br />
2200 AD 458 ppm (will probably be reached by 2060)<br />
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Callendar had some notions that were just plain wrong. We know that only about half of CO2 remains in the atmosphere. He also ignored the roles that convection and fronts have in redistributing heat in the atmosphere, and for this was roundly criticized. <br />
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But Callendar was also right in some ways. He believed that the oceans would not absorb all CO2 as it was emitted---pointing out correctly that if CO2 was absorbed so readily---then why was there any CO2 in the atmosphere at all? That caused many scientists some uneasiness--there must be some property of the ocean to resist absorbing CO2 to account for its presence. <br />
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Callendar was also right about the examination of CO2 absorption spectra and saturation. He argued that the behavior of CO2 infrared absorption in the cold dry upper levels of the atmosphere was not addressed by laboratory experiments at room temperature and pressure. <br />
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Callendar, G.S. (1941). "Infra-Red Absorption by Carbon Dioxide, with Special Reference to Atmospheric Radiation." Quarterly J. Royal Meteorological Society 67: 263-75. <br />
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However, most scientists believed Callendar was beating a dead horse there. Richard Russel, writing for the United States Department of Agriculture, pronounced that the absorption saturation was the "fatal flaw" in Callendar's argument. And that settled it for several years.<br />
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Russell, Richard J. (1941). "Climatic Change through the Ages." In Climate and Man. Yearbook of Agriculture, edited by United States Department of Agriculture. Washington, DC: US Govt. Printing Office. <br />
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For a non-meteorologist, Callendar's ideas did get a surprising amount of tolerance. Most meteorological textbooks of the 1940s and 1950s give him a short section, then rebuttals by meteorologists and physicists explaining why he was wrong. Callendar published many articles--but the general reaction of meteorologists at the time was to let him present his view, and address his ideas and answer his questions.<br />
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A short selection of more of his articles below:<br />
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Callendar, G.S. (1949). "Can Carbon Dioxide Influence Climate?" Weather 4: 310-14.<br />
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Callendar, G.S. (1958). "On the Amount of Carbon Dioxide in the Atmosphere." Tellus 10: 243-48.<br />
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Callendar, G.S. (1961). "Temperature Fluctuations and Trends over the Earth." Quarterly J. Royal Meteorological Society 87: 1-12. <br />
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Not everyone dismissed Callendar completely. Although the infrared radiation absorption saturation question was considered settled---the question of absorption of CO2 by the sea was not. It was well known that for every molecule of CO2 in the atmosphere, there were 50 in the sea. But then why didn't the sea absorb the 51st molecule?<br />
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Callendar thought that the oceans were stratified, that the surface layers did not mix readily with the deeper layers, and that the thin surface layer would be saturated quickly and not absorb more CO2. <a href="http://en.wikipedia.org/wiki/Harald_Sverdrup">Harald Sverdrup</a>, (1888-1957) perhaps the greatest oceanographer of the 20th century, and worthy of several blog entries himself, published his monumental work <i>The Oceans: Their Physics, Chemistry and General Biology</i> in 1942 and conclusively showed this was incorrect. The deep waters and surface of the oceans are exchanging readily.<br />
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So then what was keeping the oceans from absorbing all the CO2 in the atmosphere? No one was able to propose an acceptable mechanism for why the oceans would absorb CO2 until it reached 274 ppm and then stop. <br />
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Callendar lived long enough to see the first few years of the Mauna Loa readings taken by Charles Keeling. CO2 <i>was</i> accumulating in the atmosphere. <br />
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But that's for another blog entry.<br />
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Guy Stewart Callendar's picture:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.aip.org/history/climate/images/GSCallendar1934.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="500" width="385" src="http://www.aip.org/history/climate/images/GSCallendar1934.jpg" /></a></div>StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com2tag:blogger.com,1999:blog-3318930696739797298.post-66637981204108353282011-03-09T19:13:00.000-08:002011-03-09T23:10:52.644-08:00Modeling Weather Part 2Sometimes scientists and engineers have the misfortune of being born too early. Not just a decade or two early, but generations. <a href="http://en.wikipedia.org/wiki/Charles_Babbage">Charles Babbage</a> is one. <a href="http://en.wikipedia.org/wiki/Lewis_Fry_Richardson">Lewis Fry Richardson</a> <br />
(1881-1953) is another.<br />
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Lewis Fry Richardson was born to a Quaker family and was a life-long pacifist. His parents, who owned a leather goods factory, were well off, and saw to it that he got a first rate education. In 1898 he attended the Durham College of Science, where he took courses in mathematical physics, chemistry, botany, and zoology, excelling in them all. He was interested in many sciences and remained so for the rest of his life. In 1900 he received a scholarship to Kings College, Cambridge, where he took the <a href="http://en.wikipedia.org/wiki/Natural_sciences_tripos">Natural Sciences Tripos</a>, a course of study for people interested in many sciences. He graduated first in his class. His refusal to specialize prevented him from receiving a doctorate at that time, although ultimately he did receive a doctorate in mathematical psychology from the University of London in 1928.<br />
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In 1909 he married Dorothy Gannet, to whom he stayed married for the rest of his life. They were happy together, but also had sadness. They experienced 3 miscarriages, despite both being healthy. Only much later did they realize they had incompatible blood types---he was <a href="http://en.wikipedia.org/wiki/Rh_factor#Hemolytic_disease_of_the_newborn">RH positive</a> and she was RH negative. They adopted two sons and a daughter between 1920 and 1927.<br />
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Richardson's career reflects his eclectic interests:<br />
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* National Physical Laboratory (1903–1904)<br />
* University College Aberystwyth (1905–1906)<br />
* chemist, National Peat Industries (1906–1907)<br />
* National Physical Laboratory (1907–1909)<br />
* manager of the physical and chemical laboratory, Sunbeam Lamp Company (1909–1912)<br />
* Manchester College of Technology (1912–1913)<br />
* Meteorological Office - as superintendent of Eskdalemuir Observatory (1913–1916)<br />
* Friends Ambulance Unit in France (1916–1919)<br />
* Meteorological Office at Benson, Oxfordshire (1919–1920)<br />
* Head of the Physics Department at Westminster Training College (1920–1929)<br />
* Principal, Paisley Technical College, now part of the University of the West of Scotland (1929–1940)<br />
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In 1926, he was elected to the Fellowship of the Royal Society<br />
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Richardson made original contributions in many fields, but today is known chiefly for his meteorological insights and his research into fractals (a branch of mathematics not named for more than 20 years after he died.<br />
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A brief description of his work in fractals is worthy of mention. <br />
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A lifelong pacifist (he did not fight in World War I, and was an ambulance driver) he wondered if there was a mathematical basis for countries going to war with each other. In his research, he came across widely varying figures for the length of borders between nations. For instance, 380 km or 449 km between The Netherlands and Belgium. 987 km or 1,214 km between Spain and Portugal. How could this be?<br />
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He dropped his research into the mathematical causes of war between countries for a while, and wondered about the coastline of Britain. <br />
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He measured the coastline of Britain using a 200 km ruler:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/wikipedia/commons/7/78/Britain-fractal-coastline-200km.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="300" width="156" src="http://upload.wikimedia.org/wikipedia/commons/7/78/Britain-fractal-coastline-200km.png" /></a></div><br />
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Then with a 100 km ruler:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/wikipedia/commons/c/c8/Britain-fractal-coastline-100km.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="300" width="156" src="http://upload.wikimedia.org/wikipedia/commons/c/c8/Britain-fractal-coastline-100km.png" /></a></div><br />
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Then with a 50 km ruler:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/wikipedia/commons/f/f9/Britain-fractal-coastline-50km.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="300" width="156" src="http://upload.wikimedia.org/wikipedia/commons/f/f9/Britain-fractal-coastline-50km.png" /></a></div><br />
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Notice how the length of the coastline increases every time one uses a finer unit to measure! Richardson proved that there was no final measurement of the length of the coastline that could be made. For an irregular object, measuring its perimeter depends on the length of the unit you are using to make the measurement. The smaller the unit of measurement, the greater the total perimeter will be. This work was ignored for more than 40 years, but when <a href="http://en.wikipedia.org/wiki/Beno%C3%AEt_Mandelbrot">Benoit Mandelbrot</a> ran across it in the 1960s, it became the inspiration for his work <i>How Long is the Coastline of Britain</i> (1967), which was the beginning of his development of <a href="http://en.wikipedia.org/wiki/Fractal">fractal geometry</a>.<br />
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Richardson also made original contributions to <a href="http://en.wikipedia.org/wiki/Numerical_analysis">numerical analysis</a>, developing new equations for the <a href="http://en.wikipedia.org/wiki/Rate_of_convergence">convergence of a sequence</a>. Details of his mathematical work in this field <a href="http://en.wikipedia.org/wiki/Richardson_extrapolation">are here</a>.<br />
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Richardson also created a new iterative method for solving linear equations, which is now known as the <a href="http://en.wikipedia.org/wiki/Richardson_iteration">Richardson Iteration Method</a><br />
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Richardson's mathematical contributions to meteorology began with his investigations into the mathematics of turbulence. He developed a way of calculating the ratio of potential energy to kinetic energy:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/math/f/f/2/ff208e861eb1d70e84055d591ebaa443.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="41" width="72" src="http://upload.wikimedia.org/math/f/f/2/ff208e861eb1d70e84055d591ebaa443.png" /></a></div><br />
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in which <i>g</i> is the acceleration due to gravity, <i>h</i> a representative vertical lengthscale, and <i>u</i> a representative speed.<br />
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When considering flows in which density differences are small it is common to use the reduced gravity <i>g</i>' and the relevant parameter is the densimetric Richardson number.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/math/0/0/6/006819a7ee9e277a92e18058584e0c9d.png" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="42" width="76" src="http://upload.wikimedia.org/math/0/0/6/006819a7ee9e277a92e18058584e0c9d.png" /></a></div><br />
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Richardson was always interested in meteorology, and through his work as an javascript:void(0)ambulance driver in World War I, he made the first computational weather forecast. He collected observation records over central Europe for an arbitrary day he chose, May 20, 1910, with measurements of atmospheric characteristics and vectors according to the new <a href="http://en.wikipedia.org/wiki/Vilhelm_Bjerknes">Bjerknes</a> paradigm and tried to calculate what the weather would be in 3 days time. It was <b>very</b> difficult and intricate computational work, and he had to deal with interruptions not typical for today's research scientists. In April 1917 when the German army was on a local offensive, his ambulance was shelled and he had to get out of the wreckage and bury his notebooks in a metal container in a local churchyard. Then the German army took over and he had to wait for months to go back when the village was retaken. Fortunately his work survived. <br />
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His computations were discouraging. His first 'retrocast' showed impossible barometric pressure rises of more than 4.3 inches (135 mb) over central Europe, and he was discouraged. He also had a good mathematical intuition---that small variances in initial conditions would have big impacts on the future weather---a step towards <a href="http://en.wikipedia.org/wiki/Chaos_theory">chaos theory</a> (which came from <a href="http://en.wikipedia.org/wiki/Edward_Norton_Lorenz">Edward Norton Lorenz</a> in the 1960s and 1970s, also a meteorologist)<br />
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Richarson composed a little poem:<br />
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Big whirls have little whirls<br />
That feed on their velocity<br />
And little whirls have lesser whirls<br />
And so on to viscosity<br />
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The error was not identified until 2007. The error had to do with a smoothing method for interpolating between data points--Richardson had known about this method, but being shell-shocked had just forgot! Without the error, his forecast was basically correct. Three days out.<br />
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But he never knew that. <br />
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Richardson conceived of a way to forecast weather accurately, worldwide, in advance. He imagined 60,000 mathematicians working at any one time on the weather, 300,000 in shifts. With data from aircraft, a worldwide network of balloons, station observations, ships, buoys, all transmitted to computers to work out the data. <br />
