June 16, 2014
Extremely Cold Conditions Not Expected To Increase Due To Climate Change
redOrbit Staff & Wire Reports - Your Universe Online
Despite the fact that many parts of the United States experienced extremely cold conditions this past winter, the risk of such conditions increasing as a result of climate change is unlikely, according to research appearing in the latest edition of Nature Climate Change.Study author Dr. James Screen of the University of Exeter reports that the Arctic amplification phenomenon, which refers to the increased warming rate experienced in the Arctic in comparison to places located further south, has previously thought to be linked to the recent spike in severe cold spells.
However, despite the frigid conditions experienced throughout Europe and North America, his research demonstrates that Arctic amplification has actually reduced the potential risk of extreme cold throughout much of the Northern Hemisphere, calming fears that such conditions will become the rule and not the exception.
“Autumn and winter days are becoming warmer on average, and less variable from day-to-day. Both factors reduce the chance of extremely cold days,” Dr. Screen, who is a mathematics research fellow at the UK university as well as a Natural Environment Research Council (NERC) Research Fellow, said in a statement on Sunday.
In his research paper, Dr. Screen explained that there is “a common perception and growing concern” that climate change will result in an increased amount of “volatile and extreme” weather conditions. While some types of extreme weather have increased in frequency, severity or both, he noted that cold temperature variability is not one of them. In fact, he reports that it has decreased in the mid- to high-latitude Northern Hemisphere in recent decades.
The belief that there is a link between Arctic amplification and extreme weather conditions began to spread during the severe winter weather that impacted much of the US this past January. Previous research had suggested that the link between Arctic amplification and extreme weather was changes in atmospheric circulation.
As part of his research, Dr. Screen analyzed climate records to demonstrate that seasonal temperature variability in both autumn and winter has decreased significantly in these regions. The reason, he reported, it because northerly winds and the associated cold days are warming more rapidly than southerly winds and warmer days.
“Cold days tend to occur when the wind is blowing from the north, bringing Arctic air south into the mid-latitudes. Because the Arctic air is warming so rapidly these cold days are now less cold than they were in the past,” he said, adding that the latest mathematical climate models indicate that these changes will continue, with future decreases in temperature variability expected to occur in every season except for summer.
“Previous hypotheses linking Arctic amplification to increased weather extremes invoke dynamical changes in atmospheric circulation, which are hard to detect in present observations and highly uncertain in the future,” Dr. Screen wrote. “In contrast, decreases in subseasonal cold-season temperature variability… are detectable in the observational record and are highly robust in twenty-first-century climate model simulations.”