The world’s mountain glaciers store water for billions of people. Since 2000 they have been losing it faster almost every decade.
273Gt
billion tonnes of glacier ice lost each year on average, 2000–2023 — roughly 8,650 tonnes every second
01 / The pace
Every decade melts faster than the last
Average yearly loss has roughly quadrupled since the 1980s. The pace rose 36% from 2000–2011 to 2012–2023.
Six of the highest-loss years on record have come in the past seven. 2025 lost 408 Gt, about 1.1 mm of sea level, and that was only the sixth-worst year. Since 1975 glaciers have lost 9,583 Gt, or 26.4 mm of sea-level rise (WGMS).
02 / Where the water goes
Four regions supply two-thirds of the melt
Big, high-latitude ice fields shed the most tonnes. Alaska alone accounts for almost a quarter of glaciers’ sea-level contribution.
Share of global glacier ice loss, 2000–2023Share of the region’s own ice lost
03 / Who loses most
Small glaciers vanish first
Worldwide, glaciers have lost about 5% of their ice since 2000. In regions with small glaciers the losses run six to eight times higher.
Regions with less than 15,000 km² of glacier ice lost the most relative to their size. The Alps lost almost two-fifths. Regions with large glacier areas lost between 2% and 12%.
04 / Futures
How many glaciers are left by 2100 depends on us
Projected share of the world’s ~215,000 glaciers that disappear by 2100, at different levels of warming.
Even at +1.5°C, glaciers would lose about 26% of their mass this century. Under high emissions they would lose about 41% (Rounce et al., Science 2023). Many of the glaciers that disappear are small, but they feed local rivers.
05 / The stakes
Water towers, sea walls, and blind spots
Melting glaciers affect drinking water, farms, hydropower and coastlines, and most of them are never measured directly.
2B+people get freshwater from glaciers and mountain snowUNESCO / WMO, 2025
18 mmof global sea-level rise from glaciers alone, 2000–2023GlaMBIE, Nature 2025
24%of Switzerland’s glacier ice gone in one decade, 2015–2025 (10% in the 1990s)GLAMOS, 2025
<1%of the world’s ~200,000 glaciers have ever been measured on siteGlaMBIE, 2025
06 / Why it matters
What you can do
Ice lost this century will not return on any human timescale. How much more is lost is still undecided.
Count every tenth of a degree
Rounce et al. found glacier losses rise with each increment of warming, so cutting emissions still saves ice — no threshold makes effort pointless.
Back the monitors
Fewer than 1% of glaciers are measured on the ground. Long-running programmes like WGMS and GLAMOS depend on steady public funding.
Plan for “peak water”
Meltwater flows rise before they fall. Ask your region’s water and hydropower planners how they budget for the dry years after.
Share the number
273 billion tonnes a year is hard to picture: about 8,650 tonnes every second. Concrete scale helps people take it seriously.