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| Thu, 30th Apr 2020 17:53:00 |
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Nasa space lasers track melting of Earth's ice sheets |
Scientists have released a new analysis of how the Greenland and Antarctic ice sheets have changed, from 2003 to 2019.
The study shows that ice losses from melting have outpaced increases in snowfall, resulting in a 14mm rise in global sea-levels over the period.
We've had a number of very similar reports to this recently.
What makes this one of interest is that it uses data from the highest-resolution satellite system dedicated to studying the poles - IceSat.
This system flies space lasers over glaciers and other ice fields to track their constantly shifting shape.
The US space agency (Nasa) has now launched two of these altimeter instruments.
The first, IceSat, operated between 2003 and 2009; the second, IceSat-2, was put up in 2018.
Thursday's report is a first attempt to tie both satellites' observations together.
"We've essentially put the two separate missions into one giant mission to tell the story of what's happened over the 16 years," said Dr Ben Smith, a glaciologist at the University of Washington.
"Working with this long time span, we can be a lot less worried about seeing short-term behaviours that aren't so relevant to the long-term evolution of the ice sheets, such as whether it snowed a bit more this year than last. The 16 years gives us a clear picture," he told BBC News.
The headline findings from the analysis underline the impacts of a warming climate.
Greenland is losing an average of about 200 gigatonnes (billion tonnes) of ice a year. Antarctica is shedding an average of roughly 118 gigatonnes per annum.
One gigatonne of ice is enough water to fill 400,000 Olympic-sized swimming pools.
Put another way, the sum of ice loss from both polar regions (5,088 gigatonnes) over the study period could fill Lake Michigan in the US.
Read original full article
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