Paleoclimate researchers have determined that an enormous ice dome covering a large area of southern Greenland collapsed entirely about 7,000 years ago during a period of natural warming that brought regional temperatures roughly 1 to 2 degrees Celsius above pre-industrial levels — a range that global average temperatures are rapidly approaching today due to greenhouse gas emissions.
The finding, published in the journal Science, provides a direct and sobering historical analogue for what may happen to portions of the Greenland ice sheet as the Arctic continues to warm at roughly four times the global average rate.
Meters of Sea Level Rise
The disappearance of the southern dome contributed an estimated 1.5 to 2 meters of sea level rise over several centuries. If a similar process unfolded today, driven by current warming trajectories, it would place hundreds of millions of people living in coastal areas at severe flood risk — including major cities such as Miami, Amsterdam, Shanghai, and Mumbai.
"This is not a distant future scenario," said lead author Dr. Sarah Creel of Columbia University's Lamont-Doherty Earth Observatory. "The temperatures that drove this collapse 7,000 years ago are temperatures we are on track to reach within the lifetime of children who are alive right now."