The World Meterological Organization’s State of the Global Climate report published in March delivered a grim milestone: 2024 was the hottest in 175 years of record-keeping.
As temperatures soar, mountain glaciers, which are among the most sensitive indicators of climate change, are vanishing at an alarming rate. A landmark UN report released the same month laid bare the terrible toll. It details how these frozen mountain water reserves are vanishing and what their loss spells for humanity: limited water supplies, collapsing food systems and unravelling ecosystems.
We’ve long known that melting glaciers in Antarctica and Greenland threaten to drown swathes of Florida in the United States, East Anglia in the United Kingdom and Bangladesh and Sri Lanka in South Asia, and most small island states, under rising seas. But the breakneck retreat of mountain glaciers and snowpacks – already well underway – and what that portends for humanity, are less well known.
As a scientist who’s spent 45 years tracking these changes, I can tell you: the two reports confirm that the stakes in our mountains are as existential as those at the poles – and the clock is ticking faster than most realise.
Since 2000, 5.4% of mountain glacier mass has been lost worldwide. That may not sound like much, but it exceeds Greenland’s ice loss by 18% and is double the loss seen in Antarctica. Worse, the pace is accelerating, with glacier losses increasing 36% in the last decade compared to the first.
These figures can feel abstract, but here’s what they mean in real terms: since 1975, the World Glacier Monitoring Service calculates we’ve lost a 25-metre-thick slab of mountain ice covering an area the size of Germany.
This loss is about more than just landscapes – it threatens our survival. Mountain snow and ice provide between 60% (Unesco) and 70% (WMO) of Earth’s freshwater. As glaciers shrink, water security collapses. According to Unicef, over 1.4 billion people – including 450 million children – live in areas of high or extreme water vulnerability. By 2050, three in four people worldwide could face drought impacts, with current drought costs already surpassing USD 307 billion annually.
The transformation happening in our mountain freshwater reserves is happening on a breathtaking pace and scale. We’re seeing dramatic glacier retreat, disappearing snowpacks, devastating thaw of permafrost and shifting vegetation, with forests moving higher or burning at lower elevations. Rain now falls where snow once did. Wildfire soot and pollution accelerate glacial melt by up to 10% beyond record-high rates caused by global heating. Between 1982 and 2022, we lost 15 days of global snow cover per year. In high mountains, where seasonal snowmelt is the single largest contributor to freshwater supplies, this is catastrophic.
The consequences are dire. The loss of this crucial “ecosystem service” will make farming, energy production and entire communities unviable and unlivable. Downstream irrigation, hydroelectricity and water supplies are all at risk.
But the impacts are not felt equally. Some regions are losing ice at an extreme rate. Europe’s Alps have already lost 39% of their ice mass. The Andes, which supply half of the Amazon River’s water, have lost 30-50% of their glaciers since the 1980s.
The Hindu Kush Himalaya (HKH) mountain range, home to the largest ice reserves outside the geographic poles, may be the last to succumb, but the trend is clear: [approximately] one-fifth of its ice mass has melted since 2000. This is no comfort, considering that half of the population depends on the 10 river basins fed by these glaciers. These rivers sustain a significant portion of India, China and Pakistan’s GDP. A UN report warns that as HKH glaciers retreat more significantly over the long-term, reduced water flow and increased droughts will threaten food, water, energy and livelihoods. The cascading effects, from ecosystem disruptions to economic shocks to heightened risks of conflict and migration, as ICIMOD research shows, will be felt far beyond the mountains themselves.
Canada, where I’m from, is a country defined by cold: ice hockey is our national sport. We have over 20,000 of the world’s 275,000 glaciers and possibly more snow than any other nation. The country’s seasonal melt sustains millions of streams, wetlands and lakes, providing for productive aquatic ecosystems and hydropower generation. For millennia, sea ice has defended our Arctic coast and sustained Indigenous communities. Canada is so synonymous with frozen water that President Trump once called it a “very large faucet”.
Yet, this vast reservoir of ice and snow is vanishing. Canada’s long coastline makes it extraordinarily vulnerable to the multimetre sea-level rise that accelerating polar ice losses could trigger – perhaps sooner than first thought, possibly within the second part of this century. But even before that crisis unfolds, another is already well underway: the Canadian Rockies have lost almost one-quarter of glacier ice storage in the [past] century alone. At present melt rates, many glaciers in Western Canada, in common with many mountain glaciers around the world, will not survive the 21st century.
