A new study reported in the journal Nature Climate Change questions fears that Europe and North America will experience more days of cold weather over the course of the next century.
This map shows global temperature anomalies for January 1, 2000 to December 31, 2009. Image credit: Robert Simmon, NASA / Adam Voiland.
Since the mid-20th century, average temperatures have warmed about 0.6 degrees Celsius, but the warming has not occurred equally everywhere.
Temperatures have increased about twice as fast in the Arctic as in the mid-latitudes, a phenomenon known as the Arctic amplification.
The idea that there was a link between this phenomenon and extreme weather conditions became prevalent during the severe winter weather in the United States and European countries in 2014.
However, Dr James Screen from the University of Exeter, UK, has shown that the Arctic amplification has actually reduced the risk of cold extremes across large swathes of the Northern Hemisphere.
He examined detailed climate records to show that autumn and winter temperature variability has significantly decreased over the mid-to-high latitude Northern Hemisphere in recent decades.
Dr Screen found that this has occurred mainly because northerly winds and associated cold days are warming more rapidly than southerly winds and warm 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,” Dr Screen said.
Using the latest mathematical climate modeling, Dr Screen was also able to show that these changes will continue in to the future, with projected future decreases in temperature variability in all seasons, except summer.
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James A. Screen. Arctic amplification decreases temperature variance in northern mid- to high-latitudes. Nature Climate Change, published online June 15, 2014; doi: 10.1038/nclimate2268
