Still, Bloomberg has continued fighting undaunted, arguing in favor of his policies even during his last days in office.“When I came into office, I was interested in policy changes that would help people live longer, healthier lives; I believe that’s a fundamental responsibility of government,” he explains. “Over time, I came to see environmental issues in the same vein, especially around air quality. Clean air is an environmental issue as well as a public-health issue.”

In 2007, Bloomberg released PlaNYC, a sweeping collection of goals spread out over decades to prepare the city for a growing population, to strengthen the economy and enhance the quality of life for all New Yorkers. The policies looked not only to improve infrastructure but to take into account climate change and to reduce the city’s carbon footprint. Change has been rapid and dramatic, as New York has reduced emissions by 16 percent, more than halfway to its goal of 30 percent by 2030. Bike lanes snake through every borough. Trees have sprouted in concrete jungles. Major thoroughfares have become pedestrian oases.

Bloomberg, a titan of industry, took one of the major arguments against environmental initiatives — that they damage the economy — and showed not only that it wasn’t true but that when policies are thoughtfully implemented, they could increase economic activity. One example is the closing of Times Square to cars, says Rohit Aggarwala, C40 special adviser to Bloomberg and former director of long-term planning and sustainability for New York City. Despite initial ­outrage, the decision has led to improved traffic flow, better air quality and increased retail sales because of the thousands of pedestrians who roam through the pedestrian corridors every day.

“People said that New York could not be made green,” Aggarwala muses. “He demonstrated that it is doable and has significant economic gains.”