A large part of daily weather variability comes from extra-tropical cyclones, commonly referred to as low pressure systems. On longer timescales, extra-tropical cyclones are organised together into storm tracks. Closely related to the storm tracks is the jet stream, a narrow band of high velocity winds, which acts as a guide for individual extra-tropical cyclones.
Global warming, driven by rising greenhouse gas concentrations, leads to many changes of the climate system as we know it. Highly relevant for the jet stream and storm tracks are the warming of the average sea surface temperatures and loss of sea ice cover.
In this work, we study the contributions of globally increasing sea surface temperatures and sea ice loss to future changes in the North Atlantic jet stream and storm tracks, using a new set of simulations from 4 climate models. In future climates, the jet stream shifts southward over the North Atlantic and extends further over Europe. Increasing sea surface temperatures are the predominant driver of these changes. However, there are disagreements about the extension of the jet stream over Europe between the climate models due to nonnegligible effects from reduced sea ice. The storm track is projected to move east towards Europe and a weakening over the Mediterranean. Contrary to the changes in the jet stream, increasing sea surface temperatures and sea ice loss contribute with similar magnitude to the eastward shift of the storm track.
This work was funded by project CRiceS (Climate Relevant interactions and feedbacks: the key role of sea ice and Snow in the polar and global climate system, European Union's Horizon 2020 research and innovation programme under grant agreement no. 101003826) and the STORMS project (Research Council of Finland, grant no. 338615).
Köhler, D., Räisänen, P., Naakka, T., Nordling, K., and Sinclair, V. A.: The future North Atlantic jet stream and storm track: relative contributions from sea ice and sea surface temperature changes, Weather Clim. Dynam., 6, 669–694, https://doi.org/10.5194/wcd-6-669-2025, 2025.