Cities are the vanguard in the battle against climate change. We are the source of approximately 80 percent of global greenhouse gas emissions. And densely populated urban areas, particularly coastal cities, will disproportionately feel the impacts of climate change. Those of us in local government recognize the importance of national and international leadership on climate change. But we also are not waiting for others to act first.

Through PlaNYC, New York City's comprehensive sustainability plan that we released in April 2007, we are working to create a greener, greater New York. Many of the 127 initiatives in the plan focus on reducing our greenhouse gas emissions. These initiatives, including the Greener, Greater Buildings Plan, which will increase the energy efficiency of existing buildings, will help us meet our goal of reducing the city's carbon emissions by 30 percent by 2030.