A man holding his head down, grasping a water bottle

Earth’s New Gilded Era

The world is getting hotter, and the divide between rich and poor is getting bigger.

Consider the cantaloupe. It’s a decent melon. If you, like me, are the sort who constantly mixes them up, cantaloupes are the orange ones, and honeydews are green. If you, like me, are old enough to remember vacations, you might have had them along with their cousin, watermelon, at a hotel’s breakfast buffet. Those spreads are not as bad as you remember, especially when it’s hot out; add a couple of cold bagels and a pat of unmelted butter and it’s a party.

Maybe you want the cool, refreshing mildness of a melon cup at home. Unless there’s a good fruit stand nearby and cantaloupe is in season, that means taking a trip to the grocery store. Maybe you’ll stroll down aisles kept just cool enough to make the skin on your arms prickle. You’ll browse refrigerated produce shelves doused in cold water every so often. Then you’ll find it: the perfect cantaloupe. It’s round and rough, with no dimples or spots. When you thump it, there’s a satisfying, muffled thud. It’s a sweet one.

Consider how the cantaloupe got there. It likely took a long ride to the supermarket or the hotel kitchen in a truck cooled to just above freezing. Maybe, like many melons, it was planted, picked, and packed on a plantation in the town of Choluteca, in southern Honduras, before it began its careful ballet of climate control.

Workers told me they aren’t allowed phones in the fields in Choluteca, so they don’t always know exactly how hot it is. But during the growing season on the Fyffes melon plantation, temperatures hover in the mid-30s in Celsius—the mid-to-upper 90s in Fahrenheit. The sun broils the open spaces where workers chop the melons from their stems. The heat is overwhelming and omnipresent, an overseer whose hand is always heavy, and whose eye is never distracted.

Workers have told me of conditions that push the human body to its limits—sometimes, past them. Protective gloves are prohibited, they say, so their hands bleed from the rough work handling plants that are doused in corrosive chemicals. Pickers say they are hesitant to show any signs of weakness or illness, fearing that taking time off or even appearing to be sick while working will result in termination. (A Fyffes spokesperson told me that gloves are always provided upon request, and are mandatory in certain parts of the packhouse where workers handle chemicals, and that unwell workers receive sick days and are required to see a doctor.)

But the most common complaint is the most elemental: It’s damn hot in the fields. “El calor es bien fuerte,” one woman, 25, told me. She didn’t want to reveal her name for fear of retaliation, but she said she’d worked on a farm in Choluteca for four years, shuffling through almost every job available, from cleaning the facilities to picking the fruit. Many people who have worked for decades are marked by skin blemishes that, even if they’re not yet cancerous, aren’t all benign: hives, rashes, and chocolate-colored splotches. The spokesperson for Fyffes told me that the workers start very early in the morning to avoid the heat as much as possible, and are provided cold water and hats to shield them from the sun. But even for workers who begin in the dark, when sun and heat and exertion act together over long periods of time, the effects can be worrisome. “Varias mujeres se desmayan,” the same worker said. “Se les sube la presión … todo eso.” They faint. Their blood pressure spikes. And they keep working.

Thousands of miles separate the fields of Honduras and the continental breakfasts in the States. But these are terminals of a single, continuous system. Heat bears down most on the global working poor and developing countries, while their wealthier planetmates are able to evade the worst of the warming. What’s more, consumption by those wealthier folks helps create the warming, which in turn robs the poor of opportunity and walls off economic mobility. Garment workers in Cambodia and Bangladesh toil in sweatshops to sew the moisture-wicking fabrics that make summer in Phoenix or Miami or Washington, D.C., bearable. In Qatar, itinerant workers labor at the outer edge of human survivability to fabricate air-conditioned hotels, malls, and arenas for the rich. And thousands of families flee environmental pressures in Central America only to find themselves suffering from the heat in the United States.

