Climate change poses significant risks to New York City’s communities and infrastructure. Hurricane Sandy has focused attention on the effects that extreme climate events have on New York City, reminding New Yorkers that the city is vulnerable to a range of climate hazards today and in the future. The New York City Panel on Climate Change (NPCC) – a body of leading climate and social scientists and risk management experts – is charged with advising the Mayor and the New York City Climate Change Adaptation Task Force (CCATF) on issues related to climate change and adaptation. It produced a set of climate projections specific to New York City.

By mid-century, temperatures are extremely likely to be higher in New York City. Global climate models (GCMs) project that mean annual temperatures will increase. Specifically:

• By the 2020s, the middle range of projections is 2.0°F to 3.0°F and the high estimate is 3.0°F
• By the 2050s, the middle range of projections is 4.0°F to 5.5°F and the high estimate is 6.5°F

Total annual precipitation in New York City will likely increase by mid-century. Mean annual precipitation increases as projected by GCMs are:

• By the 2020s, the middle range of projections is 0 percent to 10 percent, and the high estimate is 10 percent
• By the 2050s, the middle range of projections is 5 percent to 10 percent, and the high estimate is 15 percent

Higher sea levels are extremely likely by mid-century. Projections for sea level rise in New York City are:

• By the 2020s, the middle range of projections is 4 to 8 inches, and the high estimate is 11 inches
• By the 2050s, the middle range of projections is 11 to 24 inches, and the high estimate is 31 inches

By the 2050s, the NPCC projects the following changes in extreme events:

• Heat waves are very likely to become more frequent, more intense, and longer in duration
• Heavy downpours are very likely to increase in frequency, intensity, and duration
• Coastal flooding is very likely to increase in frequency, extent, and height as a result of increased sea levels