Science & Tech · Science & Environment · 3 hrs ago
Tall glacier cliffs retreat faster than models predict, but then stall
Researchers used 20 years of laser measurements to study ice cliffs in Antarctica and Greenland.
Only 16 glaciers had cliffs above 90 metres, near the height at which a theory predicts they should collapse under their own weight.
At four glaciers, tall cliffs retreated faster than collapse formulas predict during periods of about three months.
Grounded icebergs may help hold cliffs in place by forming a jam in front of the glacier.
The findings suggest retreat can stall instead of becoming runaway, challenging an idea used in the highest projections of sea-level rise.
The study covers only a handful of glaciers and short periods, so it does not show how all ice fronts will behave over decades.
A study of glacier cliffs in Greenland and Antarctica found that tall cliffs retreat faster than current models predict, but did not undergo runaway collapse.
Researchers tracked four glaciers with cliffs near the proposed collapse height, measuring retreat over periods of roughly three months.
A cliff about 330 feet (100 metres) high lost ice at more than three times the rate predicted by a formula used in high sea-level projections.
The study found that tall cliffs are rare and suggested that retreat can stall, limiting how long rapid ice loss continues.
The findings are based on a handful of glaciers and measurements covering months, not decades.
- Who
- Caroline Needell of the MIT-WHOI Joint Program led the study with Catherine Walker and Jeremy Bassis.
- What
- Researchers found that tall glacier cliffs retreat faster than models predict, but observed no unstable retreat.
- When
- The study was published on 15 October 2026. The measurements included NASA aircraft observations from 2003 to 2019 and ICESat-2 data from 2018 onward.
- Where
- The glaciers were in Antarctica and Greenland.
- Why
- Researchers studied how tall ice cliffs behave to improve estimates of the risk of runaway collapse and future sea-level rise.
This story does not have two clearly opposing sides.
NASA aircraft collected measurements over ice margins in Greenland and Antarctica.
NASA’s ICESat-2 satellite measured ice using laser pulses.
Researchers tracked retreat over roughly three months at four glaciers with cliffs near the proposed collapse height.
Earth.com and New Scientist published reports on the study.
- Survey observations
- 15,330 ice-cliff observations
- Tall cliffs
- 16 glaciers had cliffs above 295 feet (90 metres)
- Fast retreat
- A cliff around 330 feet (100 metres) high retreated at more than three times the rate predicted by one collapse formula
- Antarctica glaciers
- Fleming, Commandant Charcot and Frost
- Greenland glacier
- Tuttulikassaap Sermia
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What people are saying
None of the glaciers we observed underwent unstable retreat, even though they did retreat much faster than our current models predict.
Perhaps the most surprising thing was, although they are still rare, the number of cliffs that were near or above the theoretical stability limit.
Over the next decades, it’s going to jump from one pinning ridge to another
The bed then begins to get real deep