Half of the world's glaciers can be saved with strong climate action

Current climate policies could allow global temperatures to rise by 2.7°C (4.9°F) by the end of this century. That level of warming would reshape coastlines, threaten ecosystems, and disrupt freshwater supplies.

Scientists emphasize the importance of limiting warming to 1.5°C (2.7°F) to protect glacier-dependent regions.

In a recent study published in the journal Science, experts modeled over 200,000 glaciers outside of the Greenland and Antarctic Ice Sheets.

“Using eight glacier models, we simulated global glacier evolution over multicentennial timescales, allowing glaciers to equilibrate with climate under various constant global temperature scenarios,” noted the researchers.

The results showed that even if global temperatures stopped rising today, 39% of glacier mass would still vanish, raising sea levels by over four inches. However, strong climate policy could save twice as much ice as current warming paths allow.

Locked into significant glacier loss

Glaciers don’t react instantly. Instead, they adjust slowly, over centuries. That lag means today’s glacier retreat reflects past emissions, not just current warming.

“The glacier melt we’re seeing today reflects warming from decades ago,” said study co-author David Rounce of Carnegie Mellon University.

Even with no more warming, we are locked into significant glacier loss. This “committed” loss arises because glaciers are out of balance with today’s climate. According to the study, 113 mm of sea-level rise will occur even if current conditions hold steady.

Each fraction of a degree counts

The study found a steep cost for every bit of extra warming. For each 0.1°C (0.18°F) rise, we lose another 2% of glacier ice and gain 6.5 mm (0.26 inches) in sea-level rise.

Under a 2.7°C (4.9°F) scenario, 76% of glacier mass would be lost. Sea levels would rise by 230 mm (9.1 inches). By contrast, staying within 1.5°C (2.7°F) preserves 53% of global glacier mass.

“Decisions we make now will determine the future of our water, coastlines, and ecosystems around the world,” said Rounce. The message is clear: small policy shifts today shape glacier survival centuries ahead.

Where glaciers will disappear first

Not all glaciers face the same risk. Regions like Arctic Canada South, Western Canada, and Scandinavia could lose over 65% of their mass – even if warming stopped.

In contrast, South Asia West and New Zealand show lower losses under current temperatures, but they are more vulnerable to future warming.

Why? Glacier elevation range matters. Wide elevation ranges allow glaciers to retreat upward and persist. In flatter regions, that’s not possible.

For example, Arctic Canada South is warming 2.2 times faster than the global average. It’s home to relic glaciers from the last Ice Age that can’t survive current warming.

Climate policy and glacier timelines

How long do glaciers take to respond? The answer: centuries. Some regions, like the Subantarctic Islands, need 800 years to lose 80% of their committed ice under a 1.5°C (2.7°F) scenario. Others, like New Zealand or the Caucasus, react in just a few decades.

This time lag means glacier changes we see in the next 100 years are only part of the story. Some glaciers that seem safe today may still vanish in the long run if warming continues.

What happens in a 5°C warmer world

At 5°C (9°F) above pre-industrial levels – an extreme possibility – only 9% of glacier mass would remain. That would raise sea levels by 282 mm (11.1 inches). Many mid-latitude regions would completely deglaciate, losing almost all their ice.

Though this scenario may seem distant, the difference between it and the 1.5°C (2.7°F) target is huge. That’s why every 0.1°C (0.18°F) matters.

The study shows the most glacier-sensitive regions are also the ones with the most to lose from small policy failures.

Climate action to protect glaciers

The United Nations has named 2025 the International Year of Glacier Preservation, highlighting the urgent need to protect glaciers worldwide.

The Carnegie Mellon study has revealed a key insight: glaciers take centuries to fully adjust to new climate conditions. That means we haven’t yet seen the full impact of past emissions – and what we do now will shape glacier survival far into the future.

Glacier loss is not a short-term crisis with quick fixes. It’s a slow-moving disaster that builds over generations. Even if we stabilize temperatures today, many glaciers are still committed to melting.

But with strong climate action, much of that loss can be avoided. The line “not just for ice, but for life” captures the stakes. Glaciers provide freshwater, prevent flooding, and support ecosystems.

Letting them vanish means risking vital resources for millions. This year, more than ever, climate pledges must be treated seriously.

The study is published in the journal Science.

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