Rapid warming of the Arctic triggers extreme winter events in the US: Study

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Issued on: 02/09/2021 – 8:06 pmChanged: 02/09/2021 – 8:04 pm

Washington (AFP)

The rapid warming of the Arctic is likely a major cause of extreme winter weather in the United States, according to a new study that addresses a long-standing apparent contradiction in climate science and could explain events like the Texas cold snap in February.

The paper, published in the journal Science, used observational data and modeling to establish a link between planetary warming associated with human activities and a phenomenon known as the stratospheric polar vortex (SPV).

The stratospheric polar vortex is a band of westerly winds that orbits the Arctic and, under normal conditions, holds back the cold air.

The team found that the rapid warming of the Arctic and its effects, namely the loss of sea ice, combined with increased snow cover in Siberia due to more moisture in the atmosphere, leads to a greater temperature difference from west to east across Eurasia.

This leads to a weakening of the SPV, which in turn can trigger cold spells like those that hit Canada, the USA and Mexico last winter. Dozens of people were killed and more than $ 200 billion in damage caused in Texas.

“It seems very counter-intuitive, it seems very unexpected that there is very strong warming in the Arctic and that it is somehow causing cooling in other regions,” said Matthew Barlow, co-author of the study from the University of Massachusetts Lowell, told AFP.

“I was a little surprised that the results came out so cleanly that we were able to relate as directly as we did.”

The Arctic is warming twice as fast as the global average, and harsh winter weather is increasing in the mid-latitudes, but whether the two are related has remained the subject of scientific debate.

Graph explaining how rapidly rising Arctic temperatures are linked to extreme weather events in the North American winter, according to a study published September 2, 2021 John SAEKI AFP

“In the past, these cold extremes against the US and Russia have been used to justify that emissions will not be reduced – and there is no longer any excuse, we have to start reducing emissions immediately,” said Chaim Garfinkel, Co -Author of the study from the Hebrew University of Jerusalem added in an accompanying video.

One of the strengths of the study, according to the authors, was that, in addition to reviewing historical data, it used a powerful climate model to test whether its hypothesis was entering new parameters, such as even more heat and snow cover in Siberia.

The results could be used to extend the lead-time for cold extreme warnings in Asia, Canada and the United States, the authors say, “maybe even a few weeks in advance,” Barlow said.

“People are starting to appreciate the reality that climate change can really hit you even if it’s not happening in your own backyard,” he added.

“Climate change in the Arctic is not only unfortunate for polar bears, it is not just a kind of curiosity.”