Scientists and people with good sense around the world recognize the manifold perils of a climate crisis: an onslaught of tropical systems in the Atlantic Ocean, the relentless burn of wildfires in California and Oregon, the hundred-year floods that now encroach annually. Less appreciated, perhaps, are the direct effects of that increasing warmth on human bodies and communities. Heat is already often deadly, and even below fatal thresholds it is a grinding attrition that saps personal and economic vitality a little more each day. In the coming century, when wealth inequality will likely increase and the spaces where humans can live comfortably will shrink, the heat gap between rich and poor might be the world’s most daunting challenge. It will reflect existing wealth disparities, but will also deepen them. It will destroy some bodies, while others are spared. It will spark uprisings and set the stage for conflict, both between and within nations. In a hot world, the heat gap will be a defining manifestation of inequality.

Left: A worker at a recycling station in Phoenix. Right: A cooling system on the Las Vegas Strip.

One billion people work in agriculture, performing the same kind of labor as the melon pickers in Choluteca. Add to that the millions and millions of people who work outdoors in construction jobs, or indoors in sweatshops and factories without air-conditioning, and significant numbers of low-income workers—including hundreds of millions of children—have little control over the temperatures in which they spend the majority of their waking hours. According to a recent report by the United Nations’ International Labour Organization (ILO), heat stress is threatening their work and their lives.

Heat stress—defined by the ILO as “heat received in excess of that which the body can tolerate without physiological impairment”—has always affected workers in the summer and in tropical or subtropical climates. Sunburns, skin cancer, heat exhaustion, fainting, dehydration, and long-term kidney problems have been accepted as basic risks of outdoor work. But as the Earth has experienced a sustained, record-breaking run of overall temperatures, these problems have become more and more of a burden—and, more and more often, a fatal one. Tord Kjellstrom, an environmental- and occupational-health expert and one of the main authors of the ILO report, told me that “it’s well understood from a physiological, medical point of view that these hot temperatures limit people’s abilities to carry out work.” It’s not just work—extreme heat can disrupt or destroy many of the pieces of a healthy life—but in his research, Kjellstrom has found productivity to be one of the main proxies for all the ways heat can affect the global poor.

Kjellstrom’s work has zeroed in on so-called mass fainting events in South Asian and Southeast Asian factories over the past decade. In 2017, hundreds of garment workers in Bangladesh fell ill with what one worker described as “nausea, vomiting and stomach pain after working [a] few hours.” That same year, “there were more than 1600 cases of factory workers in Cambodia fainting in various incidents,” according to an epidemiological study of the faintings.

Over and over, these incidents have been described as “mysterious.” One common explanation is possession by spirits. The usual official line is that mass fainting—among a mostly female workforce—is caused by “hysteria” of an inexplicable, gendered extraction. A secret report by officials in Cambodia after two such mass fainting events found its way to Kjellstrom. “Their report was quite long, and half of it was about the heat problems,” he told me. “And still, at the end they concluded that it was hysteria: You know, one young woman in the factory, she faints, and then all her friends start fainting as well. And of course that doesn’t make sense.” Epidemiological evidence also points to stress, air pollution, long hours, and the punishing pace of work as potential contributors to the fainting incidents, but with factory temperatures in Cambodia regularly topping 100 degrees Fahrenheit, the likely main contributor seems obvious.

Other places have caught Kjellstrom’s eye as well. In Qatar, where the stadiums the emirate is scrambling to build for the 2022 World Cup require lots and lots of outdoor labor, heart-disease deaths among workers have spiked during the summer months. Chronic kidney disease has swept Central America; again, the etiology of the epidemic has been described as mysterious. Similar waves of kidney disease have been observed in India and Sri Lanka. Scientists have tended toward a kitchen-sink explanation, identifying genetics, diet, pollution, and age as contributors to the epidemic. But a common factor in each outbreak—and the one that has increased most dramatically in recent years—is the heat.

