Study Forecasts Warmer and Wetter Arctic This Century

The Cryosphere, 5 March 2024

This major study reveals how Arctic rivers will change over the next eight decades if the climate continues to warm, highlighting how permafrost thaw and a faster water cycle will greatly alter this region’s landscape and ecosystems. Historically, most water going into Arctic rivers flows atop frozen permafrost soils, which typically extend hundreds of meters into the ground. A thawed layer forms at the surface each summer, extending deeper into the ground as temperatures rise. Authors found that thawed permafrost can serve as a sponge, absorbing rainfall and snowmelt before later releasing it into rivers and streams. Under a high emissions scenario, the Arctic as a whole will experience up to 25% more above-ground runoff and 30% more below-ground runoff by 2100, with the southern Arctic becoming progressively drier. Northern rivers including the Ob, Yenisey, Lena, and Mackenzie will carry more water downstream, transporting large amounts of previously frozen carbon into the Arctic Ocean. Authors warn that a lengthening permafrost thaw season and intensifying river discharge could influence Arctic sea ice, biodiversity patterns, and even the global climate by impacting ocean freshwater storage and major Atlantic currents.

Full paper: https://tc.copernicus.org/articles/18/1033/2024/
Plain-language briefing: https://theconversation.com/arctic-rivers-face-big-changes-with-a-warming-climate-permafrost-thaw-and-an-accelerating-water-cycle-the-effects-will-have-global-consequences-224869