World’s glaciers have shrunk more than 5 per cent since 2000

Glaciers worldwide have shrunk by more than 5 per cent on average since 2000, according to the most comprehensive assessment yet. This rapid rate of melting has accelerated by more than a third in the past decade as climate change continues apace.

“Any degree of warming matters for glaciers,” says Noel Gourmelen at the University of Edinburgh, UK. “They are a barometer for climate change.”

The new numbers come from a global consortium of hundreds of researchers called the Glacier Mass Balance Intercomparison Exercise. The group aimed to reduce the uncertainty around how much the planet’s 200,000 or so glaciers have melted by using a standard procedure to assess different measures of their change in size. This includes gravity and elevation measurements from 20 satellites as well as ground-based measurements.

Between 2000 and 2011, glaciers were melting at a rate of about 231 billion tonnes of ice per year, the researchers found. This melt rate increased between 2011 and 2023 to 314 billion tonnes per year, an acceleration of more than a third. 2023 saw a record loss of mass of around 548 billion tonnes.

These numbers are in line with previous estimates. But the comprehensive look “provides a bit more confidence about the change that we see on glaciers”, says Gourmelen. “And there’s a clear acceleration.”

Altogether, the thawing of more than 7 trillion tonnes of glacial ice since 2000 has raised sea levels by almost 2 centimetres, making this melt the second biggest contributor to sea level rise so far, behind the expansion of water due to warming oceans.

“This is a consistent story of glacial change,” says Tyler Sutterly at the University of Washington in Seattle. “Regions that have had glaciers since time immemorial are losing these icons of ice.”

Glaciers in the Alps have lost more ice than any other region, shrinking by nearly 40 per cent since 2000. In the Middle East, New Zealand and western North America, glaciers have also seen reductions of more than 20 per cent. Depending on future emissions, the world’s glaciers are projected to lose between a quarter and half of their ice by the end of the century.