Glaciers are melting faster and faster: global data, the consequences and what we can do

The planet’s glaciers are losing mass at a high and accelerating rate. In the hydrological year 2025 alone, glaciers outside the large ice sheets of Greenland and Antarctica lost 408 ± 132 gigatons of massequivalent to approximately 1.1 ± 0.4 mm of global mean sea level rise, as reported by WGMS Network (2026). From 1975 to 2025 the cumulative loss was 9,583 ± 1,211 Gt, and six of the seven highest loss years in the series occurred in the last seven years.

A second independent picture comes from the GlaMBIE project, published in Nature in 2025. Between 2000 and 2023, glaciers lost an average of 273 ± 16 Gt per year. The most significant figure is the acceleration: the average loss went from 231 ± 23 Gt/year in 2000-2011 to 314 ± 23 Gt/year in 2012-2023, an increase of 36 ± 10%. The maximum of the series was recorded in 2023, with 548 ± 120 Gt lost in a single year. In Central Europe the change is particularly rapid: in 2023 the glacial mass was approximately 39% lower than that of 2000.

We are in an interglacial period: is it normal for glaciers to melt?

The coordinated international monitoring of glaciers began in 1894initially through measurements of the variations of the glacial fronts. Direct measurements of mass balance on entire glaciers became widespread from the late 1940s. Today, field observations are integrated with altimetry, gravimetry, digital elevation models and satellite imagery. The updated global WGMS series reconstructs mass loss since 1975, while GlaMBIE provides a homogenized global annual series from 2000 to 2023.

About 23,000-19,000 years ago the Earth was in the Last Glacial Maximumthe maximum of the last glaciation. The global mean sea level was then approximately 125-134 meters lower than today because enormous volumes of water were stored in the continental ice sheets. The subsequent deglaciation brought the planet intoHolocenethe current interglacial period, which began about 11,700 years ago.

This context is essential: glaciers have always responded to natural climate variations. However, it is incorrect to describe the current retreat as a simple continuation of the end of the last glaciation. The IPCC concludes that warming caused by human activities has been the main driver of global glacier recession since the early 20th century, and that human influence is most likely the main driver of the near-universal retreat observed since the 1990s. The recent behavior is considered highly unusual over at least the last 2,000 years.

What are the consequences of glacier retreat

The loss of land ice directly contributes tosea ​​level rise. Between 2000 and 2023, glaciers added approximately 18 ± 1 mm to the global mean level; from 1975 to 2025 the cumulative contribution is estimated at 26.4 ± 3.3 mm.

Government regimes also change rivers. During an initial phase of strong melting, meltwater can increase the flow rate; passed the so-called “peak water“, however, the glacier has become so small that it provides less water, especially in dry periods. This can have consequences on agriculture, drinking water and hydroelectric energy. The UNESCO/UN-Water 2025 report recalls that approximately 2 billion people depend on mountain water and that these contribute to 55-60% of global annual freshwater flows: values ​​that concern the entire mountain system, not just the glaciers.

Glacial retreat Finally, it modifies natural hazards. New lakes can form in front of or on top of glaciers; if a natural dam gives way or an avalanche enters the lake, a GLOFone sudden flood from a glacial lake. A study published in Nature Communications estimates that approx 15 million people are potentially exposed to the impacts of GLOFs and that the 62% of this population is found in High Mountain Asia.

The Nepal disaster of August 26, 2026: why it is not a classic GLOF

The evidence available in the days following the event indicates that the disaster on the border between Nepal And Tibet was triggered by a large avalanche of ice and rockfollowed by a debris flow and by a catastrophic flood. There WMO he stressed that the exact dynamics are still being studied and that one possibility is the temporary formation of a debris barrier in the waterway, which was then overcome or collapsed. Satellite images compared from Reuters show the calving of part of the glacier near Langtang Lirung between August 24 and 26.

It is therefore important do not use automatically the term GLOF for any flood of glacial origin. In the high mountains the most serious disasters can becascading hazards”: sequences in which collapses of rock, ice, water and debris feed each other.

What can we do to reduce the risks due to loss

In the long run, reducing greenhouse gas emissions limits warming and therefore the amount of ice we will lose. Models show very large differences between warming levels: a 2025 study published in Nature Climate Change estimates that, in terms of the number of glaciers, close to 50% of the current ones could remain in 2100 in a scenario of +1.5 °Caround 20% in a scenario around +2.7 °C and less than 10% at +4 °C.

At a local level, however, adaptation is also needed: monitoring with satellites and sensors, early warning systems, cross-border data sharing, controlled lowering of the level of some glacial lakes, hazard maps, evacuation routes and territorial planning. In the valley sectors exposed to the most extreme phenomena, Reducing risk may above all mean not increasing exposure: avoid new constructions in flood paths and, in the most critical cases, evaluate the relocation of infrastructures or settlements.

It doesn’t mean that all mountain valleys are uninhabitable. It means that a warmer climate changes the geography of risk and that the most effective response is not always to make a building more resistant: sometimes it is to move people and infrastructure out of the trajectory of the phenomenon.