NASA studies show Antarctic ice melting at an unprecedented rate. What's left to do?

Credit image: NASA
Credit image: NASA

Article by: Andacs Robert Eugen, on 27 August 2022, at 09:29 am Los Angeles time

New research on Antarctica, including the first map of melting icebergs, doubles previous estimates of ice loss and details how the phenomenon is changing the entire continent. The biggest uncertainty in forecasting global sea level rise is how Antarctic ice loss will accelerate as the climate warms. 

Two studies recently published on August 10 and led by researchers at NASA's Jet Propulsion Laboratory in Southern California reveal unexpected new data about how the Antarctic ice sheet has lost mass in recent decades. One of the studies, published in the journal Nature, maps how the breaking off of chunks of ice from a large glacier has changed the Antarctic coastline over the past 25 years. 

The researchers found that the edge of the ice sheet has been losing icebergs faster than the ice can be replaced. This surprising finding doubles previous estimates of ice loss from Antarctic ice shelves since 1997, from 6,000 billion to 12,000 billion tons. Ice loss has weakened ice shelves and allowed Antarctic glaciers to melt faster into the ocean, accelerating the rate of global sea level rise. 

The other study, published in Earth System Science Data, shows in unprecedented detail how thinning Antarctic ice, as ocean water melts it, has spread from the continent's outer edges to its interior, nearly doubling in the western parts of the ice sheet over the past decade. Combined, the complementary reports provide the most complete picture yet of how the frozen continent is changing.

"Antarctica is collapsing toward the edges," says JPL researcher Chad Greene, lead author of the study. "And when the ice shelves shrink and lose thickness, the continent's massive glaciers tend to accelerate the rate of global sea level rise ".

For the new study, Greene and his co-authors synthesized visible-wavelength, thermal-infrared (heat), and radar satellite images of the continent dating back to 1997. Combining these measurements, they mapped the edges of the ice shelves around 50,000 kilometers from the coast of Antarctica.

The resulting losses have so far outstripped natural ice sheet growth that researchers believe Antarctica is unlikely to return to its pre-2000 extent by the end of this century. The findings suggest that greater losses can be expected: the largest ice shelves in Antarctica appear to be headed for major melting events in the next 10-20 years.

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