The Greenland Ice Sheet covers 1.7 million square kilometers (660,200 square miles) in the Arctic.
The Greenland Ice Sheet covers 1.7 million square kilometers (660,200 square miles) in the Arctic. If it melts entirely, global sea level would rise about 7 meters (23 feet), but scientists aren’t sure how quickly the ice sheet could melt. Modeling tipping points, which are critical thresholds where a system behavior irreversibly changes, helps researchers find out when that melt might occur.
Based in part on carbon emissions, a new study using simulations identified two tipping points for the Greenland Ice Sheet: releasing 1000 gigatons of carbon into the atmosphere will cause the southern portion of the ice sheet to melt; about 2500 gigatons of carbon means permanent loss of nearly the entire ice sheet.
Having emitted about 500 gigatons of carbon, we’re about halfway to the first tipping point.
“The first tipping point is not far from today’s climate conditions, so we’re in danger of crossing it,” said Dennis Höning, a climate scientist at the Potsdam Institute for Climate Impact Research who led the study. “Once we start sliding, we will fall off this cliff and cannot climb back up.”
Read more at American Geophysical Union
Image: Much of the southern Greenland Ice Sheet, shown here, will melt irreversibly if we emit about 1000 gigatons of carbon, according to models in a new Geophysical Research Letters study. (Credit: NASA GSFC)
