Arctic warming and extreme weather events in the U.S. and Europe


image: BBCMundo.com

Andrew Freedman discusses how Arctic warming is tied to extreme weather (like drought, flooding, cold spells, heat waves) in the U.S. and Europe:

The study shows that by changing the temperature balance between the Arctic and mid-latitudes, rapid Arctic warming is altering the course of the jet stream, which steers weather systems from west to east around the hemisphere. The Arctic has been warming about twice as fast as the rest of the Northern Hemisphere, due to a combination of human emissions of greenhouse gases and unique feedbacks built into the Arctic climate system.

[...] One does not have to look hard to find an example of an extreme event that resulted from a huge, slow-moving swing in the jet stream. It was a stuck or “blocking weather pattern” – with a massive dome of high pressure parked across the eastern U.S. for more than a week – that led to the remarkable March heat wave that sent temperatures in the Midwest and Northeast soaring into the 80s. In some locations, temperatures spiked to more than 40 degrees above average for that time of year.

[...] The reasons why the Arctic is heating up so quickly, a phenomenon known as “Arctic amplification,” has to do with factors that are unique to the Arctic environment, involving feedbacks between sea ice, snow, water vapor, and clouds. As the area warms in response to manmade greenhouse gases, melting ice and snow allow exposed land and water to absorb more of the Sun’s heat, which melts more ice and snow, and so on. A relatively small amount of initial warming can be greatly magnified in the Far North.


image: The Kitschest Bear by Antoine Beyeler