One way to track the increasing impact of heat on people has been to measure how much it affects working hours, because workers naturally take more breaks and perform jobs more slowly when enduring dangerous levels of heat. The ILO report projects that 2.2 percent of total working hours worldwide will be lost to high temperatures, with the greatest predicted losses coming in the developing world, by 2030. And while the productivity losses in those places are a major concern for development trajectories and population-level wealth, they also mean lost wages, more unstable work situations, and more pressure to work in those unstable conditions. The places with the most exploitative labor conditions and the steepest poverty rates also face the largest burdens from a changing climate, which then are absorbed mostly by poor people, thus reducing their mobility and economic welfare further.

construction workers rest in the shade
Workers rest in the shade during their lunch break at a construction site in Phoenix.

Women and the elderly are both overrepresented in the workforce and face unique health hazards from heat stress. “They are in jobs that cannot be air-conditioned easily or replaced by mechanization,” Kjellstrom said. “Of course, these are the people who are usually the lowest-paid and the most vulnerable in a socioeconomic sense. So as the heat affects them further and further, while at the other end, rich people sit in air-conditioned offices, then it will definitely be a reason for increased inequality.” At both the population and the individual levels, heat and poverty are something of an ouroboros, a cycle that wealthy people and countries perpetuate via emissions, but themselves are able to escape by way of air-conditioning, indoor work, and social and geographic mobility.

It might follow that people stuck on the receiving end of the heat gap would do their best to move to the other end. This happens, to some extent. The ILO found that “heat stress is increasingly becoming a driver of international migration.” Climate migration today is a dramatic new chapter in an ancient story—much of human migration in history has been, in some sense, climate-driven. But in the places where the heat gap already operates the most aggressively, leaving might not be an option. Moving is hard and costly; moving when you need a new kidney can be physically impossible.

For those who are able to move, no land is promised. Millions of people have left Central America and Mexico in the face of rising temperatures, droughts, and crop failures. But as migrants have moved northward, heat stress has followed. That’s especially true in places like California and Florida, where farmwork has always involved a good deal of exposure to high temperatures.

Jeannie Economos, a coordinator for the Pesticide Safety and Environment Health Project within the Farmworker Association of Florida, has been organizing and assisting workers in fields and on farms for a long time. Farmwork in Florida has always been hot, often dangerously so, and she’s always counted the heat as an issue. But the current climate moment is something else. “I’ve been here since 1961, and this feels different,” Economos told me. “There’s a different quality to the heat. It used to be scorching, but now it feels like it’s searing.” The science backs her up. Florida is definitely hotter now than it was a century ago, and the situation is accelerating. A report from the Union of Concerned Scientists, an advocacy group, found that a combination of rising temperatures and humidity could make a third of every year across the state dangerously hot for human bodies within the century. A few weeks’ worth of days every year already meet that threshold.

The Florida heat and sun exposure take a toll on all the farmworkers Economos encounters. Surprisingly, she worries most about a group that typically works indoors: the people who grow ferns and ornamental plants, propagating and tending and picking year-round so that poinsettias will be ready for Christmas, and fern fronds will be available for Valentine’s Day bouquets.

Towns like Pierson, Florida—the “fern capital of the world”—are dotted with ferneries. Ferns tend to prefer shade, so they are grown either under wide mesh canopies or in enclosed greenhouses. But although these places are shaded, the conditions that are good for growing ferns are bad for people: incredibly humid, and often lacking wind or ventilation. They are “brutally hot,” as Economos said. And to keep their clothes from being soaked by the wet plants and moist air, pickers often wrap themselves in black garbage bags, trapping the heat even closer to their bodies.

