We Lost 11.3 Trillion Tonnes of Ice in 44 Years. Greenland Is Why It’s Worse Than It Sounds.

What 11.3 trillion tonnes of ice means

From 1979 to 2023, the Greenland and Antarctic ice sheets together lost about 11.3 trillion tonnes of ice. The study was completed by the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) team. It draws on 27 satellite missions and 42 independent estimates. It was published in Scientific Data, a Nature sub-journal.

11.3 trillion tonnes of ice is about 12.3 trillion cubic meters. If melted into water and spread across China’s 9.6 million square kilometers, it would form a layer about 1.2 to 1.3 meters deep. Divided among the world’s 8 billion people, each person would get about 1,400 tonnes of ice. The melted water would last an average person about 30 years.

Nilsson, a researcher at Uppsala University in Sweden, offers a more intuitive comparison. If the lost ice were turned into water and spread across all of Sweden, it would form a layer about 25 meters deep. That is about 75 times the volume of Lake Vänern, Sweden’s largest lake.

What matters is the curve.

In the 1970s, the Greenland Ice Sheet was still roughly in mass balance. Gains from snowfall roughly matched losses. By the 1980s, Greenland was losing about 60 billion tonnes per year. By the 2010s, that figure had risen to about 264 billion tonnes. Antarctica is no better. Annual loss rose from about 48 billion tonnes in the 1980s to about 202 billion tonnes in the 2010s.

From the 1980s to the 2010s, the rate of ice loss from the two ice sheets quadrupled. In the 1990s, together they lost about 100 billion tonnes per year. By around 2010, the figure had exceeded 400 billion tonnes.

In 2019, 95% of the Greenland Ice Sheet’s surface melted. That year’s loss hit a record high of 532 billion tonnes. The meltwater alone raised global sea level by about 1.5 mm.

From 2020 to 2023, ice loss slowed. Unusually heavy snowfall in East Antarctica replenished some ice. Relatively mild summers in Greenland reduced surface melting. The IMBIE team considers this a short-term variation, not a reversal of the long-term trend.

What has already happened: 3.14 cm and 6 million to 9 million people

Over these 40-plus years, ice loss has already raised global mean sea level by about 3.14 cm.

The Greenland Ice Sheet contributed 1.81 cm. The Antarctic Ice Sheet contributed 1.33 cm. Together, the two ice sheets account for about 25% of global sea-level rise. The study also notes that 84% of the ice loss comes from glaciers flowing faster into the ocean. The other 16% comes from surface melting of the ice sheets.

Three centimeters sounds like very little. But sea-level rise never floods in evenly. It amplifies the destructive power of storm surges and coastal flooding. Inès Otosaka, a climate scientist at Northumbria University in the UK and the paper’s first author, points out that for every 1 cm of sea-level rise, about 2 million to 3 million people worldwide face annual coastal flood risk.

At that rate, the sea-level rise from the loss of the two ice sheets has already put an additional 6 million to 9 million people worldwide at risk of coastal flooding and erosion.

These effects vary greatly by region. Nilsson notes that for Sweden, land uplift is smaller in the south. Sea-level rise there increases coastal flood and erosion risk. In central and northern Sweden, land uplift is larger and can offset most of the sea-level rise. There is also a counterintuitive phenomenon. Ice loss from Antarctica would raise Sweden’s coastal sea level more than an equal amount of ice loss from Greenland. Part of the reason is that an ice sheet’s own gravity affects the distribution of seawater. When the ice sheet loses mass, sea level far away actually rises relatively.

Why Greenland loses more ice despite being smaller

The Antarctic Ice Sheet is about eight times the area of the Greenland Ice Sheet. Yet Greenland accounts for about 60% of the ice loss. Antarctica accounts for about 40%.

The reason is not size. It is their different physical constitutions.

First, latitude and temperature differ. The Greenland Ice Sheet lies between 60°N and 80°N. Summer temperatures often rise above freezing. Large areas of meltwater lakes and networks of runoff appear across the surface. The main body of Antarctica lies between 80°S and 90°S. Temperatures there are inherently lower. Even in the Southern Hemisphere summer, widespread or whole-ice-sheet surface melting like Greenland’s rarely occurs.

Second, elevation differs. Antarctica sits on a full continent. Its ice sheet is thick, with an average elevation above 2,000 meters. In places it is nearly 4,000 meters. In the troposphere, the higher the elevation, the lower the temperature. High elevation acts as a natural cold barrier for the Antarctic Ice Sheet.

