Lack of Arctic ice has fueled the storm of the “Beast of the East”

Extreme weather has become the new normal – whether it is precipitation, drought, wind, heat or cold. The question of how the ever-shrinking layer of Arctic sea ice has contributed to any of these changes has led to lively discussions over the past few years. Researchers have suggested that a weakened jet stream driven by disappearing Arctic sea ice could play a major role in extreme winter events, such as the falling polar vortex that hit North America earlier this year. But the idea has not held up well in light of recent evidence.

But now researchers have identified a direct link between extreme winter weather and sea ice loss. The 2018 “Beast of the East” winter storm hit Europe with record-breaking snowfall and low temperatures. And possibly as much as 88 percent of the snowfall comes from increased evaporation from the Barents Sea.

The working hypothesis is that Arctic sea ice serves as a cap for the Arctic waters, limiting evaporation. Less sea ice and warmer Arctic temperatures mean more evaporation, which could possibly explain the increasing severity of winter storms such as the Beast of the East. Until now, it has been difficult to measure direct evidence linking ice loss to extreme European winters, but recent advances in technology make it a little less challenging.

Secrets of the north

The Arctic is one of the world’s most hostile research environments, with temperatures below freezing, 24 hour darkness in winter and, yes, not much soil. To date, much of the direct data in the region has been collected by practical research boats, but these expeditions are expensive and limited in where and when they can be used.

Instead, this latest research used a recent technology – an isotope and gas concentration analyzer – that automatically collects real-time data at the impressive frequency of almost one measurement per second. Although the researchers did not install the instrument in the farthest parts of the Arctic, they added one at a weather station in Pallas-Yllästunturi National Park, northern Finland, just a few hundred kilometers from the Norwegian Sea.

They installed the instrument in late 2017 and since then they have detected the natural stable isotopes in water vapor (i.e. hydrogen and oxygen). Two of these isotopes, ¹⁸O en ²H, has been widely used for the past 70 years for the detection of hydrological processes. Because these isotopes are slightly heavier, they evaporate less likely, creating unique isotope “fingerprints” for phase transitions such as evaporation, cloud formation, rain and snow. This made it possible to trace the origin of storm systems – and the research team put this tool in place just in time for a major storm.

The Beast

Within a few months of the instrument being installed, the team noticed a major isotope peak in March 2018, just as the Beast of the East arrived in Europe. The researchers were able to trace this vapor trail back to unusual amounts of evaporation from the Barents Sea, which was warmer and ice-free than historical norms.

“The data from our study represent the first ‘correct measurements’ that prove that the loss of ice through improved evaporation contributes to mid-latitude snowfall,” says first author Hannah Bailey. “So far, scientists have investigated the link between Arctic sea ice loss and extreme snowfall using climate models, and without this technology we use, it is simply not possible to capture these kinds of natural events and processes in real time. . ”

The team also combined satellite data and modeling to calculate that up to 88 percent of the snow from the Beast storm – 140 billion tons – may have come from the Barents Sea.

Less ice, more snowfall

The team focused on the Barents Sea, as it is a literal “hotspot” of declining sea ice in the North Pole. The maximum marine sea level in March there has fallen by 54 percent since 1979. Using historical satellite observations and atmospheric models, the team confirmed that smaller amounts of Barents Sea ice have regularly correlated with higher evaporation and heavier snowfall in March over the past 30 years.

This evidence also suggests that this trend may increase with further loss of sea ice in the Barents Sea, which according to some researchers would be ice-free by 2061-2088. The team hopes to establish a network of these isotope monitoring instruments in the Arctic – both on ships and on land – to better measure these changes going forward.

“There is scientific consensus that the decline of Arctic sea ice is affecting the weather at mid-latitude, but there is a lack of consensus among the models used to investigate these processes,” says Bailey. “There is great potential for atmospheric vapor isotope data to improve weather forecasting, as well as to help predict extreme weather conditions affecting society.”

Natural Science, 2021. DOI: 10.1038 / s41561-021-00719-y (About DOIs).

KED Coan is a freelance journalist discussing climate and environmental stories at Ars Technica. She holds a Ph.D. in Chemistry and Chemical Biology.