Even on a sunny day, nearly 13 million gallons of water are pumped from New York City subways. As global warming brings rising sea levels and stormier weather, more of New York’s transit system is expected to flood.
To adapt, the Metropolitan Transportation Authority needs to develop a master plan that lays out the costs of upgrading subway tunnels, bus depots and other infrastructure most vulnerable to flooding and extreme heat, says a new report, Greening Mass Transit and Metro Regions , commissioned by the MTA and released this month.
"Can New York City survive as a world financial center if its transportation system breaks down half a dozen times a year?" asks Klaus Jacob , a scientist at Columbia University’s Lamont Doherty Earth Observatory, who contributed to the report. "It really behooves the MTA to look at what investments are worthwhile, and what investments are not."
Trained as a seismologist, Jacob more recently has branched into risk management and helping policy makers plan for global warming. About a year ago, he realized that the MTA had failed to address adaptation to climate change in its study to make the system more energy and water efficient. At Jacob’s urging, a climate adaptation task force was added, and he was named its chairman.
In the newly released report, Jacob’s task force recommends that the MTA complete a climate adaptation master plan by 2015. The plan will outline how climate forecasts--and thus, sea level rise—are considered in capital budget decisions. That might include money for flood protection in subways and highway tunnels, or increased energy supply for subways to provide fresh air during heat waves.
Sea level in New York City could rise by two to four feet by the end of the century, according to a comprehensive climate study prepared by Jacob and Cynthia Rosenzweig , a scientist at the Earth Institute’s Center for Climate Systems Research . Near-shore areas that currently flood once a year might be flooded 10 times a year by the end of the century.
Some subways may be better able to cope than others. Subway entrances at low elevations may be especially vulnerable to street-level flooding. Some entrances to the A and C trains are only seven-feet above today’s average sea level, which is not very high if sea levels rise and storm surges further extend the reach of floodwaters, says Jacob. Long Island Rail Road and Metro North commuter lines serving southern Connecticut and the Hudson Valley may also be vulnerable.
But flooded tracks are not the only hazard. The MTA will need to plan for added energy demand as the number of days above 90˚F grows, says Jacob. Currently, less than 20 days a year get that hot in New York City, but by 2100, that number could more than triple.