NYC Climate Adaptation Scenarios for 2100:

Exploring alternative, positive visions for a resilient future

Lead Authors

Elizabeth Cook, Barnard College

Jennifer Ventrella, The New School

Contributing Authors

Timon McPhearson, Urban Systems Lab, The New School

Adam Parris, ICF

Melissa Tier, Princeton University

Tischa Muñoz-Erickson, USDA Forest Service

David Iwaniec, Georgia State University

Lelani Mannetti, Georgia State University

Charlyn Green, Georgia State University

Daniela Tagtachian, The City University of New York

NYC Climate Adaptation Workshop Participants

View Report

Workshop Summary

In the face of global climate change, city governments must anticipate and guide decisions in response to extreme weather-related events, including coastal and inland flooding, heat waves, multi-hazard risks, drought, and winter extremes. With the goal of addressing this challenge, between Sept. 24 - Oct. 22, 2021, the National Science Foundation (NSF) Social-Ecological-Technological Systems (SETS) Convergence Research Network partnered with the New York City (NYC) Mayor’s Office of Climate and Environmental Justice (MOCEJ) to facilitate the NYC Climate Adaptation Scenarios workshop series, a wide ranging yet structured set of anticipatory discussions on future climate resilience and adaptation. Through a series of five 3-hour virtual workshops, diverse participants co-developed positive future visions for New York City of sustainability, resilience, and adaptation to climate change and extreme events.

Approximately 35 government practitioners from 24 city, state, and federal agencies gathered virtually over the course of five weeks (see Table 1 for agencies involved). Together, participants co-developed six distinct climate adaptation scenarios. The goal of each future scenario was to radically transform the city’s social, environmental, and physical infrastructure—including governance, green infrastructure, and water-energy-transit systems—and the city’s ability to respond to extreme events.

Participants worked in small groups to envision six scenarios for the future of New York City in 2100. The envisioned future scenarios addressed: Multiple co-occurring hazards, Coastal flooding, Extreme heat, Winter extremes, Extreme precipitation, and Drought and shifting water demand. Scenario themes were developed in response to practitioner concerns and the city’s sustainability and environmental management plans.

Through a series of workshop and post-workshop activities, including innovative ideation, timelines, visual illustrations, and day-in-the-life narratives, participants defined long-term goals and strategies for each scenario to develop radical visions for New York City in 2100. Existing NYC climate governance and strategies were seeded as a starting point to inform scenario development and build on visionary work already happening in the city.

Why did we do this? Without shared positive visions for the future we want, it is unlikely that plans we make now will achieve the equity, justice, sustainability, and resilience goals we have for our city and society. In order to create space for positive visions to occur, we have to imagine time frames far enough into the future that we can ignore the tyranny of the present demands and constraints that often make it hard to imagine the future we want. Existing planning efforts often focus on goals that are only 10, 20, or possibly 30 years into the future, yet many of our aspirations will take even longer to achieve, even if we start on those transformative pathways now. We used a 2100 timeframe of approximately 80 years from today to create a rare space for long-term planning and positive visioning. Ultimately, the workshop activities were designed to develop long-term future visions that imagine what the future ought to be and consider more transformative strategies to achieve those visions without being constrained by the inner workings of the current system.

NYC Climate Adaptation Scenarios for 2100

Scenario 1: Addressing multi-hazard events by 2100: Extreme heat, flooding, and drought

Screenshot of Ocellus, Urban Systems Lab data visualization platform. Extreme heat and coastal flooding data layers overlayed.

New York City is susceptible to multiple hazards that create new and complex risks such as from co-occurring and sequential events of extreme heat, flooding, and drought. These multi-hazard interactions can exacerbate impacts and risks and have compounding consequences on communities, ecosystems, and infrastructures. Responding to co-occurring emergencies puts a strain on governance capacities and increases levels of stress and trauma for communities. Multi-hazard events are likely to increase over the coming decades and suggest the need to develop systemic solutions that address multiple sources of risk.

A future New York City that is resilient to multi-hazard risks from extreme heat, precipitation, and drought is envisioned to have reliable, resilient, and interconnected infrastructure that addresses multiple risks and combines green and gray infrastructure solutions. The future city would have a social contract that establishes an inclusive and transformative governance system built on principles of trust, agility, and accountability and integrates community participation, expertise, and cross-agency collaboration to better address future co-occurring hazards. All New Yorkers would have equitable access to physical health, mental well-being, and economic stability that is not dependent on zip code, race, and privilege in order to be better equipped in the face of future events.

