Antarctica's ice loss is locked in, and extra snowfall won't save it—low‑lying coastal areas elsewhere to suffer

Antarctica's ice loss is inevitable, and even increased snowfall will not halt it, posing a severe threat to coastal regions worldwide. Ice sheets contain enough water to raise global sea levels by approximately 190 feet (58 meters), with Antarctica being the most critical contributor. The continent holds enough ice to raise global sea levels by about 190 feet (58 meters), but scientists have been divided on whether it will gain or lose ice this century.

A new study published in Nature Geoscience reveals that Antarctica's ice loss is locked in, and even if humanity manages to limit global warming to 1.5°C (2.7°F), the ice sheet will continue to lose more ice than it gains. The Antarctic ice sheet's future depends on a chain of events, including how greenhouse gas emissions affect the ocean and air around Antarctica, how ice shelves around the continent's margins melt, and how quickly glaciers slide over the bedrock.

When ice shelves thin or collapse, glacier flow speeds up, which is influenced by various assumptions scientists have yet to agree upon. Due to the complexity of these processes and the limitations in computing power, scientists can't test every plausible combination of assumptions, leading to cascading uncertainty. Researchers used a physics-informed machine learning model trained on an archive of Antarctic simulations to predict sea-level change with similar accuracy to the original models in a fraction of the time.

The results indicate that even with aggressive efforts to reduce greenhouse gas emissions, Antarctica will still contribute more to sea-level rise than currently projected. This means that by 2100, Antarctica could add up to 10 inches (25 centimeters) to sea levels, potentially flooding the homes of over 10 million people. The key factors influencing future sea-level rise are how ice shelves respond to a warming ocean, how ice slides over bedrock, and how fast the ocean and air around Antarctica warm.

Further understanding of these processes could significantly improve projections of the Antarctic ice sheet's future and its impact on global sea levels.