A study of nearly all the world's glaciers has revealed that they are melting fast, and at an accelerating rate. A French-led team of researchers has found that the glaciers lost 267 billion tonnes (gigatonnes, or Gt) of ice a year over past 20 years, equivalent to 4% of their total volume. The water from these melting glaciers now accounts for about a fifth of global sea-level rise, enough to cover the island of Ireland in 3 metres (10 feet) of water each year. The loss of glacier ice is doubling in speed, from about a third of a metre per year in 2000 to two-thirds of a metre in 2019. The retreat of glaciers affects the availability of fresh water for millions of people and, in the longer term, contributes to rising sea levels all over the world.
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​​​​​​​3rd May 2021

Since 1980, global warming has led to glacier retreat becoming increasingly rapid and widespread. In some parts of the world, glaciers have disappeared altogether, and the existence of many of the remaining glaciers is threatened.
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The melting of the world’s glaciers over the past 20 years is equivalent to more than 13,200 cubic kilometres of water—enough to fill Lake Superior, or more than 10 million Wembley Stadiums. It contributes more than a third of sea-level rise in this period—more than twice that contributed by Antarctic ice sheets (although accelerating ice losses from Antarctica and Greenland remain by far the greatest concern for future sea-level rise).
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The picture varies from region to region. Alaska accounts for 25% of the global loss, the Greenland coastal glaciers 12% and north and south Canada 10% each. The Himalayas and mountain glaciers of Asia lost 8%, as did the southern Andes. The thinning of New Zealand’s glaciers—1.5 metres (5 feet) a year from 2015 to 2019, is a nearly sevenfold increase compared to 2000–04. Thinning rates in the European Alps were twice the global average. Scientist predict that at the current rate, 80 to 90% of glaciers will vanish by 2050.
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A tenth of the world’s mountain glacier ice will have melted by 2050—even if the world meets the goals of the Paris Climate Agreement. This is because the loss of mountain glacier ice was caused by the build up of greenhouse gases in the atmosphere 20 or 30 years ago. It is the actions governments take from now on that can make a difference to the landscape in the second half of this century.

The research team collected their data from images supplied by NASA's Terra satellite, which was launched in 1999. The study covered 99.9% of the world’s glaciers: a total of 217,175.
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