The ongoing changes in Antarctica and the Southern Ocean could have consequences far beyond this region, with impacts on sea level, ocean circulation, weather patterns, and biodiversity. The warning was issued by Australian scientists during COP31, in a session dedicated to the importance of these regions for the climate of the Pacific and the planet.
The researchers, linked to the Australian Antarctic Division, the Australian Antarctic Program Partnership (AAPP) at the University of Tasmania, and the Australian Centre for Excellence in Antarctic Science (ACEAS), emphasized that even a temporary and relatively small overshoot of the 1.5 °C global warming limit can increase the risk of reaching climate tipping points, including potentially irreversible losses of ice in Antarctica.
The parallel session, titled “Why changes in Antarctica and the Southern Ocean are important for the Pacific and global climate,” was organized by the International Cryosphere Climate Initiative (ICCI) during the first week of the conference, which is taking place in Turkey.
Krystyna Saunders, of the Australian Antarctic Division, reminded that the consequences of changes in this region are not confined to the icy continent.
“The collapse of parts of the Antarctic ice sheet would transform the natural world and human society, triggering a rise in sea level by several metres, higher than the average elevation of some Pacific island countries,” she said.
The researcher added that continued ice loss could intensify warming through climate feedback mechanisms, while heatwaves, changes in the oceans, and melting exacerbate biodiversity loss, both in Antarctica and in other regions.
The consequences could also be felt in Pacific communities and ecosystems through disruptions to global ocean circulation, weather patterns, and the supply of essential nutrients to marine productivity.
Rising sea level and loss of carbon uptake capacity
Karen Palmer, from the AAPP and ACEAS, warned that a rise in sea level by several metres is now inevitable in the long term, and if it does not materialize by 2100, it could occur in the following centuries.
“More must be done to protect human and environmental systems that are too essential to fail, and everything should be done to prevent a rise in sea level from one to two metres from becoming a rise of 15 metres,” she argues.
For the researcher, this effort requires greater international collaboration and a strengthened commitment to observational and information systems, essential to support decision-making at both global and local scales.
The role of the Southern Ocean in regulating the climate was also highlighted. This region accounts for about 30% of the world’s ocean surface and is responsible for absorbing around 40% of the carbon dioxide drawn down by the oceans.
Elizabeth Shadwick, of the AAPP, described it as an important “buffer against climate shocks,” noting that the region’s carbon absorption capacity makes it essential to continuously monitor its changes.
“The remaining carbon budget to limit warming to 1.5 °C now equals less than four years of current-rate emissions,” she states. The researcher believes that maintaining regular observations is essential to improve projections on the evolution of the Southern Ocean and to support urgent measures.
Changes that surprised the scientific community
Nathan Bindoff, from the AAPP and ACEAS, drew attention to the speed and intensity of some changes already observed in the Southern Hemisphere, which could be amplified by a temporary overshoot of temperature thresholds.
“Changes in deep ocean circulation, a rapid decline in sea ice, and the mass loss of the Antarctic ice sheet: all these changes took the oceanographic community by surprise. No one predicted them,” he says.
The researcher argued that regular and more frequent monitoring of the Southern Ocean is necessary. These observations allow assessment of both the benefits of emission reductions and the risks of dangerous changes in the climate system.
The warning comes on the heels of a contribution presented earlier this year by the Australian Antarctic Programme to the initiative “Belem 1.5 Mission,” under the United Nations Framework Convention on Climate Change.
Among the recommendations is that Antarctica and the Southern Ocean be considered central elements of the Earth system in international climate negotiations. According to the researchers, changes in this region and crossing critical thresholds are relevant for assessing climate risks, hazards, losses, and damages on a global scale, both now and in the future.
