Arctic amplification

Summer 2024 was officially the Northern Hemisphere’s hottest on record. In the United States, fierce heat waves seemed to hit somewhere almost every day. Phoenix reached 100 degrees for more than 100 days straight. The 2024 Olympic Games started in the midst of a long-running heat wave in Europe that included the three hottest days on record globally, July 21-23. August was Earth’s hottest month in the National Oceanic and Atmospheric Administration’s 175-year record. Overall, the global average temperature was 2.74 degrees Fahrenheit (1.52 degrees Celsius) above the 20th-century average. That might seem small, but temperature increases associated with human-induced climate change do not manifest as small, even increases everywhere on the planet. Rather, they result in more frequent and severe episodes of heat waves, as the world saw in 2024. The most severe and persistent heat waves are often associated with an atmospheric pattern called a heat dome. As a...

Atmospheric rivers, those long, powerful streams of moisture in the sky, are becoming more frequent in the Arctic, and they’re helping to drive dramatic shrinking of the Arctic’s sea ice cover. While less ice might have some benefits – it would allow more shipping in winter and access to minerals – sea ice loss also contributes to global warming and to extreme storms that cause economic damage well beyond the Arctic. I’m an atmospheric scientist. In a new study of the Barents-Kara Seas and the neighboring central Arctic, published Feb. 6, 2023, in Nature Climate Change, my colleagues and I found that these storms reached this region more often and were responsible for over a third of the region’s early winter sea ice decline since 1979. More frequent atmospheric rivers By early winter, the temperature in most of the Arctic is well below freezing and the days are mostly dark. Sea ice should be growing and spreading over a wider area. Yet the...