Accelerating ice melt from glaciers worldwide means an increased loss of freshwater resources, ever-faster sea level rise and life-threatening floods and landslides. In some regions, ice loss is already overtaking scientists’ worst-case climate scenarios. Only urgent emissions cuts can make a difference.
The first time I ever saw and walked upon a glacier was in the Swiss alps, back in the 1970s. Hiking in Valais, I was fascinated, awed by the metres-thick dazzling mass of ice sparkling in the sun – and the grey rubble around and below it, showing in contrast what the land would be like beneath. In the years since, much of that alpine landscape has changed dramatically. The long tongues of ice have got shorter, leaving increasing expanses of gravelly grey.
A day to celebrate or mourn?
The 21st of March 2025 is being celebrated as the first-ever World Day for Glaciers. “Celebrate”? Yes, we should celebrate glaciers and their crucial role in sustaining life on Earth for future generations. There are more than 275,000 glaciers worldwide, covering approximately 700,000 km². Glaciers and ice sheets store about 70% of the global freshwater. More than two billion people rely on melting glaciers and snow for fresh water. However, we are destroying the life-supporting ice at an ever-increasing rate by heating up the global climate. With projections showing that one-third of glacier sites could disappear by 2050, the UN has declared the World Day for Glaciers to raise awareness of the urgent need for global action to protect these vital ecosystems. Whether we like it or not that means drastically cutting down on greenhouse gas emissions.
With all the other things going on in the world, you may not have noticed – but actually the whole of 2025 has been declared the “International Year of Glaciers’ Preservation”. The WMO and UNESCO describe this as a “Global Call for Action to Save Earth’s Vital Ice”, at a “critical moment for Earth’s Cryosphere”. The preservation of these crucial resources is essential not only for environmental sustainability, but also for economic stability and safeguarding cultural services and livelihoods, the WMO says.
Alarming ice loss over just 20 years
The message of this special focus year was dramatically illustrated by a comprehensive analysis of the world’s glaciers published in Nature on 19 February 2025 by an international research community led by researchers of the University of Zurich (UZH). Looking back over the last two decades – a mere blink in the history of our planet – the Glacier Mass Balance Intercomparison Exercise, or GlaMBIE, revealed that global glaciers are losing ice at an alarming rate, averaging 270 billion tonnes annually from 2000 to 2023, with a significant acceleration in recent years. Since 2000, mountain glaciers have actually lost more ice than the Greenland ice sheet, and more than twice that of the Antarctic ice sheet. This made glaciers a major driver of sea-level rise during these two decades: about 18mm of sea level rise can be attributed to mountain glaciers since the year 2000, making glaciers currently the second-largest contributor to global sea-level rise after expansion from the warming of the ocean.
In addition, glacier melt means the loss of essential freshwater resources in many regions. “To put this in perspective, the 273 billion [metric] tons of ice lost in one single year amounts to what the entire global population consumes in 30 years, assuming three liters per person and day,” states Michael Zemp, UZH professor at the Department of Geography, who led the study.
Overtaking the worst-case scenarios
“When it comes to sea-level rise, the Arctic and Antarctic regions with their much larger glacier areas are the key players. Almost one quarter of the glacier contribution to sea-level rise originates from Alaska,” says UZH glaciologist Inés Dussaillant, who was involved in the GlaMBIE analyses.
In some regions, like the southern Andes and New Zealand, ice loss from glaciers is already surpassing the IPCC worst case projections for 2040, the researchers found.
In relation to the total ice in a region, regions with smaller glaciated areas such as the European alps and the Pyrenees are the places with the largest relative mass loss. A staggering 40 percent of the ice has been lost there over just 23 years – “absolutely beyond dramatic,” says glaciologist Dr. Heïdi Sevestre, Deputy Secretary of the Arctic Monitoring and Assessment Programme (AMAP) in a presentation organised by the International Cryosphere Climate Initiative (ICCI) to mark the World Day for Glaciers. She stresses: “things are really accelerating”.
“Overall, this study paints a sobering picture of the world’s glaciers, which face continued and possibly accelerated mass loss until the end of this century unless ambition for climate action is dramatically improved”, concludes ICCI.
The World Meteorological Organization (WMO)’s latest State of the Global Climate Report published on March 19, 2025, confirms the findings :
“The period 2022-2024 represents the most negative three-year glacier mass balance on record. Seven of the ten most negative mass balance years since 1950 have occurred since 2016.
Exceptionally negative mass balances were experienced in Norway, Sweden, Svalbard, and the tropical Andes.
