The West Antarctic Ice Sheet will drive more sea level rise than expected

The contribution of the West Antarctic Ice Sheet to global sea level rise will be much greater than what was previously predicted, according to experts at Harvard University. 

Based on their analysis of a “water expulsion mechanism,” the researchers estimate that sea level rise associated with global warming will be at least 20 percent higher than expected. 

The West Antarctic Ice Sheet sits on solid bedrock that rebounds upward as the ice melts and the weight of the ice sheet decreases. When the bedrock lifts up from below the sea level, it drives sea level rise.

The new study has revealed that if the Antarctic ice sheet totally collapsed, the sea level would rise an additional meter compared to current estimates within 1,000 years.

“The magnitude of the effect shocked us,” said study co-lead author Dr. Linda Pan. “Previous studies that had 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 meters,” said study co-lead author Evelyn Powell. “What we’ve shown is that the water expulsion mechanism will add an additional meter, or 30 percent, to the total.”

The researchers found that by the end of this century, global sea level rise associated with the West Antarctic Ice Sheet would increase 20 percent as a result of the water expulsion mechanism.

“Every published projection of sea level rise due to melting of the West Antarctic ice sheet that has been based on climate modeling, whether the projection extends to the end of this century or longer into the future, is going to have to be revised upward because of their work,” said study senior author Professor Jerry X. Mitrovica. “Every single one.”

The study is published in the journal Science Advances.

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By Chrissy Sexton, Earth.com Staff Writer