Existing climate model simulations overestimate future sea-level rise by up to 25%, new study shows

Scientists from Utrecht University using the national supercomputer at SURFsara in Amsterdam have found that the projected sea-level rise over the next century is about 25% lower than current models predict.

Their new, higher-resolution climate model simulation reveals a slower ocean temperature increase than predicted by current models. The reason for this comes courtesy of ocean eddy processes, which were left out of many, lower-resolution models which inform public policy today.

The climate models involve vast amounts of data from numerous sources which are constantly being updated for accuracy with the help of higher-resolution data.

The new model factors in these ocean eddy processes which have a remarkable effect on the melting rate of the Antarctic ice sheet, one of the key drivers of ocean-level rise across the world. 

An eddy is a large (10-200 km) turbulent system in the ocean circulation which distributes both heat and salt. By factoring them in, the Utrecht team created what they say is a more accurate representation of ocean temperatures around Antarctica, and thus the rate of melt in the ice sheet.

While existing climate models predict increasing ocean temperatures around Antarctica, with the higher resolution simulation, in certain areas at least, the opposite was found to be true; some regions are, in fact, cooling. 

“These regions appear to be more resilient under climate change,” says Utrecht Ph.D. candidate René van Westen.

“One obtains a very different temperature response due to ocean-eddy effects,” adds professor Henk Dijkstra. 

Their model predicts dramatically smaller Antarctic mass loss as a result of ice-shelf melt; Just one third compared with current predictions.

This shift in estimates theoretically reduces the projected global sea-level rise by 25% over the coming century.

“Although sea levels will continue to rise, this is good news for low-lying regions,” Van Westen says.

Think your friends would be interested? Share this story!