Glaciers Ending in Lakes Lose Ice Fastest, Study Finds

Glaciers ending in lakes, oceans or on ice shelves account for just 3.2% of the world's glaciers but more than half of glacier ice loss, a global study finds. ^[2]

Together, these glaciers lost 134 billion metric tons of ice a year between 2000 and 2019. The study, published in Nature Communications on October 23, 2026, gives researchers a global classification of where glaciers end, a feature that can help explain how they change. ^[1][2]

These are also large glaciers: the same small group covers more than half of global glacier area. The strongest evidence of an extra vulnerability comes from a narrower comparison. Glaciers ending in lakes lost ice around 57% faster per unit area than those ending on land, even after researchers accounted for factors including climate, size and elevation. ^[2][3]

The peer-reviewed study compared 216,502 glaciers, excluding the Greenland and Antarctic ice sheets. Its findings point to a gap in many models used to project glacier change, which do not yet fully represent glaciers ending in lakes. ^[2]

"We don't yet know exactly why. It could be the lakes themselves, the size and shape of the glaciers, or a bit of both," said lead researcher Joe Mallalieu. ^[1][3]

A small count, a large share

The researchers classified glaciers in the Randolph Glacier Inventory by their terminus, the place where the glacier ends. They separated those finishing on land from those ending in lakes, in the ocean or on ice shelves. They then brought that classification together with data on glacier shape, climate, movement and changes in ice mass. ^[2]

Counting glaciers gives each one equal weight. Measuring their area or the ice they lose gives a very different picture. Almost all the glaciers in the inventory end on land, yet those glaciers accounted for 49.4% of total glacier mass loss during the study period. ^[2]

Lake-ending glaciers contributed 24.0%, ocean-ending glaciers 22.8% and ice-shelf-ending glaciers 3.9%. The published percentages are rounded, so they add to slightly more than 100%. Lakes alone accounted for nearly a quarter of the loss. ^[2]

The 3.2% figure therefore identifies where much of the ice is disappearing, but it cannot by itself show that contact with water makes a glacier lose ice faster. A group containing more than half the glacier area could be expected to contribute heavily to total loss. The comparison per unit area is what allows researchers to examine that question more closely.

That is where the lake result becomes important. The roughly 57% faster loss persisted after the analysis accounted for several physical and climatic differences between glaciers. It was more than a simple comparison between large glaciers in one setting and small glaciers in another. ^[2]

Lakes deserve closer attention

Lake-ending glaciers occur in every major glacier region. In most regions, they lost ice faster than glaciers ending either on land or in the ocean. That geographic spread makes the finding relevant well beyond any single mountain range. ^[1][3]

The team identified two possible ways lakes could contribute. Lake water may melt ice below the waterline, and glaciers can shed pieces of ice into the water, a process called calving. The study does not establish how much these processes explain the faster loss, or how much comes from glacier size and shape. ^[2][3]

Movement supplied another part of the picture. Lake-ending glaciers flowed an average of 10% faster than land-ending glaciers, while ocean-ending glaciers flowed 44% faster. ^[2][3]

Those figures measure how quickly ice moves, rather than how quickly the glacier loses mass. The largest difference in flow speed belonged to ocean-ending glaciers, while the standout finding on loss per unit area concerned lake-ending glaciers. Watching movement alone would miss part of the story.

The measurements also span different periods. The study used glacier-velocity data from 2017-2018 and mass-change estimates covering 2000-2019. Velocity measurements were available for 83.9% of the glaciers, and mass-change estimates for 93.9%.

The study has broad global reach, rather than a complete measurement record for every glacier. ^[2]

A glacier's ending can change

The categories themselves are moving. As the climate warms, some ocean-ending glaciers in parts of the Arctic are retreating onto land. Elsewhere, expanding glacier lakes are turning some land-ending glaciers into lake-ending ones. ^[1][3]

A glacier's present setting is therefore only a starting point for forecasting its future. If its retreat brings it into contact with a growing lake, the conditions at its end change too. Models need to follow that transition rather than treat the classification as permanent.

Nicholas Barrand, one of the researchers, said combining global glacier and climate datasets allows comparisons across different settings. Understanding changes at glacier ends will become more important as glaciers shift between those settings, he said. ^[3]

The researchers say their classification could improve projections of glacier evolution, sea-level rise, water resources and natural hazards. Many glacier-change models do not yet fully account for lake-ending glaciers, despite their substantial contribution to measured ice loss. ^[1][2][3]

That makes lakes a clear priority for further work. A category responsible for nearly a quarter of the measured loss deserves explicit treatment in projections, especially when glaciers can enter that category as they retreat.

The team, led by researchers from the universities of Birmingham and Leeds, has made the classification and associated data freely available on Zenodo. Mallalieu identifies the next research question as finding out why lake-ending glaciers lose ice faster. Answering it would give modellers a firmer basis for calculating what happens when a retreating glacier meets water. ^[3]