The UN and the World Meteorological Organization (WMO) have sounded the alarm over the accelerating melting of the world's glaciers, warning that preserving these water reserves is now a matter of survival. On March 21, the UN declared this date as the new International Day of Glaciers to raise awareness about their vital role in the climate system, coinciding with a UNESCO summit in Paris calling for global action to protect glaciers around the world.
According to a recent report from the WMO, five out of the past six years saw the most rapid glacier retreat on record. Large masses of perennial ice are disappearing quickly, with the organization noting that the period from 2022 to 2024 experienced the largest-ever three-year loss of glacier mass. In 2022 alone, an estimated 450 billion tons of ice was lost, making it the fourth-highest record ever observed.
"The preservation of glaciers is not only an environmental, economic, and social necessity. It is a matter of survival," said Celeste Saulo, Secretary-General of the WMO.
The World Glacier Monitoring Service (WGMS) estimates that glaciers, excluding the Greenland and Antarctica ice sheets, have lost more than 9,000 billion tons of mass since 1975. Records indicate a loss of 6,542 billion tons since 2000, which shows the acceleration of glacial retreat in recent decades. This loss is equivalent to a 25-meter-thick ice sheet covering Germany.
"This level of glacier loss is unprecedented. We are watching entire ecosystems change before our eyes. If current trends continue, glaciers in Western Canada, the USA, Scandinavia, Central Europe, the Caucasus, New Zealand, and even the Tropics will not survive the 21st century," said Michael Zemp, Director of the WGMS.
Glacier melting has contributed to rising sea levels, with the melting between 2000 and 2023 adding 18 millimeters to sea levels globally. The latest data indicates that 25 to 30 percent of sea-level rise comes from glacier melt. The WMO warns that each additional millimeter of sea-level rise exposes between 200,000 and 300,000 new people to possible flooding.
"If emissions of warming greenhouse gases are not slowed, and the temperatures are rising at the rate they are at the moment, by the end of 2100, we are going to lose 80 percent of the small glaciers," said Sulagna Mishra.
The melting glaciers are also destroying waterways that billions of people rely on for agriculture and hydropower. These natural water reservoirs are now shrinking, threatening the water supply of hundreds of millions who rely on glacier-fed rivers, especially during dry months.
Glaciers, together with the ice sheets of Greenland and Antarctica, hold about 70 percent of the world's freshwater reserves. They act as "water towers" that sustain millions of people, especially in high-mountain regions.
"At the United Nations, we can negotiate many issues, but not the laws of physics, and the melting point of ice is one of them," remarked Stefan Uhlenbrook, director of the WMO for Water and Cryosphere, emphasizing the consequences of rising temperatures.
In response to the retreat, the United Nations General Assembly has declared the year 2025 as the "International Year of Glacier Conservation," aiming to unite efforts worldwide to protect glaciers.
"Every millimeter of sea level rise exposes another 200,000 to 300,000 people to annual flooding," said Zemp. He added, "This is equivalent to a huge ice block the size of Germany with a thickness of 25 meters," referring to the total ice loss since 1975.
The WMO reported that in 2024, all 19 of the world's glacier regions recorded a net loss of mass for the third consecutive year, marking the greatest loss of glaciers ever recorded over three years.
Glaciologists determine the state of a glacier by measuring how much snow falls on it and how much melt occurs every year, according to the WGMS at the University of Zurich. Monitoring glaciers is essential to understand future water resources on Earth and the severity of the situation.
"The only way to preserve glaciers is to reduce greenhouse gas emissions," said glaciologist Nina Kirchner at Tarfala Research Station.
From a multilateral perspective, "it is really high time that we create awareness, and we change our policies and we mobilize resources to make sure that we have good policy frameworks in place, we have good research in place that can help us to mitigate and also adapt to these new changes," insisted Sulagna Mishra.
The acceleration of melting has made mountain glaciers one of the largest contributing factors to rising sea levels, putting millions at risk of floods. Glacial melting is currently estimated to be the second-largest contributor to sea-level rise, only behind the global warming of the oceans.
In Europe, glaciers have shown a loss both in their extent and thickness. In the Pyrenees, the glaciers have lost more than half of their surface area in just 12 years. "Spanish glaciers are in a critical situation. In the last 40 years, more than half have disappeared, and those that remain are shrinking," experts stated.
The WMO warns that the global retreat of ice has accelerated in the last three years, triggering "cascading damages" affecting ecosystems, economies, and communities globally, implying an "avalanche of chain effects."
"Glaciers have a simple symbolic function because they are melting so quickly and everyone can see it," said Kirchner. She added, "We must reckon with losing some glaciers."
"We will have less ice in the future, but I hope that part of it can be saved. This is also the meaning of the International Year of Glacier Conservation and the International Day of Glaciers on March 21: any additional warming that can be prevented has a direct impact on glaciers; this is the way to preserve (part of) our glaciers," said Samuel Nussbaumer.
The article was written with the assistance of a news analysis system.