Extreme weather has become the new normal – whether it’s rain, drought, wind, heat or cold. The question of how the shrinking layer of Arctic sea ice has contributed to any of these changes has sparked a lively discussion in recent years. The researchers suggested that a weak jet stream, driven by the disappearance of Arctic sea ice, could play an important role in extreme winter events, such as the descending polar vortex that hit North America earlier this year. But the idea did not hold up well in light of more recent evidence.
But now, researchers have identified a direct link between extreme winter weather and the loss of sea ice. The 2018 “Beast of the East” winter storm hit Europe with record snow and low temperatures. And potentially up to 88% of that snow came from the increased evaporation of the Barents Sea.
The working hypothesis is that Arctic ice acts as a cover for Arctic waters, limiting evaporation. Less sea ice and warmer Arctic temperatures mean more evaporation, potentially explaining the increased severity of winter storms, such as the Eastern Beast. Until now, it has been difficult to measure direct evidence linking sea ice loss to extreme European winters, but recent advances in technology make this a little more difficult.
The secrets of the north
With freezing temperatures, 24-hour darkness in the winter and, well, not much ground, the Arctic is one of the most hostile research environments in the world. To date, much of the direct data from the region has been collected by practical research boats, but these shipments are expensive and limited in terms of 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 researchers did not install the instrument in the most remote areas of the Arctic, they added one to a weather station in Pallas-Yllästunturi National Park, northern Finland, just a few hundred kilometers from the Norwegian Sea.
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Observatory station of the Finnish Meteorological Institute in Pallas-Yllästunturi National Park, Finland. Sampling antennas extending from the roof captured water vapor from the Barents Sea as they traveled south to Europe.
K. Mustonen.
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Hannah Bailey, the study’s lead author, manually collects snow samples in Finland during the Arctic winter outbreak.
Hannah Bailey
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Eric Klein, co-author of the study, performing routine maintenance of the Picarro water vapor isotope analyzer (called “R2D2”) in Pallas, Finland.
Hannah Bailey
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The sea ice cover, which acts as a cover on the surface of the ocean, was particularly low in the Barents Sea in 2018.
J. Welker
They installed the instrument in late 2017 and it allowed them to detect natural stable isotopes from water vapor – ie hydrogen and oxygen – since then. Two of these isotopes, 18And 2H, have been widely used to track hydrological processes over the past 70 years. Because these isotopes are slightly heavier, they are less likely to evaporate, creating isotopic “fingerprints” for phase transitions, such as evaporation, cloud formation, rain, and snow. This made it possible to trace the origins of storm systems – and the team of researchers put this tool in place just in time for a storm surge.
Beast
A few months after installing the instrument, the team noticed a huge increase in the isotope in March 2018, just as the Eastern Beast arrived in Europe. Researchers could track this peak of steam back to unusually large amounts of evaporation from the Barents Sea, which was warmer and ice-free than historical norms.
“The data in our study are the first ‘real measurements’ to show that the loss of sea ice by increased evaporation contributes to extreme snow events in mid-latitude,” says lead author Hannah Bailey. “So far, scientists have explored the link between Arctic sea ice loss and extreme snowfall using climate models and without this technology we use, it would simply not be possible to capture these types of events and natural processes. in real time . ”
The team also combined satellite data and modeling to estimate that up to 88 percent of the snow in the Beast’s storm – 140 billion tons – could have come from the Barents Sea.
Less ice, more snow
The team focused on the Barents Sea because it is a literal “hot spot” of falling sea ice in the Arctic. The maximum sea ice level in March has dropped by 54% since 1979. Using historical satellite observations and atmospheric patterns, the team confirmed that smaller amounts of Barents sea ice were regularly correlated with higher evaporation and snow. strongest since March in northern Europe over the past 30 years.
This evidence also suggests that this trend may intensify with the further loss of sea ice in the Barents Sea, which some researchers have predicted may be ice-free by 2061-2088. The team hopes to establish a network of these isotope monitoring tools across the Arctic – both on ships and on land – to better measure these changes as they move forward.
“There is a scientific consensus that the decline of Arctic sea ice affects mid-latitude weather, but there is a lack of consensus between the models used to investigate these processes,” says Bailey. “There is huge potential for atmospheric vapor isotope data to improve weather forecasting, as well as to help predict extreme weather events that impact society.”
Nature Geoscience, 2021. DOI: 10.1038 / s41561-021-00719-y (About DOI).
KED Coan is a freelance journalist covering climate and environmental stories at Ars Technica. He has a doctorate. in chemistry and chemical biology.