Economos has been involved in several efforts to study what the increasing heat actually does to people. One longitudinal study of 252 agricultural workers conducted with Emory University researchers found that those employed in the Pierson ferneries experienced an average heat index of 101 degrees Fahrenheit over the course of the study, a level that the National Weather Service says necessitates “extreme caution”; heatstroke or exhaustion is possible with prolonged activity. With this kind of everyday, year-round exposure to dangerous heat, damage to the body is virtually certain. In 2018, Economos’s research team found significant evidence of acute kidney injuries related to dehydration among Pierson fern harvesters, a correlation that grew stronger as the heat index increased. In essence, the “mysterious” kidney disease in Central America is now striking farmworkers in the United States.

man dehydrated in hospital and tree with no limbs
Left: A patient is treated for dehydration and heatstroke at the Maricopa Medical Center, in Phoenix. Right: Although lush tree canopies provide upscale parts of the city with a much-needed break from the scorching sun, the lack of shade in poor neighborhoods allows concrete and asphalt expanses to soak up daytime sun.

Across Florida, organizations advocating for immigrant communities are scrambling to confront this problem. Oscar Londoño, the executive director of WeCount!, a workers’ center in Miami-Dade County, says the organization has had to get up to speed on heat quickly. A few years ago, “we began seeing a lot of members that were reporting issues at their workplace,” Londoño told me. Most of those members were day laborers, farmworkers, or plant-nursery harvesters, many of them in workplaces or informal roles that don’t require breaks after heat indices reach a certain level, or other protections. “Many of the employers aren’t providing these protections voluntarily,” Londoño said.

WeCount! has pushed for legislation in Florida that would mandate more stringent heat protections. While it waits for government intervention, it is using its Spanish-and-Indigenous-language radio program, Radio Poder, to run public-service announcements about the dangers of heat. The ads tell workers to drink water, seek shade, and rest when they can. Translated from Spanish, one ad warns that “this summer is one of the hottest in history.” What it doesn’t say is that this summer will likely be remembered as a pretty mild one in our near future.

From left: A water bottle is left in front of the Bellagio, in Las Vegas; sprinklers irrigate the McCormick Ranch Golf Club’s Palm Course at night in Scottsdale, Arizona; a man fishes for coins thrown into a water fountain in front of the Venetian hotel, in Las Vegas.

For millennia, humans have lived within a slender range of temperatures. According to a study published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) in May, most people born in the past 6,000 years have lived in places with average annual temperatures of about 11 to 15 degrees Celsius, or 52 to 59 degrees Fahrenheit. (The major band of historical population densities above 20 degrees Celsius is in the Indian monsoon region, where the annual rains are the main lifeline making human thriving possible.) The places where humans live have gotten slightly warmer in those thousands of years, but they’ve done so gradually, giving people time to adapt and move.

But, thanks to human-driven global warming, that sliver of global society-friendly temperatures is due to shift more in the next 50 years than it ever did in centuries prior. The May PNAS study found that in the worst-case climate scenario—where emissions continue to rise and the global average temperature increases by 2 degrees Celsius—the average annual temperature experienced by people in 2070 will hover around 20 degrees Celsius (68 Fahrenheit), with most people living in a range of temperatures between 18 and 22 degrees Celsius, or 64 and 71 degrees Fahrenheit. Population growth is expected to be highest in the hottest places; according to PNAS’s projection, by 2070 more than 3 billion people will be regularly exposed to temperatures that are not typically found outside the Sahara Desert today.

Average annual temperatures, however, tell only part of the story. The real medical danger from heat usually comes from summer heat waves. By most accounts, including an article published in Nature this summer, extreme heat waves have increased in frequency, duration, and intensity over the past five decades. A 2019 Nature article produced a startling finding: Under the same 2-degrees-Celsius scenario as above, and assuming ever-deepening global inequality, the kinds of extreme heat waves that now happen only twice in a millennium, on average, will become events that happen multiple times each decade for billions of people by 2075.

Under each possible climate scenario, poor areas will be most affected. The 2019 Nature study predicts that even if global governments can curb emissions enough to limit warming to 1.5 degrees Celsius instead of 2 degrees, the poorest countries will still face more additional risk from heat waves than the wealthiest countries would face with the full, catastrophic 2-degree increase. In short, people in countries like Nigeria, Ethiopia, and Haiti will see a greater total increase in heat waves under the more optimistic global climate scenario than the average U.S. citizen will under the worst possible runaway global-warming crisis we can imagine.

