Designing for Extreme Heat
(Left) Thermal image of streetscape in Florence; (Right) Streetscape in West Hollywood | Los Angeles, CA
July 2023 was Earth’s hottest month on record.
This summer, global heat waves have blasted through year-over-year records with increasingly deadly effects.
In Arizona, Nevada, Texas, California, and across the South and Midwest, extreme heat claimed over 147 lives this year, which experts cite as a vast underestimate. In Europe, researchers suggest over 61,000 deaths could be attributed to heat exposure last year. The toll is surely higher in low-income countries across the Middle East, North Africa, Southeast Asia, and other areas where children, the elderly, outdoor and industrial workers, refugees, homeless people, people with limited mobility, indigenous populations, and other marginalized groups are at disproportionate risk of heat-related illness and death.
Walk through virtually any major city in the U.S. and heat inequity becomes viscerally clear. On a June day in New York, a low-income neighborhood like East Harlem can be over 30 degrees hotter than a nearby high-income neighborhood like the Upper West Side. These disparities are well-understood to be the product of decades of racist planning policies like redlining, which divided minority communities from access to green space, tree cover, and other cooling infrastructure—leaving an abundance of exposed buildings, streets, and paved surfaces that trap and radiate heat in a phenomenon dubbed “urban heat island effect.”
As designers, what role can we play in helping society adapt to a rapidly warming world? Across SWA’s eight offices, we’ve been tackling design solutions for extreme heat at all scales, studying how urban foresters can adapt to a warming climate; working with the City of Houston to develop a master plan for community “resilience hubs” providing residents life-saving access to cooling centers; and incorporating shade structures, tree cover, and other cooling infrastructure across our work, from pocket parks to regional networks.
Highland Park | Los Angeles, CA
By mid-century, 98% of LA County’s population will face moderate to extreme heat every year—a vast tapestry of 88 cities with varying levels of risk and exposure. At a county and regional scale, how can designers direct resources to municipalities overlooked in green space and infrastructure investments?
“Follow the money and think about coupling goals. As landscape architects, we’re keenly aware of grants available to small, under-resourced cities. Many of these target stormwater filtration and air pollution in communities at high risk of respiratory illness—challenges that can also be addressed through an expanded tree canopy that builds shade and lowers ambient temperature.
We can work with smaller cities and counties to raise awareness about these opportunities, partner with nonprofits on implementation, and spread the message—but we have to work quickly with the resources available to us.”
Ying-yu Hung
Managing Principal
Los Angeles, CA
Last month, the City of Houston activated its first-ever heat emergency plan, advising high-risk individuals to stay inside during the day. You recently completed work on Houston’s Resilience Hub Network Master Plan, which looked at community-scale responses to urban heat. Can you talk about what the team proposed?
“In recent years, the ‘Resilience Hub’ concept has gained traction internationally. By focusing on the local scale, it argues, we can ground planning in existing spaces, social networks, and services, working directly with communities to build capacity and address climate risks head-on.
Houston’s main challenges are flooding and heat, no surprise there. It’s not unusual to go several weeks with temperatures above 100°F—but for those in service deserts, this can be deadly or a profound health hazard.
For this project, our approach was unique in two main ways: we proposed both public and privately-owned ‘Hub,’ ‘Super Spot,’ and ‘Spot’ facilities as individual cooling centers, but also introduced the notion of a ‘Spoke’—connective, shaded sidewalks that could render the larger distribution of hubs functional as a network.”
Natalia Beard
Principal
Houston, TX
Houston Resilience Hub Network Master Plan | Houston, TX
Houston Resilience Hub Network Master Plan | Houston, TX
Last month, the City of Houston activated its first-ever heat emergency plan, advising high-risk individuals to stay inside during the day. You recently completed work on Houston’s Resilience Hub Network Master Plan, which looked at community-scale responses to urban heat. Can you talk about what the team proposed?
“In recent years, the ‘Resilience Hub’ concept has gained traction internationally. By focusing on the local scale, it argues, we can ground planning in existing spaces, social networks, and services, working directly with communities to build capacity and address climate risks head-on.
Houston’s main challenges are flooding and heat, no surprise there. It’s not unusual to go several weeks with temperatures above 100°F—but for those in service deserts, this can be deadly or a profound health hazard.
For this project, our approach was unique in two main ways: we proposed both public and privately-owned ‘Hub,’ ‘Super Spot,’ and ‘Spot’ facilities as individual cooling centers, but also introduced the notion of a ‘Spoke’—connective, shaded sidewalks that could render the larger distribution of hubs functional as a network.”
Natalia Beard
Principal
Houston, TX
“La Sombrita” shade structure | Los Angeles, CA
Talk about shade equity in your home base of LA, a city currently undergoing a suite of long-range planning efforts, including preparation for the 2028 Summer Olympics. At an urban scale, what do designers need to consider?
“Like many cities, some of LA’s most pressing equity challenges in housing, transportation, and workforce development are the same factors that compound heat risk. While designers can and should play a key role developing spatial solutions, the path is often arduous, often revealing broader societal and jurisdictional rifts.