Goal 1: Reliable and resilient infrastructure that addresses multiple risks

■ Develop fully resilient energy grid with increased renewables ■ Establish a publicly owned power generation system ■ Invest in redundancy ■ Invest in a green, community-based economy ■ Identify funding streams ■ Enforce multi-hazard design requirements ■ Fortified transit system to safely move people during hazards

Goal 2: Social contract for inclusive and transformative governance

■ Compensate community partners equitably ■ Create forums for community relationships ■ Develop grading system of elected officials to improve accountability ■ Improve transparency of roles, responsibilities, and information and data sharing across agencies ■ Increase community involvement in operations and maintenance of local assets ■ Establish resiliency hubs ■ Hold discussions and initiate mechanisms for communities at risk to retreat from coastal hazards

Goal 3: Equitable access to physical health, mental well-being, & economic stability

■ Create one-payer health system ■ Expand equitable access to affordable, high quality mental health services ■ Guarantee access to energy for heating and cooling ■ Ensure equitable distribution of and access to critical facilities and high quality, essential services such as schools and hospitals

Scenario 2: Addressing coastal flooding and storms by 2100

Visualization of coastal flooding adaptation and resilience strategies in 2100, Designer: Eleanor Davol

New York City is projected to experience increases in both the frequency of one percent annual chance of coastal floods and in the height of these floods by 2100 (NPCC, 2015; NPCC, 2019). Over this timeframe, flooding will be exacerbated by sea level rise—likely two to four feet and potentially as much as 9.5 feet (Gornitz et al., 2019). By 2100, tidal flooding is expected to increase substantially in low-lying regions of NYC (Orton et al., 2019). In addition, projected increases in nuisance flooding in some communities and permanent inundation in others will lead to severe consequences for the health, well-being, and quality of life of many New Yorkers. A disproportionate economic burden is forecasted for the city’s most vulnerable populations and, due to its deteriorating physical infrastructure, major repair and expansion projects will need support.

Ensuring that a future New York City is resilient to coastal flooding and storms requires re-envisioning collaborative governance based on a public-private-civic governance model to facilitate coordination across agencies and cross-sectorial decision-making. This future vision will ensure residents are more resilient to future flooding through a variety of mechanisms, including equitable opportunities for relocation, housing, and flood insurance. Finally, this future will focus on a systems approach to developing a retrofitted city that integrates natural elements of nature-based solutions with hard, engineered infrastructure.

Goal 1: Re-envisioning collaborative governance

■ Develop governance for multi-functional infrastructure with co-benefits ■ Mandate cross-agency and cross-sectoral decision-making and collaboration in public-private-civic model ■ Identify cross-sectoral gaps to manage climate risk ■ Establish cross-agency funding mechanisms at city and state level

Goal 2: Resilient residents

■ Ensure equitable and affordable housing with protection from both inflated property values and large storm surges ■ Buyout and relocation from flood vulnerable areas, accounting for diverse community needs and voices ■ Invest in low income, historically marginalized communities to improve resilience and equity ■ Create equitable flood insurance programs and mandate coverage

Goal 3: Retrofitted city

■ Rely on nature-based solutions and engineering with nature ■ Invest in retrofitting buildings to reduce waste and minimize flood risk ■ Integrate natural carbon sequestration via green spaces and algae into architecture ■ Create standards for waterfront elevation ■ Revise regulations to encourage infill designed for ecological purposes ■ Revise federal benefit-cost analyses to encourage nature-based solutions with multiple co-benefits, including social ones.

Scenario 3: Addressing rising temperatures and extreme heat by 2100

Visualization of extreme heat adaptation and resilience strategies in 2100, Designer: Eleanor Davol

Annual heat waves in New York City are projected to increase in quantity and severity, leading to more cases of heat-related morbidity and mortality. Based on the highest projections for 2050, there are projected to be seven heat waves per year in New York City with an increase from 18 to 57 days above 90°F by 2050, a more than three-fold increase (NPCC, 2013). In NYC, premature mortality resulting from heat waves is projected to grow between 47% and 95% by mid-century (Knowlton et al., 2007). A 2017 study projected that there may be as many as 3,331 annual heat-related deaths in New York City in the 2080s compared to 638 heat-related deaths annually between 2000 and 2006 (Petkova et al., 2017).