Glacier retreat increases short-term hazards, harms economies and ecosystems and long-term water security,” the UN weather and climate experts conclude. There can be no doubt as to the reason:
“The clear signs of human-induced climate change reached new heights in 2024, which was likely the first calendar year to be more than 1.5°C above the pre-industrial era, with a global mean near-surface temperature of 1.55 ± 0.13 °C above the 1850-1900 average.”
Fossil energy giant sued for climate damage
Just ahead of the World Day for Glaciers, an ongoing landmark court case is being heard in Hamm in Germany. Peruvian farmer Saul Luciano Lliuya, supported by the activist group Germanwatch, is suing energy giant RWE over its role in climate warming. Lliuya wants the company to pay around 17,000 euros ($18,520) toward a $3.5 million flood defence project, arguing that the company is accountable for past emissions, which are melting a glacier above his farm, increasing the risk of flooding. The court could deliver a landmark ruling if it holds the company accountable for past emissions and requires it to help fund climate adaptation for affected communities.
Regardless of the final verdict, the court has already set a precedent by accepting that the fossil fuel company can be brought before a civil court for its contribution to global warming.
A win for Lliuya could set a “groundbreaking” precedent, said Seb Duyck of the Center for International Climate Law, talking to the Yale School of the Environment. Legal questions addressed in this case, he said, could shape “claims against climate polluters worldwide as communities increasingly seek compensation.”
2025: The year of glaciers and…
Alas, 2025 – and we are only a quarter into it – has also been the year when our CO2 levels reached a “Grim Milestone for Earth’s Polar Regions”, crossing the 430 ppm mark “for the first time since records began, and likely for the first time in at least 3 million years”, as the International Cryosphere Climate Initiative puts it.
This “raises a red flag that today’s fossil fuel emissions are pushing the climate into greater and more deadly extremes,” the cryosphere experts write.
“Passing 430 ppm should be a wake-up call, especially given the accelerated response we are seeing of glaciers and ice sheets to current warming,” says Dr. James Kirkham, Chief Scientist of the Ambition on Melting Ice coalition of governments “, which includes both Germany and Peru.
The most ambitious mitigation measures outlined by the IPCC Sixth Assessment Report to slow and reverse climate change have CO2 levels peak at 430 ppm.
“Paired with the fact that 2024 was the hottest year since records began in 1880, rising above the 1.5°C for the first time, these pressing realities serve as a distress signal for the planet”, says ICCI, headed by former diplomat and cryosphere expert Pam Pearson.
“Breaking the 430 ppm level of CO2 in the atmosphere is a tragic threshold, but only underscores the need for a focus on immediate greenhouse gas emission cuts – keeping warming close to 1.5°C remains essential and achievable, but barely,” said Dr. Joeri Rogelj, IPCC lead author, of Imperial College London.”
US President attacks science and climate
In what could be the most alarming development when it comes to protecting glaciers, the cryosphere, and the planet as a whole, 2025 is also the year when the US administration under President Donald Trump is waging war not on global warming but on climate science itself.
But as Dr. Carolina Adler of the Mountain Research Initiative put it at the launch of this International Year of Glaciers’ Preservation: “Glaciers don’t care if we believe in science – they just melt in the heat.”
With wars and conflict distracting attention and funding from climate change -and increasing emissions even further – with the collection of data and analysis under threat from cuts in the US, with the rise of climate-sceptic right-wing political groups in various parts of the world despite WMO warnings of spiralling weather and climate impacts, it is hard to get glaciers the attention and resources they deserve.
Preserve the glaciers, preserve the planet
At the launch of the International Year for Glacier Preservation, one of the organizers Bahodur Sheralizoda, Chairman of the Committee for Environmental Protection of Tajikistan, expressed confidence that “this initiative will mobilize the global community, inspire action, and drive the policies and solutions necessary to protect these invaluable natural resources.”
It is hard to share that confidence with the current state of global politics. All the more reason to increase our efforts. It is not about, one day, not about one year, and it is not just about glaciers.
The past year was the warmest year in the 175-year observational record. The State of the Global Climate 2024 report underlines the massive economic and social upheavals from extreme weather and the long-term impacts of record ocean heat and sea-level rise.
“Today’s observations raise a clear signal that the Earth is responding to fossil fuel emissions faster and more intensely than anticipated”, writes the International Cryosphere Climate Initiative.
“There’s no time like the present?” It could be “now or never”. Preserving our glaciers means halting runaway climate warming and the existential threats it poses to life on our planet as we know it.