But these climate effects don’t just highlight differences among countries. Regional differences in heat exposure over the next century will also exacerbate differences in wealth within national borders. As my colleague Robinson Meyer has reported, while the convulsions and pressures of climate change are projected to squeeze the total gross domestic product of the United States by the end of the century, a closer look by researchers found that the majority of the losses will be accrued by counties in the South. The counties most affected are, on average, poorer than the counties that appear to fare well.

Indeed, while several counties in the Deep South are predicted to lose a fifth or more of their GDP, some counties in the Pacific Northwest and New England might actually see their economies grow. Deaths caused by climate change will likely be clustered in the southernmost third of the country. While the model considers several different climate-change-related problems, it’s clear that the main driver of the inequality within regions will be heat itself.

There is compelling evidence that the heat gap operates on an even more local level. In 2019, an NPR investigation found that in the majority of the 97 American cities analyzed, poor neighborhoods tend to be hotter than wealthy neighborhoods. Much of this disparity has to do with what’s called “urban heat-island effect,” whereby the asphalt, building materials, and reflective surfaces that dominate denser, poorer neighborhoods tend to absorb sunlight and trap and amplify ambient heat. Another factor is the extreme disparity in green space between rich and poor neighborhoods. Wealthy neighborhoods and single-family dwellings are much more likely to have tree cover and other forms of vegetation that cool places off by creating shade and modifying airflow.

water bottle in a sign, golf course being water, fountain in Las Vegas
A neighborhood in Phoenix. Many residents struggle to pay for electricity, without which they are left exposed to the extreme heat.

A recent New York Times article corroborates these findings, but with an alarming addendum: The disparities also seem to track closely with historical patterns of residential racial discrimination. “In cities like Baltimore, Dallas, Denver, Miami, Portland and New York, neighborhoods that are poorer and have more residents of color can be 5 to 20 degrees Fahrenheit hotter in summer than wealthier, whiter parts of the same city,” write Brad Plumer and Nadja Popovich. The hottest spots can be linked to areas that were redlined decades ago by the federal government. Black and Latino families did not simply passively settle in the hottest, most uncomfortable neighborhoods. They were placed there, and then the same white voters and leaders who placed them there turned up the thermostat even more with carbon emissions and local zoning policies.

The consequences of this increasing burden on poor communities of color are already apparent. Life on urban heat islands is associated with higher mortality from heat waves. Studies have consistently found links between poor maternal and child health outcomes and extreme temperatures, and emerging evidence suggests that the effects of heat are most damaging for Black, Latino, and Indigenous infants and mothers. A meta-analysis published in JAMA in June found a “statistically significant association between heat, ozone, or fine particulate matter and adverse pregnancy outcomes,” including preterm birth, low birth weight, and stillbirth. And the NPR investigation of heat in poor neighborhoods found that over five years, “Medicaid patients in Baltimore's hottest areas visited the hospital at higher rates than Medicaid patients in the city’s coolest areas. The low-income patients in the city’s hot spots visited more often with several conditions, including asthma, COPD and heart disease.”

When Americans think about climate change, they probably don’t have these kinds of consequences in mind—an uptick in stillbirths, or more Black children with asthma. Climate communication often tends toward the apocalyptic and the episodic, for good reason: Dramatic events are a good way to get apathetic people to care. But the destruction wrought by the heat gap in American neighborhoods is just as important as the high-profile cataclysms. That destruction is insidious and hard to follow because it plays out along existing lines of inequality and injustice. Comparable to its role in some chemical reactions, heat accelerates the logical outcomes of unequal human systems. In this reaction, heat is not necessarily a bomb that will suddenly vaporize civilizations. Here, its preferred pathway is decomposition, working slowly and steadily at severing bonds until two components are separate, if not equal.

