Planning for Urban Heat Resilience in Communities Across the U.S.

By: Ladd Keith, PhD and Sara Meerow, PhD

Heat is an increasing risk to communities across the U.S., impacting public health, economic productivity, energy and water usage and reliability, infrastructure, and the natural environment. Average annual temperatures in the U.S. have already increased 1.8°F since 1900 (1) and are projected to increase by as much as 12°F by 2100 (2) under the highest greenhouse gas emissions scenarios. The urban heat island (UHI) effect also increases temperatures in urban areas due to more impervious and heat-trapping surfaces and waste heat emissions from vehicles and buildings.

Figure 1. Caption: Trail signage educates hikers on heat safety at South Mountain Park in Phoenix. Credit: Keith & Meerow, 2022.

While heat risk is often associated with the UHI effect in large cities, heat also impacts smaller and rural communities. While urban areas may be hotter and have more population than rural communities, relative emergency heat-related deaths are 3.3% higher in rural areas (3) due to population characteristics and access to resources. Emergency department visits due to heat exposure are also higher in rural areas (4) than in their metropolitan counterparts. Rural communities face additional challenges due to other heat-related issues such as energy grid resilience, healthcare access, and higher outdoor work prevalence with extended exposure to hot temperatures.

To help advance urban heat resilience in communities of diverse sizes and geographies across the U.S., we recently published Planning for Urban Heat Resilience (5), a new Planning Advisory Report from the American Planning Association, which is freely available to download thanks to a grant from the NOAA Extreme Heat Risk Initiative. In the report, we provide an in-depth overview of the contributors to heat risk and its inequitable impacts, outline an urban heat resilience framework, and describe heat resilience strategies planners can use across a variety of plans, policies, and actions. These include heat mitigation strategies to reduce urban heat in the built environment and heat management strategies to prepare and respond to chronic and acute heat risk.

Figure 2. Caption: PAS Report 600: Planning for Urban Heat Resilience. Credit: Keith & Meerow, 2022.

Seven Principles for Heat Resilience Planning

Our report outlines seven practical considerations for planners to holistically address heat resilience in their communities. These considerations are based on the seven principles for strong climate change planning by Meerow and Woodruff (6):

  1. Setting urban heat goals. Planners should facilitate conversations in their communities to help establish heat resilience goals. Heat resilience goals should include both heat mitigation and heat management considerations.

    Metrics for success. Heat resilience goals should be directly connected to specific and measurable outcomes to track progress in achieving goals over time. A heat mitigation metric could focus on increasing the percentage of tree canopy coverage in neighborhoods, while heat management metrics may include reducing the number of heat-related illnesses, hospital visits, and deaths.

  2. Organizing urban heat information. Communities need a strong heat fact base, information that is often collected for the first time as they begin to plan for heat resilience. Many federal resources are available, including information on historical temperatures, current heat warnings, future climate projections, nationally available UHI maps, and social vulnerability indices.

  3. Developing urban heat strategies. Planners should use their community-developed goals and fact base to develop comprehensive heat mitigation and management strategies. Heat mitigation strategies are often associated with reducing the UHI effect but can also be used to create more comfortable microclimates at the site scale for community members. Heat management strategies are critical in smaller communities to help increase awareness of heat risk, address energy access and grid resilience, and ensure access to healthcare.

  4. Managing uncertainty. Planners should acknowledge sources of uncertainty and complexity in planning for heat and select strategies with co-benefits whenever possible. For example, green stormwater infrastructure can reduce urban heat and flood risk. Some strategies may require trade-offs, for instance weighing the benefits of increasing tree canopy for heat mitigation against potential increases in water usage. Strategies that are maladaptive, or have unintended negative consequences, should be avoided whenever possible.

  5. Coordination across planning efforts. Heat resilience planning should be integrated across a community’s “network of plans” or all of the plans that collectively shape the built environment. Plans relevant to heat planning include the comprehensive plan, hazard mitigation plan, sustainability plan, climate action plan, transportation plan, and parks and recreation plan.

  6. Participation in planning processes. Heat resilience planning requires coordination across levels of government, from the local community to county, state, and federal government. Inclusive engagement of community members, particularly those often left out of public participation processes, is also critical due to the inequities of heat risk.

  7. Effective implementation, monitoring, and evaluation. Finally, as with all quality planning efforts, heat planning efforts should indicate who is responsible for the implementation of strategies, offer a timeline for implementation, and identify potential funding sources. Established metrics for success should be monitored and actions adjusted as necessary over time.

Although many people think of heat resilience planning as more of a concern for larger urban areas, communities of all sizes across the U.S. are increasingly experiencing heat impacts and can take practical steps to both mitigate and manage heat.


About the Authors

Ladd Keith, PhD, is an assistant professor of planning in the School of Landscape Architecture and Planning at the University of Arizona. Sara Meerow, PhD is an associate professor of planning in the School of Geographical Sciences and Urban Planning at Arizona State University. Both Dr. Keith and Dr. Meerow won the 2022 Western Planner, Sheldon D. Gerber Merit Award, For Excellence And Outstanding Achievements In Environmental Planning


References

  1. Hayhoe, Katharine, Donald J. Wuebbles, David R. Easterling, David W. Fahey, Sarah Doherty, James P. Kossin, et al. 2018. “Our Changing Climate.” Chapter 2 in Impacts, Risks, and Adaptation in the United States: The Fourth National Climate Assessment, Volume II, edited by D.R. Reidmiller, C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, et al. Washington, D.C.: U.S. Global Change Research Program. https://nca2018.globalchange.gov/chapter/2/ 

  2. Intergovernmental Panel on Climate Change (IPCC). 2021. Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Edited by V. Masson-Delmotte, P. Zhai, A. Pirani, J.B.R. Connors, C. Péan, S. Berger, et al. Cambridge University Press. https://www.ipcc.ch/report/ar6/wg1/ 

  3. Li, Y, Emmanuel A Odame, Ken Silver and Shimin Zheng. 2017. Comparing Urban and Rural Vulnerability to Heat-Related Mortality: A Systematic Review and Meta-analysis. Journal of Global Epidemiology and Environmental Health 2017: 9-15. https://doi.org/10.29199/2637-7144/GEEH-101016 

  4. Owens, PL, ML Barrett and KW McDermott. 2022. Emergency Department Visits for Diagnoses Directly Indicating Heat Exposure: Variation Across Counties in the United States, 2016–2020. Healthcare Cost and Utilization Project. Agency for Healthcare Research and Quality. https://www.hcup-us.ahrq.gov/reports/ataglance/findingsataglance.jsp 

  5. Keith, Ladd and Sara Meerow. 2022. Planning for Urban Heat Resilience. Planning Advisory Services (PAS) Report 600. American Planning Association. http://www.planning.org/publications/report/9245695/ 

  6. Meerow, Sara, and Sierra Woodruff. 2019. “Seven Principles for Strong Climate Change Planning.” Journal of the American Planning Association 86(1): 39–46. https://doi.org/10.1080/01944363.2019.1652108

Paul Moberly