Research Highlights
Nature Reports Climate Change
Published online: 10 July 2008 | doi:10.1038/climate.2008.73
To melt Greenland
Alicia Newton
Geophys. Res. Lett. 35, L12503 (2008)
ROBAS, ISTOCKPHOTO
The Greenland ice sheet could melt completely and irreversibly if 3,000 gigatonnes of carbon dioxide are released into the atmosphere, according to scientists. Loss of the Greenland ice is of major concern, given that it could cause sea level to rise by as much as seven metres.
Sylvie Charbit at the Laboratoire des Sciences du Climat et de l'Environment, Gif-sur-Yvette, France, and colleagues simulated the long-term stability of the Greenland ice sheet under various carbon dioxide emissions scenarios. Under scenarios where cumulative emissions are less than 2,500 gigatonnes of carbon dioxide (GtC), the ice sheet melts only partially and even begins to recover within several thousand years. However, above 3,000 GtC, melting is rapid and complete, and persists for tens of thousands of years. The researchers did not include other greenhouse gases such as methane and nitrous oxide in the model, which suggests that their estimates of the carbon threshold are conservative.
Although current cumulative carbon dioxide emissions are on the order of 350 GtC, total emissions may reach 2,480 GtC by AD 2100 under worst-case scenarios — so unless emissions are curbed, runaway melting of Greenland may be triggered in the coming centuries.
