Seas rising 60 percent faster than projected, study shows

USPA News - Global sea levels are rising as much as 60 percent faster than previously estimated by the climate panel of the United Nations (UN), indicating projections for the future may be biased low as well, according to the results of a study released on Wednesday. The researchers, from the Potsdam Institute for Climate Impact Research (PIK) in Germany and the Laboratory Studies in Geophysics and Oceanography (LEGOS) in France, said satellite measurements show sea levels are rising at a rate of 3.2 millimeters (0.125 inches) per year, more than the 2 millimeters (0.078 inches) per year forecast by the UN`s Intergovernmental Panel on Climate Change (IPCC).

"This study shows once again that the IPCC is far from alarmist, but in fact has under-estimated the problem of climate change," said Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research. The findings of the research were published Wednesday in the journal Environmental Research Letters. The researchers used data from satellites which have measured the rise in sea levels by bouncing radar waves back off the sea surface. "Satellites have a much better coverage of the globe than tide gauges and are able to measure much more accurately by using radar waves and their reflection from the sea surface," said Anny Cazenave of LEGOS. The study, which looked at data from 1993 through 2011, showed the increased rate of sea level rise is unlikely to be caused by a temporary episode of ice discharge from the ice sheets in Greenland or Antarctica or other internal variabilities in the climate system because it correlates very well with the increase in global temperature. Rising seas could potentially affect millions of people around the world in coastal areas as well as megacities such as Tokyo. "To improve future projections it is very important to keep track of how well past projections match observational data," Rahmstorf stressed, adding that the physics of sea level rises is much more complex than global warming itself. Also on Wednesday, during UN talks in Qatar on combating climate change, IPCC Chairman Rajendra K. Pachauri warned that rising sea levels will begin to affect low-lying coastal areas with large populations by the end of the 21st century. "The cost of adaptation could amount to at least 5 to 10 percent of Gross Domestic Product (GDP)," he said. Pachauri explained that partial loss of ice sheets on polar land could imply meters of sea level rise, major changes in coastlines, and inundation of low-lying areas, with the greatest effects in river deltas and low-lying islands. He said such changes are projected to occur over millennial timescales, but cautioned that more rapid sea level rise on century timescales cannot be excluded.