Left: With a bag of ice on his head, a football player cools down after practice in Scottsdale, Arizona. Right: The shade under the senita cactus is the only break from the sun for Phoenix’s unhoused.

Almost 5,000 people were arrested in the streets on June 2, the height of turmoil in a summer of uprisings. That day, as protests over the killing of George Floyd by Minneapolis police entered their second week, the temperature in Minneapolis hit 90 degrees Fahrenheit, about 12 degrees above average. The same day, as protesters in Louisville, Kentucky, prepared to commemorate what should have been Breonna Taylor’s birthday, the temperature also approached 90. As opponents of white supremacy engaged in some of the most widespread, sustained protests in American history, the country also headed toward one of its hottest summers ever. The devastating fire season that would reduce much of the West to cinders was about to begin. Almost 2 million Americans had contracted COVID-19. More than 100,000 had already died.

The heat was not just part of the setting. The coronavirus pandemic and the summer of protest have both been propelled by vulnerabilities that heat and inequality create.

In the case of the pandemic, long-term climate change is not incidental to the progress of a novel coronavirus from bats to people: As my colleague Ed Yong has written, climate change is one of the key elements that pushes zoonotic diseases like COVID-19 from wild spaces into human populations. “Through intensive agriculture, habitat destruction, and rising temperatures, we have uprooted the planet’s animals, forcing them into new and narrower ranges that are on our own doorsteps,” Yong says. In considering the role of potential comorbidities in the pandemic, heat is not ancillary either. It might worsen asthma and other pulmonary diseases, and it definitely influences kidney disease and hypertension—two risk factors for complications from COVID-19.

Before George Floyd lost consciousness with officer Derek Chauvin’s knee on his neck, he had, according to the county medical examiner’s autopsy, contracted the coronavirus, and developed some level of heart disease and hypertension. The medical examiner named heart failure the official cause of death.

For some, the report served to shift blame away from the officer in a way reminiscent of the response to Eric Garner’s death in 2014, when Garner’s history of asthma and heart disease was used to minimize the culpability of the officer who put him in a chokehold. But there’s another way to think about how those risk factors really operate. Unequal exposure to heat and pollution weakens Black people’s bodies. That exposure consistently assaults Black folks’ hearts, lungs, kidneys, and blood vessels. It makes them more vulnerable to mortality from all causes, including targeted brutality from police. And so, just as protests against incidents of police brutality have also expanded their scope to denounce the bigger picture of systemic white supremacy, mass incarceration, and other necessary conditions for police violence, the heat gap should also be understood as a part in the whole of injustice.

Several other protest movements in our pandemic summer also sprang from heat-induced inequality. Lockdowns and shelter-in-place orders forced many families “to choose between cooling their homes and paying for necessities such as food, medicine, and child care,” according to the Center for American Progress. People with low incomes are less likely to have air-conditioning in their homes than wealthier people, and tend to pay more per square foot when they do have it, because their homes are less energy-efficient. And after lockdowns and pandemic-influenced contraction erased entire sectors’ worth of blue-collar jobs, even families that otherwise would have had no problem cooling their homes have faced utility shutoffs—or worse, evictions—because of lost incomes.

In Miami, activists fought this summer to try to keep the local utility companies from shutting off power to people who couldn’t pay after losing their jobs. Cheryl Holder, a faculty member at the Herbert Wertheim College of Medicine at Florida International University, regularly treats undocumented immigrants and other workers who are most at risk. “I have folks now who have air-conditioning, but they can’t afford to run it,” Holder told me. She says that among her patients, while pandemic-related pauses in work have eased some of the onslaught of kidney damage, people have still faced serious risks from staying home. In the places and times that used to provide relief for workers, now there is less to be found. “People have worked in the heat forever,” Holder said. “But they’ve relied on respite during cool nights. There are fewer and fewer cool nights. More hot nights.”

