"Sea-level rise is a hard to quantify, yet critical risk of climate change," says Michiel Schaeffer of Climate Analytics and Wageningen University, lead author of 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."
Limiting global warming could considerably reduce sea-level rise
While the findings suggest that even at relatively low levels of global warming the world will have to face significant sea-level rise, the study also demonstrates the benefits of reducing greenhouse-gas emissions. Limiting global warming to below 1.5 degrees Celsius and subsequent temperature reductions could halve sea-level rise by 2300, compared to a 2-degree scenario. If temperatures are allowed to rise by 3 degrees, the expected sea-level rise could range between 2 and 5 metres, with the best estimate being at 3.5 metres.
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," says Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research, co-author of the study. Also, low lying deltaic countries like Bangladesh and many small island states are likely to be severely affected.
Sea-level rise rate defines the time for adaptation
The scientists further assessed the rate of sea-level rise. The warmer the climate gets, the faster the sea level climbs. "Coastal communities have less time to adapt if sea-levels rise faster," Rahmstorf says.
"In our projections, a constant level of 2-degree warming will sustain rates of sea-level rise twice as high as observed today, until well after 2300," adds Schaeffer, "but much deeper emission reductions seem able to achieve a strong slow-down, or even a stabilization of sea level over that time frame." More
