Imma Perfetto
Cosmos science journalist
Glaciers worldwide have lost a staggering 6,542 billion tonnes of ice in just 23 years – contributing 18mm to the global rise in sea levels and reducing vital supplies of freshwater.
“To put this in perspective, the … [water] lost in one single year amounts to what the entire global population consumes in 30 years, assuming 3 litres per person and day,” says Michael Zemp, a professor of geography at the University of Zurich (UZH), Switzerland, and director of the World Glacier Monitoring Service.
Zemp co-led a new study, conducted as part of the Glacier Mass Balance Intercomparison Exercise (GlaMBIE), which found that glaciers around the globe have been losing an average of 273 billion tonnes of ice per year since 2000.
The rate of ice loss is accelerating, increasing by 36% in the second half of the study period (2012−2023) compared to the first (2000−2011).
“Glaciers are vital freshwater resources, especially for local communities in Central Asia and Central Andes, where glaciers dominate runoff during warm and dry seasons,” says UZH glaciologist Inés Dussaillant, who was involved in the GlaMBIE analyses.
In 2023, Cosmos reported on research which found that “peak water” is one of the 6 major risk tipping points facing life on Earth. It’s the point when a glacier produces the maximum volume of water run-off due to melting, after which freshwater availability will steadily decline.
But according to the new study, not all glacial regions are being hit equally by rising global temperatures due to climate change.
“With an annual loss of 35 billion tonnes of ice since 2000, the peripheral glaciers of Greenland are the third-largest contributors to global glacier mass loss, after Alaska and the Canadian Arctic,” says co-author Sahra Abdullahi from the German Aerospace Center (DLR).
“This is due to severe climate change in the Arctic region, which is experiencing some of the highest rates of temperature increase in the world.”
Co-author Lukas Krieger, also from DLR, adds: “The Southern Andes are losing 26.5 billion tonnes of ice annually – this corresponds to 10% of global glacier ice loss and … the fourth-highest mass loss among all glacier regions worldwide.”
Globally, all 19 glacier regions studied lost approximately 5% of their total volume. But regional losses varied widely, ranging from 2% in the Antarctic and sub-Antarctic islands to 39% in Central Europe.
To determine this, the GlaMBIE team compiled, standardised, and analysed datasets on glacier mass changes collected from field measurements and a wide range of optical, radar, laser and gravimetric satellite missions.
“We compiled 233 estimates of regional glacier mass changes from approximately 450 data providers, organised into 35 research teams,” says Zemp.
“Benefiting from the different observation methods, GlaMBIE not only provides new insights into regional trends and year-to-year variability, but we could also identify differences among observation methods.
“This means that we can provide a new observational baseline for future studies on the impact of glacier melt on regional water availability and global sea-level rise.”
Samuel Nussbaumer, UZH glaciologist and GlaMBIE project manager, says their observations and recent modelling indicate that glacier mass loss will continue and possibly accelerate until the end of this century.
“This underpins Intergovernmental Panel on Climate Change’s call for urgent and concrete actions to reduce greenhouse gas emissions and associated warming to limit the impact of glacier wastage on local geohazards, regional freshwater availability, and global sea-level rise.”
The research is published in the journal Nature.
