Overshoot Threatens Irreversible Glacier Loss and Water Scarcity

Nature Communications, 19 May 2025

A global assessment of mountain glaciers reveals that even temporarily exceeding 1.5°C of warming will have irreversible and long-lasting consequences on these vital ice reservoirs, which serve as water towers for surrounding and downstream regions. These escalating consequences of even incremental, temporary temperature rise pose a deadly hazard to communities that rely on frozen water resources for seasonal water supplies. Increasing glacier loss significantly impacts water availability in glacier-fed basins. Even if temperatures return below 1.5°C after overshoot, glaciers would store less water as ice, reducing downstream runoff for decades and centuries. The research supports the need for dramatic emissions reductions to prevent or limit overshoot, and reduce irreversible changes to glaciers and their basins.

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