Killer Heat Forces Cities to Adapt Now or Suffer
Climate change abruptly gripped North America’s Pacific Coast at the start of summer, setting new heat records by staggering margins across the region’s cities and towns. Hundreds of people died.
The sudden and extreme heat disaster — matched by other recent heat waves in the Southeastern U.S., Northern Africa, Western Asia, Japan, and Europe — means many temperate cities are in for significantly warmer conditions. At the same time, cities built to withstand 20th-century heat will now face far worse.
The question of which cities and regions will be able to adapt to new extreme heat is part of the hard math of climate change. Heat researchers see this process defined by two drivers: income and climate. It’s wealth that determines which cities have the resources to defend themselves, and future heat mortality that determines if those efforts succeed.
Compare Seattle, San Antonio and Taipei, wealthy cities with vastly different climates. Each is home to professional sports teams and global corporate headquarters. These cities also now have recent severe heat waves in common. Yet heat-related deaths are projected to diverge sharply.
Cities With Similar Incomes in Different Climates
This is one of the major insights about the relationship between temperature, income and mortality from a study that Climate Impact Lab published last summer. The research group found that preparation is central to staving off heat-related deaths, with future income growth making adaptation possible.
As of this summer, the heat records measured in Seattle, San Antonio and Taipei stand at 108°F (42°C), 111°F (44°C) and 103°F (39°C), respectively. The difference is that San Antonio has invested for decades in infrastructure such as air-conditioning, cooling centers and warning systems. Taipei has likewise followed an urban-cooling plan for at least a decade, and just this week sent out an alert on the city’s color-coded heat alert system.
Seattle, accustomed to temperate weather, was blindsided by the climate change-induced heat wave. As Seattle heads toward a Texas- or Taiwan-like climate, the U.S. city has a lot of catching up to do — and a high per-capita income should help.
Research into the hotter future ended up anticipating the present day. When Climate Impact Lab published its heat study in August 2020, the researchers mentioned in passing the obvious economic reasons that Seattle hasn’t already adapted itself to Texas-style heat. Investing in defensive measures such as cooling infrastructure made little sense, despite Seattle’s wealth, since it had little experience of severe heat. Then came the heat wave, after which Seattle and Houston suddenly had nearly matching records.
The extreme heat of 2021 adds a layer of urgency to Climate Impact Lab’s intricate analysis, which warned that the annual mortality rate at the end of this century could rise by 73 deaths per 100,000 people solely from excess heat. The recent research paper “is all about the difference—when you’re prepared and when you’re not prepared,” said Tamma Carleton, an environmental economist at University of California, Santa Barbara, and a co-author of the study. The June heat wave “was a natural experiment of climate change happening overnight, with Seattle not being prepared.”
If higher income equals more potential for adaptation and fewer future deaths, the opposite is also true. Compare cities with similar climates but very different incomes: Seattle, Kyoto and Istanbul. With far lower per-capita income, Istanbul faces the most severe obstacles of this group.
Cities With Similar Climates, Different Incomes
Local and regional governments trying to understand who is vulnerable and how to protect them increasingly need specific research into heat effects. This is true whether cities, rich or poor, are cool places facing triple-digit heat for the first time or hot places experiencing new heat records. Until recently, much economic research was limited to simple global analyses.
“Only in the last few years have we had the local-level information on climate risk that we now do,” Carleton said. “It opens the door to really important local-level policy action.”
Heat is the most intimate and universal threat. It kills more people in the U.S. than any other weather. No one is immune, but everyone can be protected. It’s an axiom repeated among emergency managers that nobody should die in a heat wave.
And yet they do, sometimes in overwhelming numbers. More than 70,000 Europeans died in the summer of 2003, the first weather disaster that scientists attributed, in part, to climate change. France alone lost 15,000 people. Some 55,000 died in Russia in 2010. Three weeks of heat left more than 1,800 dead in Argentina at the end of 2013, with daily deaths 43% above average in Buenos Aires at the time. The final death toll from the Pacific North American heat wave could exceed 1,000, the New York Times has reported.
After Ahmedabad in India lost more than 1,344 people to a heatwave in 2010 when temperatures hit 116°F (47°C), the city became the first in South Asia to issue a heat-action plan and early warning system. The plan saves an estimated 1,200 heat-related deaths a year, and has been published as a 50-page City Resilience Toolkit for other cities to adopt.
With more mass-casualty heat waves, cities around the world are investing in infrastructure and adopting practices to defend against an unfamiliar climate. Planning and preparation really save lives: France activated a heat plan in 2019 just before temperatures spiked to 115°F (46°C). The country recorded fewer than 1,500 deaths — a tenth of its losses in 2003.
