SOURCE: New Scientist, Inside Climate News, and PNAS

DATE: May 20, 2019

SNIP: The world’s coastal cities have been warned to prepare for the possibility of a sea level rise exceeding 2 metres by the end of the century, with “profound consequences for humanity.”

As coastal communities prepare for the impacts of climate change, a new report warns that ice loss from Antarctica and Greenland could cause far more sea level rise than previously thought, and it says planners should not ignore that peril.

A new assessment found runaway carbon emissions and melting ice sheets could result in such a worst case scenario, potentially double the upper limit outlined by the UN climate science panel’s last major report.

Such big sea level rises so soon would lead to nightmarish impacts, says Jonathan Bamber of the University of Bristol. “If we see something like that in the next 80 years we are looking at social breakdown on scales that are pretty unimaginable.”

Around 1.79 million square kilometres of land could be lost and up to 187 million people displaced. “Many small island states, particularly those in the Pacific, will effectively be pretty much inhabitable. We are talking about an existential threat to nation states,” says Bamber.

In Antarctica, recent detailed satellite data analyses suggest that warming ocean water is influencing East Antarctic glaciers more than in the past and that they have been losing ice faster over the past decade. In West Antarctica, research published last week found nearly a quarter of that region’s ice is now thinning and the largest glaciers, Pine Island and Thwaites, are losing ice five times faster than they were in 1992. The discovery of a giant cavity expanding under the Thwaites Glacier has also raised new questions about how warming water will affect the ice. On the Greenland Ice Sheet, scientists are developing new understanding of melting feedback loops involving microbes, among other changes.