But Sandy was plenty bad and its effects will last for years to come. On Monday, The New York Times reported that the Metropolitan Transit Authority will be forced to continue cutting back service and spending billions of dollars for years to come to deal with the damage Sandy wrought. While the MTA got the subways running again within days, it has recently had to shut down stretches of the R and G lines to repair tunnels that were flooded. There will be an estimated $3 billion worth of repair work for each of the next two years, about double what would otherwise have been needed.

New York cannot afford to be unprepared for climate change. As Bloomberg’s report lays out, the city must invest in a wide array of both hard and soft anti-flooding infrastructure improvements. Buildings must be elevated, shorelines must be regraded, beachfront boardwalks must be rebuilt with gradual rises in elevation. Buildings must move their power supplies upward, while neighborhoods must move their power lines downward, wrapping them in water-resistant materials. Sidewalks will have to be made permeable, to wick floodwater back out to sea. Meanwhile, the city must continue its efforts to be a global leader in reducing its own carbon footprint.

Though he vaguely promised to adhere to Bloomberg’s climate change agenda, de Blasio didn’t make climate preparedness an issue in his campaign. But it will likely be the central challenge of his mayoralty, and his successor’s as well.