Antarctica has lost nearly 3 trillion tons of ice since 1992

Data: IMBIE; Note: Bands above and below lines show ±1 standard deviation. Study indicates cumulative sea level rise contribution of 7.6 mm, though raw data shows 7.4 mm; Chart: Harry Stevens/Axios.

Antarctica is shedding ice at an increasing rate, raising global sea levels and threatening coastal cities, according to a new international assessment published in the journal Nature.

Why this matters: The safety of coastal populations, including growing megacities worldwide, is intricately tied to the fate of Antarctica's ice sheet. Until a few years ago, Antarctica was assumed to be far more stable than the Greenland Ice Sheet, but that is no longer the case.