Little Ice Age result of volcanic eruptions, new study says | Alaska Dispatch

The new research is consistent with other recent studies of the Little Ice Age, notes Michael Mann, a climate scientist at Pennsylvania State University, in State College. The global cooling was attributable to volcanic activity. But the regional distribution and intensity of cold temperatures owed much to the sun's weakened output, he adds in an e-mail.

The sun produces most of its radiation as ultraviolet light, which sees the largest swings in intensity with the rise and fall of the sunspot cycle. Most of the ultraviolet light is intercepted by ozone in the stratosphere; the UV light builds ozone molecules there. Ozone is a greenhouse gas. When solar radiation declines, so does stratospheric ozone, cooling the stratosphere. This changes wind patterns there. These changes eventually work their way into wind patterns in the lower atmosphere, as well.

In a paper in the journal Science in 2009, Dr. Mann and colleagues showed how these shifting patterns during the Little Ice Age – when the sun entered a pronged period of weakened radiation – would have thrown natural climate swings into one phase more often than the other.

Twitter / @BadAstronomer: The WSJ and Daily Mail pos ...

The WSJ and Daily Mail posted articles on climate change that are the wrongiest wrongs ever wronged. is.gd/qPjm5I

Germany's Top Environmentalist Turns Climate Sceptic

Fritz Vahrenholt, one of the fathers of Germany's environmental movement, no longer trusts the forecasts of the IPCC. Doubt came two years ago when he was an expert reviewer of an IPCC report on renewable energy. "I discovered numerous errors and asked myself if the other IPCC reports on climate change were similarly sloppy. I couldn’t take it any more. I had to write this book.”