2007 hottest on record & sea-level rise underestimated

Britain is on course for the warmest year since records began, according to figures from the Met Office and the University of East Anglia . Temperatures logged by weather stations across England reveal 2006 to have been unusually mild, with a mean temperature of 10.84C.
Current sea level rise projections could be under-estimating the impact of human-induced climate change on the world's oceans, scientists at the University of East Anglia suggest. By plotting global mean surface temperatures against sea level rise, the team found that levels could rise by 59% more than current forecasts. When applied to the possible scenarios outlined by the Intergovernmental Panel on Climate Change (IPCC), the researchers found that in 2100 sea levels would be 0.5-1.4m above 1990 levels. This projection is much greater than the 9-88cm forecast made by the IPCC itself in its Third Assessment Report, published in 2001.

Experts are convinced that the temperature warming can only be explained by rising greenhouse gases from human activity and rule out the impact of natural variations, such as the sun's intensity. "Our climate models show we should be getting warmer and drier weather in the summer, and warmer and wetter in the winter, and that's exactly what we're seeing," said Phil Jones, director of the climatic research unit at the University of East Anglia. "I cannot see how else this can be explained."
Mild warming is not expected to be overly problematic for the UK, but the trend towards drier summers has already seen a two-year drought devastate groundwater supplies in southern England, while sudden downpours have triggered flash flooding. Though scientists are not able to pin a single year's record temperatures on global warming, the long-term trend towards a warming climate is now irrefutable, they claim, and should be taken seriously by policy makers.

Regarding the sea-level rise, the paper's lead author, Stefan Rahmstorf, from the Potsdam Institute for Climate Impact Research, Germany, acknowledges that projecting future outcomes is a challenge. He writes in Science Express: "Understanding global sea level changes is a difficult physical problem, as a number of complex mechanisms with different timescales play a role." . These include:
- thermal expansion of water through heat absorption;
- water entering the oceans from glaciers and ice sheets;
- increased ice flows after the removal of buttressing ice shelves;
Only 40% of observed sea level rise was believed to a result of thermal expansion. The IPCC is set to publish its much anticipated Fourth Assessment Report in February 2007.