When Peter Convey first set foot on Signy Island in the South Orkney archipelago in 1989, there was a small rock poking through the surface of the McCloud Glacier. It had a name, Manhaul Rock, but it was barely worth one. You could walk right up to it, ski past it, drive a skidoo over the ice beside it. By 2024, Manhaul Rock had become a full nunatak, a craggy mass towering above what little remained of the glacier around it. The ice that once buried it had simply gone.
Convey, a biologist at the British Antarctic Survey, has been returning to the Antarctic Peninsula for 35 years. “For a casual visitor, the first impression is still inevitably that the region is ice-dominated,” he says. “However, to those of us that have the privilege to go back multiple times, there are very clear changes over time.”
Those changes are now the subject of a sprawling new analysis, published today in Frontiers in Environmental Science, that attempts something both straightforward and unsettling: modelling what happens to the Antarctic Peninsula under three different futures. A team of 24 researchers from institutions across the UK, the US, Germany and elsewhere examined everything from atmospheric temperatures and sea ice to penguin colonies and moss beds, running the numbers for low, medium-high and very high emissions scenarios. The gap between the best and worst outcomes, it turns out, is enormous. And the window for choosing which path we follow is closing fast.
“The Antarctic Peninsula is a special place,” says Bethan Davies of Newcastle University, who led the study. “Its future depends on the choices that we make today.”
That might sound like boilerplate climate rhetoric. It isn’t. The Peninsula is warming considerably faster than the global average, with Vernadsky Station on the west coast recording roughly 0.45°C of warming per decade since 1951; that works out to more than 3°C over 73 years. The highest temperature ever recorded on the Antarctic mainland, 18.6°C, was logged near the Peninsula’s northern tip in February 2020. In the same summer, George VI Ice Shelf experienced a 32-year record melt event. Two years later, another record surface melt hit the Peninsula during an extreme warm episode driven by an atmospheric river, one of those long, narrow bands of moisture that funnel heat from the subtropics towards the poles.
These aren’t one-off events any more. The years 2022 to 2024 saw the three lowest Antarctic sea ice extents in the satellite era. Atmospheric rivers reaching the Peninsula have been increasing at a rate of about 0.89 per decade since 1979. Marine heatwaves are growing more frequent and intense in the Southern Ocean. The system, in other words, is already under serious stress.
What the new study does is project that stress forward. The three scenarios correspond to global temperature rises of 1.8°C, 3.6°C and 4.4°C above pre-industrial levels by the end of the century. Under the lowest pathway, the Peninsula warms by about 2.3°C relative to pre-industrial temperatures. Under the highest, that figure climbs to roughly 6.1°C. And the consequences cascade through every part of the system in ways that, under high emissions, become practically irreversible.
Take sea ice. Under low emissions, seasonal reductions stay modest, between 1 and 2 percent. Under the very high scenario, winter sea ice around the Peninsula drops by nearly 20%, with the Weddell Sea losing more than a fifth of its autumn coverage. That matters because krill, the tiny crustaceans that underpin much of the Antarctic food web, depend on winter sea ice as a nursery for their young. Lose the ice, lose the krill. Lose the krill, and you start losing the whales, seals and penguins that feed on them. The 2022 record low sea ice in the Bellingshausen Sea already triggered breeding failure among regional emperor penguin colonies. Under higher warming, those kinds of catastrophic seasons could become the norm rather than the exception.
Then there are the ice shelves, those vast floating platforms that buttress the glaciers behind them. When Larsen B collapsed in 2002, the Hektoria Glacier behind it retreated more than 16 kilometres in less than two decades. Under very high emissions, the study finds that both Larsen C and the Wilkins ice shelves are likely to collapse by 2100. Surface melt would saturate the porous firn layer, creating meltwater ponds that crack through the ice by hydrofracture. It is a sort of slow-motion structural failure. George VI Ice Shelf, despite having exceptionally high surface melt rates already, might survive longer thanks to a compressive flow regime that makes it more resistant to fracturing, but even that resilience has limits. Were it to collapse by 2300 under the worst scenario, sea level contributions from the Peninsula alone could reach about 116 millimetres.
Under the low emissions pathway, by contrast, the models actually predict slight growth of Peninsula land ice, largely offset by increased snowfall. Sea level contributions would be negligible, perhaps negative. Most glaciers would remain recognisable. The ice shelves would hold. “A lower emissions scenario would mean that although the current trends of ice loss and extreme events would continue, they would be much more muted,” says Davies.
The biological picture is perhaps harder to pin down. The Peninsula’s terrestrial ecosystems, dominated by mosses, lichens and tiny invertebrates like mites and springtails (many of them found nowhere else on Earth), would probably benefit from modest warming in isolation. Longer growing seasons, more liquid water, expanded ice-free habitat. But the study warns that under higher warming, native species could increasingly bump up against their upper thermal limits, and invasive species carried in on drifting kelp rafts, ship hulls or tourist boots could start gaining footholds. There’s also the emerging threat of rain-on-snow events, a phenomenon already causing havoc in Arctic Svalbard; thick ice layers form on the ground beneath the snowpack, suffocating vegetation and the invertebrates living in it. It is a problem nobody in Antarctic biology had really considered until quite recently.
“What concerns me most about the higher emissions scenario is just how permanent the changes could be,” says Davies. “These changes would be irreversible on any human timescale. It would be very hard to regrow the glaciers and bring back the wildlife that makes Antarctica special.” Current policies give us a 0% chance of staying below 1.5°C of warming and, according to the latest UN assessment, a 66 percent chance of keeping below 2.8°C. “In 2019, we demonstrated how the Antarctic Peninsula would be affected by the 1.5°C climate scenario,” says Martin Siegert of the University of Exeter, a co-author. “Now, in 2026, we share what exceeding 1.5°C looks like for the Antarctic Peninsula, which is a frightening prospect.”
The honest difficulty is that predicting exactly how much ice the Peninsula will lose remains fiendishly uncertain. Current ice-sheet models struggle with the region’s complex mountain topography, and the big differences between scenarios only really emerge after 2150. But the direction is clear enough, and the choices that determine which trajectory we end up on are being made right now. “Changes in the Antarctic do not stay in the Antarctic,” Davies says. “If we don’t make changes now, our great-grandchildren will have to live with the consequences.”
Study link: https://www.frontiersin.org/journals/environmental-science/articles/10.3389/fenvs.2025.1730203/full
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