But while there’s still uncertainty about the rate at which sea levels are rising, it has become increasingly clear that temperature increases alone could severely tax a large city’s infrastructure. Late last year, the Union of Concerned Scientists in Cambridge, MA, released a report titled “Climate Change in the U.S. Northeast.” Produced in collaboration with climate scientists, the report predicts that by midcentury, northeastern cities could be experiencing an average of 30 to 60 days of temperatures above 90 ºF each year, up from 10 to 15 days historically. By the end of the century, these cities could see 14 to 28 days of temperatures over 100 ºF, if the higher-emission scenarios are realized.
Armed with such predictions, the city of New York and a prominent regional civic-planning group, the Regional Plan Association (RPA), are starting to think about how to respond. Jennifer Cox, a senior planner and director of geographical information systems at the RPA, is superimposing estimates of heat waves and storm surges onto city maps showing topography and socioeconomic characteristics. And GISS is collaborating with a consortium of universities whose members are now plugging temperature estimates into air-quality models, to see how bad ozone levels could get during the hotter summer days of the 2040s or 2060s. High ozone levels could produce severe health crises as heat waves overwhelm emergency facilities, water supplies, and the power grid.
But such studies are just the first academic pass at planning. The scenarios they envision are still relatively vague. And while suggested remedies abound, they reflect more imagination than engineering. Physical oceanographer Malcolm Bowman of the State University of New York at Stony Brook, for one, would place a tidal-surge barrier at the Verrazano Narrows (between Brooklyn and Staten Island); another near the Throgs Neck Bridge, where the East River meets Long Island Sound; another between Perth Amboy, NJ, and Staten Island; and a fourth across Rockaway Inlet at the entrance to Jamaica Bay. The barriers–more ambitious versions of the storm-surge barrier at the mouth of the Thames River outside London–could theoretically prevent tens of billions of dollars in damage. With the models and computational power available now, however, it’s hard to determine whether and when such ideas need to be acted on. “If you look at European experience,” says Bowman, “it takes a major flood and a major loss of life to get the bureaucracy to do anything.”
The Dry West
Colorado Springs, CO, is a boomtown in an arid region–just one of many cities that rely for water on the melting snowpack of the nearby mountains, delivered via the Colorado River and Arkansas River watersheds. Many other cities get their water similarly from the Sierra Nevada Mountains of California. But right now, the western United States is facing a slow-motion water-supply catastrophe wrought by climate changes that will inexorably reduce the snowpack. “The western U.S. is really not in good shape at this point,” says Linda Mearns, a climatologist at the National Center for Atmospheric Research (NCAR) in Boulder, CO, where she is director of the Institute for the Study of Society and Environment. This has become fairly clear “even without the regional detail” in climate models, she adds.