Third, ice-shelf protection differs. Antarctica has several huge ice shelves extending into the sea. They include the Ross Ice Shelf and the Filchner-Ronne Ice Shelf. Like buttresses, they hold back inland glaciers from the front and slow their flow into the ocean. The Greenland Ice Sheet lacks this protection. Many glacier termini reach directly into narrow fjords and come into contact with warm seawater.

Fourth, erosion by warm ocean water differs. Warm water from the North Atlantic continuously erodes the bases of Greenland’s glaciers. That causes their fronts to calve and their flow to accelerate. Jakobshavn Glacier, one of Greenland’s largest glaciers, has seen a marked acceleration over the past 20 years. Meltwater also acts like a lubricant at the bed. It speeds the ice sheet’s slide toward the ocean.

Greenland is smaller. But it is warmer and lower, and its glaciers meet the ocean directly. That is why it is currently the main contributor to ice loss.

Ice-sheet melting is not just sea-level rise

The most direct consequence of ice-sheet melting is sea-level rise. But it also triggers deeper climate chain reactions.

The first is albedo feedback. Snow and ice are among the most reflective natural surfaces on Earth. Their albedo can be as high as nearly 90%. They can reflect a large amount of solar radiation back into space. That helps keep the planet cool. But as ice sheets shrink, bright white ice is replaced by dark rock and ocean. The Earth then absorbs more solar radiation. Absorbing more heat means warming. Warming in turn accelerates glacier melting.

The second is a weakening of the Atlantic Meridional Overturning Circulation (AMOC). Large amounts of meltwater from Greenland flow into the North Atlantic. This meltwater comes from high latitudes. It is fresh water. It is lighter and less likely to sink than seawater. Normally, seawater south of Greenland cools and becomes denser, then sinks. That drives AMOC. But the influx of large amounts of fresh water is weakening sinking in this region.

A complete AMOC collapse this century is unlikely. A substantial weakening is highly probable. That is enough to affect global climate and change monsoon and rainfall patterns in some regions.

Meanwhile, the ocean has absorbed about 91% of the extra heat in the global system. This makes marine heatwaves more frequent and more severe. At present, almost all oceans except within the Arctic Circle have experienced marine heatwaves. For marine-terminating glaciers and coral reefs, this is fatal.

Antarctic ice-shelf collapse events are also increasing. In 2017, the Larsen C Ice Shelf collapsed. The giant iceberg A-68 calved off. In early 2025, the world’s largest iceberg, A23a, continued to melt and break up. It was officially retired because it had become too small. These events are not isolated.

The future if warming continues

The response of ice sheets to warming is one of the largest sources of uncertainty in sea-level projections. Long-term satellite records help improve projections of future ice loss and sea-level rise.

Under an intermediate emissions scenario, warming by the end of this century could reach 2.5°C. Global sea level could rise by about 50 cm. Fifty centimeters is a global average. In some regions, sea-level rise and the resulting storm surges and wave impacts will be greater. That is quite unfavorable for low-lying coastal areas such as the Yangtze River Delta and Pearl River Delta.

If carbon emissions are poorly controlled and the world approaches a higher emissions pathway, warming by the end of this century could reach 3°C. In that case, glacier melting and the adverse effects on other systems would all be more severe. Under an intermediate warming scenario, the Greenland and West Antarctic ice sheets would almost completely melt. That would deliver an even greater shock to the global climate system.

Further in the future, the Antarctic and Greenland ice sheets could disappear together. The effects of albedo feedback and the North Atlantic warm current would be more intense and rapid.

Every centimeter has a cost

The 11.3 trillion tonnes of ice did not disappear overnight. It is the accumulated result of more than 40 years of repeated marine heatwaves and collapsing ice shelves.

Glacier melting did not begin now. It is a long-term outcome and will become more severe in the future. As early as a century ago, as global warming began, glacier melting worldwide started in tandem. It is only now receiving attention because glacier melting has accelerated sharply.

Even if carbon emissions stopped immediately, the heat already accumulated would continue to affect the ocean. Glacier melting would not stop at once. But controlling emissions still determines whether the future heads toward 2.5°C, 3°C, or worse.

Ice sheets are the silent giants of Earth’s climate system. They do not cry out in pain. But every centimeter of sea-level rise becomes a flood in a coastal city or a village that has to move.

After 11.3 trillion tonnes of ice have vanished, the remaining question is how fast the effects arrive and how well coasts can prepare.