Already, the Kinbasket Reservoir’s lakebed has been transformed into a dust bowl because of spring snow drought. Glaciers alone cannot sustain these reservoirs – sufficient seasonal snowmelt is needed. Canada’s hydroelectricity and water exports both plummeted in 2023 due to a lack thereof.
And it’s not just glacial ice we’re losing: Canada’s permafrost, or permanently frozen ground, is thawing fast. Projections suggest we could lose [around] 90% of permafrost in the Mackenzie and Yukon river basins by century’s end, with devastating ecological consequences. In these landscapes, where soil is a fragile mix of ice and dirt, melting permafrost causes the ground to collapse. Entire forests tilt and fall – a phenomenon known as “drunken forests”. Once fallen, they burn. Meanwhile, thawing ground structurally undermines towns, roads, pipelines and runways, causing their collapse.
The warning signs are already here. Last summer, record heat in the Canadian Rockies fuelled wildfires that burned down much of Jasper’s tourist centre and parts of Jasper National Park. Year after year, temperatures break new records.
The same heat waves that sparked these wildfires are also exacerbating glacier melt. Ash and soot from the wildfires settle on glacier surfaces; this darkens them, reducing their ability to reflect sunlight, and accelerating glacier melt.
As glaciers retreat, late-season streamflow in places like Jasper, Alberta, will collapse, crippling the region’s ability to cope with worsening wildfires.
Glaciers’ drought resilience on verge of collapse
Glaciers are already making floods in mountain regions more commonplace and destructive, yet paradoxically, they also provide a temporary boost to streamflow. This extra water has lulled us into a false sense of security by helping sustain hydropower, freshwater supplies and agriculture.
This reliance is unsustainable. As glaciers retreat, so too will the water they provide. Humanity’s attempts to wean itself off its dependency on these disappearing resources – especially as droughts intensify – will be ugly.
It’s tempting to think we can control the world around us, but glaciers, snow and ice are what actually govern the natural order of things and, indirectly, the stability of our societies.
While problems spiral into a vicious cycle, we must urgently find solutions to forge a sustainable future.
In Canada, we talk about “braiding” – the weaving together of traditional and scientific knowledge. Doing more of this will be fundamental as we confront the single greatest challenge of humanity’s existence.
Indigenous peoples everywhere, from Canada to Japan and the Himalayas, have managed water sustainably for thousands of years, integrating snow and glaciers into their traditions. Their ancestral knowledge may not offer direct solutions to today’s crisis, but understanding past resilience will help us meet the challenges of the future. For millennia, humans have been master water managers, extracting water from the ground, diverting rivers, irrigating dry soils. Now, we must adapt these practices for a future without glaciers. Crucially, we must accept, as Indigenous communities do, that not everything can be for human use.
Some societies facing glacier loss are exploring ways to delay water release for irrigation, but these solutions come with high costs and risks. Many require expensive infrastructure and could trigger unintended consequences, like flooding valleys, displacing human settlements and damaging ecosystems.
I remain an optimist, but we’re heading in the wrong direction
Indigenous teachings in Canada emphasise thinking seven generations ahead: how will our choices today impact people 200 years from now? This long-term vision must replace five-year political cycles if we are to survive.
One way Canada is adapting is by expanding beaver populations. These emblematic and charismatic “hydro-fauna” engineers build millions of dams that store vast amounts of water, regulate floods and recharge groundwater. By protecting the beaver, we help conserve our water supply.
World leaders must understand the full implications of losing mountain snow and ice. The same conditions causing glacial collapse will also bring deadly heatwaves, fatal water shortages, floods that destroy cities and homes and sea level rise that submerges entire coastal communities.
Where will millions – perhaps billions – of displaced people go when these disasters unfold? The world is unprepared for this scale of migration.
I remain an optimist, but we’re heading in the wrong direction. We’re too slow to reach agreements to lower greenhouse gas concentrations in the atmosphere. This is the year we must turn things around.
One day, I hope we can look back and say that, despite all the chaos and noise of today’s world, we made the right choices – having taken decisive steps to protect the ice and snow that sustains life itself. Perhaps this will be our species’ grandest challenge: by saving our glaciers, we save ourselves and our civilisation.
The first-ever World Glacier Day, observed on 21 March, was celebrated at the UN General Assembly in New York and the Unesco headquarters in Paris. More can be found out here. This article is an edited version of remarks Pomeroy delivered in March 2025 at the headquarters of the International Centre for Integrated Mountain Development (ICIMOD) in Lalitpur, Nepal.
The International Conference on Glaciers’ Preservation 2025 will be held in Dushan, Tajikistan, between 29-31 May.
