Melting Antarctic Ice Threatens the World's Megacities

A new report predicts global sea levels will rise 20 percent higher than previously thought.

Adélie penguins stand atop a block of melting ice on a rocky shoreline at Cape Denison, Commonwealth Bay, in East Antarctica on Jan. 1, 2010. (Photo: Pauline Askin/Reuters)

Kristine Wong is a regular contributor to TakePart and a multimedia journalist who reports on energy, the environment, sustainable business, and food.

A first-of-its-kind study finds that global sea levels could rise 20 percent higher by 2100 than previously estimated because of melting ice in Antarctica.  

“A 20 percent higher sea level makes a bad situation worse,” said Robert Bindschadler, a glaciologist and coauthor of the study, which was published in the journal Earth Systems Dynamics.  

“Right now nine of the 10 largest cities—Mexico City being the only exception—are coastal cities,” said Bindschadler, an emeritus researcher at NASA Goddard Space Center who collaborated with Anders Levermann at the Potsdam Institute for Climate Impact Research. “Nearly half of the world’s population, almost 3 billion people, live at or near the coast. We are placing ourselves in harm’s way.”

Bindschadler’s estimates are higher than those released by the Intergovernmental Panel on Climate Change in an April report.  

His study doesn’t incorporate data from two studies published in May that found the West Antarctic ice sheet is headed to an irreversible meltdown and collapse due to global warming driven by greenhouse gas emissions.

Bindschadler’s team found that Antarctica’s ice melt will contribute seven to 28 centimeters in additional sea level rise by the end of the century. That would boost the IPCC assessment of total global sea level rise to as much as 111 centimeters, said Bindschadler.

It’s plausible that these numbers could get “quite a bit worse,” he said, given that the range of projections showed more cases of much higher than lower sea levels. The models also tend to underestimate sea level rise, but the scientists don’t know by how much, he added.

Bindschadler’s research improved on previous studies by integrating information about the nature of Antarctica’s basal melt—that is, how much ice is melting at the base of the continent’s ice shelves owing to warming oceans—with atmospheric and ocean modeling data.

“It’s important that they put great value in these projections,” Bindschadler said of policy makers. “They should incorporate those numbers into whatever they’re building near the coast as it isn’t going to remain where it is today.” 

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