Climate research – West Antarktis at the tipping point

White, unaffected and endless, the ice desert of the Antarctic seems to be. But under this majestic surface there is a threat of a scenario that could change the world’s oceans dramatically: According to experts, the western antecarated ice shield (wais) may already have reached the point where its withdrawal is irreversible. Should this process be used, it would take over centuries to thousands of years – but it would not be stopped. In the end, the global sea level rose by more than three meters, with serious consequences for coastal cities and millions of people worldwide. This warning comes from a new study that in the “Nature” journal published became. Scientists from the Australian National University (Anu) and the University of New South Wales (unsw) as well as researchers from all major Australian Antarctic centers were involved.

The scientists describe how abruptly and potentially irreversible ice, oceans and ecosystems of the continent change – and what global effects this could have, especially for Australia. They warn that the current changes in Antarctica are closely intertwined. The possible collapse of the waist is only one of several dramatic developments. Nerilie Abram, main author of the study and currently chief scientists at the Australian Antarctic Division (AAD), said that a collapse of the West Antarctic ice sheet had “serious consequences for generations”.

Irreversible process

The withdrawal of the huge ice sheet would theoretically be stopped if the sea does not heat up under the ice. But the researchers consider this to be extremely unlikely. It is much more likely to be assumed that the process will continue – and the seas will continue to increase over many generations. Rapid changes in ice, oceans and ecosystems can already be measured in the Antarctic, which intensify with every fraction of a degree of additional global warming. Abram also emphasized that the loss of the Antarctic sea ice triggered a chain reaction: “This makes the floating shelves around the Antarctic more susceptible to breakdowns driven by waves.”

In addition to the decline in sea ice, which changes heat storage in the climate system, the slowdown of deep circulation in the southern Ocean is also worrying. According to new knowledge, these currents react significantly more sensitive to climate change than previously assumed. Without the reflective ice sheet, more solar energy is also absorbed in the ocean, which also accelerates the warming in the region.

Co-author Matthew England from the Unsw and the Australian Center for Excellence in Antarctic Science (Aceas) said abrupt changes in the climate and ecosystems of Antarctic had “serious consequences for Australia”. This included rising sea levels that threaten coastal communities, a warmer and low -oxygen southern ocean that could absorb less CO₂, as well as increased regional warming due to the loss of sea ice.

Penguins, seals and krill threatened

The effects on the animal world are also particularly dramatic. The loss of the sea ice increases the extension of the end for imperial penguins, the chicks of which are dependent on stable ice surfaces until they develop their waterproof plumage. There are also risks for krill as well as other types of penguin and seals, since their chances of survival and reproduction are threatened by the changes. At the same time, key species of phytoplankton suffer from increasing octopus heat and acidification. These losses could destabilize entire food chains. “Another risk is a collapse of antarctic circulation circulation,” warned England. In this case, important nutrients would remain on the sea floor instead of getting back to the surface, where they are indispensable for the marine life.

The study also makes it clear that the previous measures in the context of the Antarctic Treaty are not sufficient to protect the ecosystems. Abram said: “While these measures are decisive, they cannot prevent climate -related effects that already use.” The researchers emphasize that only a quick and drastic reduction in greenhouse gas emissions can prevent further abrupt changes.