Science Advances, 12 October 2023
Latest observations reveal that 71 out of the 162 massive ice shelves around Antarctica are shrinking with no sign of recovery, providing striking evidence of Antarctica’s vulnerability to climate warming. Ice shelves extend from the continent and float atop sea water, stabilizing the massive glaciers behind them. Researchers expected these ice shelves to go through cycles of rapid, short-lived shrinking followed by slow regrowth. This study measuring the current stability of the ice shelves raises alarm bells. Rather than observing ice shelf recovery, satellite data reveals that they lost 7.5 trillion tons of ice over the past 25 years. Most concerning, authors found that 48 ice shelves lost more than one-third of their ice during this period.
Most ice shelf loss took place along the western half of the content, where warm water appears to be rapidly eroding the ice shelves from below. An additional 1.3 trillion tons of ice was lost from the Pine Island ice shelf, as large sections broke away in addition to widespread melting. The Getz ice shelf however lost the most ice: 1.9 trillion tons over the study period, almost entirely due to melting from below. In contrast, the ice shelves off East Antarctica are currently protected by a band of cold water at the coast, allowing them to remain relatively stable for now. Continued loss from Antarctica’s ice shelves and glaciers will have a major effect on ice sheet stability and likely alter Southern Ocean currents, where this influx of freshwater could slow the formation of deep waters that drive global ocean circulation.