Global sea levels are rising faster than predicted as a result of warming temperatures driven by burning fossil fuels, according to researchers who now say an increase of at least three feet (1 meter) is likely “unavoidable.”
The world’s oceans, expanding due to added heat and melting ice, have risen an average of almost 3 inches since 1992, with some areas seeing an increase of as much as 9 inches, NASA scientists said at a briefing Wednesday that cited new satellite data. Heat already stored in the sea means further sea level rise is almost certain, although how quickly remains unclear, according to a statement from the U.S. National Aeronautics and Space Administration.
“People need to be prepared,” Josh Willis, an oceanographer at the agency’s Jet Propulsion Laboratory in Pasadena, California, said on a conference call. “We’re going to continue to have sea level rise for decades and probably centuries.”
The new numbers up the stakes for coastal communities from Miami to Tokyo to Dhaka, the low-lying Bangladeshi capital where more than 14 million people live. NASA’s projections are on the high end of the 1 to 3-foot increase estimated two years ago by the Intergovernmental Panel on Climate Change, a United Nations-organized group that’s considered the world authority on climate science.
In Greenland and Antarctica, “the data collected over the last few years make me more concerned about rapid decay of ice sheets,” Eric Rignot, a University of California-Irvine glaciologist, said on the call. “This is not a futuristic scenario.”
Uncertainties remain over how fast polar ice and glaciers will melt, and natural variations mean the impact will differ around the globe, researchers said. In parts of the Pacific Ocean off the U.S. West Coast, sea levels have risen more slowly and in some cases decreased, though they are likely to catch up with the increases elsewhere in coming decades, Willis said.
Negotiators from more than 190 nations are trying to reach an agreement this year, committing all countries to rein in pollutants blamed for climate change. While that won’t reverse warming that’s leading oceans to rise, negotiators are aiming to keep the increase to no more than 2 degrees Celsius (3.6 degrees Fahrenheit) by the end of the century.
© 2015, Bloomberg