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But not computers the way we think of them. Computers were the people doing the computing! And I have to imagine it would be tedious work! It's like something out of a <a href="http://en.wikipedia.org/wiki/John_Varley_%28author%29">John Varley</a> novella. At this moment <i><a href="http://www.imdb.com/title/tt0089759/maindetails">Overdrawn at the Memory Bank</a></i> is replaying in my head ;)<br />
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Richardson wrote all this out in a monumental work that reads as much like science fiction as science, <i>Weather Prediction by Numerical Processes</i> (1922). It is well worth a read in the original. <br />
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Here is a passage from the book:<br />
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“After so much hard reasoning, may one play with a fantasy? Imagine a large hall like a theatre, except that the circles and galleries go right round through the space usually occupied by the stage. The walls of this chamber are painted to form a map of the globe. The ceiling represents the north polar regions, England is in the gallery, the tropics in the upper circle, Australia on the dress circle and the Antarctic in the pit.<br />
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A myriad computers are at work upon the weather of the part of the map where each sits, but each computer attends only to one equation or part of an equation. The work of each region is coordinated by an official of higher rank. Numerous little "night signs" display the instantaneous values so that neighbouring computers can read them. Each number is thus displayed in three adjacent zones so as to maintain communication to the North and South on the map.<br />
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From the floor of the pit a tall pillar rises to half the height of the hall. It carries a large pulpit on its top. In this sits the man in charge of the whole theatre; he is surrounded by several assistants and messengers. One of his duties is to maintain a uniform speed of progress in all parts of the globe. In this respect he is like the conductor of an orchestra in which the instruments are slide-rules and calculating machines. But instead of waving a baton he turns a beam of rosy light upon any region that is running ahead of the rest, and a beam of blue light upon those who are behindhand.<br />
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Four senior clerks in the central pulpit are collecting the future weather as fast as it is being computed, and despatching it by pneumatic carrier to a quiet room. There it will be coded and telephoned to the radio transmitting station. Messengers carry piles of used computing forms down to a storehouse in the cellar.<br />
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In a neighbouring building there is a research department, where they invent improvements. But these is much experimenting on a small scale before any change is made in the complex routine of the computing theatre. In a basement an enthusiast is observing eddies in the liquid lining of a huge spinning bowl, but so far the arithmetic proves the better way. In another building are all the usual financial, correspondence and administrative offices. Outside are playing fields, houses, mountains and lakes, for it was thought that those who compute the weather should breathe of it freely.”<br />
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Richardson of course knew that the idea of 300,000 mathematicians employed for computing the weather was a fantasy. But it would work! <br />
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Richardson thought he would never live to see it: "Perhaps some day in the dim future it will be possible to advance the computations faster than the weather<br />
advances.....But that is a dream."<br />
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Richardson discussed the way the meteorologists of his time made forecasts---they studied the maps they created, remembered past occasions when the maps were similar, and made forecasts based on what happened next during prior occasions when the weather maps were similar. Richardson took a dim view of this.<br />
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"The forecast is based on the supposition that what the atmosphere<br />
did then, it will do again now.....The past history of the atmosphere is used, so to speak, as a full-scale working model of its present self"<br />
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Richardson compared this to astronomical predictions of the positions of the planets and stars:<br />
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"The Nautical Almanac, that marvel of accurate forecasting, is not based on the principle that astronomical history repeats itself in the aggregate. It would be safe to say that a particular disposition of stars, planets and satellites never occurs twice. Why then should we expect a present weather map to be exactly represented in a catalogue of past weather?"<br />
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Another quote from Richardson:<br />
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"The scheme is complicated because the atmosphere is complicated."<br />
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The 'scheme' referring to hundreds of thousands of mathematicians working on the weather.<br />
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Inexplicably, wikipedia does not have an article on "<i>Weather Prediction by Numerical Process</i>". <a href="http://books.google.com/books?id=Kye3f5HKJHMC&lpg=PP1&dq=Weather%20Prediction%20by%20Numerical%%2020Process&pg=PP2#v=thumbnail&q&f=false">Fortunately, google books does have it.</a> Credit to John for finding it when I failed! <br />
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Reviews of "Weather Prediction by Numerical Process" were quite positive, although many thought the idea of using computational power--either through hundreds of thousands of mathematicians or by mechanical calculators to be a fantasy. There was also the problem of his forecast for May 20, 1910--with the wildly high barometric pressure. The book didn't sell well, and dropped out of sight. I came across it on the stacks of the GA Tech library in 1993 and read it---it was fascinating to me.<br />
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Richardson left the Meteorological Office in 1920 when it was made a part of the <a href="http://en.wikipedia.org/wiki/Air_Ministry">Air Ministry</a>, which later became part of the Ministry of Defence. As "<i>Weather Prediction by Numerical Process</i>" was being published, Richardson discovered that his work on meteorology and atmospheric motion was being used to predict how to deploy mustard gas and chlorine--gas warfare. Richardson, as a life-long pacifist, was outraged. He removed all his work and notes from his office, destroyed them and then resigned. That caused a lot of controversy, but it did not stop him from being elected as a fellow of the <a href="http://en.wikipedia.org/wiki/Royal_Society">Royal Society</a> in 1926.<br />
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Disillusioned with the military appropriation of his work for gas warfare, he became interested in psychology (recall his doctorate) and the mathematics of violence. He worked in that field for the rest of his life, although maintaining himself in other disciplines. In 1949 Richardson published "Arms and Insecurity" in which he demonstrated that the length of two countries' common border was very strongly correlated with the risk of their going to war, among other factors. In 1950, he published "<i>Statistics of Deadly Quarrels</i>" in which he researched every conflict from 1815 to 1945 and discovered that the size of wars' death tolls varied by a logrithmic scale, very close to a base ten logarithmic scale. There were many more small conflicts than large ones, and the death tolls followed a <a href="http://en.wikipedia.org/wiki/Poisson_distribution">Poisson distribution</a> very closely. Richardson also determined this was true for gangland murders in Chicago and Shanghai---there were very many cases of one or two murders, 3 or 4 being less common and incidents like the <a href="http://en.wikipedia.org/wiki/St._Valentine%27s_Day_Massacre">St. Valentine's Day Massacre</a> being very rare.<br />
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Richardson was not quite as out of time as Charles Babbage. Babbage never saw a modern computer. But Richardson was still alive when <a href="http://en.wikipedia.org/wiki/ENIAC">ENIAC</a> made the first weather prediction in 1950. Richardson called it "an enormous advance".<br />
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A truly excellent summation of the history of numerical weather prediction is <i><a href="http://www.rsmas.miami.edu/personal/miskandarani/Courses/MPO662/Lynch,Peter/OriginsCompWF.JCP227.pdf">The origins of computer weather prediction and climate modeling</a></i> by Peter Lynch. It is well worth a read!StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com0tag:blogger.com,1999:blog-3318930696739797298.post-85910327774201399532011-03-05T19:08:00.000-08:002011-03-05T20:27:37.484-08:00Modeling Weather Part 1Again, this post is not strictly related to global warming. This post is about the beginning of weather modeling. Not many are aware that many of the principles and procedures of weather modeling began more than 20 years before the invention of computers. <br />
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<a href="http://en.wikipedia.org/wiki/Vilhelm_Bjerknes">Vilhelm Bjerknes</a> (1862-1951) was a groudbreaking meteorologist who in 1895 developed <b><a href="http://en.wikipedia.org/wiki/Primitive_equations">primitive equations</a></b> used to approximate atmospheric flow--and are still used in modern weather prediction models.<br />
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The forces involved are gravity, the pressure gradient, and viscous friction.<br />
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The equation terms:<br />
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* u is the zonal velocity (velocity in the east/west direction tangent to the sphere)<br />
* v is the meridional velocity (velocity in the north/south direction tangent to the sphere)<br />
* ω is the vertical velocity in isobaric coordinates<br />
* T is the temperature<br />
* Φ is the geopotential<br />
* f is the term corresponding to the Coriolis force, and is equal to 2Ωsin(φ), where Ω is the angular rotation rate of the Earth (2π / 24 radians per sideral hour), and φ is the latitude<br />
* R is the gas constant<br />
* p is the pressure<br />
* cp is the specific heat on a constant pressure surface<br />
* J is the heat flow per unit time per unit mass<br />
* W is the precipitable water<br />
* Π is the Exner function<br />
* θ is the potential temperature<br />
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The pressure gradient force causes an acceleration forcing air from regions of high pressure to regions of low pressure. Mathematically, this can be written as:<br />
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The gravitational force accelerates objects at approximately 9.81 m/s2 directly towards the center of the Earth. The force due to viscous friction can be approximated as: <br />
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Therefore, to complete the system of equations and obtain 6 equations and 6 variables:<br />
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Using Newton's second law, these forces (referenced in the equations above as the accelerations due to these forces) may be summed to produce an equation of motion that describes this system. This equation can be written in the form:<br />
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p = ρRT.<br />
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Bjerknes's work inspired <a href="http://en.wikipedia.org/wiki/V._Walfrid_Ekman">Wagn Walfrid Eckman</a> (1874-1954), a Swedish oceanographer and <a href="http://en.wikipedia.org/wiki/Carl-Gustaf_Arvid_Rossby">Carl-Gustaf Arvid Rossby</a> in their work on the fluid motions of the oceans and the atmosphere, and laid the groundwork for the discovery of the <a href="http://en.wikipedia.org/wiki/Ekman_spiral">Eckman Spiral</a> and <a href="http://en.wikipedia.org/wiki/Rossby_waves">Rossby Waves</a>.<br />
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The Eckman Spiral is one of the most counterintuitive discoveries in oceanography. Imagine a permanent large high pressure center over the middle of an ocean, like the Bermuda-Azores high. The winds circle around counterclockwise. But the effects of the Coriolis effect and friction cause the water right at the surface to move a little bit to the right of the wind motion. The water right under the topmost layer moves a little to the right of the topmost layer, and loses a little force through friction. Each layer down moves a little to the right, and loses a little force due to friction. Eckman was able to sum this up and discovered that the sum of all these currents is a tremendous inwards flow towards the center of the high pressure. <br />
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Oceanographers and meteorologists, when they thought about it at all, just assumed that the water level under a large permanent high pressure system was several inches lower than the surrounding water. Instead, Eckman showed it is several <i>feet</i> higher! This was so counterintuitive that for decades oceanographers had difficulty believing it was true, although it did explain why noreasters bring such high tides to the Atlantic coast. The sum of the force of the currents is 90 degrees to the right of the wind---a prolonged northeast wind will drive water to the <i>northwest</i> onto land. And Eckman's work was finally confirmed by satellite observations of sea level.<br />
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Eckman's spiral illustrated:<br />
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Ocean currents changing directions at an angle to the surface winds because of Coriolis effect<br />
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1. Wind<br />
2. force from above<br />
3. Effective direction of the current flow<br />
4. Coriolis effect<br />
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Rossby waves are perturbations in the atmosphere that result from the variation in the strength of the Coriolis effect with latitude. The mathematical equations are considerably more numerous and complex than the primitive equations I posted, so I will omit those from the entry. Rossby waves are key to the transport of cooler air equatorward and warm air poleward. <br />
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Rossby waves are illustrated below, showing in this example how cold air can be drawn equatorward:<br />
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Back to Vilhelm Bjerknes. By 1913, he had come up with 7 variables that are capable of describing the characteristics and behavior of the atmosphere. These are:<br />
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The characteristics:<br />
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1. Pressure<br />
2. Temperature<br />
3. Density<br />
4. Water vapor content<br />
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The vectors (wind)<br />
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5. East<br />
6. North<br />
7. Up<br />
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For the wind vectors, negative numbers would be used for the wind moving from a westerly direction, a southerly direction, or a downward direction (subsidence).<br />
