The Causes of Climate Change conference--Boulder, CO 1965

Are 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.

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 30 billion tons for the first time in 2010, q.v.).

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.


Second, the work of Drs. Roger Revelle and Gilbert Plass showed that the oceans would not, could not, absorb all of humankind's carbon dioxide emissions, and that additional carbon dioxide would increase absorption of infrared radiation.

And then, Dr. Charles Keeling proved through his meticulous measurements of atmospheric carbon dioxide, and his isotopic analysis, that humankind's activities were 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 possible 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.

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:

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 Dr. Walter Orr Robertsm who founded the National Center for Atmospheric Research 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.

The National Center for Atmospheric Research. The futuristic buildings served as a set for the comedy classic Sleeper, directed and written by Woody Allen.

Also in 1963, Dr. Ried Bryson (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 global dimming would trigger global cooling--and that was the major threat that humankind's activities would have on the environment, a view that influenced Dr. Isaac Asimov (1920-1992) during the 1960s and 1970s.

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.

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.

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.

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 Dr. Arthur C. Clarke's novel 2001: A Space Odyssey (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 uniformitarian mindset that typified earth science studies from the time of geologist Dr. James Hutton 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 neo-catastrophism mindset, of which the extinction of the dinosaurs by the impact of a comet/asteroid is the most prominent example.

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 (q.v.) Their discoveries also indicated that climate change could have been rapid, although this discovery was resisted. However, in the early 1960s, work by Dr. Wallace Smith Broecker (Wally) (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, Dr. Edward Lorenz (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.

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.

The work by Dr. Charles Keeling (q.v.) 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.

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"*

*National Academy of Sciences, Committee on Atmospheric Sciences Panel on Weather and Climate Modification, Weather and Climate Modification: Problems and Prospects. 2 vols. (Washington, D.C., National Academy of Sciences, 1966), col. 1, p. 10.

Charles David Keeling

Dr. Charles David Keeling (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.

Dr. Charles Keeling was born in Scranton, PA on April 20, 1928. A precocious child, he obtained his B.S. in chemistry from the University of Illinois in 1948 at age 20, and earned his PhD in chemistry from Northwestern University in 1954.

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 California Institute of Technology 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 electron capture dectector invented by Dr. James Lovelock in 1957, which was adopted worldwide for sampling in the 1960s.
In 1956 he was invited to join the Scripps Institution of Oceanography by Dr. Roger Revelle (q.v.)

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.

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 International Geophysical Year of 1957-1958 (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 Mauna Loa Observatory, beginning March 1, 1958. Dr. Keeling also supervised a carbon dioxide sampling program from the new Antarctic bases established during the IGY.
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.

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.

Dr. Keelings measurements soon showed that carbon dioxide was 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!

Dr. Keeling published his preliminary findings in the June 1960 of Tellus in the article "The Concentration and isotopic abundances of carbon dioxide in the atmosphere" This article contains the graph I embedded below:

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.

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 National Science Foundation. (NSF) But in January 1964 the money ran out. Carbon dioxide measurements at Mauna Loa Observatory stopped.

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.

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 ENSO 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.

Note the funding hiatus in 1964. Mind the gap!

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.

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. 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).

Whenever a denier claims that the scientific community was predicting global cooling in the 1970s, that denier is either ignorant, or deliberately lying.

Dr. Keeling was concerned enough about rising carbon dioxide levels to participate in a panel by the Conservation Foundation on March 12, 1963 "Implications of Rising Carbon Dioxide Content of the Atmosphere", 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)

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.

Dr. Keeling did have a monomania concerning carbon dioxide, but it was a productive 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:

Second Half Century Award of the American Meteorological Society, 1981
Maurice Ewing Medal of the American Geophysical Union, 1991
Blue Planet Prize from the Science Council of Japan and the Asahi Foundation, 1993
National Medal of Science, by George W. Bush in 2002
Tyler Prize for Environmental Achievement in 2005 (shared with Lonnie Thompson)

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. Dr. Ralph Keeling is the current director of the Scripps CO2 Program.

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.


A picture of Dr. Charles Keeling in 1997:

Here is the latest Keeling Curve, with the full record of carbon dioxide levels in the atmosphere:

A report released today (May 30, 2011) by the IEA reports that our CO2 emissions reached a new record in 2010, 30.6 billion tons. CO2 emissions in 2010 were 5% higher than the previous record in 2008.

A striking image of arctic sea ice concentrations in 2007

I thought this deserved it's own entry. I wonder how this year will shape up? Arctic sea ice has been falling very rapidly so far in May, but it's too early to say if arctic sea ice will reach a record low this year.

Plus a couple of news stories I found interesting:

Murky exoplanet 'could host life'

Human arrival 'wiped out' Hawaii's unique crabs

Gilbert Norman Plass

Dr. Gilbert Norman Plass (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 would increase infrared radiation absorption and global surface temperatures, along with Roger Revelle's 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.

Back at the end of the 19th century, Svante Arrhenius made his famous proposal of anthropogenic global warming. But although a few lonely scientists believed him and carried on research in anthropogenic global warming, Knut Johan Ångström 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.

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. Frank Washington Very and Samuel Pierpont Langley 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 proved 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!

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.

After World War II, as part of the United States' rapidly expanding scientific research, the Office of Naval Research. 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).

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 Thule (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?

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, proving it was another.

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 quantum mechanics. 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 he contributed to an article in Time magazine saying so. 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 prove that infrared absorption was not saturated at current levels of carbon dioxide in the atmosphere.

Dr. Plass published his work in the July 1956 issue of American Scientist. 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 1957-1958 International Geophysical Year, 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 still cited by deniers).

Dr. Plass's paper is summarized and discussed here.

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.

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.

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.

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.

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 Charney report of 1979, 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.

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.

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.

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.

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.


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.

And Charles Keeling was to definitively answer it. But that's for the next blog entry.

Here is a picture of Dr. Gilbert Plass:

Dr. Plass left Lockheed in 1960 to join the research staff of Ford's aeronautical division. Dr. Plass also edited Infrared Physics and Technology, 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.

More 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!

In the meantime a cartoon by the 2010 Pulitzer prize winner for editorial cartoons, Mike Keefe:

And I like this new video, adding it back after the outage:






And...for the very first time on record, the concentration of CO2 exceeded 393 ppm at Mauna Loa, during April 2011.

Which fits well with my new entry about Dr. Charles Keeling, coming soon!