As a co-chair of the advocacy group Florida Clinicians for Climate Action, Holder has given serious thought to figuring out how to break the bond between heat stress and poverty. The pandemic has accelerated her inquiry. “How do we get our infrastructure to support good health?” she asked. She’s got a laundry list of things that obviously might help. Adding green space and shade in working-class and poor communities, providing more water and more breaks on the job, providing more access to public cooling centers, and providing both affordable air-conditioning and efficiency upgrades for poor homes are all important bullet points on that list. The main barrier she encounters is an eternally vexing one for people with any kind of imagination: “Who’s going to help pay the bills?”

man with sweat soaked shirt  from behind
A woman stands in front of a fan at the Society of St. Vincent de Paul’s Sunnyslope Dining Room, in Phoenix.

In a TED Talk she delivered earlier this year, Holder outlined her own theory of how climate change and poverty were linked. “Poor, vulnerable people are already feeling the effects of climate change,” she said. “They are the proverbial canary in a coal mine. Truly, their experiences are like oracles or prophecies.” This view of climate justice transforms the dominant narrative of climate change from one of a shared experience of gradual challenges into one where poor people, women, and minorities are on the front lines, serving as a vanguard against oblivion.

In the end, everything comes down to a handful of considerations. Poor people—and those otherwise marginalized by way of race, class, caste, or gender—are more likely to live in hot places and do jobs in the heat. And the people who generated most of the emissions making those places and jobs hotter are likely to be wealthier, living in conditions that shelter them from the heat. This is true on every level: Developed countries have emitted the lion’s share of the carbon that got us into this mess in the first place. According to Oxfam and the Stockholm Environment Institute, even as rapid industrialization has brought more intermediate and developing economies into the fold of powerhouse emitters, the wealthiest 1 percent of the global population has been responsible for twice as much carbon output as the poorest half. And in America, the individual carbon footprint of high-income homes is significantly higher than that of poor ones.

The climate catastrophe might one day be so overwhelming that the ordeals of poor people and racial minorities become predictive in some way for the experiences of the elite. But maybe they aren’t really the canaries in the climate-change coal mine. Maybe they are the victims of a massive, global wealth transfer that affects almost every facet of life in a warming world, and will continue to do so well into the future. The people on the margins of society assume an unwanted role as buffers—absorbing the climate risks that the rest of the world has created and now shirks. Following melons and pickers from the fields in Honduras on their journey north and witnessing epidemics of kidney failure migrate with them, this dynamic is in clear view.

On some level, this is not surprising. The climate has always had a hand in the fate of societies, and climate pressures have always animated global conflict and class division. Yet generations of humanity have now been born into a world where the global totality of those climate pressures is directly controlled not by God nor by random gradients in the atmosphere, but by a small, insular cadre of humans. Perhaps it is true that recent history has all been a grand game played by elites, with the lives of everyone else in the balance. But now, in the climate crisis, the spaces on the board, the rules of the game, and the moves available cannot be hidden.

In the past century, the American liberal order has celebrated advancements in racial and gender equality and the proliferation of civil and human rights. The country defeated malaria in the swamps of the South and fought back against the kind of hunger that once starved people in city slums. In the age of carbon, global life expectancy has increased steadily, abject poverty is abating in some places, and there has never been a safer era in human history to have a baby.

But heat presents a challenge to every single advance in health and medicine. It aids the spread of infectious diseases and makes chronic diseases worse. Heat might be reversing precious gains in infant and maternal mortality. And it’s creating new economic burdens on the global poor. All while the better-off folks crank up their air conditioners and travel in cars to climate-controlled white-collar jobs, where they stream data from servers kept chilled in massive, power-sucking farms.

We have a long, hot century ahead of us. Human civilization will face threats and challenges that seem beyond the scope of our imagination, and definitely lie beyond the scope of our experience. As it turns out, humanity is familiar with the enemy it faces. That nemesis may now come heralded by “bomb cyclones” and mega-droughts, but a peek beneath its smog shroud reveals its true nature. The enemy is human-engineered inequality, as powerful—and as vulnerable—as it has always been.