Case in point, the controversial ‘La Sombrita’ shade structure recently installed at bus stops across the city has fueled a public debate not just about shade equity, but also about womens’ safety on public transit—a physical example of DOT’s Gender Equity Action Plan and an attempt to bypass the city’s lengthy planning process through private funding.”
Gerdo Aquino
Co-CEO
Los Angeles, CA
Talk about success stories for scaling urban heat mitigation. Are there cities that have scaled solutions in an equitable way? Where should we look for inspiration?
“Look to cities the next rung up on the climate ladder. If you’re an urban planner in Paris, a city with warm summers (Cfb), look to those with hotter summers in the same precipitation regime (Cfa) like Taipei, Brisbane, or Atlanta. How have they coped with heat and humidity in the past?
If you’re looking at a longer-term horizon, you might look to Casablanca, Sacramento, or Perth (Csa)—by 2100, Paris is projected to have a similar temperature and precipitation to those areas today.”
Note: These refer to climate groups in the Köppen-Geiger climate classification system. Cfb indicates a climate with “fully humid” precipitation and warm summer temperature. Cfa indicates a climate with “fully humid” precipitation and hot summer temperature; and Csa indicates a climate with “summer dry” precipitation and hot summer temperature.
Anya Domlesky
Director of Research, XL Lab
Chicago, IL
Köppen-Geiger climate classification system
Köppen-Geiger climate classification system
Talk about success stories for scaling urban heat mitigation. Are there cities that have scaled solutions in an equitable way? Where should we look for inspiration?
“Look to cities the next rung up on the climate ladder. If you’re an urban planner in Paris, a city with warm summers (Cfb), look to those with hotter summers in the same precipitation regime (Cfa) like Taipei, Brisbane, or Atlanta. How have they coped with heat and humidity in the past?
If you’re looking at a longer-term horizon, you might look to Casablanca, Sacramento, or Perth (Csa)—by 2100, Paris is projected to have a similar temperature and precipitation to those areas today.”
Note: These refer to climate groups in the Köppen-Geiger climate classification system. Cfb indicates a climate with “fully humid” precipitation and warm summer temperature. Cfa indicates a climate with “fully humid” precipitation and hot summer temperature; and Csa indicates a climate with “summer dry” precipitation and hot summer temperature.
Anya Domlesky
Director of Research, XL Lab
Chicago, IL
Grasshopper model for visualizing heat impact
Designers across the field are finding new ways to quantify and respond in real time to climate impacts on projects of all scales. Can you talk about tools SWA has developed to incorporate heat data?
“Two of our Associates, Andrew Gressett and Elvis Wong, recently created a script to calculate and visualize site-specific heat impacts through Grasshopper. This tool can be used as a new way to inform planning decisions around priority greenspaces, canopy coverage, and even material selection. It also allows us to paint a clear picture to clients what the user experience of their site would be without landscape as a heat buffer. Taking our analysis one step further, we’re currently finding ways to integrate predictive heat data in these models to anticipate impacts on our project sites in a drastically hotter climate.”
Alejandra Hinojosa
Climate & Sustainability Specialist
Dallas, TX
Learn more
Spanning over 60 years of work, SWA has addressed extreme heat through public landscapes, green infrastructure, multi-year planning initiatives, and leading-edge research across geographies and contexts.
This year, following up the firm’s annual Patrick T. Curran Fellowship, SWA staff Han Fu and Qiaoqi Dai published “Short on Shade,” findings from a research project analyzing barriers to shade equity across Los Angeles. XL Lab, our firmwide platform for research and innovation, is currently working on three projects that address extreme heat:
- Climate Infrastructure Toolkit | Looking across SWA’s portfolio of 700+ projects a year, precedents from the field, and literature review, XL Lab developed an easy-to-use tool to guide climate-conscious design choices from the earliest stage of concept design through post-occupancy—including material selection to avoid heat absorption, conduction, and retention, as well as other adaptive features. (Anticipated release: November 2023)
- Future Trees: Pre-adapting the Urban Forest | Studying projected climate shifts in temperature and precipitation through 2100, this foresight project will allow designers to understand future hardiness trends for urban trees, helping guide species selection and improving tree survivability. (Currently in development)
- Public Life in the Urban Night | Exploring the evening and nighttime uses of ten small urban spaces across a temperate downtown area in Dallas, this project incorporates emergent research methods including thermal imaging, infrared photography, and cell phone data sets to understand what design features perform best. (Anticipated release: October 2023)
Take action
As a collective, the AEC industry bears a tremendous responsibility toward contractors and suppliers—many of whom are low-wage outdoor workers, often immigrants—at disproportionate risk from heat-related illness and death.
This summer, the Biden administration worked with the Department of Labor to issue the first-ever Hazard Alert for extreme heat, including enhanced worker protections through federal law—but there’s much more to be done.
Introduced in late July 2023, the Preventing HEAT Illness and Deaths Act would strengthen funding and support to the National Integrated Heat Health Information System (NIHHIS), allowing it to submit a federal strategy every five years to reduce heat-related deaths and illnesses. It would also authorize the NIHHIS to allocate heat-resilience funding to community groups, workforce development boards, and other eligible institutions under the Justice40 initiative, which focuses resources toward Black and Brown communities most impacted by climate change and environmental hazards.