By Erik Kirschbaum BERLIN, July 15 (Reuters) - Sea levels could rise by 2.3 metres for each degree Celsius that global temperatures increase and they will remain high for centuries to come, according to a new study by the leading climate research institute, released on Monday.
Anders Levermann said his study for the Potsdam Institute for Climate Impact Research was the first to examine evidence from climate history and combine it with computer simulations of contributing factors to long-term sea-level increases: thermal expansion of oceans, the melting of mountain glaciers and the melting of the Greenland and Antarctic ice sheets.
Scientists say global warming is responsible for the melting ice. A U.N. panel of scientists, the IPCC, says heat-trapping gases from burning fossil fuels are nudging up temperatures. A small number of scientists dismiss human-influenced global warming, arguing natural climate fluctuations are responsible.
"We're confident that our estimate is robust because of the combination of physics and data that we used," Levermann told Reuters. "We think we've set a benchmark for how much sea levels will rise along with temperature increases."
Sea levels rose by 17 cm last century and the rate has accelerated to more than 3 mm a year, according to the IPCC. A third of the current rise is from Antarctica and Greenland.
Almost 200 governments have agreed to limit global warming to less than 2 degrees Celsius (3.6 Fahrenheit) above pre-industrial times and plan to agree, by the end of 2015, a deal to curb emissions.
Global average surface temperatures have risen by 0.8C (1.4F) since the Industrial Revolution and the IPCC has said temperatures are likely to be 0.4 to 1.0 degrees Celsius warmer from 2016-35 than in the two decades to 2005.
"In the past there was some uncertainty and people haven't known by how much," Levermann said. "We're saying now, taking everything we know, that we've got a robust estimate of 2.3 meters (7 feet, 6.6 inches) of rising sea per degree (Celsius) of warming........"