“I brought all the kids to the third floor, and in about an hour and a half the water was past the first floor… The waves were hitting my house. It felt like I was in the middle of the ocean. It made it up to the second floor of my house,” Staten Island resident Aly Mahgoub told Time. Mahgoub had a front-row seat for Hurricane Sandy, the deadliest northeastern hurricane in four decades. The storm killed 159 Americans and cost the state of New York $42 billion. The region is still recovering from the disaster, as thousands remain without homes.

“If we do nothing about climate change, New York city will become a far harder place to live.”

Cynthia Rosenzweig, NASA climatologist and Co-Chair of the New York Panel on Climate Change, said Sandy was “a major wake-up call for the entire region.” Rosenzweig’s previous research identified which parts of New York would be most vulnerable to extreme weather. “Guess what?” she said. “All those regions are the ones that were damaged severely by Hurricane Sandy.”

In the wake of Sandy, New York’s political leaders, Democrats and Republicans alike, embraced the warnings of climate scientists. “Both Mayor Bloomberg and Governor Cuomo said we have to take increasing risks due to climate change into account during the rebuilding. That was the tipping point,” explained Rosenzweig. For the first time they understood, she said, “If we do nothing about climate change, New York City will become a far harder place to live.”

Runaway climate change would serve a host of new threats to the Big Apple, with rising sea levels and severe heat waves chief among them. According to the latest report from the New York Panel on Climate Change, by the 2080s, the kind of flood that now only occurs once a century could become a semi-regular event. Temperatures could rise by as much as 8º F, and the frequency of heat waves could triple (a trend that is already underway). Rosenzweig said that warm days pose a significant threat to the elderly, who stand at higher risk of heat stroke, adding, “My mother is 100 years old. When it’s hot, I’m always calling her and saying, ‘Mom, have you turned on the air conditioner?’”

Sea level rise will render large parts of New York vulnerable to the kind of flood that now only strikes once every 100 years.

With a view to the risks ahead, New York is now leading the charge on climate change. Last September, Mayor Bill de Blasio pledged the Big Apple would cut carbon pollution by 80 percent by 2050. Said De Blasio, “Global warming was much more of an abstraction to New York City until two years ago,” a reference to Hurricane Sandy. In June, the mayor announced the third New York City Panel on Climate Change, noting that the panel will ensure “that as we adapt our city to the risks of climate change, we’re using the best available climate science.”

New York is not the only city partnering with scientists to prepare for climate change. Dr. Rosenzweig pointed to her work with the Urban Climate Change Research Network at Columbia University, a consortium of hundreds of scientists around the globe guiding civic leaders on climate policy. Cities are home to more than half of humanity, and they are responsible for more than 70 percent of the world’s energy-related greenhouse gas emissions. Said Rosenzweig, “That’s why the role of cities is absolutely fundamental to solving climate change.”

As more and more people flock to the world’s urban centers, local governments will play an increasingly important role in the fight to stem carbon pollution. Former New York mayor Michael Bloomberg, writing in Foreign Affairs magazine, explained, “Influence will shift gradually away from national governments and toward cities, especially in countries that suffer from bureaucratic paralysis and political gridlock.” Already, 15 percent of the world’s largest cities, New York included, have pledged to cut carbon pollution by at least 70 percent before 2050. Said Bloomberg, “City leaders seek not to displace their national counterparts but rather to be full partners in their work — an arrangement that national leaders increasingly view as not just beneficial but also necessary.”

Jeremy Deaton writes for Nexus Media, a syndicated newswire covering climate, energy, policy, art and culture. You can follow him @deaton_jeremy.