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Thanks to Bjerknes, Rossby, and Eckman (a LOT of other meteorologists, physicists, and mathematicians also made contributions, but these are the giants) we had the mathematical tools to predict weather. And with some modifications, climate. There were some big problems though. How could we ever get enough data to make meaningful use of the equations. And even if we had enough data, how could we ever <b><i>solve</i></b> the equations fast enough to make timely forecasts?<br />
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100 years ago these problems seemed insurmountable. But <a href="http://en.wikipedia.org/wiki/Lewis_Fry_Richardson">Lewis Fry Richardson</a> was about to try. And in the next entry, I'll tell you about him.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com1tag:blogger.com,1999:blog-3318930696739797298.post-76580657516124279292011-03-02T20:37:00.000-08:002011-03-03T14:02:29.515-08:00Vladimir VernadskyFrom 1910 until the 1930s there was not much said about anthropogenic global warming. A few scientists were concerned about it in some of their writings, but not much research or investigation was done. <a href="http://en.wikipedia.org/wiki/Knut_%C3%85ngstr%C3%B6m">Knut Ångström's</a> experiment which showed that CO2 infrared radiation absorption was saturated by current levels of CO2 in the atmosphere was widely accepted, and it was widely believed that any excess CO2 would be absorbed by the oceans. <br />
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But some relevant work was done about the atmosphere and geochemistry---the most interesting contributions being made by <a href="http://en.wikipedia.org/wiki/Vladimir_Vernadsky">Vladimir Vernadsky</a><br />
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Vladimir Vernadsky (1863-1945) was a sort of dreamy person in his writings, and seems to have had a thick layering of pagan naturalism in his beliefs. Perhaps his non-Christian viewpoints were a factor in surviving the Stalin purges. With his thick goatee, dreamy manner, belief in naturalism, and slightly odd mannerisms he in some way resembled a druid or a sweet grandfather. However he had to have had prodigious political skills to survive the Stalinist purges that decimated so much of the Russian science establishment. Stalin seemed to prefer scientists who thought outside the box, and more specifically had viewpoints similar to his own. In most cases, Stalin's viewpoint was dreadful--his embrace of <a href="http://en.wikipedia.org/wiki/Trofim_Lysenko">Trofin Lysenko</a> set back Soviet agriculture by 30 years.<br />
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Vernadsky was different---although dreamy, his science was valid. And he made many original contributions to <a href="http://en.wikipedia.org/wiki/Geochemistry">geochemistry</a>, <a href="http://en.wikipedia.org/wiki/Biogeochemistry">biogeochemistry</a> (both fields he practically invented) and <a href="http://en.wikipedia.org/wiki/Radiogeology">radiogeology</a> (in which he was one of several scientists who developed the field)<br />
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Vernadsky wrote his wife in 1888:<br />
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...to collect facts for their own sake, as many now gather facts, without a program, without a question to answer or a purpose is not interesting. However, there is a task which someday those chemical reactions which took place at various points on earth; these reactions take place according to laws which are known to us, but which, we are allowed to think, are closely tied to general changes which the earth has undergone by the earth with the general laws of celestial mechanics. I believe there is hidden here still more to discover when one considers the complexity of chemical elements and the regularity of their occurrence in groups...<br />
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One of the things that puzzled him was how the Earth has an atmosphere of nitrogen and oxygen. Both are reactive gases and should not be present in more than trace amounts. A century ago (and until the 1960s in the west) it was believed that oxygen in the atmosphere resulted from the splitting of water molecules (H2O) by ultraviolet radiation---the heavier oxygen would remain in the atmosphere and the hydrogen would escape to space. Some believed that was the reason for so many shallow seas in the Cretaceous Period--the Earth was slowly, but surely, drying out. This belief had several difficulties---it was obvious that the Triassic and Permian periods had plenty of dry land and deserts, to say nothing of earlier periods. <br />
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It is surprising that this belief held on so long in the west---the final nail in the coffin was an experiment aboard Apollo 17 which looked at the atmosphere of the Earth and proved that hydrogen was not escaping at anything close to what had been believed---enough to lower the volumes of the oceans only an inch in a hundred million years. And definitely not supply Earth with much oxygen! <br />
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Vernadsky proved that the absorption of oxygen by chemical weathering was far to rapid to permit oxygen to accumulate in the atmosphere, even using a much more generous estimate of water dissociation.<br />
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It is said that oxygen results from plant photosynthesis. That <i>is</i> where our atmospheric oxygen comes from, but it is not so simple. Plants excrete oxygen, but animals, fungi and many single-cell organisms consume it. It's a giant closed loop. And this was why it was believed that oxygen had to result from dissociation of water--oxygen had to be continually introduced into the cycle.<br />
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Vernadsky proposed that what was <i>really</i> going on was <b>carbon sequestration</b> Plankton in the sea would release oxygen into the atmosphere, and when they died their bodies would sink to the abyssal plains, where their remaining carbon would be effectively removed from the biosphere. To a lesser extent, he also held that burial of surface plants and heating and compressing them would convert them to coal, with the carbon sequestered as coal beds.<br />
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Both of these are correct, although the oceanic sequestration of carbon is far more important. But not in a way that Vernadsky envisioned.<br />
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A flaw in Vernadsky's hypothesis is that most of the oceans are really biological deserts. Ocean fauna and flora live exuberantly in continental zones, where rivers bring in minerals and organic material, and in a few places where upwelling brings in water rich in oxygen. But most places in the ocean--the surface waters are almost devoid of life--not much plankton to sink. Vernadsky used assumptions for carbon sequestration that were far too high, and proposed that more carbon was ultimately returned to the biosphere than in reality.<br />
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What actually happens is more interesting. And weird. Carbon sequestration does produce our surplus of oxygen--but it needs another mechanism. It needs continental drift.<br />
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Continental drift was in the air, with the famous hypothesis of <a href="http://en.wikipedia.org/wiki/Alfred_Wegener">Alfred Wegener</a>, but was not considered valid by most of the scientific community. Through <a href="http://en.wikipedia.org/wiki/Subduction">subduction</a>, carbon laid on the ocean floor is transported deep into the earth, removing it from the biological cycle. This means that surplus oxygen remains. Vernadsky was correct, but his figures were way off. He assumed that large amounts of carbon were continually sinking down to the sea floor with most returning to the biosphere eventually. In reality, a little carbon is sinking, but what is sinking is removed from the biosphere far more efficiently. <br />
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This has interesting implications for life requiring the presence of free oxygen, our animal life, on other planets. <br />
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All modeling now shows that without continental drift and subduction, there is no way for carbon to be sequestered in amounts sufficient to generate much free oxygen. Continental drift requires the presence of enough radioactivity in the core of the Earth to keep the interior of the planet hot enough for continental drift to occur. <br />
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A curious feature of our solar system is that we are <b>not</b> in an 'average' solar system. Our solar system is anomalously high in metals--about 25%-30% higher than other stars like our own in our region. There has been evidence for a long time that our solar nebula formed from the residue and interaction of several supernova explosions, which created lots of heavy elements, including radioactive elements. <br />
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Models of planetary development show that if the Earth had 25% fewer radioactive materials in its core there would not be enough heat generated to drive plate tectonics after 2-3 billion years. Which means that carbon sequestration could not take place, and oxygen could not accumulate. Even if photosynthetic organisms developed that released oxygen, it would not accumulate enough to support animal respiration--oxygen would stay below 1%-2%. <br />
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Earth life developed quickly after the <a href="http://en.wikipedia.org/wiki/Late_Heavy_Bombardment">Late Heavy Bombardment</a>, but for reasons not well understood remained mostly single celled for the next three billion years, not increasing much in complexity. If life on other planets follows a similar course, by the time complex animal life began to try to develop, it would be too late--plate tectonics would have shut down. Carbon could not be sequestered, oxygen could not accumulate, and animal life based on oxygen respiration could not develop. <br />
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Of course other forms of life based on other elements and chemical pathways are possible--not using oxygen, and perhaps motile 'animals' analogous to ourselves could develop. It is very difficult to imagine a large motile 'plantimal' generating enough oxygen to support its metabolic needs.<br />
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Surveys of our region of the galaxy show that among stars of near solar mass, not one star in a thousand approaches our own in its heavy metal content. (Stars near the center of the galaxy have higher metal contents, but are subject to far more stellar instabilities, nearby nova explosions, and perturbations that could wipe out or set back complex life). <br />
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This information, developed over the past 20 years, is one of the keystones of the <a href="http://en.wikipedia.org/wiki/Rare_earth_hypothesis">Rare Earth Hypothesis</a>, and I believe one of the strongest elements of it. The Rare Earth Hypothesis says that while simple celled life may be quite common, complex animal life may be very rare. And a reason why the galaxy is not all colonized by aliens by now.<br />
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There is a way around this---what if life, instead of pausing at the single-cell level, had just kept evolving to more complex forms and large animals and plants appeared within a few hundred million years? Then plate tectonics would not have stopped yet and complex oxygen-metabolizing animal life could have developed. <br />
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The reason(s) why Earth's life 'paused' in its complexity for 3 billion years are not well understood as yet. It may be that most life bearing planets evolve more quickly to complex forms---or it may be that the progression to complex forms is very difficult, very unlikely, and that we are an outlier in how rapidly it occurred.<br />
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Back to the atmosphere:<br />
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Another question for Vernadsky is why does the Earth have nitrogen in its atmosphere? Most people, if they think about it at all, consider nitrogen to be an inert element. But it isn't, not really. Nitrogen is not reactive the way oxygen is, but it does react with lightning flashes (which produce nitrogen compounds vital for plant life) and with some minerals. The basic stable form for nitrogen is as nitrite ions in the oceans. This was much easier---nitrogen fixing bacteria release lots of ammonia---which is also released in plant decomposition, the breakdown of urea, and to a limited extent, in animal decomposition. 4 NH3 + 3 O2 molecules results in 6 water molecules + 2 molecules of nitrogen (N2). There are other more complicated pathways in a carbon dioxide and methane atmosphere, before oxygen was a major part of the atmosphere, but they do work to liberate nitrogen gas (while creating a lot of cyanides and other compounds)<br />
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Ammonia does react with oxygen fairy rapidly and is produced in large amounts---Vernadsky was able to demonstrate that the amount of ammonia produced by biological processes would reduce the oxygen content by 1% of the atmosphere of the Earth every 20,000 years (from 21% to 20% and so on) This reduction of the oxygen content of the atmosphere, a continuous biological drain, made the dissociation hypothesis for oxygen even more untenable.<br />
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Nitrogen stays in the atmosphere because while it is not completely inert, it is not very reactive. It has a long residence time in the atmosphere before it is zapped by lightning or incorporated in microbes. It does react with some minerals and becomes part of their chemical structure, but not often or in large amounts. Nitrogen is believed to be the only element on the Earth for which the majority of it is contained within the atmosphere.<br />
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[This is not certain however. Argon is created by the decay of <a href="http://en.wikipedia.org/wiki/Potassium-40">potassium-40</a> deep in the Earth. Although argon is an inert gas and very reluctant to form compounds, it does remain in rocks fairly well and does not diffuse to the surface quickly. It is believed that most argon has remained in the Earth.]<br />
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Vernadsky had demonstrated that the atmosphere of the earth is a biological construct. <br />
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Vernadsky's work was published in 1926 as <i>The Biosphere</i>, a word he did not invent, but did not have a real meaning until his book. Vernadsky described the Earth not as layers of rock with water and air above, but a construct in which life (biogeochemical processes) takes the premier role. In his book, he describes the Earth as covered by an almost continuous surface of biological matter--life--whose chemical activity created the present atmosphere which blankets the earth, and had profound effects on the geology of the earth, extending to its interior. <br />
