Wednesday, June 15, 2011

New Maunder Minimum? Don't Count on it!

There's been a lot of loose talk in the past couple days about a new Maunder Minimum 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.

A NASA image of the Maunder Minimum:

Andrew Rivkin writes about this latest deus ex machina here.

Dr. Doug Biesecker, the head of NOAA's sunspot team, has created a slideshow presentation here.

And Dr. Biesecker has written up a report "Predicting Solar Cycle 25" which goes into further detail.

An article about the case for a second Maunder Minimum, from The Economist, a source I generally find credible, is here.

Richard Black of the BBC also has an interesting take on the possibility of a Maunder Minimum II and its effects here.

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.

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.

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.


  1. It should also be noted that even if another Maunder Minimum occurred, it is likely that TSI during the MM didn't go any lower than it did the past few years; in other words, there is no long term trend in the "baseline" (at least not on relevant scales; such as the 10% increase per billion years). that is shown in newer reconstructions of TSI which have trended towards less variability, as shown here, note also what it says at the bottom (screenshot taken from this PDF, which also argues that sunspots were undercounted in the past, thus, the apparent increase in the 20th Century is an artifact and it was really not much different from the 19th Century):

    That is also apparent when you compare the last minimum to the one before the strongest solar cycle in the past century:

    Of course, to add to the confusion, there was a recent study that claimed that TSI (in the visible wavelengths) actually increased during minima, but that hasn't been proven yet.

  2. Michael, thanks for your excellent comment! I had suspected that sunspot counts in the 1600s could be low---after all how well could 17th century technology find sunspots, and how many were looking, anyway? And I had forgotten about the study showing that visible light solar emissions *may* have increased during the MM, although I did read that on realclimate when it came out.

    There's been a bad outbreak of pseudoscientific crap this week about a new Little Ice Age about to be triggered by a long-term decline in solar activity and radiative emissions. This has been played up tremendously by bloggers on another weather site.

    Three points---we don't have the capability to predict low solar emissions for the next 50 years. Even if such a thing does happen, we didn't observe the sun with scientific tools before the Maunder Minimum, so we don't know what signs to look for.

    Second, our knowledge of the Maunder Minimum is vague to say the least. There is just enough information to be a tease, but we can't confidently say what exactly the Maunder Minimum was, what caused it, or what the solar emission spectra were during the 17th century.

    Third, the solar forcing from the addition carbon dioxide we have emitted into the atmosphere, along with other greenhouse gases vastly outweighs even the most radical estimates for the greatest declines in solar emissions. If a new Maunder Minimum does happen, it might slow global warming but not stop it (and the acceleration in warming when Maunder Minimum II ends would be catastrophic.)

    I'm not sure what the Little Ice Age was, or what caused it. It's not clear it was global in extent. Colonial accounts in the 1600s in the USA show some cold winters, but nothing out of line with winters in later centuries. There is nothing in 17th century colonial records to match the winters of 1780-81, or 1899. Cold in Europe in the 17th century was definitely a real event--and it *did* snow in Cairo in January 1639--and hasn't since.

    I had thought that the Little Ice Age in the 17th century might have been triggered by a change in the circulation of the North Atlantic Ocean. However, I have come across accounts of very cold winters in China in the 1680s. Snow fell to the beaches on Hainan island in January 1684 and nothing close to that has happened in modern times. I'm not sure a change in the Atlantic circulation could account for that. But the Little Ice Age was more marked in Europe than other places.

    This whole Maunder Minimum II projection is pretty much crap.

  3. “The example I like to use is that greenhouse warming right now is the equivalent of 2 watts of power illuminating every square meter of the Earth’s surface. It’s like a Christmas tree light over every square meter. By mid-century, it will be closer to 4 watts,” said Mann, who was a co-author on that 2001 Science paper. “The maximum impact factor of the sun is 0.2 watts per meter squared.” [ ]

  4. If the sun spots do wink out and another Maunder like minimum occurs, you can bet your britches that it's going to get much colder. Offset by GHGs and CO2, baaah humbug! Don't poney up to the OK corral on that one. Normal and variable global warming is happening. Unprecedented warming created by man is not. Rise in CO2 lags air temps. It stands to reason that CO2 decreases prior to atmospheric cooling as the oceans chill down. Also,as the insulated effects of Arctic ice are lost, the Arctic waters will chill down more quickly (to reform the ice).

  5. CO2 is not decreasing in concentration, it is increasing steadily as we emit more CO2 into the atmosphere. And the radiative forcing from CO2, methane, and other greenhouse gases we are emitting is already greater than the decrease in radiation from the sun during the Maunder Minimum. At most a new Maunder Minimum type event would slow global warming, but would not stop it.