How is Antarctica melting, exactly? Crucial details are beginning to come into focus

The front of the Ross Ice Shelf floats in the Ross Sea, Antarctica. Matt Siegfried/Scripps Institution of Oceanography, CC BY-NC Madelaine Gamble Rosevear, University of Tasmania; Ben Galton-Fenzi; Bishakhdatta Gayen, The University of Melbourne, and Catherine Vreugdenhil, The University of MelbourneThe size of the Antarctic ice sheet can be hard to comprehend. Two kilometres thick on average and covering nearly twice the area of Australia, the ice sheet holds enough freshwater to raise global sea levels by 58 metres. Ice loss from this sheet is projected to be the leading driver of sea level rise by 2100, yet its contribution remains highly uncertain. While sea levels are certain to rise this century, projections of the contribution from Antarctic ice vary from a 44 cm rise to a 22 cm fall. Much of this uncertainty is because the ocean processes that control the fate of the sheet occur on an incredibly small scale and are very difficult to measure and model. But recently scientists have made significant progress in understanding this “ice-ocean boundary layer”. This progress is the subject of our new review paper, published today in Annual Reviews. Shrinking, thinning and retreating At the margins of the Antarctic ice sheet, glaciers flow into the Southern Ocean, forming floating ice shelves. These ice shelves act as...

Read More........→January 22, 2025

Melting Antarctic ice will slow the world’s strongest ocean current – and the global consequences are profound

Mongkolchon Akesin, Shutterstock Taimoor Sohail, The University of Melbourne and Bishakhdatta Gayen, The University of MelbourneFlowing clockwise around Antarctica, the Antarctic Circumpolar Current is the strongest ocean current on the planet. It’s five times stronger than the Gulf Stream and more than 100 times stronger than the Amazon River. It forms part of the global ocean “conveyor belt” connecting the Pacific, Atlantic, and Indian oceans. The system regulates Earth’s climate and pumps water, heat and nutrients around the globe. But fresh, cool water from melting Antarctic ice is diluting the salty water of the ocean, potentially disrupting the vital ocean current. Our new research suggests the Antarctic Circumpolar Current will be 20% slower by 2050 as the world warms, with far-reaching consequences for life on Earth. The Antarctic Circumpolar Current keeps Antarctica isolated from the rest of the global ocean, and connects the Atlantic, Pacific and Indian oceans. Sohail, T., et al (2025), Environmental Research Letters., CC BYWhy should we care? The Antarctic Circumpolar Current is like a moat around the icy continent. The current helps to keep warm water at bay, protecting vulnerable ice sheets. It also acts as a barrier to invasive species such as southern bull kelp and any animals hitching a ride on these...

Read More........→March 17, 2025