Arctic warming linked to extreme winter weather in the U.S.

In a new study published by AAAS, scientists have identified a link between climate change in the Arctic and extreme winter weather events in the United States. The surprising findings suggest that climate warming is driving severe winter weather in a phenomenon called stratospheric polar vortex (SPV) disruption.

“Anthropogenic global warming is projected to increase some weather extremes – for example, more heat waves and heavy precipitation events – but not severe winter weather such as cold air outbreaks and heavy snowfalls. Yet, contrary to global climate model (GCM) projections, recent weather extremes have included an increase in cold air outbreaks and/or heavy snowfalls across the Northern Hemisphere since 1990 up to the recent past,” explained MIT climatologist Judah Cohen and co-authors.

“The most recent example of extreme winter weather was the anomalous cold weather of January and February 2021 in Asia, Europe, and especially the United States (US). The US Southern Plains cold wave of February 2021 may be exceptional in the observational record for the region based on the aggregate severity of the cold intensity, cold duration, and widespread disruptive snowfall.” 

“The collapse of the Texas energy infrastructure could make it the state’s costliest natural disaster, even more so than previous hurricanes and at least twice as costly as the entire record-breaking North Atlantic 2020 hurricane season. This event has reignited the debate whether climate change contributes to more severe winter weather.”

The researchers used observational and modeling data to establish a physical link between anthropogenic climate change and stratospheric polar vortex (SPV) disruption. This atmospheric feature is defined by the strong westerly winds that encircle the Arctic and – under normal conditions – keep its cold air contained.

The study shows that accelerated warming in the Arctic, or Arctic amplification (AA), is driving extreme winter weather by disturbing the Arctic stratospheric polar vortex. 

According to the researchers, their results could be used to extend the warning lead time of cold extremes in Asia, Canada, and the United States. They emphasize that the analysis is also informative for policy-makers. 

“Preparing for only a decrease in severe winter weather can compound the human and economic cost when severe winter weather does occur, as exemplified during the Texas cold wave of February 2021,” wrote the study authors.

The study is published in the journal Science. 

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By Chrissy Sexton, Earth.com Staff Writer