Self-correcting feedback mechanisms? When warming leads to cooling

An interesting paper from Curry et al. providing further evidence of a relationship between melting ice in the Arctic regions and widespread cold outbreaks in the Northern Hemisphere. Forcing mechanisms are all the rage where feedback loops lead to runaway effects. In general – in my experience with things technical – natural feedback loops are most often self-correcting. Sometimes they may appear in the short-term to amplify effects but in the long-term they drive back to an equilibrium condition. If feedback mechanisms are not known or if the true cycle-time of the feedback is unknown then short-term effects can be misleading.

Jiping Liu, Judith A. Curry, Huijun Wang, Mirong Song, and Radley M. Horton. Impact of declining Arctic sea ice on winter snowfallProceedings of the National Academy of Sciences, February 27, 2012 DOI:10.1073/pnas.1114910109

Newswise: 

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.”

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