The weakened jet stream is due to climate change
In addition, with the new model the researchers can also more closely analyse the causes of the meandering jet stream. “Our study shows that the changes in the jet stream are at least partly due to the loss of Arctic sea ice. If the ice cover continues to dwindle, we believe that both the frequency and intensity of the extreme weather events previously observed in the middle latitudes will increase,” says Prof Markus Rex, Head of Atmospheric Research at the AWI. “In addition, our findings confirm that the more frequently occurring cold phases in winter in the USA, Europe and Asia are by no means a contradiction to global warming; rather, they are a part of anthropogenic climate change.”
The team’s efforts also represent a significant technological advance: “After the successful use of machine learning in this study, we are now for the first time employing artificial intelligence in climate modelling, helping us arrive at more realistic climate model systems. This holds tremendous potential for future climate models, which we believe will deliver more reliable climate projections and therefore a more robust basis for political decision-making,” says Markus Rex.
During the Arctic expedition MOSAiC, which will begin in September and during which the German research icebreaker Polarstern will drift through the Central Arctic along with the sea ice for an entire year, the researchers plan to gather the latest ice and atmospheric data. This will help them apply the new climate model to the future, so as to simulate the future development of the Arctic climate and sea ice. As Markus Rex explains, “Our goal is to understand in detail how the Arctic sea-ice retreat will progress – because only then will we be able to gauge how and on what scale the changes in the Arctic will lead to weather extremes in the middle latitudes.”