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Sea Levels Are Rising Faster

Sea level rise has been accelerating during the satellite era, according to a report in Nature Climate Change that combined tide gauge data and GPS measurements of land movement to refine satellite data from 1993 to 2014.

“Previously, it was clear that the rate of rise over the past 20 years was roughly double the rate determined over the past century,” said lead author Dr Christopher Watson of the University of Tasmania.

“What was curious was that the rate appeared slower in the last decade relative to the one before. That slowing has puzzled scientists because it coincides with an increase in water entering our oceans from Greenland and West Antarctica.”

Watson said the research had highlighted a small overestimation of the sea level rise in the period from 1993 to 1999. This had been distorting the overall trend, making it appear that the rate of sea level rise was slowing between 1993 and 2014 when in reality it had accelerated.

“An estimate of acceleration is striking in that it is consistent with the projections of future sea level published by the Intergovernmental Panel on Climate Change,” Watson said.

Co-author Dr John Church from CSIRO said that projections are for up to a 98 cm rise by 2100 if global greenhouse gas emissions are allowed to continue unabated. “The projections reduce to a rise of between 28 and 61 cm if we follow paths that include very stringent mitigation of global emissions,” he said.