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This view has had some surprising confirmations---there are strong indications that without life and photosynthesis that the small amount of photosynthesis 2.5 billion years ago created the ozone layer (which does not require large amounts of oxygen), which thereby warmed the stratosphere, which kept the stratosphere from mixing with lower moist layers of the Earth (the troposphere), sealing moisture in and keeping dissociation of water from drying the Earth. That greenhouse effect may have saved our oceans (the sun was 30-40% fainter 4 billion years ago and has been slowly brightening and warming, more than doubling ultraviolet emissions. It seems that before 2.5 billion years ago, ultraviolet emissions from the sun were not enough to dissociate much water, and about 2.5 billion years ago an ozone layer formed from the traces of oxygen released by photosynthesis, warming the stratosphere, stopping mixing with the troposphere, which became a separate atmospheric layer, trapping moisture in the troposphere) Without oceans of water pressing down on the seafloor rock and permeating them, plate tectonics might not exist. (Water seems to be <i>vital</i> for plate tectonics--rocks without water seem to be much stiffer in experiments in the lab, and Venus, similar in size and composition does not have plate tectonics. So without life, water would have dissociated with hydrogen irretrievably lost, and with the loss of the oceans, plate tectonics would have stopped, and making complex life impossible, in a sort of fortuitous feedback)<br />
Vernadsky had many accomplishments, including the establishment of the first academy of science in the Soviet Union (the <a href="http://en.wikipedia.org/wiki/Ukrainian_Academy_of_Sciences">National Academy of Sciences of Ukraine</a>)<br />
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Vernadsky's work, being Soviet, was largely unknown in the west until the 1960s, when <a href="http://en.wikipedia.org/wiki/James_Lovelock">James Lovelock</a> read <i>The Biosphere</i> and realized that much of what it said made sense. Lovelock's citations of Vernadsky's work created a great deal of interest in Vernadsky's research and hypothesis, and, with modifications, much of Vernadsky's work has been proven largely correct, or at least in the right direction.<br />
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Vernadsky however had a distinct New-Agy, mystical side. He believed that we are entering the third great epoch of the Earth--the first being the geosphere, when the Earth was a geological construct solely, to the biosphere, during which life began altering the planet and changed the Earth in ways that increased its suitability for life (an anticipation of the <a href="http://en.wikipedia.org/wiki/Gaia_hypothesis">Gaia Hypothesis</a>). Vernadsky postulated in 1936 that the Earth was entering a third epoch: the <a href="http://en.wikipedia.org/wiki/Noosphere">Noösphere</a>. This New-Agy concept is about the Earth entering the age of thought, in which the human mind would be the driving force behind the reshaping of the Earth, perhaps evolving towards a group mind. The Earth will become what our thoughts make of it. \<br />
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Vernadsky had some oddball ideas. He believed in <a href="http://en.wikipedia.org/wiki/Telepathy">telepathy</a> and other forms of <a href="http://en.wikipedia.org/wiki/Psionics">psionics</a>--not necessarily that they were an important factor now, but would be an 'emergent property' of human thought as people became more interconnected. (Vernadsky did not used the term 'emergent property' but the concept is clearly in his work)<br />
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Vernadsky as I have said was a 'dreamy' person. He frequently would lost attention to what others were saying, and have a blank expression on his face--daydreaming--even when in an animated conversation with one other person---and have to be brought back to reality with a hand on the shoulder. He took long walks in woods, collecting mushrooms, or wandering around gardens, with a blank look on his face. He was always kindly to children--young children nearby would snap him out of his daydream state and he would give them flowers with a smile on his face. In his gardens, he resembled a gnome. He certainly resembled a shaman or druid. <br />
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It is difficult to imagine how he became a premier part of the Stalin/Soviet scientific establishment. The picture of a dreamy, mystical scientist somehow jars with Stalinism. It also jars with the concept we have of a 'serious' scientist today. But he did first rate geochemical work, and his work in <a href="http://en.wikipedia.org/wiki/Radiogeology">radiometric dating </a>makes him one of the founding fathers of that science. <br />
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Another jarring juxtaposition with his dreamy, mystical demeanor was his strong advocacy for Soviet nuclear development including the atom bomb. Vernadsky apparently wrote a letter to Stalin very much like the famous letter <a href="http://www.dannen.com/ae-fdr.html">Einstein wrote to President Roosevelt</a> urging that the Soviet Union develop the atom bomb. I have not been able to find this letter or much about it, but the letter is spoken of frequently in my sources on Vernadsky. <br />
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Here is a picture of Vladimir Vernadsky. <br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.synergeticpress.com/images/vernad1934sm.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="983" width="600" src="http://www.synergeticpress.com/images/vernad1934sm.jpg" /></a></div><br />
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This entry has been another diversion from global warming---but I still think it is relevant. Vernadsky, 40 years before western scientists took the idea seriously, showed that the atmosphere is a biological construct. He demonstrated that oxygen, nitrogen, and carbon cycle through the atmosphere, and that it is largely controlled by biological processes. During the 1910s and 1920s there was practically no work on anthropogenic global warming, and Vernadsky is an interesting character, so I thought his insights worth sharing.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com5tag:blogger.com,1999:blog-3318930696739797298.post-76878046583514616412011-02-13T14:39:00.000-08:002011-02-13T16:47:33.564-08:00Benjamin Franklin, Thomas Chamberlin, and the circulation of the oceans.Benjamin Franklin made the first widely publicized contribution to knowledge of ocean circulation. He was inspired in this by his stay in Paris during the summer of 1783---a summer of busy negotiations, but also one in which he observed the 'volcanic fog' from the eruption of the Icelandic volcano Laki--and experienced the exceptionally severe winter of 1783-1784 back in the USA. Could large volcanic eruptions cause dust clouds big enough to cool the Earth temporarily? Franklin thought so---and expanded on his ideas about weather and climate in a speech he gave in 1784 titled 'Meteorological Imaginations and Conjectures' which he later submitted as a paper to the <i>Memoirs of the Literary and Philosophical Society of Manchester</i> where it was published in pages 373-377 in their 1789 folio. <br />
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Of more relevance to the topic of ocean circulation, Franklin wrote the first serious scientific paper about ocean circulation in 1786 which he submitted to the <i>American Philosophical Society</i> . <a href="http://books.google.com/books?id=fPQfNx2TQLAC&pg=RA1-PA23&lpg=RA1-PA23&dq=%22Maritime+Observations%22+%22American+Philosophical+Society%22+transactions+1786&q=%22Maritime+Observations%22+%22American+Philosophical+Society%22+transactions+1786&hl=en#v=snippet&q=%22Maritime%20Observations%22%20%22American%20Philosophical%20Society%22%20transactions%201786&f=false">Google has a link to it, but none of the pages are up. I'm linking anyway hoping that his article is added later.</a><br />
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<i>Maritime Observations</i>, the title of Franklin's monograph, is mostly about the Gulf Stream. Mariners had known about ocean currents for centuries, but Franklin was the first to write about them in a science publication that got wide circulation--therefore making the topic 'stick' in the scientific community. Franklin was the first to give the Gulf Stream credit for Europe being so mild when it was so far north--Paris being further north than Montreal, and Great Britain and Ireland at the latitude of Labrador. He got the broad outline of the North Atlantic surface ocean circulation right--the trade winds pushing the tropical waters west, where they entered the Caribbean and Gulf of Mexico, turned north off the coast of the eastern United States, and then northeast towards Europe, carrying warmth.<br />
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It is interesting to read accounts from the first settlers in the 1600s about the weather. New York and Boston are at the latitude of central and southern Italy, and Jamestown is at the latitude of Gibraltar. Colonists were shocked to discover that it "freezes and snows severely in winter". <br />
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This was noticed and discussed by scientists in the 17th and 18th centuries, and before Franklin it was believed that forests kept places colder---that snow lingered in the shade of trees and kept the land colder as a feedback. Thomas Jefferson had written that as the land was cleared and the forests replaced by fields and towns, that American would get warmer---the widespread belief of educated people in the 1700s. We know now that was wrong. <br />
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For the next hundred years---what else was added to knowledge of the ocean circulation system? Not much (and truth be told, the oceanographic expeditions of the late 19th century and early 20th century didn't add much knowledge either) But there was one expedition that generated some interesting ideas.<br />
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The <a href="http://en.wikipedia.org/wiki/Challenger_expedition">Challenger Expedition</a> was perhaps the greatest scientific expedition of the 19th century. It went world-wide travelling more than 70,000 nautical miles (80,000 statute miles), the longest scientific journey undertaken to that point. Not until astronauts went to the moon and retrieved moon rocks did a scientific expedition travel further. Before Challenger, people had only observed the top few fathoms of the ocean. <br />
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To enable her to probe the depths, the Challenger's guns were removed and her spars reduced to make more space available. Laboratories, extra cabins and a special dredging platform were installed. She was loaded with specimen jars, filled with alcohol for preservation of samples, microscopes and chemical apparatus, trawls and dredges, thermometers and water sampling bottles, sounding leads and devices to collect sediment from the sea bed and great lengths of rope with which to suspend the equipment into the ocean depths. Because of the novelty of the expedition, some of the equipment was invented or specially modified for the occasion. In all she was supplied with 181 miles (291 km) of Italian hemp for sounding, trawling and dredging.<br />
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Challenger returned to Spithead, Hampshire, on 24 May 1876, having spent 713 days at sea out of the intervening 1,606.[1] On her 68,890-nautical-mile (127,580 km) journey,[1] she conducted 492 deep sea soundings, 133 bottom dredges, 151 open water trawls, 263 serial water temperature observations, and discovered about 4,700 new species of marine life. Copies of the written records of the Challenger Expedition are now stored in several marine institutions around the UK including the National Oceanography Centre, Southampton and the Dove Marine Laboratory in Cullercoats, Tyne and Wear. The complete set of reports of the Challenger Expedition, written between 1877 and 1895, are available online at <a href="http://19thcenturyscience.org/">http://19thcenturyscience.org.</a><br />
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Given the achievements of the Challenger Expedition, it is perhaps a bit harsh to say that knowledge of the deep ocean was not advanced very much. It did expand knowledge many times over, but from virtually nothing to very very small. It did make many interesting observations.<br />
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The most important was that globally, the deep oceans more than a few hundred yards down are very very cold. Close to freezing. Everywhere. And that most of the cold water in the deep oceans originated from the margins of Antarctica. Cold, oxygen-rich water sank near Antarctica, and to a much lesser extent near Greenland and in the Arctic Ocean. After analyzing the observations, it was believed that water rose near the equator where solar heat warmed the waters and currents flowed poleward to balance the cold water sinking. <br />
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The Challenger expedition discovered another interesting feature. The Mediterranean Sea is considerably saltier than that world ocean (part of the reason why the Atlantic is saltier than the Pacific) and this warm salty water <b>sinks</b> about 5,000 feet to form a distinctive and identifiable layer throughout most of the Atlantic!<br />
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That the Atlantic is saltier than the Pacific and Indian Oceans was something of a surprise, given that such huge rivers drain into it. The Amazon river of course, and the Congo river. The Parana river system. The Mississippi river is only 4th!<br />
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On the west coast of the Americas, the Columbia River is the only sizable river. In East Asia, the Amur, Yangtze, and Mekong are major rivers, but the whole flow from East Asia is smaller than the Amazon alone. Australia contributes almost nothing to the Pacific. <br />
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Even stranger, the Arctic Ocean is really an arm of the Atlantic, and receives several large Rivers in the Russian Arctic--the Ob, Yenisey and Lena rivers--and the Arctic is the least salty of all oceans and mixes freely with the Atlantic. The Mediterranean inflow explains a little of the difference, but only a few percent. The salty Atlantic was not explained until the 1960s.<br />
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The deep warm water layer from the Mediterranean interested an American geologist, <a href="http://en.wikipedia.org/wiki/Thomas_Chamberlin">Thomas Crowder Chamberlin</a>. Chamberlin (1843-1928) was an interesting person---together with astronomer <a href="http://en.wikipedia.org/wiki/Forest_Ray_Moulton">Forest Ray Moulton</a> he crafted the <a href="http://en.wikipedia.org/wiki/Chamberlin-Moulton_planetesimal_hypothesis">Chamberlin-Moulton planetesimal hypothesis </a>to how the solar system formed--two suns nearly colliding and ripping off solar material which condensed into planets. He believed solar systems were very rare, since such stellar near collisions would be very rare--and calculated that our sun and the other sun in the near collision might have the only solar systems in the Milky Way's galactic arms! That hypothesis was wrong, but Chamberlin did make a lot of valid contributions to geology.<br />
