Global Glaciers Record Net Mass Loss for Fourth Consecutive Year in 2025

NEWS CONTENT ENGLISH

• 2025 was the fourth consecutive year in which every major glaciated region recorded a net loss in ice mass, according to the World Meteorological Organization’s State of Global Water Resources 2025 report.

• During the hydrological year from October 2024 to September 2025, glaciers worldwide lost approximately 408 ± 132 gigatonnes of mass, equivalent to around 1.1 ± 0.4 mm of global sea-level rise.

• The continued loss of glacier mass highlights the growing impact of climate change on freshwater resources and the global water cycle.

• Glaciers are long-lasting bodies of ice formed from accumulated snow that gradually compacts and flows under its own weight. 

• Their condition is assessed through glacier mass balance, which represents the difference between ice and snow accumulation and ice loss through melting, sublimation and other processes. 

• When accumulation exceeds loss, the glacier has a positive mass balance, while greater loss results in a negative mass balance. 

• Persistent negative mass balance generally leads to glacier retreat and a reduction in stored freshwater.

• According to the WMO, mountain glaciers lost about 6.2 per cent of their ice mass between 2000 and 2025. 

• Glacier ice loss has increased in almost all regions since the 1990s and accelerated considerably after 2000, mainly because summer melting has increasingly exceeded winter accumulation. 

• Six of the seven largest annual glacier mass losses on record occurred during the last seven years.

• The primary driver of glacier mass loss is rising temperature associated with human-induced climate change.

• Higher temperatures increase surface melting and can also alter precipitation patterns, causing more precipitation to fall as rain rather than snow in some regions. 

• Reduced snowfall limits the accumulation of new ice, while heatwaves and changing seasonal weather patterns can further intensify glacier melt.

• Black carbon and other dark particles deposited on snow and ice can also contribute to local melting. 

• These particles reduce the surface albedo of snow and ice, allowing greater absorption of solar radiation. Changes in snowfall, rainfall, atmospheric circulation and extreme weather events can further influence glacier mass balance.

• The loss of glacier mass has important implications for global water security.

• Glaciers act as natural freshwater reservoirs, particularly in mountain regions where meltwater contributes to river flows during warmer and drier periods. 

• In the initial stages of rapid melting, increased runoff may occur. However, as glaciers continue to shrink, their capacity to provide stored water in the long term also declines.

• This is linked to the concept of peak water. It refers to the stage when glacier meltwater contribution to runoff reaches its maximum and subsequently begins to decline as the glacier loses mass. 

• The WMO report indicates that some regions, including the Caucasus, western Canada and the United States, and central Europe, may already have reached peak-water conditions.

• The situation is particularly important for High Mountain Asia, which contains the largest volume of ice outside the polar regions. 

• According to WMO’s State of the Climate in Asia 2025,all 23 monitored glaciers in High Mountain Asia lost mass during the 2025 glaciological year. 

• Above-average temperatures and below-average winter snowfall were important contributing factors. 

• The region has experienced sustained glacier retreat over recent decades, with the retreat accelerating since the mid-1990s.

• For India, glacier change is closely linked with water security because the Himalayan region influences major river systems, including the Indus, Ganga and Brahmaputra. 

• Changes in snow and glacier melt can affect seasonal river flows, agriculture, hydropower generation, ecosystems and downstream communities. 

• In the short term, rapid melting can contribute to higher runoff and flood risks, while long-term glacier shrinkage can reduce the amount of stored freshwater available during dry periods.

• Glacier retreat can also increase the risk of mountain hazards. The formation or expansion of glacial lakes behind unstable moraine dams can create conditions for Glacial Lake Outburst Floods (GLOFs). 

• A sudden failure of such a natural dam can release large volumes of water downstream, threatening settlements, roads, bridges and hydropower infrastructure. WMO reported multiple GLOFs and glacier collapses in High Mountain Asia during 2025.

• Glacier melt also contributes to global sea-level rise. The approximately 408 ± 132 gigatonnes of glacier mass lost during the 2025 hydrological year corresponded to about 1.1 ± 0.4 mm of sea-level rise. 

• Mountain glaciers should, however, be distinguished from the Greenland and Antarctic ice sheets, which are much larger ice masses and have different geographical and physical characteristics.

• Monitoring glacier change requires a combination of field observations and modern technologies. 

• Satellite-based remote sensing, digital elevation models, GPS measurements, ground surveys and other observation techniques are increasingly used to assess glacier area, volume and mass changes. Such monitoring is particularly important for identifying rapidly changing glaciers and potentially hazardous glacial lakes.

• Addressing glacier loss requires both mitigation and adaptation. Reducing greenhouse gas emissions remains essential for limiting long-term warming, while reducing short-lived climate pollutants such as black carbon can provide additional benefits in vulnerable snow and ice regions. 

• At the local level, continuous glacier and glacial-lake monitoring, GLOF early-warning systems, hazard mapping, climate-resilient infrastructure, efficient water management and community participation are important measures.

• The fourth consecutive year of global net glacier mass loss in 2025 demonstrates that glacier change is not merely a cryosphere issue. 

• It is closely connected with water security, disaster risk, agriculture, energy, ecosystems and sea-level rise. For India, protecting Himalayan water systems requires stronger scientific monitoring, disaster preparedness, climate adaptation and cooperation among countries sharing transboundary mountain and river systems.

MCQ English

Q. Consider the following statements regarding global glacier mass loss in 2025:

1. 2025 was the fourth consecutive year in which every major glaciated region recorded a net loss in ice mass.

2. Global glaciers lost approximately 408 ± 132 gigatonnes of mass during the 2025 hydrological year.

3. The glacier mass loss during 2025 was equivalent to approximately 1.1 ± 0.4 mm of global sea-level rise.

4. All 23 monitored glaciers in High Mountain Asia gained mass during the 2025 glaciological year.

Which of the statements given above is/are correct?

A. 1, 2 and 3 only

B. 1 and 4 only

C. 2 and 3 only

D. 1, 2, 3 and 4

Answer: A

Explanation: According to the WMO, 2025 was the fourth consecutive year in which every major glaciated region recorded net mass loss. Global glaciers lost approximately 408 ± 132 gigatonnes of mass, equivalent to around 1.1 ± 0.4 mm of sea-level rise. In High Mountain Asia, all 23 monitored glaciers lost mass during the 2025 glaciological year; therefore, statement 4 is incorrect.