Sea Level Rise From Antarctic Melt 30 percent Higher Than Previously Anticipated

While the world's attention has been focussed on taking control of the novel coronavirus pandemic, a new study by researchers at Harvard University has found that seawater levels are rising faster due to climate change than they were thought to be earlier. The rise in the global sea level due to the possible collapse of the West Antarctic Ice Sheet may have been underestimated on a significant level, says the study published in Science Advances. As per the study, if the West Antarctica Ice sheet collapsed, global sea levels could rise by about 3.2 metres (over 10 feet).

The study makes use of new calculations for the water expulsion mechanism, scientists say. The phenomenon occurs when the solid bedrock — on which the West Antarctic Ice Sheet sits — rebounds upward after the melting of ice, causing the total weight of the ice sheet to decrease. According to predictions in the new study, global sea-level rise estimates would be amplified by an additional metre within 1,000 years if there's a total collapse of the ice sheet.

In a statement, Linda Pan, a PhD in earth and planetary science in GSAS who co-led the study with fellow graduate student Evelyn Powell, says the magnitude of the effect shocked them, adding the previous research that considered the mechanism dismissed it as "inconsequential".

“If the West Antarctic Ice Sheet collapsed, the most widely cited estimate of the resulting global mean sea level rise that would result is 3.2 metres," Powell said. "What we've shown is that the water expulsion mechanism will add an additional metre, or 30 per cent, to the total."

A simulation that Pan and Powell worked on hinted that the global sea-level rise due to the melting of the West Antarctic Ice Sheet will increase 20 per cent by the water expulsion mechanism by the end of the century.

Rising sea levels threaten island nations and coastal cities that shelter more than two billion people across the globe.

Jerry X. Mitrovica, the Frank B. Baird Jr. Professor of Science, Department of Earth and Planetary Sciences, and a senior author on the paper, says every published estimation of sea-level rise based on climate modelling will have to be revised upward because of the latest study carried out by Pan and Powell. "Every single one."

The two researchers were working on another sea-level change project but channelled their energy into this one after they noticed more water expulsion from the West Antarctic ice sheet than they expected.

Pan said no matter what scenario they used for the collapse of the West Antarctic Ice Sheet, but they always found this extra one metre of global sea-level rise.

"Sea level rise doesn't stop when the ice stops melting," Pan said. "The damage we are doing to our coastlines will continue for centuries."