A rise of at least two meters in the world's sea levels is now almost unstoppable, experts told a climate conference at Oxford University on Tuesday.
"The crux of the sea level issue is that it starts very slowly but once it gets going it is practically unstoppable," said Stefan Rahmstorf, a scientist at Germany's Potsdam Institute and a widely recognized sea level expert.
"There is no way I can see to stop this rise, even if we have gone to zero emissions."
Rahmstorf said the best outcome was that after temperatures stabilized, sea levels would only rise at a steady rate "for centuries to come," and not accelerate.
Most scientists expect at least 2 degrees Celsius warming as a result of man-made greenhouse gas emissions, and probably more. The world warmed 0.7-0.8 degrees last century.
Rahmstorf estimated that if the world limited warming to 1.5 degrees then it would still see two meters sea level rise over centuries, which would see some island nations disappear.
His best guess was a one meter rise this century, assuming three degrees warming, and up to five meters over the next 300 years.
"There is nothing we can do to stop this unless we manage to cool the planet. That would require extracting the carbon dioxide from the atmosphere. There is no way of doing this on the sufficient scale known today," he said.
01 October 2009
If Sea Level Rise is Unstoppable . . .
If sea level rise is unstoppable, as argued by Stefan Rahmstorf in news article excerpt below (emphasis added), then what does that imply for justifying mitigation policies based on modulating, even stopping, sea level rise in the next century?