Knowing how much sea levels are likely to rise during this century is vital to our understanding of future climate change, but previous estimates have generated wide ranges of uncertainty. In our research, published today in Nature Climate Change, we provide an improved estimate of how much our oceans are going to warm and its contribution to sea level rise, with the help of 15 years’ worth of measurements collected by a global array of autonomous underwater sampling floats.
Our analysis shows that without dramatic reductions in greenhouse gas emissions, by the end of this century the upper 2,000 meters of the ocean is likely to warm by 11–15 times the amount of warming observed during 2005-19. Water expands as it gets warmer, so this warming will cause sea levels to rise by 17–26 centimeters. This is about one-third of the total projected rise, alongside contributions from deep ocean warming, and melting of glaciers and polar ice sheets.