Less Snow and More Above-freezing Temperatures Speeding Arctic Glacier Melt

The Cryosphere, 15 August 2024

The Arctic contains one-fourth of the world’s glaciers, and this study detailed how rising temperatures are causing them to melt faster. Glaciers consist of compressed snow that accumulates over many years, turning into thick ice. Snowfall that accumulates on top of glacier ice also insulates it from summer melt. Researchers looked at 269 glaciers across the Arctic (above 60 degrees North latitude), encompassing Alaska, Canada, Greenland, Scandinavia and Russia; and found that the snow line (the altitude at which snow accumulates each year) had risen by 150 meters over the past four decades. Today’s high levels of sustained warming had reduced the number of days each year in which snow falls, rather than rain. Without a protective snow cover, glaciers both lose ice faster in summer, and fail to accumulate enough snow to grow or at least maintain their ice each year. Measurements showed that snowlines had retreated Arctic-wide, and twice as fast on low-elevation glaciers compared to high-elevation ones. The study concluded that if emissions continue at their current pace, over 50% of these Arctic glaciers will no longer have any snow accumulating on their surface by 2100, dooming them eventually to disappear entirely.

全文 https://tc.copernicus.org/articles/18/3591/2024