Scientists are already aware that the West Antarctic ice sheet may be beyond saving, and due to raise sea levels by about 10 feet over the next decade. Now, it appears that things aren’t any sunnier on the east side of the Antarctic, as scientists have recently discovered that warm water is causing the Totten Glacier’s ice shelf to melt. If unchecked, the Eastern Antarctic sheet itself has the potential to raise sea levels by another 11 feet over time.
“It’s only one glacier, but it’s changing now and it is significant for sea levels globally,” said study co-author Professor Martin Siegert, Co-Director of the Grantham Institute at Imperial College London. “The 3.5 metre rise may take several centuries to complete, but now the process has started it is likely irreversible. This is another example of how human-induced climate change could be triggering major changes with knock-on impacts that will be felt globally.”
The Totten Glacier’s floating ice shelf is relatively small, with an area of 90 miles by 22 miles. However, due to warm water creeping in beneath it, the Australian Antarctic Division determined that it’s losing an amount of ice every year equivalent to 100 times the volume of Sydney Harbor.
In order to make the determination, a team of researchers from the United States, Britain, France and Australia performed flyovers for the purpose of taking various measurements of the fast-thinning ice sheet. Though the glacier is relatively small, it blocks an outlet for a much larger store of ice, the loss of which would be roughly equivalent to the ice released by the Western Antarctic ice sheet.
Most of Antarctica’s ice is grounded, or attached to the bedrock and typically, the eastern part of the continent is surrounded by cooler water that keeps warm water away. However, the scientists found a 2-mile wide valley running underneath Totten Glacier that allows warm water to reach all the way to the bedrock. If the warm water erodes those bonds, it could potentially work its way around much of the continent, rapidly accelerating the melting of the ice sheet.
“Once a certain region starts to change, the implications for the connected ice are potentially significant. We are using computer modelling to understand whether changes in Totten Glacier could lead to changes in both adjacent and more distant places in Antarctica. While this work needs to be undertaken, the change at Totten Glacier itself is significant and concerning,” said Professor Siegert.
The only thing the scientists don’t know is the temperature of the water actually reaching the ice shelf. That would require underwater robotic vehicles, which were not used in the study. They are sure, though, that the stores of warm water actually run much deeper than the cooler layers above them, due to their higher salinity levels and corresponding higher density.