Rising sea levels and catastrophic storm surges could displace 280 million people from the world’s coastlines and produce “misery on a global scale” unless countries speed up their efforts to control the greenhouse gas emissions responsible for the climate crisis, according to a draft United Nations report obtained last week by Agence France-Presse.
The report, the latest produced by the Intergovernmental Panel on Climate Change (IPCC), warns that “the same oceans that nourished human evolution are poised to unleash misery on a global scale unless the carbon pollution destabilizing Earth’s marine environment is brought to heel,” AFP reports . “Without deep cuts to man-made emissions, at least 30% of the northern hemisphere’s surface permafrost could melt by century’s end, unleashing billions of tonnes of carbon [or equivalent] and accelerating global warming even more.”
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The 900-page scientific assessment concludes that “destructive changes already set in motion could see a steady decline in fish stocks, a hundred-fold or more increase in the damages caused by superstorms, and hundreds of millions of people displaced by rising seas,” the news agency adds. And “as the 21st century unfolds, melting glaciers will first give too much and then too little to billions who depend on them for fresh water.”
By mid-century, the assessment report concludes, “many low-lying megacities and small island nations will experience ‘extreme sea level events’ every year, even under the most optimistic emissions reduction scenarios,” AFP writes. “By 2100, ‘annual flood damages are expected to increase by two to three orders of magnitude,’” or 100- to 1,000-fold. At a 2.0°C threshold for average global warming, “the global ocean waterline will rise enough to displace more than a quarter of a billion people,” with experts disagreeing on whether that would happen by 2100 or sometime after.
AFP makes no reference to a more modest sea level rise scenario at 1.5°C. But “even if the number is 100 or 50 million by 2100, that’s still a major disruption and a lot of human misery,” said Climate Central CEO and Chief Scientist Ben Strauss. “When you consider the political instability that has been triggered by relatively small levels of migration today, I shudder to think of the future world when tens of millions of people are moving because the ocean is eating their land.”
Strauss added that, “if we warm the planet by 2.0°C, by 2100 we will only be at the beginning of a runaway train ride of sea level rise.” The report traces a scenario in which sea level rise accelerates rapidly into the 22nd century, to a point where it “could exceed rates of several centimetres per year”—about 100 times faster than today.
In what seems to be shaping up as a standard practice for IPCC scientific assessments, the full report on the oceans and cryosphere  found its way into the public domain a month before countries meet in Monaco to hammer out the much more condensed—and far more political—summary for policy-makers. “While the underlying science—drawn from thousands of peer-reviewed studies—cannot be modified, diplomats with scientists at their elbow will tussle over how to frame the findings, and what to leave in or out,” AFP writes.
The summary is set to be released September 25, two days after UN Secretary General António Guterres convenes his much-anticipated climate action summit in New York.
AFP contrasts countries’ greenhouse gas reduction commitments to date with the cataclysmic outcomes predicted in the IPCC report. It cites China, the United States, the European Union, and India as leading emitters that may be on the verge of disappointing anyone hoping to see big changes announced at the New York meeting.
“The Big Four—accounting for nearly 60% of global fossil fuel-based emissions—all face devastating ocean- and ice-related impacts, but none seem [ready] to just announce more ambitious goals for purging carbon from their economies,” the news agency notes.
“There is a pervasive thread in the U.S. right now promoted by techno-optimists who think we can engineer our way out of this problem,” said veteran climate hawk Michael Mann, director of the Earth System Science Center at Pennsylvania State University. “But the U.S. is not ready for a metre of sea level rise by 2100. Just look at what happened in the wake of Superstorm Sandy, Katrina, in Houston, or Puerto Rico.”