ISTANBUL
For years, glaciologist Sridhar Anandakrishnan has been studying the massive Thwaites Glacier in Antarctica, often referred to as the “Doomsday Glacier.”
Its colossal size holds the potential to raise global sea levels by 60 to 70 centimeters if it were to lose all its mass – an increasingly possible scenario as climate change accelerates the rate at which the glacier is melting.
“Think about the entire globe, all the oceans on the planet – the Indian Ocean, Pacific Ocean, Atlantic Ocean. Now imagine 60 or 70 centimeters of water draped over all of those oceans. That’s an enormous amount of water all over the world,” Anandakrishnan explains.
The pressing question, however, remains: will this happen over the next 100 years or the next 500 years? While it is unlikely that Thwaites will collapse entirely in the near future, its ongoing retreat poses a significant concern for coastal communities worldwide.
“The bottom line is that all glaciers in Antarctica and Greenland are losing mass or volume, and that water has to go somewhere – and that somewhere is the oceans,” Anandakrishnan warns.
Global call to action
As the effects of climate change intensify, glaciers – once symbols of Earth’s frozen stability – are retreating at an alarming rate, threatening ecosystems, water resources, and human communities.
In response to this growing urgency, the UN has declared 2025 the International Year of Glaciers’ Preservation, with March 21 set to mark the inaugural World Day for Glaciers.
“It’s a new development that shows the whole world is becoming more aware of the problems related to glaciers,” says Stefan Uhlenbrook, director of hydrology, water, and cryosphere at the World Meteorological Organization (WMO).
There are more than 200,000 glaciers across the planet, and glaciologist Matthias Huss warns that they “are declining everywhere, be it the European Alps, the Arctic, High Mountain Asia, Patagonia, Alaska.”
“Record-shattering events have occurred everywhere around the world in recent years. For example, in 2022 in the European Alps, 2023 in western Canada, and 2024 in the Arctic, including Norway, Svalbard, and parts of High Mountain Asia,” said Huss.
Why are glaciers important?
Glaciers form when snow accumulates over time, compresses into ice, and flows outward and downward under its own weight. They are more than icy relics of the past, playing critical roles in maintaining ecosystems, providing freshwater resources, and regulating global sea levels.
There are three places around the world where most of the ice is concentrated – the largest is in Antarctica, followed by Greenland, and then the Himalayas, home to thousands of glaciers, explained Anandakrishnan, a professor of glaciology and geophysics at Pennsylvania State University.
Huss highlights the glaciers’ importance to regional ecosystems and communities.
“If the ice is gone, an important water contribution, especially during hot and dry summer periods, will be lacking. This can be problematic for irrigation of fields and water supply,” he said.
“Most importantly, regions in Asia and South America are affected by this. In many regions, glacier water is also used for hydropower production, which might see cuts if the glaciers are gone.”
On a global scale, melting glaciers contribute significantly to sea-level rise. “Over the next few decades, glaciers will contribute a large amount of water to the sea,” Huss said, reiterating that the impact would be felt globally, especially in coastal regions vulnerable to flooding and storm surges.
Climate change and glacier retreat
At this point, the planet’s melting glaciers have become “an icon of climate change,” said Uhlenbrook.
In the Swiss Alps, he added, the total glacier mass has been reduced by 10% over just two hydrological years.
“This is enormous. We never had that before and that’s because of two very warm summer periods, as well as relatively warm … rather dry winters in most part of the Alps,” he explained.
During winter, glaciers are replenished with snow, but the balance has shifted due to global warming, as the amount of melt during summer now far exceeds the accumulation during winter, the WMO official said.
Anandakrishnan underscored the uniformity of this phenomenon, with glacier cover being lost everywhere from the Himalayas to the Alps, to North and South America, and even Greenland and Antarctica.
“It’s really a long-term ongoing phenomenon that is due to human-caused modification of the atmosphere,” he said.
Critical turning point
The UN’s declaration of 2025 as the International Year of Glacier Preservation is a vital step toward addressing the crisis. However, experts agree that meaningful progress requires tackling the root cause: climate change.
“The most effective path to preserve glaciers is stabilizing the climate,” said Huss.
Anandakrishnan emphasized that the state of the cryosphere – the Earth’s frozen regions – is at a critical juncture, pointing to diminishing sea ice as a major cause for concern.
Every winter, less sea ice forms than the year before, and every summer, more ice melts than in previous summers, he explained.
In the Arctic, once-impassable ice now allows regular shipping traffic.
Fifty years ago, only specialized icebreaker ships could navigate these areas, but today, much of the ice has fragmented, he said.
The same trend is evident in Antarctica, where sea ice is no longer as robust as it once was.
“We’ve been measuring and monitoring a lot of glaciers in Antarctica and Greenland for a number of years and not one of them is growing,” said Anandakrishnan.
“Every single one is either stable or shrinking, so that’s also very indicative that … it’s a uniform effect in the Himalayas, in Greenland, in Antarctica.”
Existence of glaciers and human lives at risk
The retreat of glaciers poses direct threats to human communities, particularly those living near rivers and coastal areas.
“As glaciers melt … the ice they lose turns into water that flows into the oceans, raising sea levels,” Anandakrishnan explained.
In the Himalayas, melting glaciers endanger millions of people reliant on glacial-fed rivers for drinking water, agriculture, and industry.
With the Himalayan glaciers, there is significant concern for both, people living in mountainous areas, as well as down river in countries such as Pakistan, India, Bangladesh, Myanmar, and others, he said.
He also emphasized the risk of catastrophic floods caused by glacial lake outbursts.
Moreover, the shift from snow-covered glaciers to exposed rock accelerates the melting process, with snow that once lasted for months now disappearing in a matter of weeks, disrupting the steady flow of rivers that people depend on, he explains.
Uhlenbrook adds that sea-level rise exacerbates challenges for coastal communities, including saltwater intrusion into freshwater supplies.
“It’s much more difficult to live in these coastal environments. So, this is a global problem … which really leads to challenges for water supply, and floods and droughts globally,” he said.
On the future of glaciers, experts agree that everything hinges on humanity’s actions – or inaction.
“There is indeed cause for concern. It’s not cause for panic, but it is certainly true that if we do nothing then, in the next hundreds of years, all the glaciers will indeed melt,” Anandakrishnan warns.
While it is challenging to predict short-term changes, Huss says the long-term trend is clear, especially as greenhouse gas emissions are expected to remain dangerously high.
“This will drive glaciers toward further retreat, and many will further shrink or even disappear,” he said.
