Scientists reveal our best and worst case scenarios for a warming Antarctica

Antarctica. Roy Rashti | Unsplash

Antarctica’s pale expanses of ice keep water locked up and reflect heat from the planet but the climate crisis is putting these safeguards at increasing risk.

Antarctica is warming faster than anywhere else on Earth, which could destroy its ecosystems and put other parts of the planet at risk by driving sea level rise and damaging food webs.

Prof. Angus Atkinson MBE, Senior Marine Ecologist at Plymouth Marine Laboratory and co-author on the review, comments: “The projected changes are alarming, but what I find most concerning is that changes can be so sudden and hard to predict. The recent step-wise reduction in Antarctic sea ice was a good reminder of this”.

In this most recent review, scientists modelling possible climate crisis outcomes for the Antarctica Peninsula show just how high the stakes are if we do not act now but also how much harm can still be prevented.

“The Antarctic Peninsula is a special place,” said Prof Bethan Davies of Newcastle University, lead author of the article in Frontiers in Environmental Science. “Its future depends on the choices that we make today. Under a low emissions future, we can avoid the most important and detrimental impacts. However, under a higher emissions scenario, we risk the loss of sea ice, ice shelves, glaciers, and iconic species such as penguins.”

“Though Antarctica is far away, changes here will impact the rest of the world through changes in sea level, oceanic and atmospheric connections and circulation changes. Changes in the Antarctic do not stay in the Antarctic.”

A race against time

The scientists focused on the Antarctic Peninsula, a center for research, tourism and fishing that is both very well-studied and very vulnerable to anthropogenic changes.

Prof Peter Convey of the British Antarctic Survey and co-author, said. “For a casual visitor, the first impression is still inevitably that the region is ice-dominated. However, to those of us that have the privilege to go back multiple times, there are very clear changes over time.”

The scientists used scenarios that estimate future emissions to model outcomes for the Antarctic Peninsula: low emissions (1.8°C temperature rise compared to preindustrial levels by 2100), medium-high emissions (3.6°C), and very high emissions (4.4°C). They looked at eight different aspects of the Peninsula’s environment affected by climate change: marine and terrestrial ecosystems, land and sea ice, ice shelves, the Southern Ocean, the atmosphere, and extreme events like heatwaves.

“In 2019, we demonstrated how the Antarctic Peninsula would be affected by the 1.5°C climate scenario,” said Prof Martin Siegert of the University of Exeter and co-author. “Now, in 2026, we share what exceeding 1.5°C looks like for the Antarctic Peninsula, which is a frightening prospect.”

High stakes

In higher emissions scenarios, the Southern Ocean will get hotter, faster. Warmer ocean waters will erode ice on land and at sea and the higher temperatures get, the more likely ice shelves are to collapse and drive sea level rise.

Under the highest emissions scenario, sea ice coverage could fall by 20%, devastating species that rely on it, such as krill, an important prey for whales and penguins, and amplifying ocean warming worldwide. Higher ocean warming would also stress ecosystems and contribute to extreme weather.

Although it is difficult to predict how these environmental changes would combine to affect animals, the scientists expect that under very high emissions scenarios, many species will move south to escape higher temperatures. Warm-blooded predators may cope with temperature changes but if their prey cannot, they will starve.

An uncertain world

Researchers are not safe from the consequences of climate change either: damage to infrastructure is making it more dangerous to carry out research so it is harder to collect the data needed to forecast the future effects of climate change. Although numerical models simplify reality, more data makes them more accurate.

The study team emphasise that we must act now to avoid the worst-case scenarios. “At the moment, we’re on track for a medium to medium-high emissions future,” said Davies. “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 than under a higher scenario. Winter sea ice would be only slightly smaller than today, and sea level contributions from the Peninsula would be limited to a few millimeters. Most of the glaciers would be recognizable and we would retain the supporting ice shelves.”

“What concerns me most about the higher emissions scenario is just how permanent the changes could be. 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. If we don’t make changes now, our great-grandchildren will have to live with the consequences.”