Simulations show likely amount of sea level rise in coastal cities around the world

(Phys.org)—An international team of researchers has run multiple global climate computer simulations multiple times and has used the simulation results to estimate the local impact of rising sea levels on coastal cities around the globe. In their paper published in Proceedings of the National Academy of Sciences, the group outlines the first serious attempt to account for multiple factors in making predictions about sea level rise amounts around the world.

Contrary to what might seem obvious, sea levels do not rise in a uniform manner—levels may rise more in parts of Asia, for example, than along the California coast. These differences are due to factors such as ocean currents and the location of melting ice. Thus, as the planet heats up and more ice melts, resulting in higher sea levels, some coastal areas will see higher levels than others. In this new effort, the researchers sought to predict how much rise individual coastal cities are likely to experience as global temperatures reach two landmarks—2 °C and 5 °C higher than pre-industrial levels.

To make their estimations, the researchers ran approximately 24 computer simulations approximately 5000 times—the models accounted for such factors as temperature rise of the air and ocean, ocean currents and the impact of melting ice. The models offered results very similar to those previously made by other researchers regarding global sea rising amounts, but they also offered estimates locally, showing, for example, that many parts of South and South East Asia are likely to see higher rises than other parts of the world. They also showed that the more levels rise, the faster the rise becomes if the factors contributing to global warming are not changed.

If things continue on their current path, the researchers suggest, global temperatures are likely to become 2 °C higher than pre-industrial levels by 2040 or 2050 and 5 °C higher by 2100. If these milestones are reached, the simulations suggest, the Earth would experience a global sea rise of approximately six inches by mid-century and two feet by the end of the century. If that happened, the models suggest the East Coast of the U.S. would experience a sea rise of a foot by mid-century and cities like Lagos, Manilla and Ho Chi Minh City would experience a rise as much as three feet by the end of the century; New York City could see a rise of more than three and a half feet.