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In 1904, he was going over the Challenger Expedition results, leafing through them. The Mediterranean water layer struck him. The Atlantic was already saltier than the rest of the oceans--what if it got saltier? If a local climatic change decreased the flows of the Amazon and Congo rivers, what would happen then?<br />
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Chamberlin thought that the tropical oceans would get so salty that the whole ocean circulation system would flip. Instead of cold water sinking near the poles, warm, but very salty water would sink in the tropical Atlantic, and instead of warm surface currents flowing north, cold currents like the Labrador current would flow much further south, cooling the climate and triggering an ice age! <br />
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Chamberlin thought that it would work like this. The sun heats the equatorial regions most strongly during the equinox when it passes overhead at noon. The equator gets less sun during the solstices, even though the day length stays the same. Chamberlin thought that when the precession of the equinoxes caused the sun to be closest to the Earth near the solstice, rainfall would decline with less convection triggered, causing the Amazon and Congo river flows to decline, which would cause salinity to increase--the Gulf stream to collapse, causing more cooling, and the cooling would trigger ice sheet formation, cooling the whole world, and cooling the tropics, making the tropical water less prone to evaporate, making the tropics drier, and the tropical water even denser--in a feedback. <br />
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The feedback would be broken when the sun was closest to the earth during the equinox again, and trigger more convection, triggering more rainfall, triggering more river flows, lowering the density of the tropical oceans, stopping the sinking of the tropical oceans, and letting the Gulf stream flow again, and the whole feedback operating in reverse.<br />
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Chamberlin's ideas triggered a lot of discussion when they were published in 1906. He was known for coming up with wild 'out there' ideas like his solar near collision hypothesis, and tossing them out into the scientific community to be discussed and picked apart. But triggering questions and research. <br />
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Having ice ages triggered by changes in tropical rainfall and ocean currents was an original idea, and was a good reminder that ice ages are <i>global</i> phenomena, and that their causes and triggers might be found outside the polar regions.<br />
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Chamberlin's ocean circulation reversal idea is wrong on several points, but it did generate for a time some interest in researching how ocean circulation works and how it changes---and how that might impact the climate. <br />
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Unfortunately, technology for detailed mapping of the ocean circulation system was not available 100 years ago. There were some proposals for new expeditions, using submarines this time to help map the deep ocean circulation system (which the Challenger Expedition did not have the technology to map---it generated hypotheses and some information on the cold state of the deep ocean, but no answers). But World War I brought an end to those ideas, and after World War I the idea was no longer in fashion, for whatever reason. The Chamberlin hypothesis faded away.<br />
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Chamberlin's hypothesis had one glaring fault. Evaporation and rainfall is a circular process. Water evaporating from the tropical Atlantic falls back into the sea, or flows back in rivers. Increasing the evaporation rate increases river flow back into the Atlantic. Decreasing the evaporation decreases the river flow back. It doesn't change the salinity appreciably.<br />
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But Chamberlin was the first to hypothesize that the ocean circulation system can have a big impact on climate. And it was an original idea--unlike ice ages and greenhouse warming, which have many fathers, going from person to person and being strengthened---he thought of this all by himself. No one had thought of it before.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com5tag:blogger.com,1999:blog-3318930696739797298.post-12533456189216788532011-02-09T21:16:00.000-08:002011-02-15T20:16:26.062-08:00Svante Arrhenius part 2Arrhenius had some good data to observe. It had already been noted by Frank Washington Very and Samuel Pierpoint Langley that the infrared radiation from the moon which was observed at the surface of the earth changed its characteristics according to the angle of the moon above the horizon. These observations agreed with the properties of infrared absorption by carbon dioxide observed by Tyndall. (This also had a very important implication, which was missed by everyone, including Arrhenius, for more than 50 years after Arrhenius published his greenhouse theory. More on this later.)<br />
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Arrhenius also had a new analytical tool--the <a href="http://en.wikipedia.org/wiki/Stefan-Boltzmann_law">Stefan-Boltzmann law</a> which had been deduced by <a href="http://en.wikipedia.org/wiki/Joseph_Stefan">Jožef Stefan</a> in 1879, with some refinements added in 1884 by his student <a href="http://en.wikipedia.org/wiki/Ludwig_Boltzmann">Ludwig Boltzmann</a>. Arrhenius needed these mathematical tools to do his calculations. In theory, it was simple to calculate. Arrhenius was smart enough to realize it would not be so simple.<br />
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Aside from the stress coming from his divorce, which his wife Sofia Rudbeck was making as difficult as possible (this being the late 19th century, when divorce was strongly frowned upon and scandalous in itself) and teaching students and grading papers, which Arrhenius could do on autopilot, there was not much else to do. Arrhenius threw himself into the problem.<br />
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First he formulated his 'greenhouse law' (which still stands the test of time.)<br />
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<i>If the quantity of carbonic acid increases in geometric progression, the augmentation of the temperature will increase nearly in arithmetic progression.</i><br />
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This simplified expression is still used today:<br />
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ΔF = α ln(C/C0)<br />
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In short, each doubling of carbon dioxide in the atmosphere increases global warming by the same amount. A rise from 300 ppm to 600 ppm will increase global temperature the same amount as a rise from 600 ppm to 1,200 ppm will. <br />
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Arrhenius also took into account the effect that decreased snow cover would have on the albedo (reflectivity) of the Earth--showing how the feedback of decreased snowcover (or increase if carbon dioxide declined and the temperature fell) would augment the effects of changed in the carbon dioxide concentration. Arrhenius also took into account the effect that a warmer atmosphere would have on water vapor in the atmosphere---a warmer atmosphere could hold more water vapor--and water vapor is a potent greenhouse gas in itself. Figuring out how these feedbacks would augment each other was complex. He spent all of 1895 in tedious calculation, which gave him something to do while going through his divorce, and published <i>On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground</i> in the <i>London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science</i> in the April 1896 issue <a href="http://www.globalwarmingart.com/images/1/18/Arrhenius.pdf">here</a>.<br />
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Arrhenius' theory of anthropogenic global warming made a big splash. It was vigorously debated at the time (and still is, of course.) <a href="http://en.wikipedia.org/wiki/Knut_%C3%85ngstr%C3%B6m">Knut Ångström</a> made a strong criticism using the results of his experiments on the absorption of infrared radiation by carbon dioxide--which indicated that carbon dioxide was at a high enough level already that it absorbed all the infrared radiation that it could. Ångström and Arrhenius battled it out, but most physicists considered the Ångström criticism to be valid. <br />
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It later turned out that while CO2 absorbs all the IR radiation it can in two bands, CO2 absorbs in other bands as its concentration increases. Ångström had made his measurements with accurate equipment, but in a laboratory at room temperature. He didn't try matching the conditions one would see in the polar or upper level environments. As it turns out, in the polar regions and at dry mid and upper levels of the atmosphere there is not enough CO2 to absorb infrared radiation even in the two primary bands. <br />
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And there was another clue, staring people in the face---although no one realized it for over 50 years. When Frank Washington Very and Samuel Pierpoint Langley took their measurements of infrared radiation from the moon, the absorption increased when the moon was close to the horizon, and decreased when it was high in the sky. That showed right there that the absorption of infrared radiation was not saturated---otherwise it would have been the same---saturated in every direction equally! But no one realized this!<br />
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Arrhenius fought Ångström hard on the infrared absorption issue, but there was another problem. The ocean is alkaline, and was believed to absorb CO2 (carbonic acid) efficiently. In other words, we could emit CO2 into the atmosphere, but it would be mopped up in the ocean. The chemistry of the ocean was being determined and it was apparent that there was about 50 times as much CO2 in the oceans as in the atmosphere. Surely the ocean could absorb what CO2 we emitted easily!<br />
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Arrhenius was doubtful about that---although he admitted the oceans could have a buffering effect. Arrenhius' main arguement was that the oceans would not absorb CO2 immediately---and there was also the fact that despite the oceans are alkaline, there is still CO2 in the air? Why wasn't all atmospheric CO2 absorbed completely?<br />
There must be some mechanism that keeps CO2 in balance and prevents its complete absorption by the oceans. And that mechanism could prevent all additional CO2 mankind emitted from being absorbed by the seas.<br />
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But this was a weak argument without chemical knowledge and proof of such a buffering effect, and Arrhenius knew it. Arrhenius had strong support from Alfred Wallace in that there must be a buffering effect from the sea, despite the seas' alkaline nature. But it was not until the late 1950s and early 1960s that the buffering effect was shown to exist---and that came about because the rising CO2 levels documented by Charles Keeling in the first few years of his measurements defied explanation otherwise. (there was some work in the late 1950s that suggested that CO2 absorption by the oceans was buffered, but it was not until Keeling's graph that a strong research effort was done).<br />
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Arrhenius also publicized another radical idea--<a href="http://en.wikipedia.org/wiki/Panspermia">panspermia</a>---the spread of life from planet to planet by spores. As is usually the case, panspermia was an idea that had been kicked around by others before him---but as a speculative idea--not as a serious one. He first wrote about panspermia in 1903, and made it a major part of his book for educated popular audiences, <i><a href="http://books.google.com/books?id=1t45AAAAMAAJ&printsec=frontcover#v=onepage&q&f=false">Worlds in the Making--the Evolution of the Universe</a></i> The original English translation is from 1908 (which I have linked). The translation is a bit rough and stilted, since the book was originally published in Swedish as <i>Världarnas utveckling</i> in 1906 and translated into German as <i>Das Werden der Welten</i> (1907). The English translation is from the German--and it would be interesting to see if the book is available translated directly into English in more modern language. We could get Grothar on it ;)<br />
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Worlds in the Making--the Evolution of the Universe</i> also talks about the anthropogenic greenhouse effect. Some extracts follow:<br />
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"To a certain extent the temperature of the earth's surface, as we shall presently see, is conditioned by the properties of the atmosphere surrounding it, and particularly by the permeability of the latter for the rays of heat." (p46)<br />
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"That the atmospheric envelopes limit the heat losses from the planets had been suggested about 1800 by the great French physicist Fourier. His ideas were further developed afterwards by Pouillet and Tyndall. Their theory has been styled the hot-house theory, because they thought that the atmosphere acted after the manner of the glass panes of hot-houses." (p51)<br />
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"If the quantity of carbonic acid in the air should sink to one-half its present percentage, the temperature would fall by about 4°; a diminution to one-quarter would reduce the temperature by 8°. On the other hand, any doubling of the percentage of carbon dioxide in the air would raise the temperature of the earth's surface by 4°; and if the carbon dioxide were increased fourfold, the temperature would rise by 8°." (p53) [these are degrees Celsius, not Fahrenheit]<br />
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"Although the sea, by absorbing carbonic acid, acts as a regulator of huge capacity, which takes up about five-sixths of the produced carbonic acid, we yet recognize that the slight percentage of carbonic acid in the atmosphere may by the advances of industry be changed to a noticeable degree in the course of a few centuries." (p54)<br />
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*note--it turns out that the oceans absorb only half of CO2 we emit, not 5/6ths<br />
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"Since, now, warm ages have alternated with glacial periods, even after man appeared on the earth, we have to ask ourselves: Is it probable that we shall in the coming geological ages be visited by a new ice period that will drive us from our temperate countries into the hotter climates of Africa? There does not appear to be much ground for such an apprehension. The enormous combustion of coal by our industrial establishments suffices to increase the percentage of carbon dioxide in the air to a perceptible degree." (p61)<br />
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The last quotation from <i>Worlds in the Making--the Evolution of the Universe</i>, seen below, is interesting. Arrhenius thought that the anthropogenic greenhouse effect would be a benefit to mankind. Vast areas of Canada and Russia would be open to cultivation. Arrhenius correctly predicted that global warming would be more pronounced at the poles than in the tropics, so tropical life would not be affected greatly, he felt. The consequences of ice sheet melt and sea level rise do not seem to have entered his mind. Perhaps it was two factors that limited his foresight. <br />
