An anonymous reader quotes a report from The Guardian: Greenland’s ice is starting to melt faster than at any time in the past 12,000 years, research has shown, which will raise sea levels and could have a marked impact on ocean currents. New measurements show the rate of melting matches any in the geological record for the Holocene period — defined as the period since the last ice age — and is likely to accelerate, according to a paper published in the journal Nature. The increased loss of ice is likely to lead to sea level rises of between 2cm and 10cm by the end of the century from Greenland alone, according to the study.
These changes, over the relatively short period of less than a century, appear to be unprecedented. Greenland’s ice sheet shrank between 10,000 and 7,000 years ago, and has been slowly cumulating over the past 4,000 years. The current melting will reverse that pattern and within the next 1,000 years, if global heating continues, the vast ice sheet is likely to vanish altogether. If greenhouse gas emissions continue to rise strongly, the rate of melting could accelerate further to be four times greater than anything found in the past 12,000 years.
The team behind the latest Greenland study made their estimates by producing a computer model of a section of the south-western region of the ice sheet over the past 12,000 years and then projecting forward to the end of this century. They checked their findings against what we can tell actually occurred with the ice, through satellite measurements and other instruments, and also by mapping the position of boulders containing beryllium-10. These are deposited by glaciers as they move, and measurements of beryllium-10 can reveal how long the boulders have been in position, and therefore where the edge of the ice sheet was when the boulder was deposited.
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Source: Slashdot – Greenland’s Ice Melting Faster Than At Any Time In Past 12,000 Years