Heat waves are the most deadly climate disaster, killing far more people every year than wildfires, hurricanes and floods combined.
But rising temperatures aren’t the only reason that extreme heat is becoming a bigger risk.
Other important reasons include discriminatory urban planning, the insidious nature of heat illness itself and the decade-long federal tug of war over how to respond to heat waves.
Here are five reasons — aside from climate change — why heat risk is worsening.
The US spent years ‘moving backward’ on heat
In 2013, President Barack Obama issued a sweeping executive order that aimed to make U.S. communities more resilient in the face of the impacts of climate change — from rising seas to rising temperatures.
That order sought to coordinate actions by federal agencies to protect populations from climate risk — and to ensure that infrastructure spending wasn’t inadvertently making the country less safe.
It was specifically intended to begin the process, using science, to ensure cities and infrastructure were strengthened in the face of climate change.
Systems to “pay attention to vulnerable communities in particular” were also a part of the order, said Robert Verchick, who served in the Environmental Protection Agency during the Obama administration and now serves as president of the Center for Progressive Reform.
For communities, Verchick said, “you could do simple things like get more tree cover and put in more awnings. Or if you’re living in Phoenix or Las Vegas, we’ve got issues where people just standing outside waiting for a bus can end up in the emergency room — so some of it is about rebuilding bus stops or making sure that buses run more regularly.”
But that rule won’t be out until late this year at the earliest — about a decade after the original Obama executive order.
Heat is a quiet killer
While heat danger — and deaths — are rising, the public sense of that risk hasn’t kept up with its actual magnitude.
Repeated studies have shown that people’s sense of heat risk — even among those most vulnerable — often doesn’t correspond to its actual risk.
Heat’s tendency to fly under the radar has serious impacts for both individual behavior and public policy.
One reason is that unlike other threats from extreme weather, heat waves don’t create the kind of visually dramatic moments that characterize floods or wildfires.
“Even if there’s record-breaking temperatures, there’s still usually less to see than when something dramatic happens — like the flooding that was happening in New England just a couple of days ago,” said Ladd Keith, who studies heat and urban planning at the University of Arizona.
While heat’s impacts are subtle, its death toll isn’t.
In Arizona’s Maricopa County alone, at least 12 people died from heat this year, compared with a single death in the Vermont floods.
Last year, 425 people died in the county from heat — an increase of 25 percent over the prior year, and nearly five times the number of U.S. residents that died during Hurricane Ida.
But because those populations “tend to fall off the radar” for policymakers, Keith said, the rising toll hasn’t caused much political action.
Housing is getting less affordable
Because access to water and air conditioning largely eliminates the risk of death from heat, those who die from heat tend to be those who struggle to secure shelter — or to keep the power on.
There is no county in the United States where a person working a full-time, minimum-wage job can earn enough for a two-bedroom apartment, according to the National Low Income Housing Coalition.
And in June, researchers published the results of a survey of thousands of people living without housing in California about how they had lost housing — with most saying that high costs had forced them out.
Due to health crises, rent hikes, layoffs or simple bad luck, “people just ran out of the ability to pay, whether it happened quickly or slowly,” lead author Margot Kushel of the University of California, San Francisco, told National Public Radio.
In Maricopa County, exposure to the elements was the biggest risk factor for dying of heat: 80 percent of those killed in 2022 died of heat injuries they sustained outdoors — and the rise in outdoor deaths was the largest component.
Most of those outdoor deaths — and the largest single cadre of fatalities — were the 178 people experiencing homelessness who died in Maricopa last year.
Energy prices are rising
Even those who have housing may be at risk. Most of those who died indoors in 2022 in the Phoenix area lived in houses with air conditioning — but in nearly 80 percent of those cases, it didn’t work.
Keith of the University of Arizona said that’s another factor of housing prices.
Rents or mortgages “also strain the resources available to upkeep homes,” he added.
When air conditioners break, many don’t have the money to repair or replace them.
According to a report by the Federal Reserve, 37 percent of Americans in 2022 couldn’t have come up with $500 in cash to deal with an emergency. That sum is about ten percent of the price of a new air conditioner, which costs an average of $5,000.
Energy prices also rose 14 percent in 2022, twice as fast as inflation, according to the U.S. Bureau of Labor Statistics. The main driver behind that rise was “global calamities,” Tyson Slocum of Public Citizen told Utility Dive.
Slocum noted that high electricity prices are disproportionately borne by poorer Americans, who tend to rent their homes. Slocum told Utility Dive that this caused a paradox, because “to cut costs, consumers must improve efficiency. But renters can’t make the investments needed to boost energy efficiency.”
That helps explain the people who died in houses with air conditioning units that were functional but not turned on, Keith said. “If you’re spending more money on housing, less money is available to go towards the utility bill — which may lead you to turn on the air conditioner less.”
Urban fixes don’t target those who need them most
Especially when the air conditioning fails, heat risk tends to be less a function of abstract temperature and more a function of urban design, which can drive up urban heat indexes faster than climate change itself.
The science on how to confront this risk is simple to state, if tough to implement, Keith said. He called for targeting projects so that they prioritize reducing heat risk areas where that risk is most serious.
But in a study of five major cities carrying out pilot projects to reduce heat, Keith and his collaborators found that only Boston had done so.
The others — Ft. Lauderdale, Houston, Seattle and Baltimore — had no discernible relationship between the areas where people were most at risk and the projects they funded.
There is a common blind spot around heat interventions, Keith said: Many cities set generic benchmarks, rather than targeted ones. “You say, ‘You’re going to plant a million trees’ — but you don’t specify where or say that it has to go to the places that need it most.”