A new study has found that a stagnant polar jet stream is causing severe heatwaves in parts of North America, Europe, and Asia. The jet stream, a narrow band of westerly winds encircling the Northern Hemisphere, has become stationary and is trapping heat in certain regions due to climate change. The collision of cold Arctic air with warm southerly air forms the jet stream, but as the Arctic warms faster than the lower latitudes, the temperature difference narrows. This causes the jet stream to slow down and become more wavy, allowing warm air to flow north and become trapped, resulting in intense heatwaves and wildfires. The study used weather data from 1979 to 2022 and found that as snow cover decreased in northern Canada, the jet stream became more wavy, causing rapid ice melt in Greenland. The findings suggest that these extreme weather conditions are likely to increase in the future.
https://e360.yale.edu/digest/jet-stream-climate-change-heat-wave