High Emissions May Result in 40m Committed Sea-level Rise from Antarctica over Millennia: Need for Stronger NDCs Today

The Cryosphere, 25 September 2024

Most projections of future sea-level rise deal with timescales of decades (2100), or occasionally to the year 2300. However, ice losses from Antarctica will not stop for thousands of years because of the inertia of the ice sheet’s response to global warming from fossil fuel emissions. In a new study, researchers used two ice sheet models to assess the sea-level commitment from Antarctica in response to low- and high-emission pathways over many centuries. Their results show that even low emissions may lock in up to 6 meters of sea-level rise from Antarctica over thousands of years into the future.

The global challenge will grow far larger however if the world continues on a high emission trajectory. Such carbon emissions triggered the collapse of the West Antarctic Ice Sheet before 2100 in all model simulations. High emissions also would make Antarctic air temperatures warm enough to trigger substantial ice loss from portions of the East Antarctic Ice Sheet through surface melting. With these factors combined, a continued high emissions trajectory would commit the world to 40 meters of sea-level rise over the course of several thousand years.

While far beyond the timescales currently considered by the political level, or even coastal infrastructure planners, these findings highlight how policies made in the next few decades will decide the scale and pace of the loss and damage caused by sea-level rise from Antarctica that will challenge humanity for millennia.

Full paper: https://tc.copernicus.org/articles/18/4463/2024/