Antarcticaʼs ice shelves are shedding ice twice as fast as expected. Nature does not have time to restore it.
The research was conducted by researchers from NASAʼs Jet Propulsion Laboratory.
The analysis found that thinning and chipping ice has reduced the mass of Antarcticaʼs ice shelves by 12 trillion tons since 1997, double the previous estimate.
According to scientist, Chad Green, lead author of the study, the net loss of the continentʼs ice sheet due to ice breakup alone over the last quarter of a century is nearly 37 000 square kilometers — an area almost the size of Switzerland.
"Antarctica is collapsing at the edges," Green stated. As the ice shelves deplete and weaken, the continentʼs massive glaciers tend to increase the rate of global sea-level rise.
Measured losses from ice breakup are so far outpacing the ice shelfʼs natural replenishment that researchers say itʼs unlikely Antarctica will return to 2000 glacier levels by the end of this century.
"The good news is that if we stick to the 2 degrees of global warming, promised by the Paris Climate Agreement, sea-level rise across the East Antarctic Ice Sheet should be modest," the researchers added. However, failure to curb greenhouse gas emissions could lead to many meters of sea level rise over the next few centuries.
Ice shelves take thousands of years to form and act as buttresses holding back glaciers that would otherwise easily slide into the ocean, causing sea levels to rise. When ice shelves are stable, the long-term natural cycle of ice loss and re-accretion keeps their size fairly constant. However, in recent decades, warming oceans have weakened the shelf from below — an average of 149 million tons of ice was lost annually from 2002 to 2020.