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First, he was a Swede. Sweden is a cold place, where summers are pleasant, brief, and looked forward too. Arrhenius thought that places like Sweden would benefit from global warming. <br />
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Second, Arrhenius seriously underestimated how much the consumption of coal would increase---and he ignored oil and natural gas, which were not being used much at the time. By the 1890s, we knew about how much CO2 was in the air---measurements had narrowed it down to between 250 ppm and 350 ppm---300 ppm was what Arrhenius estimated. And that figure was close to correct at that time. However, by missing the growth in the consumption of fossil fuels, Arrhenius underestimated badly how rapidly CO2 would rise. He thought it would take 3,000 years for CO2 to double to 600 ppm. Instead we will do it before the 21st century is over--less than 200 years. A period of 3,000 years would be easier to adapt to, with so much more time. And as it turned out, Arrhenius was right about the oceans not absorbing all the CO2 humankind emits. But he underestimated there too. The oceans absorb only half the CO2 we emit, not 5/6ths. But we need to give Arrhenius credit for realizing that not all CO2 that we emit would be absorbed by the seas.<br />
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The last quote is below:<br />
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"We often hear lamentations that the coal stored up in the earth is wasted by the present generation without any thought of the future, and we are terrified by the awful destruction of life and property which has followed the volcanic eruptions of our days. We may find a kind of consolation in the consideration that here, as in every other case, there is good mixed with the evil. <i>By the influence of the increasing percentage of carbonic acid in the atmosphere, we may hope to enjoy ages with more equable and better climates, especially as regards the colder regions of the earth, ages when the earth will bring forth much more abundant crops than at present, for the benefit of rapidly propagating mankind</i>." (p63)<br />
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It has to be said that Arrhenius was not a person with great integrity. In 1900 he became part of the Nobel Prize Committee on Physics, and the <i>de facto</i> head of the Nobel Prize Committee on Chemistry. Arrhenius basically awarded the 1903 Nobel Prize for Chemistry to himself! And he used (abused) his position to award Nobel Prizes to his friends (Jacobus van't Hoff, Wilhelm Ostwald, Theodore Richards) and to deny Nobel Prizes to his enemies (Paul Ehrlich, Walther Nernst). Both of the later did receive Nobel Prizes, but Paul Ehrlich never got a Nobel Prize in Chemistry, being granted a Nobel Prize for Medicine instead. Walther Nernst received a Nobel Prize in 1920 after Arrhenius blocked it for 20 years---his achievements in chemistry were so notable that the rest of the Nobel Committee revolted in 1920 to award him the prize. Arrhenius definitely had a vindictive side to him.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com0tag:blogger.com,1999:blog-3318930696739797298.post-38669237767998267362011-02-09T18:00:00.000-08:002011-02-09T18:42:42.374-08:00Svante Arrhenius part 1By the end of the 19th century, the world had changed more since 1800 than in the thousand years before. From under 1 billion at the beginning of the century, the population was 1.5 billion and rising nearly 1% a year. Humankind was rumbling towards the population explosion of the 20th century. Advanced economies like the UK (35 million), Germany (60 million) and the USA (75 million) were industrialized and consuming hundreds of millions of coal per year. Railroads and coal burning ships had revolutionized transportation---the telegraph and telephone had revolutionized communications. Automobiles were just beginning to emerge, although not an environmental factor yet. Oil consumption was low, but about to explode. Humankind was on the threshold of being able to effect global environmental changes. <br />
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The dates of geological periods are always a bit arbitrary, except for the Cretaceous extinction--but sometime between 1800 and 2000 future scientists will say "Here marks the beginning of the Anthropocene period" and they will be right---although most were unaware of it at the time, and it is debated even now.<br />
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Svante August Arrhenius (1859-1927) was the first to realize that humankind could affect the global environment, and was in fact doing so. Although all the other figures I have discussed were important, it is with Arrhenius that the realization began that we are changing the global environment and the climate.<br />
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Arrhenius was a prodigy as a child, teaching himself to read at age 3 from the figures in his fathers' surveyor books and accounting figures. At age 8 he entered school at the fifth grade, and quickly became more adept at math than any of the other students in his school (which ran to high school) He sent for mathematical books from colleges and universities when his instructors were no longer able to teach him---and he was bored in high school. He wanted to attend the University of Uppsala early, but they would not admit him until he was 18--so in high school he studied his borrowed mathematics texts and waited.<br />
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In 1876 he entered the University of Uppsala and quickly became dissatisfied with the level of instruction he received--although he broadened his interests to chemistry. Due to rocky relationships with most of the faculty, whom he regarded as fools, he left the University of Uppsala in 1881 (without academic credit) after a serious dispute with <a href="http://en.wikipedia.org/wiki/Per_Teodor_Cleve">Per Teodor Cleve</a>, who found his chemistry work incomprehensible, to study at the Physical Institute of the Swedish Academy of Sciences in 1881. There Arrhenius researched under <a href="http://en.wikipedia.org/wiki/Erik_Edlund">Erik Edlund</a> about the electrical conductivity of electrolytes.<br />
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<a href="http://en.wikipedia.org/wiki/Michael_Faraday">Michael Faraday</a> had believed that salts dissolved into charged particles, which he called 'ions', a name we used for charged atoms and molecules today. This required an electric current--Faraday believed small electric currents were required to allow ionic chemical reactions to proceed. Arrhenius' insight was that ions could react with each other <i>by themselves</i>, <b>without</b> an intervening electrical current.<br />
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Arrhenius finished his doctoral thesis in 1884, a 150 page work (not exceptional for a doctoral thesis). What was exceptional was that his thesis contained 56 new ideas about physical chemistry--mostly to do with ionic chemical reactions. His thesis team was lead by Per Teodor Cleve, with whom Arrhenius had battled in the past--he came to the Physical Institute of the Swedish Academy of Sciences after Arrhenius did. <br />
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Arrhenius' thesis advisers thought his doctoral thesis mostly incomprehensible--giving it a rating in the 4th class. Upon Arrhenius' defense, they upgraded it to third class--barely acceptable. Arrhenius was incensed!<br />
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Arrhenius had his thesis translated into German (Germany being the center of physical chemistry and research in Europe) where it received wide admiration. <a href="http://en.wikipedia.org/wiki/Rudolf_Clausius">Rudolf Clausius</a>, <a href="http://en.wikipedia.org/wiki/Wilhelm_Ostwald">Wilhelm Ostwald</a>, and <a href="http://en.wikipedia.org/wiki/J._H._van_%27t_Hoff">Jacobus Henricus van 't Hoff</a> were <b>very</b> impressed. Ostwald even came to visit Arrhenius to persuade him to join his research team. Arrhenius wanted to very badly, but his father was very ill and in fact died later that year, so he declined. <br />
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Arrhenius's 1884 doctoral thesis won him the Nobel Prize for Chemistry in 1903.<br />
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After the heavyweights of the German chemists' establishment leaped so strongly to his defense, Arrhenius had a secure academic reputation--his old academic enemies could no longer hurt him. He became a traveling researcher for the Physical Institute of the Swedish Academy of Sciences, studying with Ostwald in Riga (then in Russia, now in Latvia), with <a href="http://en.wikipedia.org/wiki/Friedrich_Kohlrausch">Friedrich Kohlrausch</a> in Würzburg, Germany, with <a href="http://en.wikipedia.org/wiki/Ludwig_Boltzmann">Ludwig Boltzmann</a> in Graz, Austria, and with van 't Hoff in Amsterdam.<br />
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In 1889, Arrhenius developed the concept of <a href="http://en.wikipedia.org/wiki/Activation_energy">activation energy</a>, the energy chemical reactions must absorb from their environment to proceed. Energy didn't come from nowhere, it must be present in the environment for chemical reactions to occur, and Arrhenius worked out how to determine what activation energies were needed for various chemical reactions to occur. This work resulted in the <a href="http://en.wikipedia.org/wiki/Arrhenius_equation">Arrhenius equation<br />
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In 1891 Arrhenius became lecturer in Physics at the Stockholm University College (now Stockholm University) and promoted to professor in 1895 (over much bitter opposition from his earlier academic battles). Arrhenius also had a bit of a personal scandal. In 1892 he began dating his student, Sofia Rudbeck--the old 'sex with the professor' thing. It was....unseemly. He married her in 1894, and it seems clear that the marriage was something he felt required to do to get the professorship. The marriage quickly curdled in a few months--she left him in 1895 right after he got the professorship. Arrhenius was devastated. And bored. He had worked hard to become a professor, but it was not what he wanted. Teaching second-rate minds in a second-rate college. Office hours. Grading papers. Quite a come-down after his achievements!<br />
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Arrhenius was bored. His reputation had gotten him a professorship, but it was not what he expected. He felt depressed, and trapped.<br />
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Arrhenius came across some works by Joseph Fourier, who had originated the idea that the atmosphere can cause a greenhouse effect. For the first time, infrared observations of the moon, by <a href="http://en.wikipedia.org/wiki/Frank_Washington_Very">Frank Washington Very</a> and <a href="http://en.wikipedia.org/wiki/Samuel_Pierpont_Langley">Samuel Pierpont Langley</a> beginning in 1890 had confirmed that the average temperature of the moon, day and night sides put together, was around 0 F. This confirmed that the calculations by Fourier and others were correct---without a greenhouse effect, the temperature of the Earth would be close to 0 F. And the only thing that could account for Earth's warmer temperature was the atmosphere. It had been known since Tyndall's time that carbon dioxide was a an infrared absorber. <br />
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Wait. Coal consumption was now a couple hundred million tons a year---carbon dioxide therefore was being emitted at almost a billion tons a year. Could humankind be changing the atmospheric composition and climate? <br />
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Arrhenius' head snapped up. It was a cloudy dull morning. February 21, 1895.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com0tag:blogger.com,1999:blog-3318930696739797298.post-24704798369601178952011-02-04T21:00:00.000-08:002011-02-13T21:13:24.453-08:00The discovery of NeptuneOr the story of nice guy John Couch Adams and nasty guys James Challis and George Biddell Airy. <br />
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William Hershel discovered Uranus in 1781, as noted in an <a href="http://stsimonsislandgaguys.blogspot.com/2011/01/study-of-global-warming.html">earlier blog entry of mine.</a> This discovery doubled the size of the solar system and made William Hershel the most famous astronomer of the age. But could there be more planets?<br />
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First, we need to go back to Isaac Newton and his discovery of how gravitation works. The gravitational attraction between two bodies depends on the mass of the two bodies multiplied by the square of the distance between the bodies. However, in the real universe there are uncounted numbers of bodies which each attract each other. Unfortunately, the attraction that <a href="http://en.wikipedia.org/wiki/Three_body_problem">three bodies in motion have on each other cannot be solved, even in principle. </a> Let alone <a href="http://en.wikipedia.org/wiki/N-body_problem">many more.</a> The three body problem has still not been solved. However, we can reach a very good approximation by solving the gravitational attraction and motion of two massive bodies and then adding a third body (either less massive or further away) and then a fourth body, a fifth, and so on. The changes in velocity these further bodies have on the first bodies included in the equation are called perturbations. <br />
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For instance determining the orbital behavior of the moon around the earth, you first solve how the earth and moon attract each other, then put in the sun, Jupiter, Venus, Mars, Mercury, and Saturn. This was <i>very</i> complicated, and determining the moon's orbit drove Newton to distraction--Newton himself said that the problem of the moon's motion was the only one that ever made his head ache.<br />
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While a perfect solution to a many-body problem is impossible, by taking into account all the perturbations of the planets the error can be made vanishingly small. By the end of the 18th century the motion of the planets agreed with Newton's law perfectly as far as the telescopes of the time could determine. <br />
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Solving the problem of Uranus' orbital motion was relatively simple. You had to account for the sun, a small perturbation from Saturn, another small perturbation from Jupiter--and that was it. The inner planets (Mercury, Venus, Earth and Mars) were too small and too far away to have a measurable effect on Uranus's orbit.<br />
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But then came trouble.<br />
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In 1821 the French astronomer collected all the observational data or Uranus's orbit. He even went back through all the observations back to 1690 (Uranus had been first seen through a telescope and charted in 1690, but until Hershel it was just assumed to be a star. One astronomer charted Uranus <i>13</i> times in the middle 1700s, and assumed he had charted 13 stars!<br />
