Melting Arctic leads to snowy winters
That missing iceberg is 12" deep on your driveway
Georgia Tech has lobbed a small grenade into the climate change debate, with a study suggesting a correlation between melting Arctic pack ice and snowy winters in the Northern Hemisphere.
The study, announced February 27, notes that above-average snow cover in the Northern Hemisphere has been measured each year since 2007 (when Arctic sea ice reached a record low level). During the 2009-2010 and 2010-2011 Northern Hemisphere winters, snow cover reached its second and third highest 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.”
The NASA- and NAS-supported research seeks to identify the mechanisms by which declining Arctic sea ice might influence winter weather conditions.
Georgia Tech researcher Jiping Liu said the research suggests that higher-than-usual sea ice melts in late Northern Hemisphere summers appears to be altering atmospheric currents – “weakening westerly winds, increasing the amplitude of the jet stream” – while at the same time lifting atmospheric moisture content.
Simulations run by the researchers also suggest that as the sea ice retreats, it results in surface warming in Greenland, north-eastern Canada, and the Arctic Ocean. This is matched by a corresponding surface cooling over Northern America, Europe, Siberia and eastern Asia, leading to above- average snowfall in those regions.
More simply: the moisture lost to the Arctic in the form of melting sea ice has to end up somewhere – and it appears to be falling as snow during the northern winter.
The Georgia Tech announcement says: “The consistent relationships seen in the model simulations and observational data illustrate that the rapid loss of sea ice in summer and delayed recovery of sea ice in autumn modulates snow cover, winter temperature and the frequency of cold air outbreaks in northern mid-latitudes.”
The research has been published in the Proceedings of the National Academy of Sciences. ®