Climate change: Satellites record history of Antarctic melting

[nitpicker]

https://www.bbc.com/news/science-environment-53725288

Climate change: Satellites record history of Antarctic melting
By Jonathan Amos
BBC Science Correspondent
1 hour ago

Twenty-five years of satellite observations have been used to reconstruct a detailed history of Antarctica's ice shelves.

These ice platforms are the floating protrusions of glaciers flowing off the land, and ring the entire continent.

The European Space Agency data-set confirms the shelves' melting trend.

As a whole, they've shed close to 4,000 gigatons since 1994 - an amount of meltwater that could all but fill America's Grand Canyon.

But the innovation here is not so much the fact that the shelves are losing mass - we already knew that; relatively warm ocean water is eating their undersides. Rather, it's the finessed statements that can now be made about exactly where and when the wastage has been occurring, and where also the meltwater has been going.

Some of this cold, fresh water has been entering the deep sea around Antarctica where it is undoubtedly influencing ocean circulation. And this could have implications for the climate far beyond the polar south.

"For example, there've been a couple of studies that showed that including the effect of Antarctic ice melt into models slows global ocean temperature rise, and that can actually lead to an increase in precipitation in the US," explained Susheel Adusumilli from the Scripps Institution of Oceanography in San Diego.

Mr Adusumilli and colleagues analysed all of the observations made by Esa's long series of radar altimeter missions - ERS-1, ERS-2, EnviSat and CryoSat-2.

These spacecraft have tracked the change in thickness in Antarctica's ice shelves since the early 1990s.

Combining their data with ice velocity information from other sources, and the outputs of computer models - the Scripps group has gained a high-resolution view of the pattern of melting during the study period.

As might be expected, there's been quite a lot of variation, with mass loss and gain, even within the same individual shelf. And the rate of mass loss over time has also gone up and down. But the overall picture is clear: the shelves are wasting.
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