The weekend forecast for the Western United States once again called for widespread extreme heat, after June was the hottest on record. Parts of Arizona, California and Nevada broiled last month on the heels of a heat wave that claimed hundreds of lives across the Pacific Northwest and Canada. We've collectively pushed our climate to a point where famously mild Portland, Oregon, experienced multiple days above 110 degrees last month. Is anywhere in the country safe from extreme heat? And is anywhere truly prepared for the consequences?
If those emissions continue to rise through the end of the century, simply walking outside for short periods of time during the summer could be dangerous or even deadly.
The events of the past few weeks have made it clear that, from north to south and east to west, we're all at the mercy of a climate crisis of our own making, and no place is immune or prepared. Our attention to extreme weather associated with climate change in the U.S. has often focused on geographically contained and destructive events like hurricanes and wildfires. But consistently rising temperatures are wreaking a new form of quieter, steadier havoc in the form of unbearable heat, which could alter daily life in myriad ways throughout the country.
In our 2019 study Killer Heat, my colleagues and I unfortunately found that, if we fail to reduce heat-trapping emissions by mid-century, the country will experience four times as many days with a heat index — or "feels like" temperature — above 105 degrees than we did at the end of the 20th century. And if those emissions continue to rise through the end of the century, simply walking outside for short periods of time during the summer could be dangerous or even deadly in broad swaths of the U.S.
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Already, the heat this summer has disrupted daily life in countless ways in the Pacific Northwest, a climate so mild that many homes lack air conditioning and localities are unprepared for high temperatures. In Portland, the intense heat caused asphalt roads to buckle. In Seattle, light rail transit had to be slowed or canceled because rails can expand at high temperatures and overhead power lines can sag. Meanwhile, one of the city's community pools closed because the deck reached unsafe temperatures. Inland, Spokane, Washington, playgrounds were off-limits as their black rubber surfaces logged temperatures above 150 degrees. And thousands of Washington homes were left without power when they needed it most as utility companies struggled to meet heightened electricity demands.
And it’s not just the Pacific Northwest. For weeks, one part of the country or another has been under a heat advisory or an excessive heat warning, and the high temperatures are taking their toll. A weeklong heat wave in Maricopa County, Arizona, raised the county's heat-related death toll to a shocking 73 people before the end of June. In New England, few schools are air-conditioned, resulting in closures or early student dismissals when an early-June heat wave made classrooms unbearably hot.
Like other hardships in our society, the difficulties posed by extreme heat aren't shared equally among the population, with marginalized groups suffering more. More than half the people who died of heat-related causes in Maricopa County last year were unhoused. Those with substandard housing also suffer disproportionately. While there’s no data about which state and federal prisons lack air conditioning, every year we see reports of incarcerated people falling victim to heat-related illnesses or death.
In urban areas, neighborhoods with lower-than-average incomes tend to be hotter. With a greater preponderance of heat-absorbing asphalt and concrete, these neighborhoods are left to bake while higher-income neighbors cool off with parks under the shade of trees. And these differences nearly always fall along racial lines. Chronic underinvestment has left many Black and brown people with nowhere to go to escape the heat even as they have less financial security to meet the challenge of the above-average electric bills that come with trying to stay cool at home.
Similarly, while many of us can hunker down in air-conditioned offices and bedrooms, those who work outdoors have no such luxury. Farmworkers, construction workers and countless others who keep our society functioning and fed have up to 35 times the risk of dying from heat as the general population. People of color are often disproportionately employed in such jobs and thus incur far more than their fair share of risk.
The Asunción Valdivia Heat Illness and Fatality Prevention Act, introduced recently in both the House and the Senate, could go a long way toward keeping such workers safe. This legislation would direct the Occupational Safety and Health Administration to set protective standards — such as mandating that employers provide adequate hydration, shade and rest breaks — for outdoor workers regularly exposed to heat.
But ultimately, nothing short of transformative changes in our society will blunt climate change's effects. From the way we get our energy to the cars we drive to the rights we afford our farmworkers, the time for half-measures is long past. To stave off the worst climate impacts — including limiting the number of days of extreme heat — the U.S. must make robust contributions to global climate action, including reducing its global warming emissions at least in half by the end of the decade and reaching net-zero emissions by 2050.
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Such reductions in global emissions would set us on a path consistent with limiting future global warming to less than 2 degrees Celsius above pre-industrial temperatures. Compared to a scenario in which we let emissions continue to rise unchecked, aggressively reducing emissions now would result in half as many days of dangerous heat annually later this century.
The choices before us are clear: We can buckle down by demanding and providing incentives for the changes we so desperately need to keep our communities safe and livable. Or we can lie awake at night wondering when the heat is coming for us.
