As the world marks World Water Day 2025, attention turns to one of the most critical yet overlooked aspects of the global water system: glaciers. These ancient ice formations, which cover 10% of the Earth's land surface, serve as the planet’s largest freshwater reserves. Their seasonal meltwater supplies billions with drinking water, sustains agriculture, powers hydroelectric plants, and regulates river ecosystems. However, climate change is accelerating their retreat at an unprecedented rate, with severe consequences for water security, environmental protection, and global sustainability.
The alarming rate of glacier loss
Glaciers have been retreating since the end of the Little Ice Age (circa 1300–1850), but the current rate of decline far exceeds natural variability. According to the World Glacier Monitoring Service (WGMS), glaciers have lost over 9,000 cubic kilometres of ice since 1900, enough to cover the United States in one metre of water. In just the past two decades, global ice loss has surged by 65%, with 273 billion tonnes of ice melting per year from 2000 to 2023.
In Europe, the Alps have lost 60% of their glacier mass since 1850, and models predict that by 2100, over 90% of Alpine glaciers could disappear under current emission scenarios. The Himalayas, often referred to as the "Third Pole," have seen glacial retreat double in speed since the early 21st century, threatening water supplies for 1.65 billion people dependent on major river systems like the Ganges, Indus, and Yangtze.
In polar regions, the Greenland Ice Sheet is losing ice seven times faster than in the 1990s, contributing to rising sea levels at an accelerating rate. If the West Antarctic Ice Sheet collapses, it could trigger a global sea level rise of over 3 metres, displacing millions in coastal cities from New York to Dhaka.
The impact on global water cycles and natural disasters
The loss of glaciers has profound implications for hydrological cycles. Glaciers act as natural reservoirs, slowly releasing water during warmer months to maintain river flows. Their rapid decline leads to short-term increases in river discharge, followed by long-term water shortages as glaciers diminish. This phenomenon has already begun in the Andes, where declining glaciers threaten drinking water and hydropower for Lima, Bogotá, and La Paz.
Moreover, glacial retreat amplifies climate extremes, increasing the frequency of glacial lake outburst floods (GLOFs), landslides, and droughts. In 2021, a massive rock and ice avalanche in the Indian Himalayas caused catastrophic flooding in Uttarakhand, destroying villages and hydropower plants. Without intervention, such disasters will become more frequent, affecting populations worldwide.
Scientific forecasts: What the future holds
According to the Intergovernmental Panel on Climate Change (IPCC), even if global warming is limited to 1.5°C above pre-industrial levels, one-third of the world's glaciers will disappear by 2100. Under a high-emissions scenario, nearly two-thirds could be lost. A study published in Nature (2023) warns that half of the Earth's 215,000 glaciers are on track to vanish by 2100, leading to 6–10 cm of additional sea level rise, exacerbating flooding risks for 600 million people living in coastal regions.
However, strong mitigation efforts can significantly slow down these losses. The IPCC highlights that achieving net-zero emissions by 2050 could preserve an additional 40% of glaciers compared to a high-emission scenario.
Global responses and glacier preservation initiatives
Recognising the urgency, the United Nations has declared 2025 the International Year of Glaciers' Preservation, urging nations to prioritise glacier protection in climate policies. UNESCO, in partnership with the World Meteorological Organization (WMO), has launched a global glacier monitoring initiative, enhancing satellite and AI-based tracking of ice loss.
Countries are also taking direct action:
· Switzerland has implemented experimental measures such as glacier blankets, covering ice with reflective materials to slow summer melting.
· Argentina became the first country to pass a National Glacier Protection Law (2010), restricting industrial activities in glacial and periglacial zones.
· China has launched massive afforestation projects in the Tibetan Plateau to mitigate regional warming and glacial retreat.
The role of the global society in tackling glacier loss
The global society has a crucial role in addressing this crisis. Climate action, rooted in international collaboration, is essential to curb emissions and implement sustainable water management. The preservation of glaciers aligns with the Sustainable Development Goals (SDGs), particularly:
· SDG 6: Clean Water and Sanitation – Ensuring long-term water security for billions.
· SDG 13: Climate Action – Reducing carbon emissions to slow glacier retreat.
· SDG 15: Life on Land – Protecting ecosystems reliant on glacial meltwater.
· SDG 16: Peace, Justice and Strong Institutions – Strengthening legal frameworks to hold industries accountable for emissions driving glacial melt.
The preservation of glaciers is not just an environmental concern—it is a survival strategy for humanity. As World Water Day 2025 reminds us, the choices made today will determine whether glaciers endure for future generations. Through scientific advancements, policy interventions, and collective global action, the world must strive to safeguard these frozen reservoirs. The time to act is now.
Further reading
For more information on global efforts to preserve glaciers and combat climate change, consider exploring:
Engaging with these materials provides deeper insights into the science, policies, and global initiatives aimed at tackling the escalating crisis of glacial retreat.