Greenland on Verge of Meltdown

Greenland on Verge of Meltdown

The complete collapse of the massive Greenland Ice Sheet -- which has a mean height of about two kilometres -- now appears inevitable, and could raise sea levels seven metres. "It's a sobering message, I think," says Tim Lenton, of the School of Environmental Sciences at Britain's University of East Anglia.


Lenton's research group surveyed climate and glacial experts around the world and the consensus is that the recent evidence shows that rising temperatures will soon reach the Greenland Ice Sheet's "tipping point", where it will break up within 300 years, raising sea levels by seven metres and flooding millions out their homes long before the year 2300.


Recent calculations show the Greenland collapse could be triggered by temperature rise of just 1 degree Celsius warmer than today. This is an example of what scientists call a "non-linear response", in which a small change can make a big difference, more commonly described as "tipping points".


And this point is coming much sooner than it looks. Due to a time lag in the atmospheric warming response, even if there were no more greenhouse gas emissions from this day forward, temperatures would still rise another 0.6 degrees Celsius.


"I don't want to say the Greenland meltdown is inevitable, but it will be very difficult to avoid," Lenton told IPS. James Hansen, head of NASA's Goddard Institute for Space Studies, believes that without drastic international efforts, a sea level rise of up to five metres is possible before the end of this century. "In my opinion, if the world warms by 2 to 3 degrees Celsius, such massive sea level rise is inevitable, and a substantial fraction of the rise would occur within a century," Hansen wrote in the Jul. 25 issue of New Scientist magazine.