Glaciers disappear by the thousands, history melts with them

Although glaciers have long been studied for their role in sea-level rise and water supply - including by CMU’s own Center for Engineering Resilience and Climate Adaptation - a new international study highlights a different dimension of their decline: the disappearance of individual glaciers themselves. Beyond ice mass and area loss, the extinction of glaciers threatens landscapes that hold deep cultural, spiritual, and touristic significance. 

Using three global glacier models, researchers project a sharp rise in the number of glaciers vanishing worldwide, peaking between 2041 and 2055 with up to 4,000 glaciers disappearing annually. This peak glacier extinction marks a profound turning point for mountain regions across the globe.

“While we often think about the largest glaciers for their contributions to sea-level rise and water resources,” said David Rounce, assistant professor of civil and environmental engineering at Carnegie Mellon and co-author of the paper. “The reality is that, by number, most glaciers are quite small, and it’s these smaller glaciers that will be lost in great numbers over the next several decades.”

The study, published in Nature Climate Change, reveals sharp regional differences. Areas dominated by smaller, fast-responding glaciers, such as the Alps and the Caucasus, could lose more than half of their glaciers within the next 10 to 20 years. In contrast, regions with large, slow-reacting glaciers, like Alaska, Svalbard, and Arctic Canada, will reach their extinction peak later in the century.

The stark reality is that our actions as a global society have a huge impact on the future of these glaciers

David Rounce, Assistant Professor, Department of Civil and Environmental Engineering and Engineering and Public Policy

The team also calculated how many glaciers will remain by 2100, finding substantial differences between warming scenarios. Should global temperatures rise by 1.5°C, relative to pre-industrial levels, a low emissions scenario that is increasingly unlikely, nearly half of the glaciers we see today could remain. Under current climate policy pledges of +2.7°C, only about 20% of today’s glaciers would survive. Additionally, under the highest warming scenario researchers projected, fewer than 10% of present-day glaciers are expected to remain if global temperatures rose by 4°C. In the European Alps, for example, only 110 glaciers may remain under +2.7°C, and as few as 20 under +4°C.

“The stark reality is that our actions as a global society have a huge impact on the future of these glaciers,” Rounce said. “By reducing our greenhouse gas emissions, we have the ability to preserve large numbers of our glaciers and the way we currently get to view our mountains. We have a chance to make a long-lasting impact, we just have to act.”

Glaciers have always been symbols, spiritual landmarks, tourism destinations, and water sources for millions of people around the globe. Communities have already begun to respond to their loss through public rituals known as glacier funerals in Iceland, Switzerland, and Nepal. Iceland has established a global glacier graveyard, while initiatives like the Global Glacier Casualty List aim to preserve the names and histories of vanishing glaciers. 

“Glacier extinction is becoming a human story,” says Lander Van Tricht, lead author of the paper and a postdoctoral researcher at ETH Zurich. “Behind every disappearing glacier lies a place, a history, and a community that will feel its absence.”

The study coincides with the conclusion of the United Nations (UN) Year of Glacier Preservation and the launch of the UN Decade of Action for Cryospheric Sciences. By introducing the concept of peak glacier extinction, the researchers aim to provide information that can guide policymakers and communities in planning for the future. 

This publication was conducted in collaboration with researchers from ETH Zürich, the Swiss Federal Institute for Forest, Snow and Landscape Research, Vrije Universiteit Brussel, University of Fribourg, Universität Innsbruck, and Bristol Glaciology Centre at the University of Bristol.