After an extended heat wave combined with inadequate infrastructure and poor communication to kill 739 in Chicago in 1995, city planners established multiple generations of preparedness plans. The result can be seen in reformed emergency services and improved communication. Chicago’s ongoing response is noteworthy for its continual evolution and includes crucial community partnerships. Many victims in 1995 were low-income, elderly and lived in neglected neighborhoods, and a disproportionate number were Black.
“If people don’t know you, they won’t feel comfortable answering their phone, telling you where they live,” said Ernesto Gonzalez, marketing manager for My Block My Hood My City. “It’s crucial to start working years before. You need to make a plan.”
Heat Deaths in Cities Around the Globe
Read More: The Unequal Costs of Adapting to Warmer Climates
It doesn’t take catastrophe to motivate a city. Miami-Dade County in Florida is already hot and so far not prone to heat spikes, plus there’s nearly universal access to air-conditioning, according to Jane Gilbert, the region’s first chief heat officer. But air-conditioning can break, power can fail and high electricity bills can inhibit usage. After public surveys showed that people were especially worried about heat, Gilbert said officials moved to create a statewide agreement with the local utility not to shut off power for a failure to pay when the temperature is above 95°F (35°C).
“We do have a whole series of evacuation shelters that do have backup power that are designed for hurricane response,” Gilbert said. “It’s just we want to create more capacity that isn’t in the format of a shelter, it’s more sort of a neighborhood resource.”
Heat-management strategies tend to recommend common tactics and tools, whether they’re crafted in New York, Paris, Buenos Aires, Ahmedabad or Victoria. A 2017 report called Strategies for Cooling Singapore, for instance, offers a readable and comprehensive overview of more than 80 steps cities can take, from green parking lots to artificial ponds, shaded walkways, lighter car-colors and “urban geometry,” or the physical layout of streets and buildings.
A heat wave “is something else in London than it is in Capetown or Sao Paulo,” said Regina Vetter, senior manager of climate adaptation at C40 Cities, one of several groups that help governments manage heat risk. But the necessary steps to prevent harm are similar, which means the “interchange really works out well across the regions.”
Some of the most important actions are the least expensive, Vetter said, especially those that target the vulnerable, such as public education and early communication. The differences between rich and poor cities’ tactics are more stark when heat-protection involves infrastructure and planning more than emergency-management, community organizing and communication.
A chronic problem everywhere is called the “urban heat-island effect,” the phenomenon of city infrastructure absorbing and retaining heat, lifting temperatures above rural areas. It’s not a problem that governments may prioritize when they’re busy looking for every poverty-eradicating development opportunity they can find.
Rapidly urbanizing Cairo, for example, saw hard surfaces grow from 23% to 35% of its land between 2000 and 2019. Green areas fell by three percentage points, and bare land by nine. The heat-island effect consequently worsened. At the same time Cairo was growing the old-fashioned way, richer cities have had the luxury and presence of mind to attend to heat-island cooling strategies. Los Angeles wants to lower the city-rural temperature difference by at least 3°F by 2035 and Melbourne wants to be more than 7°F cooler.
There are many ways to accomplish this. Phoenix’s Maricopa County saw a record 145 days in 2020 that reached above 100°F (37.8°C) and suffered 323 heat-related deaths. The city in June approved the new position of tree and shade administrator, a role meant to help a push for 25% of the city to fall under a shade canopy by 2030. A cost-benefit analysis found that the city earns a return of $2.23 on every tree planted, with total annual benefits of more than $40 million.
Materials and design also figure into many cities’ heat plans. Just as glaciers reflect solar energy and cool the planet, white roofs reflect 80% of light, compared with 5% for standard dark roofs. A comparison of white and red roofs in Auckland found the lighter roof was 18°F cooler.
Roofs of grass and other vegetation similarly prevent heat absorption in buildings, a feature prominent in marquee “sustainable” buildings, such as Singapore’s ParkRoyal hotel or Chicago’s City Hall. City dwellers have found that green roofs can muffle noise, too.
“Actually changing our urban environment to mitigate urban heat island impacts can take more time,” said Gilbert of Miami-Dade County. “Getting people knowing what to do when they start to feel heat stress is something we can address more short-term.”
There’s an irony to the Climate Impact Lab heat-mortality work, with its granular focus on the power of adaptation to avoid deaths in places that can afford it. That, ultimately, is not the motivation for their research. The team instead set out to estimate, in dollars, how much damage every metric ton of emitted carbon-dioxide inflicts on the global economy. When the cost of carbon-dioxide is known, the thinking goes, governments can use it to write policy that prevents global heating.
Scientists have for decades pointed to only three possible responses to climate change: prevention of rising temperatures, adaptation to a much warmer world, and human suffering in the heat. The deadly extreme heat of 2021 has put the focus on the suffering that comes to cities that aren’t ready or able to adapt.