Re: SC65

http://www.theage.com.au/news/world/scientist-turns-up-the-heat-with-new-alert-on-warming/2008/04/07/1207420309396.html

Scientist turns up the heat with new alert on warming

A LEADING climate scientist says the European Union and its international partners must urgently rethink targets for cutting carbon dioxide in the atmosphere because of fears they have grossly underestimated the scale of the problem.

Dr James Hansen, head of the NASA Goddard Institute for Space Studies in New York, calls for a sharp reduction in carbon dioxide limits.

Dr Hansen said the EU target of 550 parts per million of carbon dioxide — the most stringent in the world — should be slashed to 350 ppm.

He said the cut was needed if "humanity wishes to preserve a planet similar to that on which civilisation developed".

A final version of the paper Dr Hansen co-wrote with eight other climate scientists has been posted on the Archive website.

Instead of using theoretical models to estimate the sensitivity of the climate, the team used evidence from Earth's history, which they contend gives a much more accurate picture. They studied cores taken from the bottom of the ocean, which indicate carbon dioxide levels millions of years ago. They show that when the world began to glaciate at the start of the ice age around 35 million years ago, the concentration of carbon dioxide was about 450 ppm.

"If you leave us at 450 ppm for long enough, it will probably melt all the ice — that's a sea rise of 75 metres," Dr Hansen said. "What we have found is that the target we have all been aiming for is a disaster — a guaranteed disaster."....................