Antarctica’s coastal glaciers are shedding icebergs more rapidly than nature can replenish the crumbling ice, doubling previous estimates of losses from the world’s largest ice sheet over the past 25 years, a satellite analysis showed.

The first-of-its-kind study, led by researchers at NASA’s Jet Propulsion Laboratory (JPL) near Los Angeles and published in the journal Nature, raises new concerns about how fast climate change is weakening Antarctica’s floating ice shelves and accelerating the rise of global sea levels.

The study’s key finding was that the net loss of Antarctic ice from coastal glacier chunks “calving” off into the ocean is nearly as great as the net amount of ice that scientists already knew was being lost due to thinning caused by the melting of ice shelves from below by warming seas.

Taken together, thinning and calving have reduced the mass of Antarctica’s ice shelves by 12 trillion tons since 1997, double the previous estimate, the analysis concluded.

The net loss of the continent’s ice sheet from calving alone in the past quarter-century spans nearly 37,000 sq.m (14,300 sq. miles), an area almost the size of Switzerland, according to JPL scientist Chad Greene, the study’s lead author.

The consequences could be enormous. Antarctica holds 88 per cent of the sea level potential of the entire world’s ice, he said.

The losses measured from calving outpaced natural ice shelf replenishment so greatly that researchers found it unlikely Antarctica can return to pre-2000 glacier levels by the end of this century, CNN reported.