World Set To Lose 39% Of Glaciers, Says Study

If global warming were to stabilise at current levels — 1.2°C above pre-industrial levels — the world would still lose 39% of its glacier mass that existed in 2020, leading to 113 mm sea level rise, a new study with a novel approach to data finds. “This substantial present-day committed mass loss highlights that today’s glaciers are strongly out of balance with current climatic conditions due to their long response times,” the study says.

Meeting the limits of the Paris Agreement (limiting warming up to 1.5 and 2°C) could mean committing to 47% and 63% of glacier mass loss relative to 2020 levels. The findings — three times larger than most other projections — is the result of an approach using eight glacier models across 80 climate scenarios.

“One of the key strengths of our study is that we were able, for the first time, to project global glacier evolution over multi-centennial timescales, and did so using eight models instead of one or two,” said Harry Zekollari, lead author of the study from Vrije Universiteit Brussel in a statement. “Most glacier studies stop at 2100, which is problematic when simulating the long-term impact of today’s climate policies, given the long-term response of glaciers over time,” he added.

What drives glacier loss is air that warms at a rate 80% more than the global average — “a relationship that is consistent regardless of the future global temperature increase,” the study says. The glaciers likely to see the most loss are located within smaller elevation ranges, because there is limited scope to adapt by retreating to higher elevations.

At current levels of warming, the glacier region Arctic Canada South is projected to lose around 85% of its glacier mass, followed by Western Canada and the United States (74%), Scandinavia (66%) and the Russian Arctic (65%). Glacier regions like South Asia West, Central Asia, and New Zealand will see relatively fewer losses — 5%, 12%, and 15% — because they’re present in areas with higher elevation range.

Glaciers present in regions where there is a higher range of elevation with rugged terrain will likely lose their mass over a longer timescale, possibly a millennium, the study suggests. “This long response time is largely due to high-latitude regions, which contain by far most of the global glacier mass and require multi century timescales to respond to changing climatic conditions,” it says.

For example, it would take more than 800 years for the Subantarctic and Antarctic Islands to lose 80% of their glacier mass at 1.5°C of warming, and more than 200 years for Arctic Canada North, Russian Arctic, Greenland Periphery, Iceland, Svalbard, and Arctic Canada South to see changes of the same kind.

The fastest responding glacier regions are Central Europe, Caucasus and Middle East, Low Latitudes, and New Zealand, which “need less than five decades for 80% changes to occur and each have lost more than 20% of their mass over the first two decades of the 21st century,” says the study.

Current and near-term policies aimed at mitigating global warming “will play a decisive role in shaping the future evolution of glaciers, influencing not only immediate glacier changes but also those that will unfold over multi centennial timescales. The findings stress the pivotal role of climate policies in preserving our glaciers, which should be a central focus of the United Nations International Year of Glaciers’ Preservation in 2025,” the study concludes.