Previous estimates of how much the world's sea level will rise as a result of global warming may have seriously underestimated the problem, according to new research.
The study, published in Science, uses a new "semi-empirical" method instead of relying purely on computer modelling. While some modelling significantly underestimates the amount of sea-level rise that has already been seen over the last century, the new method matches the observed rise very closely, says Stefan Rahmstorf, at the Potsdam Institute for Climate Impact Research, Germany, who conducted the new study.
The existing computer model deviates even more from the actual observations built into the new estimates included in a draft of the next report of the Intergovernmental Panel on Climate Change, due to be released in February 2007.
At the top of the range of possible temperature rises estimated by the last IPCC report, the rise could be as great as 140 centimetres by 2100. That would be bad new for cities like London and New York, which lie close to sea level, and would leave them facing an increased risk of devastating storm surges. Even the lowest predicted temperature rises would cause a 50 cm rise, Rahmstorf says.
The predictions in the previous IPCC report ? its third ? ranged from 9 cm to 88 cm by 2100, and the initial draft of the next report was to cut those figures in half. But Rahmstorf, who is a lead author of the paleoclimate section of the upcoming report, says he hopes his new results will be incorporated before IPCC 4 is officially released in February 2007.
The full story is at:
http://environment.newscientist.com/arti...an-thought.html
