How Can Cities Adapt to Rising Temperatures? Change the Weather

Brian Stone of the Georgia Institute of Technology writes about a recent article he co-authored in the Journal of Planning Education and Research.

3 minute read

December 4, 2019, 2:00 PM PST

By JPER


Louisville, Kentucky

Louisville's annual WorldFest, pictured in September 2019. | Robin B G / Shutterstock

In the age of climate change, can trees and reflective roofing save lives? This question lies at the heart of a forthcoming study on urban heat management and heat-related mortality in Louisville, KentuckyFound to rank among the most rapidly warming cities in the United States, Louisville has been heating up at a rate five times greater than that of the planet as a whole over the last several decades. A rapid rate of warming across all large U.S. cities holds significant consequences for human health, with the U.S. Global Change Research Program projecting an increase in annual heat-related deaths of more than 9,000 in U.S. cities by 2030—a seven-fold increase that, if realized, would elevate heat-related mortality to the most rapidly rising cause of the death in the United States (USGRP 2016; Schwartz et al. 2015).

Urban heat management is an emerging field of planning through which municipal governments seek to lessen the intensity and duration of heat exposure through strategies that reduce the urban heat island (UHI) effect—the widely observed phenomenon through which cities exhibit higher temperatures than nearby rural areas. In this study, we model the extent to which urban greening strategies, such as street trees and green roofs, alone and in combination with cool roofing strategies, can reduce the intensity of outdoor heat exposure. We then make use of neighborhood temperature data to estimate how many residents are likely to succumb to heat-related mortality during the summer months. We rely on a previous study associating heat-related mortality in Louisville with temperature to inform our estimates of how many lives could be saved by urban heat management strategies.

As detailed in the study, we found heat management strategies to have a significant cooling effect across Louisville. A combination of urban greening and cool roofing strategies yielded reductions in average summer afternoon temperatures of more than 2°F in many neighborhoods. For single hot afternoons, cooling benefits in excess of 5°F were found, suggesting the potential to reduce the UHI effect by 50% or more in heavily developed zones (typical UHI intensities range from 2 to 10°F in most US cities).

The implications of these modeled reductions in temperature for public health were significant. Overall, we estimated the number of heat-related deaths in Louisville to be more than 50 in a single summer—exceeding the average number of deaths from hurricanes each year across the United States as a whole. Following the implementation of greening and cool roofing strategies in urban core neighborhoods, heat-related mortality was reduced by 22%, suggesting urban heat management programs hold the potential not only to lower ambient temperatures but to save lives in cities as they warm from climate change. A new class of climate adaptation plans—plans focused on managing heat through changes to the built environment—provide an essential complement to established heat wave management strategies, such as early warning systems and the provision of cooling centers. In this sense, the design of the city carries with it the potential to modify the weather—a potential that must be realized to manage the rising threat of extreme heat to human health.

References

Schwartz, J., Lee, M., Kinney, P., Yang, S., Mills, D., Sarofim, M., Jones, R., Streeter, R., Juliana, A., Peers, J., Horton, R. 2015. Projections of temperature-attributable premature deaths in 209 U.S. cities using a cluster-based Poisson approach. Environmental Health, 14. USGCRP, 2016.

The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment. Crimmins, A., J. Balbus, J.L. Gamble, C.B. Beard, J.E. Bell, D. Dodgen, R.J. Eisen, N. Fann, M.D. Hawkins, S.C. Herring, L. Jantarasami, D.M. Mills, S. Saha, M.C. Sarofim, J. Trtanj, and L. Ziska, Eds. U.S. Global Change Research Program, Washington, DC, 312 pp.


JPER

In this new series, Journal of Planning Education and Research (JPER) articles will be made available to Planetizen readers subscription free for 30 days. This is possible through collaboration between SAGE Publications and the Association of Collegiate Schools of Planning. JPER is currently edited by Clinton Andrews and Frank Popper of the Edward J. Bloustein School of Planning and Public Policy at Rutgers University. The managing editor is Karen Lowrie ([email protected]).

Follow JPER on Twitter: @JPER7

Sweeping view of Portland, Oregon with Mt. Hood in background against sunset sky.

Oregon Passes Exemption to Urban Growth Boundary

Cities have a one-time chance to acquire new land for development in a bid to increase housing supply and affordability.

March 12, 2024 - Housing Wire

Aerial view of green roofs with plants in Sydney, Australia.

Where Urban Design Is Headed in 2024

A forecast of likely trends in urban design and architecture.

March 10, 2024 - Daily Journal of Commerce

Cobblestone street with streetcar line, row of vintage streetlights on left, and colorful restaurant and shop awnings on right on River Street in Savannah, Georgia.

Savannah: A City of Planning Contrasts

From a human-scales, plaza-anchored grid to suburban sprawl, the oldest planned city in the United States has seen wildly different development patterns.

March 12, 2024 - Strong Towns

Aerial View of Chuckanut Drive and the Blanchard Bridge in the Skagit Valley.

Washington Tribes Receive Resilience Funding

The 28 grants support projects including relocation efforts as coastal communities face the growing impacts of climate change.

March 18 - The Seattle Times

Historic buildings in downtown Los Angeles with large "Pan American Lofts" sign on side of building.

Adaptive Reuse Bills Introduced in California Assembly

The legislation would expand eligibility for economic incentives and let cities loosen regulations to allow for more building conversions.

March 18 - Beverly Press

View from above of swan-shaped paddleboats with lights on around artesian fountain in Echo Park Lake with downtown Los Angeles skylien in background at twilight.

LA's Top Parks, Ranked

TimeOut just released its list of the top 26 parks in the L.A. area, which is home to some of the best green spaces around.

March 18 - TimeOut

News from HUD User

HUD's Office of Policy Development and Research

Call for Speakers

Mpact Transit + Community

New Updates on PD&R Edge

HUD's Office of Policy Development and Research

Write for Planetizen

Urban Design for Planners 1: Software Tools

This six-course series explores essential urban design concepts using open source software and equips planners with the tools they need to participate fully in the urban design process.

Planning for Universal Design

Learn the tools for implementing Universal Design in planning regulations.