A future New York City that is resilient to rising temperatures and extreme heat would eliminate heat-related illness and mortality through a combination of infrastructure and health reforms. The future scenario will rely on green vegetation and water features to mitigate heat. It will also ensure excess heat waste (e.g., from air conditioning) is reduced or reused through heat recovery systems in order to minimize new energy use.

Goal 2: Minimize and reuse waste heat sources and maximize the city’s green and blue infrastructure (vegetation and water features)

■ Require low-energy building design ■ Reduce use of absorptive building materials ■ Incorporate heat recovery systems ■ Integrate water features for evaporative cooling ■ Electrify truck fleets and reduce truck traffic ■ Expand access to public transit ■ Repurpose private street parking ■ Integrate green infrastructure and cool corridors

Goal 1: Eliminate heat-related illness and mortality

■ Update construction codes to include shade requirements ■ Mandate cooling breaks for workers ■ Increase funding for community health programs ■ Reform and expand LIHEAP ■ Ensure universal access to sustainable cooling ■ Ensure quality, single-payer healthcare

Scenario 4: Addressing winter extremes (cold snaps and winter warms) by 2100

Winter extremes scenario visualization, Artist: Ann Armstrong

Although extreme cold events are predicted to decrease over the course of the next century, a number of associated risks remain or are expected to be exacerbated by this change. First, concerns about community vulnerability, public well-being, and physical infrastructure will continue during the remaining cold snaps. In fact, existing vulnerabilities will likely become heightened as high-risk events become less common; cold weather planning and infrastructure will still remain critical, but may need more concerted effort to stay salient. Second, an increase in winter warms and more frequent fluctuation between hot and cold temperatures will likely have myriad effects on building heat systems, transportation infrastructure, biodiversity, and more. As the climate continues to warm, the frequency of extreme cold days is projected to decrease over 33 percent by the 2050s and ~50 percent by the 2080s while polar vortex events may be on the rise (González et al., 2019; NPCC, 2015).

A future New York City that is resilient to winter extremes would minimize community vulnerability and improved preparedness. The future will rely on investing in zero-carbon infrastructure that can withstand freeze-thaw cycles. There will be a focus on clean and reliable heating sources to reduce disruptions and increase resiliency during winter extremes. Finally, the future will also maximize public well-being and mental health, ensuring residents are prepared for winter weather and can enjoy its benefits.

Goal 2: Invest in strong, zero-carbon infrastructure that is resilient to winter extremes

■ Transform water, energy, and transit infrastructure to withstand freeze-thaw cycles ■ Invest in clean, reliable fuel sources and electric heating Implement heated sidewalks and roadways ■ Promote building retrofits for energy efficiency ■ Put more electric lines underground ■ Reduce disruptions and emergency response

Goal 1: Minimize community vulnerability and improved preparedness

■ Create localized early warning system and consistent public messaging ■ Foster mentality to enjoy winter weather and accept restrictions ■ Increase tele-work and tele-health options ■ Increase community-level education ■ Build out citizen science initiatives ■ Expand social safety programs ■ Allow access for anyone who qualifies or applies for LIHEAP ■ Mandate that housing is available for all, and that housing is a right ■ Implement emergency shelters

Goal 3: Maximize well-being and mental health during winter colds/storms

■ Ensure public transportation and bike lanes are fully functional year-round. ■ Treat bike lanes equal to roads ■ Improve wheelchair and other accessibility ■ Construct pedestrian covered/heated bridges or tunnels ■ Move snow to designated park areas ■ Expand community involvement in citizen science initiatives

Scenario 5: Addressing extreme precipitation and flooding by 2100

Visualization of extreme precipitation adaptation and resilience strategies in 2100, Designer: Eleanor Davol

Annual precipitation, as well as flash flood events due to heavy rainfall, in New York City is projected to increase between 4 and 11 percent by the 2050s, and between 5 and 13 percent by the 2080s (González et al., 2019; NPCC, 2015). Because New York has a high percentage of impervious surfaces, which do not allow for natural infiltration of water and can increase runoff during rain events, and an under-capacitated sewer system, the social, environmental, and infrastructural impacts from extreme precipitation are exacerbated.

