Troubling new research shows warm waters rushing towards the world’s biggest ice sheet in Antarctica

Warmer waters are flowing towards the East Antarctic ice sheet, according to our alarming new research which reveals a potential new driver of global sea-level rise.
The research, published on 2 August 2022 in Nature Climate Change, shows changing water circulation in the Southern Ocean may be compromising the stability of the East Antarctic ice sheet. The ice sheet, about the size of the US, is the largest in the world.
The changes in water circulation are caused by shifts in wind patterns, and linked to factors including climate change. The resulting warmer waters and sea-level rise may damage marine life and threaten human coastal settlements.
Our findings underscore the urgency of limiting global warming to below 1.5℃, to avert the most catastrophic climate harms.
Ice sheets and climate change
Ice sheets comprise glacial ice that has accumulated from precipitation over land. Where the sheets extend from the land and float on the ocean, they are known as ice shelves.
It’s well known that the West Antarctic ice sheet is melting and contributing to sea-level rise. But until now, far less was known about its counterpart in the east.
Our research focused offshore on a region known as the Aurora Subglacial Basin in the Indian Ocean. This area of frozen sea ice forms part of the East Antarctic ice sheet.
How this basin will respond to climate change is one of the largest uncertainties in projections of sea-level rise this century. If the basin melted fully, global sea levels would rise by 5.1m.
Much of the basin is below sea level, making it particularly sensitive to ocean melting. That’s because deep seawater requires lower temperatures to freeze than shallower seawater.
What we found
We examined 90 years of oceanographic observations off the Aurora Subglacial Basin. We found unequivocal ocean warming at a rate of up to 2℃ to 3℃ since the earlier half of the 20th century. This equates to 0.1℃ to 0.4℃ per decade.
The warming trend has tripled since the 1990s, reaching a rate of 0.3℃ to 0.9℃ each decade.
So, how is this warming linked to climate change? The answer relates to a belt of strong westerly winds over the Southern Ocean. Since the 1960s, these winds have been moving south towards Antarctica during years when the Southern Annular Mode, a climate driver, is in a positive phase.
The phenomenon has been partly attributed to increasing greenhouse gases in the atmosphere. As a result, westerly winds are moving closer to Antarctica ...