A recent study by Verisk Analytics’ Atmospheric and Environmental Research (AER) business and Rutgers University, has claimed that the frequency and severity of extreme winter weather in the U.S. is related to fluctuations in Arctic temperatures.
Published in Nature Communications, the study observed that extreme winter conditions in the eastern U.S., like cold temperatures and heavy snowfalls, were two to four times more likely when Arctic temperatures were abnormally high.
AER also linked Arctic warmth with colder winter conditions across much of the Northern Hemisphere midlatitudes, including Europe and East Asia, and endorsed existing theories that have connected severe winter weather to disruptions in the polar vortex.
These findings come after a season of particularly severe winter weather across the U.S., and may provide further evidence for the various ways in which adverse weather conditions are suspected to be affected by climate change.
The study also follows a recent report by Aon, which revealed that extreme winter weather conditions across the U.S. and Europe this year caused hundreds of millions of dollars of re/insurance losses.
However, in the Western U.S., the study finds either no relationship between winter conditions and Arctic temperatures, or, in some cases, finds them exacerbated by unusually cold Arctic temperatures.
AER also investigated potential relationships between extreme winter weather in the Eastern U.S. and Arctic amplification, the term used to describe the rapid warming of the Arctic region relative to the rest of the globe.
While this did not yield a robust connection, AER did find statistically significant increases in heavy snowfalls related to Arctic amplification.
Moreover, the study established particularly strong links between severe winter weather in mid-to-late winter in the northeastern U.S. and disruptions in the stratospheric polar vortex triggered by deep layer Arctic warming, or warming that extended beyond the surface.
“The publication of the paper is especially timely given the extreme winter of 2017/2018, which has included a record-warm Arctic and record-low sea ice, record-breaking polar vortex disruption, record-breaking cold in both the U.S. and Europe, disruptive snowfalls in both the U.S. and Europe, severe ‘bomb cyclones,’ and costly nor’easters,” said Dr. Judah Cohen, Director of Seasonal Forecasting at AER and lead author of the study.
Cohen added: “This paper argues that the weather was cold not in spite of climate change but likely because of climate change.
“In fact, our statistical analysis shows that one is more likely to be struck by lightning, attacked by a shark, and win the Powerball all at the same time than the possibility of severe winter weather in the northeastern U.S. not being related to Arctic temperatures. That’s how robust our findings are.”
Co-author Jennifer Francis, also said: “Five of the past six winters have brought persistent cold to the eastern U.S. and warm, dry conditions to the West, while the Arctic has been off-the-charts warm.
“Our study suggests that this is no coincidence. Exactly how much the Arctic contributed to the severity or persistence of the pattern is still hard to pin down, but it’s becoming very difficult to believe they’re unrelated.”
AER’s study also comes as extreme weather and environmental risks once again top the World Economic Forum’s (WEF) annual Global Risk Perception Survey.