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The observations didn't fit. The distance observed between Uranus's <i>theoretical </i>position and its <i>actual</i> position was never more than 2 minutes of an arc. Or one-fifteenth of the apparent diameter of the full moon. Astronomers were dismayed. They didn't want a discrepancy of 2 arc-minutes. There shouldn't have been a discrepancy like that at all!<br />
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How to account for this? One idea was that Newton's inverse-square law of gravitation was wrong. Suppose instead of falling off to the second power (<i>d</i>2), it really fell off at an exponent of <i>d</i>2.001? Or <i>d</i>1.999? Then Newton's inverse-square law would seem to be correct until observing a really distant planet like Uranus before the discrepancy showed up. <br />
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The other possibility was that there was another planet out there, one that could account for Uranus's orbital behavior. Which was correct?<br />
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There was some thought that Newton might be slightly wrong--and there could be no surer way to scientific fame that to discover and correct a flaw in Newton's gravitational equations! But most scientists in general and astronomers in particular were against this idea. Newton's <i>d</i>2 formula was aesthetic. It was <i>elegant</i>. And most astronomers didn't want to mess with elegance.<br />
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Enter James Adams who graduated first in his class in mathematics from Cambridge in 1841. He decided to try and solve the problem of planet 8. The behavior of Uranus put some boundaries on the problem. If planet 8 was on the other side of the sun, it would be too far to perturb Uranus. So they had to be on the same side. Uranus had been ahead of it's predicted position through the late 1700s and into the early 1800s, but was now falling back closer to its predicted position. That meant that Uranus had overtaken Planet 8 sometime in the early 1800s and that Planet 8 was now behind Uranus (Uranus, closer to the sun would orbit faster. The actual overtaking was later determined to be in 1822).<br />
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The closer agreement between Uranus's actual position and its theoretical position during the 1800s also made some believe it was observational error that was being resolved as telescopes improved. However, that did not explain why the errors in Uranus's position were all on the same side.<br />
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Adams made some simplifying assumptions. Since Saturn is roughly twice the distance of Jupiter from the sun, and Uranus twice as far as Saturn is, Adams assumed that Planet 8 was twice as far from the sun as Uranus is. Adams also assumed that Planet 8's orbit was perfectly circular. Adams knew very well that all planetary orbits are ellipses, but most planetary orbits are close to circular, and calculating orbits was complicated enough on paper without trying all sorts of different elliptical configurations.<br />
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So Adams did simplify things, and some of his assumptions were off. One in particular turned out to be far off. Planet 8 is not twice the distance from the sun Uranus is, but only 1.5 times as far. But Adam's simplifications were reasonable ones.<br />
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By 1845 Adams had completed his calculations, and determined that on October 1, 1845, and for the rest of the decade, Planet 8 would be in the constellation Aquarius. <br />
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Adams gave his results to James Challis, the first villain of the story. James Challis was director of the Cambridge Observatory. Adams hoped that with the Cambridge Observatory at his disposal, Airy would make observations with dispatch. Adams was wrong. Airy, knowing that the observational search was likely to be tedious and most likely turn up nothing, ducked. He told Adams he was too busy, but he did fob Adams off with a letter of recommendation to the Royal Astronomer, George Burdell Airy.<br />
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Airy was a petty tyrant, always a nitpicker for detail and missing the big picture. Much later in life, he labored over expeditions sent around the world to measure the exact times the disc of Venus intersected the sun during transits in 1874 and 1882. By measuring from different vantage points on the Earth the exact times Venus's disk began and finished crossing the sun, the distance of Venus from Earth could be calculated precisely--and therefore all the distances of the planets from each other and the sun. Airy failed to account for Venus's atmosphere, which had been known about since the last pair of transits in the 1700s. The blurring effect of Venus's atmosphere ruined the the observations, and Airy's <i>very</i> expensive expeditions were failures. <br />
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The only success Airy had was a personal one. He developed eyeglass lenses that could correct astigmatism. He was himself astigmatic, literally and figuratively.<br />
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Airy, whose harsh treatment of his assistants and disdain for students was legendary, was the main Adams tried to contact. His letters to Airy went unanswered. In the days before the telephone, telegraph, and widespread railroads, Adams went down to Greenwich to visit Airy. Airy wasn't home. He went again. Airy wasn't home that time either. On a third visit, Adams was left to wait in the entryway for an hour before being informed that Airy was having dinner and would not be disturbed. <br />
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Adams left his paper with Airy who leafed through it and wasn't impressed. Airy was convinced that Newton's inverse-square law was in error and that he was going to find the error and correct Newton! Airy was convinced there was no new planet 8. Airy then wrote back to Adams sending him calculations using an adjustment of the inverse-square law, and nitpicking on two spelling mistakes Adams made in his paper.<br />
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Adams, realizing that he was dealing with a petty idiot, didn't bother to answer. He gave up.<br />
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Meanwhile, across the Channel, a young astronomer, <a href="http://en.wikipedia.org/wiki/Leverrier">Urbain Jean Joseph Leverrier</a> was also working on the same problem. He made the same assumptions Adams did, and located Planet 8 in the same part of Aquarius Adams had done. Leverrier had done some astronomical work and made some contributions (as Adams had not--Adams was a mathematician) <i>and</i> Leverrier had the support of his superiors. Leverrier published his calculations with his superiors' support. Leverrier made his calculations 6 months after Adams.<br />
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Airy read the paper, and wrote Leverrier back with irrelevant nit-picking objections. Leverrier wrote back, and pointed out that Airy's objections were irrelevant. <br />
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Airy was reluctantly impressed. He did not write back that Adams had made the same calculations, and never wrote back Adams either telling him about Leverrier. He certainly did not recommend Adams' paper for publication.<br />
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Airy then wrote Challis and told him to start looking for Planet 8. This Challis did, but in a desultory way, not comparing stars positions from night to night. He didn't even start looking for three weeks after he got Airy's letter. As the weeks went by, Leverrier, hearing nothing back from Airy or Challis, lost patience. It had been 9 weeks since Airy had written Leverrier that he would be leading the effort to find Planet 8, and after so much time, it was obvious that the English were not putting any effort into the search.<br />
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The director of the Berlin Observatory received Leverrier's letter on September 18, 1846 and he was interested. He asked the lead astronomer, Gottfried Galle to take care of it. <br />
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The next few days had lots of clouds, while Galle prepared for the obsevations. It would have been tedious work, but then a graduate astronomy student, Heinrich Ludwig D'Arrest, reminded Galle that the Berlin Observatory had been preparing new star charts more accurate than any before, and to see if Aquarius had been charted. It <i>had</i> been, only 6 months before! A lucky break!<br />
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The night of September 23 was clear. The Aquarius star charts were in their hands. Galle and D'Arrest got to work, moving the telescope methodically across the constellation, calling out the stars and their positions one by one. Only 30 minutes later D'Arrest cried out "That's not on the chart!" It was the planet! And it was only about 1.4 times the diameter of the full moon away from the predicted position! <br />
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Naturally Galle and D'Arrest observed the planet for a week, enough to determine its slow motion and a small disc. On September 30, 1846, they announced their discovery.<br />
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Once the discovery was announced, Challis went back over his observations and discovered he had observed Planet 8 <i>four times</i> but had not bothered to compare positions and did not know what he had seen.<br />
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Both Airy and Challis had made fools of themselves, and they knew it. Neither mentioned Adams' paper. <br />
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John Hershel, an English astronomer,, the son of William Herschel who had discovered Uranus, had heard of Adam's work and made sure it was published--and tried very hard to get proper credit to Adams, and publicized the incompetence of Airy and Challis. Herschel had long disliked Airy, considering him a tyrant and unfit for the position of Royal Astronomer. Herschel had also heard of Airy's abusive practices towards Herschel's and others' students, but his attempt to get Airy dismissed went nowhere. Airy tried to blackball John Herschel from astronomy in Great Britain, but Herschel's well-deserved reputation (as well as his father's reputation for discovering Uranus and infrared rays) prevented this.<br />
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The whole thing became a huge row. The French were convinced that the English establishment was trying to steal credit for calculating Planet 8's existence and position. The English raged about the perfidious French. The French offered a sop---name Planet 8 'Leverrier' and change Uranus (Georgium Sidus) back to Herschel. No one really liked <i>that</i> idea, however. Several astronomers suggested that since Planet 8 was blue-green in color, it should be named Neptune, for the god of the sea--and this was adopted.<br />
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Leverrier and Adams met and became friends. <br />
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In 1860, Challis retired as director of the Cambridge Observatory, and nominated Adams for the post, in what seems to have been an apology. Challis was not really evil---just slipshod. Adams stayed there for 21 years, until he was offered the post of Royal Astronomer when Airy retired, having served for 45 years. However Adams by this point was 61, and had suffered some illnesses, and did not feel up to taking the position, and became a teaching professor at Cambridge. Adams chaired the International Meridian Conference in 1884, which set the Greenwich Observatory as the Earth's prime meridian for time. Adams and Airy both died in January 1892.<br />
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Gottfried Galle survived to July 1910, one month past his 98th birthday.<br />
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John Couch Adams<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/wikipedia/commons/2/2b/John_Couch_Adams.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="326" width="295" src="http://upload.wikimedia.org/wikipedia/commons/2/2b/John_Couch_Adams.jpg" /></a></div><br />
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Urbain Jean Joseph Leverrier<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/wikipedia/commons/8/89/Urbain_Le_Verrier.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="851" width="669" src="http://upload.wikimedia.org/wikipedia/commons/8/89/Urbain_Le_Verrier.jpg" /></a></div><br />
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It needs to be said that none of the people in this entry were the first to see Neptune. The first person to see it (and the first person to actually be first to see a new planet, since Uranus is visible to the naked eye) was Galileo--who observed it near Neptune December 27, 1612--more than 200 years before its discovery!<br />
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In this drawing, Neptune is the 'star' in the green box with the notation 'fixa' or fixed--as in a fixed star. Here is the image from Galileo's notebooks:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjaoGEaaiUc6EUc7R1h8bHBl_jO7tI7wE2zZvF5yscTduCmEoYsm1vfDOQxqVy-7a8yN8DzS2O4VZaOcfInWGv0hgeJXv9m2g00ElvxAyQSS7rvF2ie6yc9GoRNbcRXhM8XgvC2KnZrXIJL/s400/Galileo+Neptune.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="109" width="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjaoGEaaiUc6EUc7R1h8bHBl_jO7tI7wE2zZvF5yscTduCmEoYsm1vfDOQxqVy-7a8yN8DzS2O4VZaOcfInWGv0hgeJXv9m2g00ElvxAyQSS7rvF2ie6yc9GoRNbcRXhM8XgvC2KnZrXIJL/s400/Galileo+Neptune.jpg" /></a></div><br />
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Galileo's notebook from January 27, 1613<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://www.fourmilab.ch/documents/sftriple/figures/galileo_neptune.gif" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="366" width="360" src="http://www.fourmilab.ch/documents/sftriple/figures/galileo_neptune.gif" /></a></div><br />
Interestingly in July 2009, David Jameson, a physicist from Melbourne Australia, discovered that Galileo used a different type of ink to mark Neptune's location in the January 1613 observation--one different from the rest of the page. Neptune was just turning retrograde in December 1612, its motion was not apparent. But it was moving more quickly against the fixed stars by late January 1613. Was Galileo aware that he had discovered a new planet? His notes don't say. But it is interesting that he used a different ink to mark Neptune, and that he did not label it a fixed star.<br />
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Perhaps he thought that the discoveries he had publicized were disturbing enough to the church--another planet that could not be seen with the naked eye would be just too much. So he kept the knowledge to himself--knowing the world was not yet ready for it. I'd like to think that was so.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com1tag:blogger.com,1999:blog-3318930696739797298.post-76356180704721564692011-01-31T20:09:00.000-08:002011-01-31T20:09:32.270-08:00The study of Global Warming Part 5: Joseph Adhemar and James CrollJoseph Adhemar (1797-1862) was the first person to develop an astronomical theory for the ice ages and interglacials. Aggasiz's publication of Etudes sur les glaciers stimulated a great interest in the causes of climate change, now that it was shown to have occurred.<br />
