Scientist: “The warm extremes kept trending just as one would expect in a period of accelerating global warming.”
Locations where the seasonal “severe cold index” (blue circles) or “severe heat index” (red circles) fell above the 95% confidence interval of the North Atlantic Oscillation regression for (a, c) Winter 2010 and (b, d) Winter 2011.
JR: Here is a little-covered news release from the American Geophysical Union from last month. The study itself is here (subs. req’d). I never got around to posting it but for some reason the study seems appropriate today:
Last two winters’ warm extremes more severe than their cold snaps
During the last two winters, some regions of the northern hemisphere experienced extreme cold not seen in recent decades. But at the same time, the winters of 2009-10 and 2010-11 were also marked by more prominent, although less newsworthy, extreme warm spells.
New research examines daily wintertime temperature extremes since 1948 The study finds that the warm extremes were much more severe and widespread than the cold extremes during the northern hemisphere winters of 2009-10 (which featured an extreme snowfall episode on the East Coast dubbed “snowmaggedon”) and 2010-11. Moreover, while the extreme cold was mostly attributable to a natural climate cycle, the extreme warmth was not, the study concludes.
“We investigated the relationships between prominent natural climate modes and extreme temperatures, both warm and cold. Natural climate variability explained the cold extremes; the observed warmth was consistent with a long-term warming trend,” says Kristen Guirguis, a postdoctoral researcher at Scripps Institution of Oceanography, UC San Diego and lead author of the study, which is set to be published in the journal Geophysical Research Letters, a publication of the American Geophysical Union.