If global warming continues unabated, sea levels worldwide are expected to rise by several metres in the coming centuries.
A study by a university in The Netherlands is the first to give a comprehensive projection, based on observed sea level rise over the past millennium as well as on scenarios for future greenhouse gas emissions.
Advertisement"Sea-level rise is a hard to quantify yet critical risk of climate change," said Michiel Schaeffer of the Climate Analytics and Wageningen University who led the study.
"Due to the long time it takes for the world's ice and water masses to react to global warming, our emissions today determine sea levels for centuries to come," a university statement quoted Schaeffer as saying.
The potential impacts are significant.
"As an example, for New York City it has been shown that one metre of sea level rise could raise the frequency of severe flooding from once per century to once every three years," said Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research, the study's co-author.
Also, low lying deltaic countries like Bangladesh and many small island states are likely to be severely affected. The warmer the climate gets, the faster the sea level climbs.
"Coastal communities have less time to adapt if sea levels rise faster," Rahmstorf said.
Limiting global warming to below 1.5 degrees Celsius and subsequent temperature reductions could halve sea level rise by 2,300, compared to a two-degree scenario.
If temperatures are allowed to rise by three degrees, the expected sea-level rise could range between two and five metres, with the best estimate being at 3.5 metres.
"In our projections, a constant level of two-degree warming will sustain rates of sea level rise twice as high as observed today, until well after 2,300," said Schaeffer.
"Much deeper emission reductions seem able to achieve a strong slow-down, or even a stabilization of sea level over that time frame."
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