Antarctic ice cliffs collapse faster than predicted, then stabilize

Overview

Updated 1 hour ago

For ten years, a scary scenario dominated Antarctic ice-sheet science: tall ice cliffs, once exposed, would collapse in a self-sustaining cascade and rapidly raise global sea levels. A new satellite study in Science challenges that fear. Researchers at MIT and the Woods Hole Oceanographic Institution tracked 15,330 ice cliffs from 2019 to 2023 and found that while the tallest cliffs fall faster than models predict, the retreat quickly stabilizes instead of running away.

The study targets a specific hypothesis — marine ice cliff instability — which holds that cliffs taller than about 100 meters, roughly the height of the Statue of Liberty, should collapse under their own weight. The researchers found cliff height alone does not determine collapse. The shape of the bedrock underneath, how fast the ice thins, and the depth of the sea water all govern stability, meaning runaway loss may be far less likely than worst-case projections assume.

Why it matters

If runaway ice-cliff collapse is unlikely, projected Antarctic sea-level rise falls — changing how coastal cities worldwide budget for flooding.

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Key Indicators

15,330

ice cliffs surveyed

Satellite laser altimetry measured 15,330 ice cliffs around Antarctica's margins from 2019 to 2023.

years of satellite monitoring

Data collected every three months from 2019 to 2023, capturing how cliffs changed over time.

100 m

critical collapse threshold

Cliffs above this height — about the Statue of Liberty's height — were expected to collapse under their own weight.

Voices

Curated perspectives — historical figures and your fellow readers.

Ever wondered what historical figures would say about today's headlines?

People Involved

Caroline Needell

Lead author; doctoral student in the MIT-WHOI Joint Program

Studying at MIT and the Woods Hole Oceanographic Institution

Mathieu Morlighem

Professor of Earth sciences at Dartmouth College; led companion modeling study

Active at Dartmouth College

Organizations Involved

Massachusetts Institute of Technology (MIT)

Research university

Co-led the ice-cliff study

Research university in Cambridge, Massachusetts that co-led the satellite analysis of Antarctic ice cliffs.

Woods Hole Oceanographic Institution

Nonprofit marine research institution

Co-led the ice-cliff study

Nonprofit marine research institution in Woods Hole, Massachusetts that co-led the study.

Dartmouth College

Research university

Hosted the companion modeling study

University in Hanover, New Hampshire that hosts Mathieu Morlighem's ice-sheet modeling group.

Science Corporation

Peer-reviewed scientific journal

Published the ice-cliff study

One of the world's leading peer-reviewed research journals, published by the American Association for the Advancement of Science.

Timeline

March 2016 October 2026

3 events Latest: Today

October 2026
Satellite survey finds fast collapse, then stabilization
Today Study

A Science study tracking 15,330 Antarctic ice cliffs from 2019 to 2023 finds tall cliffs collapse fast but retreat quickly stabilizes.
Today
2024
Thwaites modeling study resists runaway retreat
Modeling study

A Dartmouth-led Science Advances study simulating Thwaites Glacier finds realistic cliff-failure rates do not produce collapse.
2024
March 2016
Marine ice cliff instability proposed
Scientific hypothesis

DeConto and Pollard propose in Nature that ice cliffs above a critical height would collapse in a runaway cascade.
March 31st, 2016

Scenarios

Worst-case sea-level projections drop marine ice cliff instability

Likely Resolves by End of 2029

Discussed by: IPCC assessment cycle and the ice-sheet modeling community

Ice-sheet modelers fold the new calving rates and stabilization drivers into their simulations. If bed topography and ice-thinning rates are accounted for across the continent, the next major assessment projects a lower upper bound for Antarctic sea-level rise than current worst cases, which assume runaway cliffs.

Researchers identify Antarctic glaciers still vulnerable to rapid cliff retreat

Possible Resolves by Oct 16, 2028

Discussed by: MIT-WHOI team and glaciologists studying Thwaites and Pine Island

The study shows stabilization depends on local conditions — bedrock bumps, water depth, and ice-thinning rates. Follow-up work will map which West Antarctic glaciers sit over deep, flat beds where sustained rapid retreat might still occur. Those regions could still contribute fast sea-level rise.

Debate persists; MICI keeps its place in high-end projections

Uncertain Resolves by End of 2029

Discussed by: Climate modelers who defend the original DeConto-Pollard mechanism

Some modelers argue four years of data and a handful of tall cliffs are too thin a record to retire the hypothesis. They keep marine ice cliff instability in high-end scenarios, and the next IPCC report may retain it alongside the new observational constraints.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

February–March 2002

Larsen B ice shelf collapse (2002)

About 3,250 square kilometers of the Larsen B ice shelf on the Antarctic Peninsula shattered into icebergs within roughly a month, ending 35 years of gradual retreat.

Then

Glaciers that had been held back by the shelf accelerated two to six times after it disappeared.

Now

The collapse showed how quickly Antarctica can lose ice and helped seed the concern that exposed cliffs could retreat in cascades.

Why this matters now

The new study directly tests that concern: it found cliffs do fall fast, but the retreat stops rather than cascading across the ice sheet.

January 1978