Probabilistic projection of sea-level change along the world's coastlines

Abstract

Climate change causes global mean sea level to rise due to thermal expansion of seawater and loss of land ice from mountain glaciers, ice caps and ice-sheets. Locally, sea-level changes can strongly deviate from the global mean due to ocean dynamics. In 5 addition, gravitational adjustments redistribute seawater away from shrinking ice masses, an effect currently not incorporated in climate models. Here, we provide probabilistic projections of sea level changes along the world’s coastlines for the end of the 21st century under the new RCP emission scenarios, taking into account uncertainties across the cause-effect chain from greenhouse-gas emissions to ocean heat uptake 10 and regional land-ice melt. At low latitudes, especially in the Indian Ocean and Western Pacific, sea level will likely rise more than the global mean (mostly by 10–20 %, but up to 45% in Tokyo area). Around the North Atlantic and the North-Eastern Pacific coasts, sea level will rise less than the global average or, in some rare cases, even fall. Our probabilistic regional sea level projections provide an improved basis for coastal 15 impact analysis and infrastructure planning for adaptation to climate change.