To begin, New York City assessed its climate vulnerability as described within the Climate Risk Information Report (2013) (33 pp, 1.2 MB). New York City derived temperature and precipitation projections using a matrix of 35 Global Climate Model simulations under two Representative Concentration Pathways.
(Learn more about this process on the U.S. Global Change Research Program Models website.) New York City analysis identified an average baseline of two heat waves per year between 1970-2000. Under the 90th percentile high estimate, the number of heat waves could increase to up to seven per year by 2050 and the number of days over 90°F could triple from an 18 average baseline to 57 by 2050. New York City incorporated this climate risk within local hazard mitigation plans and supported actions to reduce vulnerability and adapt to climate changes.
New York City also promoted resilience to current extreme conditions, particularly for vulnerable populations. The City promotes resilience through outreach efforts to particularly vulnerable populations including the elderly, the poor and those already suffering from chronic illnesses. One example, the Be-a-Buddy Program, shares life-saving information with vulnerable residents. This and other similar programs constitute resilience actions as they reduce vulnerability under current conditions, and can be scaled accordingly, but do not reduce the level of increased future climate risk.
In addition to addressing extreme heat for vulnerable populations, New York City implemented adaptation actions that provide co-benefits to air quality, water management and emergency preparedness. The City implemented several adaptation actions to address the increasing risk of heat events including promoting cool roofs, urban forestry initiatives and other strategies to prepare for the projected increase in future heat waves, including reducing the urban heat island effect. For example, the New York City Cool Roofs Program trains local individuals to work with a team to coat city rooftops with a white reflective coating. In its 2013 Annual Report (PDF)(13 pp, 12MB), the New York City Cool Roofs Program had “cooled and coated” 2,077,537 square feet of rooftop by utilizing over 1,000 local volunteers and funding from corporate and individual donations, sponsorships and local government.Also, New York CIty adopted the Million Trees initiative to plant one million trees in the city by 2017. This action anticipates the future climate change risks and provides adaptation benefits for reducing the urban heat island and for greenhouse gas mitigation benefits.
New York City evaluated performance and risk under the best-available science. The City partnered with the Princeton Plasma Physics laboratory to help analyze, evaluate and quantify its climate resilience, adaptation and mitigation actions. New York City updated its vulnerability assessment in 2015 with Building the Knowledge Base for Climate Resiliency (PDF) (22 pp, 994 K), including projecting climate risk out to 2100 for the first time.