In response to these challenges, a future NYC that is resilient to extreme precipitation will ensure the city embraces living with water and residents have agency in decision making to enhance individual and community resilience.

A future New York City that is resilient to extreme precipitation would embrace living with water through integrated watershed management and combined natural-green and hard-engineered infrastructure to convey water in times of heavy rainfall. New Yorkers would have the information, infrastructure, and ability to be both mobile and stable in the case of an extreme rain event. In particular, there would be prioritized and expanded affordable housing in low flood risk areas.

Goal 2: Embrace living with water

■ Design semi-naturalized streetscapes, reutilizing transport spaces for water conveyance ■ Implement natural systems to reduce stormwater runoff across city ■ Update sewer and stormwater systems ■ Rely on best practices for fast stormwater drainage to prevent disease risk ■ Integrate cloudburst management practices ■ Integrated watershed management ■ Daylight streams

Goal 1: All New Yorkers have agency and choice in mobility & stability

■ Expand affordable and temporary housing supply in low flood risk areas ■ Improve risk communication and education ■ Invest in networks of community stewards ■ Develop shelter in place and emergency methods for getting to higher ground ■ Prioritize infrastructure investments based on vulnerability ■ Expand access to flood insurance ■ Expand stock of resilient buildings ■ Establish land trusts

Scenario 6: Drought and shifting water demands

Drought scenario visualization, Artist: Rose Zhang

Droughts are expected to become more frequent and over longer extended periods. By 2050, the severity of widespread summer drought in New York is projected to more than double and will be five times greater by 2080. There is a likelihood of persistent drought lasting longer than five years in the future (González et al., 2019), which could impact the City’s water supply. In addition, future drought will lead to increased salinity in the estuary with ecological impacts throughout the watershed and the coastal ecosystem, as well as potential corrosion of infrastructure.

A future New York City that is resilient to drought and shifting water demand would use a regional approach to maintain freshwater supply, to minimize potable water waste to protect water quality and quantity, and to ensure that all New Yorkers have equitable access to clean water.

Goal 2: 100% equitable access to water

■ Establish water pricing based on tier use and income ■ Ensure access to potable and freshwater for all

Goal 1: Maintain freshwater supply for local and regional ecosystems including people

■ Create regional water supply and demand plan ■ Establish community engagement specialists ■ Increase educational programming on drought vulnerability ■ Install automated water leak monitoring ■ Create (dis)incentives to reduce water imports from other regions

Goal 3: Landscapes are conserved and managed to be resilient and protect water

■ Increase drought tolerant vegetation ■ Expand availability of water conservation and reuse measures ■ Increase permeable pavement ■ Create systems for stormwater capture ■ Develop health regulations on gray water ■ Develop infrastructure to collect, store, and move rainwater ■ Establish incentives for low water use appliances

Near-Term and Long-Term Timelines

Workshop participants developed a detailed near-term (present day to 2035) and a longer-term (present day to 2100) timeline of strategies to achieve their 2100 goals for each scenario. Click on the image below to enlarge, and zoom-in to see the details. The large circles represent the scenario goals for 2100. The squares represent individual strategies to achieve these goals and are color-coded by theme. Strategies connected by a line build on one another over time to achieve the end goal. Finally, the smaller circles within the timeline represent specific targets for goals.

Multi-hazard Scenario

Coastal Flooding

Extreme Heat

Winter Extremes

Extreme Precipitation

Drought

Acknowledgments

We wish to thank all the City, State, and Federal agencies that participated in the NYC Climate Adaptation Scenarios Workshop Series, the Mayor’s Office of Climate and Environmental Justice (MOCEJ) for their partnership in facilitating the workshop series, and our workshop notetakers Ava Chow, Renata Happle, Lauren Kahme, Eleanor Ludkey, Delaney Michaelson, and Tanisha Reddy and visualizations and report design Ann Armstrong, Eleanor Davol, Edi Friedlander, Chris Kennedy, and Rose Zhang.

This material is based upon work supported by the National Science Foundation under Grant Number 1934933. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

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