Delivering Urban Resilience

February 20, 2018

Greg Kats and Keith Glassbrook of Capital E in Partnership with NLC’s Sustainable Cities Institute

How cities manage the sun and rain that fall on them has a huge impact on city resilience and on residents’ health and quality of life. Some cities have established programs supporting adoption of cool roofs, solar PV or reflective pavements, while others promote expansion of green roofs and trees. But even in a city like Washington, D.C. - which is a national leader in urban sustainability, or in Philadelphia - which is a leader in water management, adoption of these measures is fragmented and limited. This reflects very limited data and analysis to date on the costs and benefits of these solutions.

City and town leaders, planners and developers lack the data and tools needed to understand and quantify the costs and benefits of technologies such as cool roofs, green roofs and porous pavements that could allow them to manage their city’s rain and sun far more effectively and cost-effectively. As a result, cities mismanage their two great natural gifts of sunshine and rain. This mismanagement costs billions of dollars in unnecessary health, energy, and stormwater-related costs, degrades city comfort, decreases livability and resilience, and contributes to climate change.

The benefits of city wide adoption of smart surfaces would be greatest in low-income areas, which are characterized by little greenery and dark impervious surfaces that result in excess summer heat and air pollution, excess respiratory illness, heat stress, and high health costs. Building on earlier work by Capital E for The JPB Foundation and for Washington, D.C., this report documents and quantifies large physical disadvantages of low-income neighborhoods relative to cities as a whole. A broad review published in Environmental Health Perspectives examined heat risk–related land cover and found that, in U.S. cities, African Americans and Hispanics are 51% and 21% more likely, respectively, to live in high heat risk urban areas than non-Hispanic white Americans. The extent of impervious surface is greater in neighborhoods with low incomes, and this systematic structural inequity appears endemic to many U.S. cities.

This work tackles the full range of smart surface technologies and quantifies many of their benefits for the first time. In all cases, application of what we are calling “smart surface solutions” both city-wide and to low-income neighborhoods would produce financial benefits that exceed costs. At a neighborhood level, such as North Philadelphia and Ward 5 in Washington, D.C., application of these smart surface technologies would provide a net present value of several hundred million dollars.

The net present value of deploying the smart surface solutions analyzed in this report would be large: $540 million for El Paso, $1.8 billion dollars for Washington, D.C., and $3.5 billion for Philadelphia. Including the estimated value of avoided summer tourism revenue losses for Washington, D.C. and Philadelphia increases estimated net benefits to $4.9 billion and $8.4 billion, respectively. City-wide adoption of smart surfaces would also deliver large gains in city comfort, air quality, and livability, as well as significant reductions in greenhouse gasses.

Rapidly rising urban temperatures threaten the livability of many cities, including the 3 cities analyzed here, which are already almost unbearably hot for part of the summer. These “smart surfaces” can also make our cities more resilient and less vulnerable in the face of hurricanes and severe weather events that scientists tell us will be increasingly frequent with climate change.

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