A new study led by the Georgia Institute of Technology provides further evidence of a relationship between melting ice in the Arctic regions and widespread cold outbreaks in the Northern Hemisphere….
Since the level of Arctic sea ice set a new record low in 2007, significantly above-normal winter snow cover has been seen in large parts of the northern United States, northwestern and central Europe, and northern and central China. During the winters of 2009-2010 and 2010-2011, the Northern Hemisphere measured its second and third largest snow cover levels on record.
“Our study demonstrates that the decrease in Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation,” said Judith Curry, chair of the School of Earth and Atmospheric Sciences at Georgia Tech. “The circulation changes result in more frequent episodes of atmospheric blocking patterns, which lead to increased cold surges and snow over large parts of the northern continents.”
That’s from the news release of an NASA- and NSF-funded study in the journal Proceedings of the National Academy of Sciences, “Impact of declining Arctic sea ice on winter snowfall.”
I think Curry’s use of the phrase “cold surges” is important. Although there have definitely been some major cold blasts, our winters aren’t actually getting colder — see the 10/11 Climate Progress post, “Last Two Winters’ Warm Extremes More Severe Than Their Cold Snaps, Study Finds.” And that’s without counting this winter. Of course, winters are just going to keep getting warmer globally — so I think some of the reporting on this study has been a tad misleading.
The point is that it now appears over the next couple of decades, the gradual rate of warming will not be able to overcome the occasional incredible winter cold surges fueled by the loss of Arctic ic. This is particularly true if, as I and others have argued, we’re going to see continued rapid ice loss in the next decade (see “The New Arctic Abnormal: Record Low Sea Ice Volume, Area and Extent*” and “The death spiral continues“).
Arctic sea ice in September 2007 reached its lowest extent on record, approximately 40% lower than when satellite records began in 1979. Sea ice loss in 2011 was virtually tied with the ice loss in 2007, despite weather conditions that were not as unusual in the Arctic.
The new PNAS report is about the third study to come to the same conclusion:
The disinformers have repeatedly suggested that big snowstorms disprove (!) climate science. They can’t stand the fact that actual science says that the Snowpocalypses we’ve been seeing can be directly linked to global warming, which, of course, wasn’t news to anyone who actually reads the scientific literature or talks to real climatologists (see “An amazing, though clearly little-known, scientific fact: We get more snow storms in warm years!“).
This study is probably particularly annoying to the disinformers since it was co-authored by Curry, who has transformed herself from climate science advocate into a promoter of many long-debunked disinformers (see “The curious incident of Curry with the fringe“).
The lead author, Jiping Liu, a senior research scientist at Georgia Tech, explained that the study looked at more than just changes in atmospheric circulation. It also looked at changes in atmospheric water vapor content, which into scientists have long said would increase because of global warming and drive more extreme precipitation events, which in fact is what has happened (see “Two seminal Nature papers join growing body of evidence that human emissions fuel extreme weather, flooding that harm humans and the environment“).
As ABC News reports, “more water is evaporating into the air as Arctic ice at the ocean’s surface melts away”:
“This greatly enhances the transfer of moisture from the ocean to the atmosphere,” Liu said. That humidity, he says, essentially acts as fuel to help supercharge “Snowmageddon”-type storms like the ones that paralyzed parts of the northeastern U.S. in 2010. A more recent, deadly deep freeze in Eastern Europe left 650 people dead.
“The record decline in Arctic sea ice is at least a critical contributor to recent snowy winters in northern continents,” Liu said.
Liu says the new research may also help connect the dots between human-caused global warming, vanishing ice and our changing weather.
As Climate Central notes, “The Arctic has been warming at about twice the rate of the rest of the globe, a trend studies show is largely due to manmade climate change. Fall sea ice cover declined by 27 percent between 1979-2010, and the five lowest sea ice extent years have all occurred during the past five years.”
They spoke to another leading expert on the subject: