Greenland’s ice sheet may have reached a tipping point that sets it on an irreversible path. Nearly 40 years of Greenland satellite data showed that its glaciers have shrunk so much that even if global warming stopped today, the ice sheet would continue to shrink.
According to the new study, published in the journal Nature Communications Earth and Environment, Greenland’s glaciers have passed a tipping point, where the snowfall that replenishes the ice sheet each year cannot keep up with the ice flowing into the ocean.
This is a roaring glacial melt, under the bridge to Kangerlussiauq, Greenland where it’s 22C today and Danish officials say 12 billions tons of ice melted in 24 hours, yesterday. pic.twitter.com/Rl2odG4xWj
— Laurie Garrett (@Laurie_Garrett) August 1, 2019
“We’ve been looking at these remote sensing observations to study how ice discharge and accumulation have varied. We’ve found is that the ice that’s discharging into the ocean is far surpassing the snow that’s accumulating on the surface of the ice sheet,”
– Said Michalea King, a researcher at Ohio State University’s Byrd Polar and Climate Research Center and a lead author of the study.
They combined more than three decades of remotely sensed observational products of outlet glacier velocity, elevation, and front position changes over the full ice sheet. Comparing decadal variability in discharge and calving front position, they found that increased glacier discharge was due almost entirely to the retreat of glacier fronts, rather than inland ice sheet processes.
They showed that widespread retreat between 2000 and 2005 resulted in a step-increase in discharge and a switch to a new dynamic state of sustained mass loss that would persist even under a decline in the surface melt.
“By the end of the century, global sea level is likely to rise at least one foot above 2000 levels, even if greenhouse gas emissions follow a relatively low pathway in coming decades,”
Even for the Greenland ice sheet, the future holds more tipping points – degrees of collapse that will accelerate the glaciers’ melt even more. Limiting global warming could delay those tipping points and give the world more time to prepare.
You can find the complete published at Nature.