Greenland's rapidly melting ice sheets could raise global sea levels by at least 10.6 inches (27 cm), more than double what was previously predicted, according to a study published Monday.

This ice layer is called zombie ice. That’s doomed ice that, while still attached to thicker areas of the ice, is no longer getting replenished by parent glaciers now receiving less snow. Without replenishment, the doomed ice is melting from climate change and will inevitably raise seas, said study co-author William Colgan, a glaciologist at the Geological Survey of Denmark and Greenland.

The unavoidable ten inches in the study is more than twice as much sea level rise as scientists had previously expected from the melting of Greenland’s ice sheet. The study in the journal Nature Climate Change said it could reach as much as 30 inches (78 centimetres). By contrast, last year’s Intergovernmental Panel on Climate Change report projected a range of 2 to 5 inches (6 to 13 centimetres) for likely sea level rise from Greenland ice melt by the year 2100.

Colgan responded that he didn't know how long it would take for the damaged ice to melt, possibly by the end of this century or at least by 2150.

Colgan said this is actually all a best-case scenario. The year 2012 (and to a different degree 2019 ) was a huge melt year when the equilibrium between adding and subtracting ice was most out of balance. If Earth starts to undergo more years like 2012, Greenland melt could trigger 30 inches (78 centimetres) of sea level rise, he said. Those two years seem extreme now, but years that look normal now would have been extreme 50 years ago, he said.

“That’s how climate change works,” Colgan said. “Today’s outliers become tomorrow’s averages.”

source: ap news