Ashley Dawson | Extreme Cities: The Peril and Promise of Urban Life in the Age of Climate Change | Verso | October 2017 | 17 minutes (4,461 words)
This story is recommended by Longreads contributing editor Dana Snitzky.
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An utter transformation of human habitation across the globe within one generation.
Milestones on the road toward climate chaos are all too frequent these days: in 2015, the Manua Loa Observatory in Hawaii reported that the daily mean concentration of CO2 in the atmosphere had surpassed 400 parts per million (ppm) for the first time; each year Arctic sea ice levels grow lower and lower; permafrost in areas like Siberia and Alaska is melting, releasing dangerous quantities of methane into the atmosphere; and each year brings more violent storms and more severe droughts to different parts of the world. Indeed, news of apocalyptic climate-related events is so manifold that it can feel overwhelming, producing a kind of disaster fatigue. One recent announcement merits particular attention, however: in the summer of 2014, a team of NASA scientists announced conclusive evidence that the retreat of ice in the Amundsen Sea sector of West Antarctica had become unstoppable. This melting alone, they concluded, will drive global sea levels up by over 1 meter (3 feet). As the Pine Island, Thwaites, and other glaciers of the Amundsen Sea sector collapse into the ocean, the effect is expected to be like a cork removed from a bottle of champagne: the ice the glaciers held back will rush rapidly into the sea, and the entire West Antarctic ice sheet will collapse. Sea levels will consequently rise 3 to 5 meters (10–16 feet). In addition, it was recently discovered that the same process that is driving this collapse, the intrusion of warmer ocean water beneath the glaciers in West Antarctica, is also eroding key glaciers in East Antarctica. The East Antarctic ice sheet contains even more ice than the western sheet: the Totten glacier alone would account for 7 meters (23 feet) of sea level rise. As if this weren’t bad enough news, a similar process of melting is also taking place in Greenland, where fjords that penetrate far inland are carrying warm water deep underneath the ice sheet.
These reports overturn long-held assumptions about the stability of Greenland’s glaciers: until recently, scientists had predicted that Greenland’s ice sheet would stabilize once the glaciers close to the warming ocean had melted. The discovery of ice-bound fjords reaching almost sixty-five miles inland has major implications since the glacier melt will be much more substantial than anticipated. The Antarctic and Greenland ice sheets combined contain over 99 percent of the Earth’s glacial ice. If they were to melt completely, they would raise global sea levels a virtually inconceivable 65 meters (200 feet). Although it remains unclear exactly how long the disintegration of these ice sheets will take, the implications of such melting for the world’s coastal cities are stark, and still almost totally unacknowledged by the general public. As Robert DeConto, co-author of a recent study that predicts significantly faster melt rates in the world’s largest glaciers, points out, we’re already struggling with 3 millimeters per year of sea level rise, but if the polar ice sheets collapse, “We’re talking about centimeters per year. That’s really tough. At that point your engineering can’t keep up; you’re down to demolition and rebuilding.”
Shockingly, few orthodox scientific predictions of sea level rise have taken the disintegration of the Antarctic and Greenland ice sheets into consideration. The latest report by the Intergovernmental Panel on Climate Change (IPCC), for example, projects a high of three feet of sea level rise by 2100, but this prediction does not include a significant contribution from the West Antarctic ice sheet. Like the IPCC’s projection for Arctic sea ice collapse, which has moved up from 2100 to 2050 in the latest report, this prediction is clearly far too low. What explains such gross miscalculations? The protocols of scientific verifiability provide a partial explanation. The general public has urgently wanted to know, after city-wrecking hurricanes like Katrina and Sandy, whether the devastation was caused by climate change. But unfortunately scientists have until quite recently been unable to make direct links between particular extreme weather events and climate change in general. This, as environmental philosopher Dale Jamieson puts it in Reason in a Dark Time, would be like saying that a specific home run is “caused” by a baseball player’s batting average. If scientists are becoming less reticent to make these links, as the science of attribution grows more sophisticated and able to track the causes of weather extremes, the change is still occurring slowly.
Nevertheless, the IPCC’s failure to account for the destruction of the Antarctic and Greenland ice sheets can only add to skepticism toward their predictions, especially after they were widely attacked for their 2007 calculations about the speed of Himalayan glacial melting. Further fueled by the climate change denial industry, the IPCC’s own excessively rosy predictions for the future will only increase skepticism. In their 2000 report, for example, the body assumes that nearly 60 percent of hoped-for emissions reductions will occur independently of explicit mitigation measures. As the urban theorist Mike Davis has pointed out, the IPCC’s mitigation targets assume that profits from fossil capitalism will be recycled into green technology rather than penthouse suites in soaring skyscrapers. The IPCC projects a market-driven evolution toward a post-carbon economy, a set of assumptions that, as spiraling levels of greenhouse gas emissions since 2000 demonstrate all too clearly, are dead wrong. These projections concerning sea level rise and the vulnerability of coastal cities will have to be radically revised, especially after spectacular urban disasters hammer home the inadequacy of current projections. But these world-changing transformations will not take place in the distant future. Citing evidence drawn from the last major ice melt during the Eemian period, an interglacial phase about 120,000 years ago that was less than 1ºC warmer than it is today, climatologist James Hansen predicts that, absent a sharp and enduring reduction in greenhouse gas emissions, global sea levels are “likely to increase several meters over a timescale of 50 to 150 years.” Should they prove accurate, Hansen’s forecasts spell an utter transformation of human habitation across the globe within one generation. Read more…