High Arctic Temperatures and Low Sea-Ice Levels Cause Heatwaves at Mid-Latitudes

Environmental Research Letters, October 12

As the Arctic rapidly warms, the temperature difference between that region and warmer lower latitudes decreases, resulting in a weakened polar jet stream (the ribbon of very fast winds that greatly influences mid-latitude weather). Changes in the shape of the polar jet stream over the past decade have allowed for more cloudy and less windy conditions over the Arctic Ocean in late summer, allowing greater amounts of summer sea ice. However, this wind pattern did not occur to the same extent in 2019 and 2020, which explains the near record-breaking minimum sea ice extents in both years. While cloudier and cooler summers occur in the Arctic, this wavier jet stream also has led to persistent heat waves in Canada, East Asia, Scandinavia, and the North Pacific Ocean — contributing to conditions leading to record wildfires from drought and heat, and potentially to higher surface water temperatures in the North Pacific.

https://iopscience.iop.org/article/10.1088/1748-9326/abc047

艾米·印第克整理。.