World Water Day 2025: disappearing glaciers threaten the global water balance
On the 22nd of March 2025, World Water Day, the whole world turns its eyes to a tragic and imminent crisis: the accelerating disappearance of glaciers. These towering masses of ice have been fundamental to the water balance for millennia, regulating the flow of rivers and supplying water to millions of people. What may appear to us to be awe-inspiring ice highways are the very source of development for entire ecosystems, and also for the communities that depend on their melting for agriculture, consumption and energy generation.
On World Water Day 2025, the world confronts a growing crisis: the rapid disappearance of glaciers
Global warming, driven by uncontrolled greenhouse gas emissions, has accelerated the retreat of glaciers at an alarming rate. Our most stable source of freshwater for centuries is being severely depleted, becoming a stealthy threat to water security in many regions of the world. The river flows that depend on meltwater are beginning to fluctuate dramatically, with periods of abundance followed by extreme droughts. Meanwhile, rising sea levels from melting Greenland and Antarctic ice threaten to reshape the geography of coastal cities around the world.
Throughout history, humankind's survival has depended on glaciers without our awareness of their fragility, and now the threat of their imminent disappearance exposes the vulnerability of a system that seemed unalterable. The decline of these ice giants does not only affect countries with mountainous regions but has repercussions across the globe. The disruption of the water cycle, the instability of precipitation patterns and the impact on biodiversity make it clear that the meltdown crisis is not an isolated phenomenon, but a profound transformation of the ecosystems that sustain life.
The impact is global, from the peaks of the Andes to the poles, from the rivers of Asia to the water supplies of Europe. If current trends continue, the entire planet will face a future in which access to freshwater will become increasingly uncertain. The question that arises is whether we will be able to anticipate the consequences or whether we will continue watching as we destroy our ancient, life-giving ice currents.
Melting ice threatens water security, ecosystems, and coastal cities, reshaping our planet’s future.
Science confirms this with alarming figures: glaciers globally have lost an average of 267 ± 16 gigatonnes of mass per year between 2000 and 2019, according to the study “Accelerated global glacier mass loss in the early twenty-first century” (Hugonet et al., 2021). To put this in perspective, this amount of water would be equivalent to filling approximately 107 million Olympic-size swimming pools each year.
The problem lies not only in the amount of ice that is being lost, but in the speed at which this is happening. In some regions, such as Alaska, the Andes or the Himalayas, the rate of glacier thinning has quadrupled in the last 30 years. In simple terms, what used to take a century to melt now takes just a few decades. Global temperature is on an upward trend of 0.030 °C per year, suggesting that this process will only intensify in the near future.
Despite their appearance as buttresses of mountain ice, glaciers also regulate sea level rise. Indeed, glaciers in Greenland and Antarctica are contributing to this rise, threatening coastal cities and island communities. The interconnection of these phenomena with extreme weather events, such as more intense hurricanes and torrential rains, elevates this crisis to a global scope.
A more extreme and unpredictable water cycle
Glaciers have played a key role in regulating water availability. They act as natural “water banks”, accumulating snow in winter and gradually releasing it in summer, ensuring a constant supply of water to rivers and aquifers. Here's why this balance is collapsing.
The article “A call for an accurate presentation of glaciers as water resources” (Gascoin, Simon, 2023) warns that the disappearance of glaciers does not mean an immediate impact on water availability, but a progressive alteration of the hydrological cycle. Initially, the accelerated melting generates an increase in river flow, which could give the false impression that more water is available. However, this effect is temporary. As glaciers continue to shrink, there will come a point at which there will no longer be enough ice to sustain flows in times of drought.
This phenomenon is already evident in the Himalayan region. Rivers such as the Indus, Ganges and Brahmaputra have experienced an increase in their flow due to accelerated melting, but climate models warn that they could suffer drastic reductions in volume in the coming decades. For millions of people who depend on these water sources for agriculture and daily consumption, this change could have devastating consequences.
In addition, the lack of water from melting snow will force communities to rely more on groundwater, increasing the overexploitation of aquifers. This could lead to additional problems such as desertification and land degradation, affecting agricultural production and food security in many regions of the world.
Retreating glaciers: a global problem
The melting of glaciers is not a localised phenomenon, but a problem that affects millions of people in all regions of the world
The melting of glaciers is not a localised phenomenon, but a problem that affects all regions of the world. From the Andes to the Himalayas, the Alps, the Rocky Mountains and other major mountain ranges, the retreat of these ice masses is transforming the global water balance and affecting millions of people.
In his comprehensive study, Simon Gascoin sheds light on the state of the world's most iconic glaciers. In South America, the Andes Mountains are home to some of them, vital sources of water for cities such as Lima and Santiago. However, recent studies have revealed that Andean glaciers have lost almost half of their mass in the last century, and some of them could disappear in the coming decades. This reduction of ice not only affects the availability of drinking water, but also increases the risk of landslides and avalanches caused by the weakening of mountain slopes,
The Himalayas, known as the “water tower of Asia”, face a similar scenario. Glaciers in this region supply key rivers such as the Ganges, Brahmaputra and Indus, on which more than a billion people depend. Reduced flows could lead to tensions over access to water in densely populated countries such as India, China and Pakistan. In the short term, accelerated melting may lead to devastating floods, but in the future, it will result in a drastic reduction of water supply in times of drought.
In the European Alps, where glaciers have shaped landscapes and been part of the local culture and economy for centuries, the situation is no less alarming. During the hottest summers in recent history, some glaciers have lost several metres in thickness in a matter of months. The shrinking ice not only affects the region's natural beauty and mountain tourism, but also compromises hydroelectric power generation, a key source of electricity in several European countries.
Could we imagine an Antarctica without glaciers?
A team of international scientists led by the British Antarctic Survey (BAS) has recently produced a map (Bedmap3) that simulates a view of Antarctica as if its 27 million cubic kilometres of ice had disappeared, revealing the hidden location of the highest mountains and deepest canyons. This map is not only interesting on a geographical level, but shows us a clear and shocking vision of the consequences of a possible loss of the ice that contains the Antarctic continent, approximately 90% of the planet. If its entire ice mass were to melt, sea levels would rise by some 58 metres, enough to submerge entire cities, from New York to Shanghai. Beyond sea level rise, the collapse of Antarctic glaciers would cause irreversible changes in ocean currents, affecting the climate of the entire planet.
Glaciers not only store water, they also play an essential role in regulating global temperatures. By reflecting sunlight, they contribute to maintaining the Earth's thermal balance. Without their presence, the oceans would absorb more heat, further accelerating global warming and affecting marine life.
Glaciers not only store water, they also play an essential role in regulating global temperatures
In addition, the total melting of Antarctic glaciers would expose ancient sediments and micro-organisms trapped in the ice for millennia. Some scientists warn that this could release unknown viruses and bacteria, with possible implications for global health. Large amounts of carbon and methane, trapped in the permafrost, would also be released, intensifying the greenhouse effect and further increasing global temperatures.
While this scenario may seem remote, the loss of ice shelves in Antarctica is already underway. Cracks in the Antarctic Peninsula Ice Shelf and massive break-up events have been detected and have changed the configuration of the region in recent decades. A glacier-free Antarctica is not just a theoretical possibility, but a possible future if immediate action is not taken to curb climate change.
The retreat of glaciers is an undeniable sign of climate change in action. Their disappearance affects not only the people who depend directly on them, but also the stability of the global climate. While scientists warn of the urgent need to reduce carbon emissions and take adaptation measures, glaciers continue to melt, irreversibly transforming the world.