This Decade Will Shape The Fate Of Antarctica’s Ice Shelves

Two of Antarctica’s largest floating ice shelves are projected to collapse entirely by the end of this century under a very high emissions scenario, and a new scientific review warns that the choices made in the next few years will determine whether that future plays out.

Published in Frontiers in Environmental Science, the study draws on climate models, satellite data, and decades of field observations to map out three very different futures for the Antarctic Peninsula, the long arm of land that juts northward toward South America. Under the worst-case scenario, the Larsen C and Wilkins ice shelves are likely to shatter by 2100. Once that happens, the glaciers they hold back will accelerate into the ocean, driving up sea levels worldwide. “The future of the Antarctic Peninsula,” the authors write, “depends strongly on choices made today.”

Led by researchers at Newcastle University, the review is blunt on timing. “The choices made in this decade will determine which scenario is followed,” it states. Current global policies put the planet on track for as much as 2.8°C of warming above pre-industrial temperatures, far closer to the very high emissions scenario than the low one. According to a United Nations Environment Program report cited by the authors, there is effectively no chance of staying below 1.5°C under current policies, the threshold set by the Paris Climate Agreement.

Antarctic Ice Shelves Are Already Losing Ground

The Peninsula has been warming since at least the 1950s, outpacing the global average. Vernadsky Station, on the west coast of the mainland, has warmed by about 3.3°C over 73 years, more than double the global average rise of roughly 1.3°C to 1.4°C. Regional warming on parts of the Peninsula already exceeds 1.5°C above pre-industrial levels, though that is a regional measurement rather than the global metric the Paris Agreement targets.

Record heat events have punctuated this trend. In February 2020, a station near the northern tip hit 18.6°C, the highest temperature ever recorded on the Antarctic mainland. That same summer, the George VI Ice Shelf logged a 32-year record for surface melting and meltwater pond formation. The years 2022 through 2024 produced the three lowest sea ice extents in the history of satellite observation, and in 2022 the drop was severe enough to cause widespread breeding failures in emperor penguin colonies. Chicks need stable sea ice to survive their first months; that year, the ice simply wasn’t there.

What Three Warming Scenarios Mean for Antarctica’s Ice Shelves

Under the lowest emissions path, limiting warming to about 1.8°C by 2100, sea ice would decline slightly, ice shelves would thin but likely hold together, and the annual number of days above freezing would increase by only about 1.5. Manageable, if not painless.

The middle scenario, which most closely matches where current policies are headed, is considerably worse. Ocean warming intensifies, warm water pushes more persistently onto the continental shelf, and sea ice drops by more than 13% in winter. Rainfall increasingly replaces snowfall, posing challenges for infrastructure not designed for wet conditions.

Under the worst-case scenario, the Peninsula changes dramatically. Days above freezing nearly triple, from about 19.7 per year today to nearly 48 by century’s end. Sea ice declines by nearly 20% in winter. Surface melt surges, draining the layer of compressed snow, called firn, that currently absorbs meltwater like a sponge. Once that layer is gone, water pools on impermeable ice and wedges into cracks, a process called hydrofracture that can cause shelves to disintegrate with startling speed.

Larsen C and Wilkins are assessed as likely to collapse by 2100 under this highest emissions scenario. George VI Ice Shelf, further south and more resistant to cracking because of how its ice flows, could still give way by 2300. Its loss alone would sharply raise the Peninsula’s contribution to global sea levels, which under the worst case could reach roughly 4.6 inches by 2300, though estimates carry wide uncertainty and reflect the Peninsula’s contribution only, on top of rise from Greenland and the rest of Antarctica.

Ice Shelf Loss Would Reshape the Antarctic Food Web

Krill, the small crustaceans at the base of the Antarctic food web, depend on winter sea ice as a nursery for their young. Under higher warming scenarios, their range is projected to contract southward, squeezed between warming water and the continent itself. That contraction ripples up the food chain to the whales, seals, and penguins that rely on krill as a primary food source.

Meanwhile, the same warming that opens new ice-free ground for native mosses and lichens also strips away the barriers that have kept invasive species out for millennia. Stronger storms and more ship traffic raise the odds that outside organisms will gain a foothold in an ecosystem that has never had to compete with them.

Limiting warming to close to 1.5°C, the study concludes, would result in comparatively modest changes and greater resilience for the Peninsula. Its ice shelves would likely remain intact, and its wildlife would face pressure but fewer extreme disruptions. That outcome remains physically possible. Whether it is politically achievable is a question this decade will answer.

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