Climate change is not responsible for extreme winters

Cold snaps like the ones that hit the eastern United States in the past winters are not a consequence of climate change as had previously been assumed. To the contrary: global warming will actually reduce temperature variability.

The range of temperature fluctuations will decrease in most places as the climate warms, conclude scientists from the Swiss Federal Institute of Technology (ETH) in Zurich and the California Institute of Technology. Their findings contradict the long-standing theory that the polar jet stream, a strong wind current several kilometres high in the atmosphere, would be weakened by climate change, thus leading to greater fluctuations in temperatures in mid-latitudes.

The scientists started from the position that higher latitudes are indeed warming faster than lower ones, which means that the temperature difference between the Equator and the poles is decreasing. The less the temperature difference between the two, the lower the temperature variability in the mid-latitudes as well as North America, according to their recent study.

The researchers limited their work to temperature trends and not to other extreme events such as storms with heavy rain or snowfall. They also concluded that despite lower temperature variance, there will be more extreme warm periods in the future because the Earth is warming.


Photo credit: Ceyhun (Jay) Isik, flickr/Creative Commons

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