Antarctica is likely to lose more ice than it gains this century even if global warming is limited to 1.5°C, according to a new study published in Nature Geoscience.
Researchers examined hundreds of thousands of possible Antarctic ice sheet futures using a physics informed machine learning model trained on existing ice-sheet simulations. The analysis also compared the scenarios with satellite observations of Antarctica’s ice mass since 2002.
The study found that increased snowfall over Antarctica which is expected as a warmer atmosphere holds more moisture, would not be enough to offset ice losses caused by warming oceans and changes in glacier flow.
The Antarctic ice sheet contains enough frozen water to raise global sea levels by about 58 metres if it were to melt completely. Researchers said its continued ice loss would add to sea level rise already caused by melting glaciers Greenland ice sheet and the thermal expansion of warming oceans.
Under a very high emissions scenario, Antarctica alone could contribute up to 25 centimetres of sea level rise by 2100, potentially causing permanent flooding in areas inhabited by more than 10 million people.
Scientists identified three factors as particularly important for improving future projections how ice shelves respond to warmer oceans how ice moves over bedrock, and how rapidly the surrounding ocean and atmosphere warm.
The researchers cautioned that some processes including ice cracking and changes in rivers and lakes beneath the ice sheet, are not yet fully represented in current models. These uncertainties could affect estimates of how quickly Antarctic ice reaches the ocean.
The findings underline the long term connection between greenhouse gas emissions and sea level rise, with lower emissions expected to reduce the pace and extent of future Antarctic ice loss.