Solution Provide step-by-step instructions for supplementing historic climate data with specific, regional, forward-looking climate change projections in the design of city facilities, applied consistently across nearly all municipal capital projects. Key challenge Codes and standards that regulate the design of facilities already incorporate historic weather data to determine how to design for today’s conditions, but historic data does not accurately represent the projected severity and frequency of future storms, sea level rise, heat waves and precipitation - threatening to undermine capital investments and impede critical services over the full useful life of facilities designed today. Context New York City faces challenges resulting from a rapidly changing climate. Many capital projects, including infrastructure, landscapes and buildings ("facilities"), will experience extreme flooding, precipitation and heat events, and the intensity and severity of these events will increase over the 21st century. With 520 miles of coastline across its five boroughs, several low-lying locations across the dense urban area will experience monthly tidal inundation resulting from higher seas. The New York City Panel on Climate Change (NPCC) prepares and regularly refines projections for the metropolitan region, covering temperature and extreme heat events, precipitation and sea level rise by the 2050s and 2080s. Solution in practice The Climate Resiliency Design Guidelines, developed by the Mayor’s Office of Climate & Environmental Justice (previously the Mayor’s Office of Resiliency and, before that, the Mayor’s Office of Recovery and Resiliency) in collaboration with city agencies that oversee capital project development, provide a consistent methodology for engineers, architects, landscape architects and planners to design facilities that are resilient to changing climate conditions. They complement the use of historic data in existing codes and standards, and are built on NPCC projections with the intent that they are updated as those projections are refined. An initial version was released in April 2017; Version 2.0 followed in April 2018 after a year-long expert testing and review phase; Version 4.0 was published in September 2020 and Version 4.1 in May 2022. The Guidelines are used throughout the design process - from capital planning initiation, as a reference in requests for proposals, through a conceptual or study phase to final design - for all new construction and substantial improvements, and apply to all City capital projects except coastal protection projects such as sea walls, bulkheads and levees, for which the City is developing separate guidance. All new projects and substantial improvements assess risks to climate hazards in the context of the project’s purpose. More than 20 City agencies contributed, including Environmental Protection, Transportation, City Planning, Buildings and Design & Construction. Impact / outcome Consistent forward-looking design methodology applied across City capital projects, developed with 20+ City agencies (v4.1, May 2022). Next steps Future versions of the Guidelines will explore additional climate stressors as the science evolves, in coordination with the New York City Panel on Climate Change. NYC is undertaking a study to assess projected changes to extreme wind hazards and identify risks to the city’s built environment, as firm projections on future wind conditions have not yet been developed. The City is separately developing guidance for coastal protection projects, which currently sit outside the scope of the Guidelines. Organizations involved Authoring: NYC Mayor's Office of Climate & Environmental Justice Actors: New York City Panel on Climate Change (NPCC) Implementation partners Local Governments; Regulators & Policymakers; Data Providers; Property value chain stakeholders