Published in Nature Climate Change, the study found that if global temperatures temporarily exceed 1.5C by up to 3C before stabilizing, glaciers could lose up to 16% more mass by 2200 compared to a scenario where the threshold is never crossed.
Dr Fabien Maussion, Associate Professor in Polar Environmental Change at the University of Bristol and a corresponding author of the study, highlighted the risks: "Current climate policies are putting the Earth on a path close to 3C. It's clear that such a world is far worse for glaciers than one where the 1.5C limit is held."
The study modeled a strong overshoot scenario where global temperatures rise to 3.0C around 2150, before dropping to 1.5C by 2300. It found that even if temperatures eventually fall, glaciers will lose significantly more mass, including an extra 11% by 2500, compounding the 35% loss already projected if the 1.5C limit is never exceeded.
Lead author Dr Lilian Schuster from the University of Innsbruck noted the long-term impact on smaller glaciers: "Our models show it would take many centuries, if not millennia, for the large polar glaciers to recover from a 3C overshoot. For smaller glaciers like those in the Alps, the Himalayas, and the Tropical Andes, recovery might be possible by 2500."
The study also warns that melting glaciers will significantly affect downstream water supplies. As glaciers recede, they enter a phase known as "trough water," where less meltwater reaches rivers, potentially impacting communities that rely on glacier-fed water during dry seasons.
The research was conducted as part of the EU-funded PROVIDE project, which focuses on the global impacts of climate overshoots.
Dr Maussion stressed the long-term implications: "Overshooting 1.5C, even temporarily, locks in glacier loss for centuries. Our study shows that much of this damage cannot simply be undone - even if temperatures later return to safer levels. The longer we delay emissions cuts, the more we burden future generations with irreversible change."
Research Report:Irreversible glacier change and trough water for centuries after overshooting 1.5C
Related Links
University of Bristol
Beyond the Ice Age
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