Did Arctic heat cause extreme winters in US, UK?

"Our work presents tantalizing new evidence of links between global warming, which is enhanced in high northern latitudes, and recent extreme winter weather events," says Edward Hanna. (Credit: bettlebrox/Flickr)

Arctic temperatures are increasing two to three times faster than those at the mid-latitudes, and researchers say there’s fresh evidence suggesting a link between that warm-up and extreme weather in other parts of the world.

Some scientists have suggested that warming Arctic temperatures contribute to weaker upper level westerly winds and a wavier jet stream. This wavier path may have caused cold weather conditions to stall over the eastern seaboard and midwest United States during recent winters, according to these theories.

In a new paper published in the Journal of Climate, researchers paint a picture of links that vary by region and season, although they say it’s too soon to know for certain whether the Arctic played a role in persistent cold events during the extreme wet UK winter of 2013-14 and record-breaking snow in 2014-15 in the US northeast.

“Our work presents tantalizing new evidence of links between global warming, which is enhanced in high northern latitudes, and recent extreme winter weather events in the UK and further afield, as well as a timely review of much recent literature which has appeared in this important field of research,” says Edward Hanna, a geology professor at the University of Sheffield and a coauthor of the paper.

“However, since the climate system is highly complex, many missing parts of the puzzle remain and much further work needs to be done.”

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Professor James Overland of the National Oceanic and Atmospheric Administration, the lead author of the paper, agrees: “We are in the pre-consensus stage of a theory that links continued warming of the Arctic with some severe weather events.”

A way to advance research from a pre-consensus stage is to further investigate the meandering jet stream and the connection between the warmer Arctic and the negative phase of an index showing the dominant pattern of sea level air pressure in the Arctic.

“We are where other major theories such as plate tectonics and El Niño were before they were widely accepted,” adds Overland.

“We need a Grand Science Challenge to advance weather forecasting abilities and climate change prediction.”

Source: University of Sheffield