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Joseph Adhemar was the first to propose an astronomical cause for the ice ages. Adhemar's theory was wrong, but it did point later scientists in a useful direction.<br />
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Adhemar knew about the precession of the equinoxes (which made such a splash a few weeks ago when it was revealed that astrological signs are no longer correct). The Earth's orbit is elliptical, and as a result the earth moves more slowly when it is further away from the sun. Now, the Earth is closest to the sun during the first week of January, and furthest during the first week of July. As a result, the polar night is 178.8 days at the North Pole and 186.5 days at the South Pole. <br />
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As a result, Adhemar believed that ice ages alternated by hemisphere, with the Southern Hemisphere currently in an ice age, and the Northern Hemisphere in an interglacial. He published his ideas in <i>Revolutions of the Sea<i><i></i></i></i> (1842). He believed the length of the polar night was the determining factor. This was wrong, he didn't take into account that when the polar night is longer, the sun is closer to the Earth during the summer, and actually delivers more heat. And of course it turned out that ice ages are global, not alternating by northern and southern hemisphere. <br />
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And yet, Adhemar did stimulate new investigations into astronomical influences on climate change.<br />
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James Croll (1821-1890) was the first scientist to develop a good astronomical mechanism for causing the ice ages. His ideas were valid--although his calculations contained many errors and his timing was way off. However, these errors were not his fault.<br />
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Croll was not from a wealthy background and was not formally educated. Many bright people in the 19th century never were able to obtain a high school, let alone university education. He was apprenticed as a wheelwright when he was 16, but being very bright was not happy with his lot in life. He read when he could and self-taught himself physics and astronomy, and became a tea merchant, then a manager of a hotel, and then an insurance agent. In 1859 he became caretaker to the museum of the <a href="http://en.wikipedia.org/wiki/Andersonian_College_and_Museum">Andersonian college (presently the University of Strathclyde</a>), so as to have access to the college library, where he could get information on his pet project---solving the mystery of the ice ages!<br />
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Croll worked for over a decade, working out how variations in the eccentricity of the orbit of the Earth, the procession of the equinoxes, changes in the tilt of the Earth's axis and variations in sunlight received at the poles that these variations caused could cause the ice ages. <br />
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An objection to astronomical influences on climate had been that the changes in sunlight in the polar regions were so small and subtle. Croll realized that these variations could be more than 10% and therefore significant. Croll also had a key insight. The albedo variations caused by changes in snow cover could <b>amplify</b> the changes in climate--a positive feedback! This new idea when combined with orbital and axial variations enabled them together to account for all the temperature change needed to plunge the Earth into an ice age, and bring it out!<br />
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Unfortunately, information was not available to calculate accurately how the gravitational attraction of other planets changed the eccentricity of the Earth's orbit. The distances of the planets from each other and the Earth were known to a relative degree, but the absolute distances were still not known to within a few percent. The masses of the planets were also not known very well. Jupiter and Venus influence the orbit of the Earth more than other planets (although all the planets from Saturn inwards have measurable effects). In particular, while the mass of Jupiter could be determined with some accuracy due to the orbital motions of the Galilean satellites---Venus has no satellites, and therefore there was no way to determine its mass. The same thing with Mercury. <br />
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Another factor was that relativity had not been discovered. In relativity, mass and energy are equivalent, and the energy of gravitation has its own mass---which changes the orbit of Mercury enough so that its orbit had motions not accounted for in Newtonian mechanics. In fact, there was a widespread belief that there had to be a planet closer to the sun than Mercury to account for its orbital behavior, and astronomers were on the hunt for the planet Vulcan, believed to be between one-third and half the distance from the sun that Mercury is.<br />
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The result of all this is that while Croll calculated accruately with the best available information he had, his solutions to the equations for determining variations in the orbit of the Earth were wrong. Way wrong.<br />
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Croll thought the last ice age had ended 80,000 years ago. Before carbon dating emerged after World War II, it was impossible to date material accurately. But there were two clues that indicated 80,000 years was far too long. <br />
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First, Niagara Falls. By the late 19th century, Niagara Falls had been observed for more than 200 years, and its rate of erosion back along the Niagara River was well known. Timing back from when the falls first started on the Niagara Escarpment yielded estimates of around 10,000-12,000 years for the age of the falls when the ice sheet receded. Of course the river flow and the condition of the rocks could be different in the past, and the extreme outlier estimates were as young as 6,000 years and a few estimates were beyond 20,000 years---30,000 at the very extreme. But there was no way, geologically, that Niagara Falls was 80,000 years old.<br />
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There were also annual deposits of silt in lakes that left thin layers---and these could be investigated. None of these lake deposits went back more than 20,000 years. And during the oldest lake deposits, investigations of pollen in lake bed sediments revealed that the vegetation was from colder adapted plants more than 10,000 years ago, and no lakes in areas were ice sheets occurred seemed to be older than 19,000 years. <br />
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Croll's ideas about the influence of orbital variations, axial tilt and procession of the equinoxes were much discussed, and regarded as interesting. But they just didn't fit the direct evidence of erosional rates of Niagara Falls and other falls, and the lake deposits. And as more and more lake deposits were studied, the evidence against such an ancient end to the last ice age became untenable. <br />
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It was not until Milutan Milankovitch did his work well into the 20th century, with <i>accurate</i> figures for the mass and orbit of the planets that a workable astronomical theory of the ice ages was developed. <br />
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Croll was just ahead of his time--he had the right ideas, but didn't have the right information to make his theory stand up.<br />
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Despite this, Croll was well respected among scientists. He had regular correspondences with Charles Lyell from 1864 on, and Charles Darwin. Croll published his work <i>Climate and Time, in Their Geological Relations</i> in 1875, and reviews from other scientists were very positive. (it took over a decade for him to make all the astronomical calculations!) In 1876, despite never having completed a middle school education, Croll was elected as a fellow of the Royal Society, and granted an honorary degree from St. Andrew's university. It may have helped that Croll was friendly, funny, and well liked. Croll retired in 1880 due to ill health but at least he got to the pinnacle of scientific respect. Quite an achievement for a wheelwright with a 6th grade education!<br />
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If you interviewed a geologist or physicist from 100 years ago they would probably tell you that Croll was a brilliant man who had an interesting idea about the ice ages, researched it well, and was just plain wrong. <br />
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No he wasn't wrong--he just had inaccurate information to work with. Croll was ahead of his time.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com2tag:blogger.com,1999:blog-3318930696739797298.post-87509477057341043172011-01-26T20:35:00.000-08:002011-01-26T22:13:10.804-08:00The Study of Global Warming Part 4: John TyndallJohn Tyndall (1820-1893) was a distinguished physicist with many interests. Although his first papers were about magnetism, explaining magnetic polarity, his papers ranged across almost every branch of physics. He also invented many scientific instruments, such as the <a href="http://en.wikipedia.org/wiki/Nephelometer">nephelometer</a> and <a href="http://en.wikipedia.org/wiki/Turbidity">turbidimeter</a>. He was the first to create germ free air. He discovered <a href="http://en.wikipedia.org/wiki/Thermophoresis">thermophorisis</a>. He discovered that ozone is a form of oxygen. <a href="http://en.wikipedia.org/wiki/Tyndallization">He developed the first method of sterilization that was effective against bacterial spores that were not killed by boiling water</a>. Among his more practical inventions were the firemen's respirator and an effective foghorn. <br />
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Of more relevance to the atmosphere and climate, he discovered the <a href="http://en.wikipedia.org/wiki/Tyndall_Effect">Tyndall Effect</a>, a form of radiation scattering by colloidial suspensions.<br />
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His interest in climate began when he visited Switzerland in the summer of 1856 and became fascinated with glaciers. For the rest of his life he spent almost every summer in Switzerland, and became an accomplished mountaineer, becoming the first person to climb the <a href="http://en.wikipedia.org/wiki/Weisshorn">Weisshorn</a> in 1861.<br />
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Tyndall was enthralled by glaciers---how they flowed, how they changed. How they eroded landscapes and modulated river flow. Glaciers were much talked about after Louis Agassiz had published his Ice Ages hypothesis--the first indication that climate can change!<br />
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In the 1850s, it was believed that the atmosphere was transparent to infrared radiation. After all, how else would the Earth get warm? Fourier's insight that light could penetrate the atmosphere and reach the earth, which then absorbed some of it and re-radiated it as infrared radiation had been largely forgotten or discarded. (Even though Fourier didn't think the atmospheric greenhouse effect was real, he was the first to seriously discuss the idea)<br />
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Tyndall thought this was nonsense. If the atmosphere was transparent to infrared radiation, then how could Earth stay warm? Fourier had thought that outer space was not that cold. But observations of asteroids that looked like they were composed of ice contradicted that idea. If they could survive as ice bodies that close to the sun, he calculated that interstellar space <i>had</i> to be close to absolute zero. <br />
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So how to test this his hypothesis that the atmosphere could trap infrared radiation? In 1859 he built this apparatus:<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="http://upload.wikimedia.org/wikipedia/en/d/d4/TyndallsSetupForMeasuringRadiantHeatAbsorptionByGases_annotated.jpg" imageanchor="1" style="clear:left; float:left;margin-right:1em; margin-bottom:1em"><img border="0" height="400" width="600" src="http://upload.wikimedia.org/wikipedia/en/d/d4/TyndallsSetupForMeasuringRadiantHeatAbsorptionByGases_annotated.jpg" /></a></div><br />
He tested oxygen and nitrogen. Both were transparent to infrared radiation. So he then tried coal gas (mostly methane, with some carbon dioxide, carbon monoxide and water vapor). Eureka! Coal gas blocked infrared radiation as much as an inch of wood!<br />
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He also tested carbon dioxide and found that it also absorbed part of the infrared rays. <br />
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And then tested water vapor which was also avidly absorbed infrared radiation. And measured the temperature of these gases--the absorbed infrared radiation indeed warmed the gas!<br />
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This was a very important discovery. Gases could trap radiation and warm the earth!<br />
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But it was also limited. Water vapor is the greatest contributor to our present temperature deviation from equilibrium--but what of methane and carbon dioxide? <br />
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The problem was that both gases are rare. Methane is less than 2 parts per million in the atmosphere, and CO2 was less than 1/3000th of the atmosphere. In 1859 there was no way to accurately measure the concentration of such gases in the atmosphere. In fact, methane levels were too low to be detected. It was obvious that carbon dioxide <i>must</i> be part of the atmosphere--after all every animal exhales it. Tyndall was able to determine that carbon dioxide was present between 100 ppm and 600 ppm by pumping controlled amounts of air through a weak alkaline solution and see how much was converted to its salt, reacting with the carbon dioxide. But that margin of error told him nothing. He had no way to accurately measure carbon dioxide changing its concentration from night to day, season to season, year to year. <br />
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In 1862 Tyndall wrote this: "As a dam built across a river causes a local deepening of the stream, so our atmosphere, thrown as a barrier across the terrestrial [infrared] rays, produces a local heightening of the temperature of the Earth's surface." from <i>Further Researches on the Absorption and Radiation of Heat by Gaseous Matter</i><br />
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By 1863, frustrated by his inability to measure what effect methane and carbon dioxide had on trapping infrared radiation, and recognizing that water vapor was the most important greenhouse gas (which it is) he wrote that water vapor "is a blanket more necessary to the vegetable life of England than clothing is to man. Remove for a single summer-night the aqueous vapor from the air....and the sun would rise upon an island held fast in the iron grip of frost." from "On Radiation through the Earth's Atmosphere", <i>Philosophical Magazine</i> pp. 204-205.StSimonsIslandGaGuyshttp://www.blogger.com/profile/07442103883395280194noreply@blogger.com3