Take a look back at how others have survived—and thought about—the high heat of summer.

By: Matthew Wills  July 28, 2024

Staying Cool: Helpful Hints From History

In an episode of The Twilight Zone called “The Midnight Sun,” first broadcast in November 1961, the apocalyptic temperature of an Earth getting ever closer to the Sun is represented by a thermometer bursting at…130°F. On July 5, 2024, Palm Springs, California, reached 124°F, while the next day, Death Valley hit 128°F, amidst a shattering of triple-digit temperature records across the American West.

Benchmarks have shifted. In 1961, the amount of carbon dioxide (CO₂) in the atmosphere was 318 parts per million by volume (ppmv). CO₂ is a greenhouse gas, acting as atmospheric insulation, preventing heat radiation from dissipating into space. Last year, 2023, the amount of CO₂ in the atmosphere was 421 ppmv. It continues to increase, not least as we battle the resulting heat by burning fossil fuels to stay cool. We’re in a global greenhouse, and the doors seem to be locked as we paradoxically produce more CO₂ to stay cool in the face of heating caused by the production of more CO₂.

Humans have long worked to beat the heat, especially in the tropics and in deserts. Their perfectly rational strategies—stay out of the midday sun, live underground, cover up completely—may once have been criticized by those from temperate zones, sometimes in racist terms, but more and more parts of the world are having to learn the lesson of those strategies.

What, after all, would it be like without air conditioning? Take a look at this Before Air-Conditioning piece in Scientific American’s “Hints for Keeping Cool.” Published in July 1858, the piece begins with a dietary suggestion: eat “fruits, vegetables, and farinaceous food, and the lighter kinds of meat.” In 1858, the amount of CO₂ in the atmosphere was 286 ppmv. Seven years earlier, Dr. John Gorrie, striving to cool down his malaria and yellow fever patients in Florida, patented the first ice-making machine (1851, 285 ppmv).

The first modern, electrical air condition system dates to 1902 (297 ppmv), when inventor Willis Carrier cooled and dehumidified the Sackett-Wilhelms Lithographic & Publishing Company in Brooklyn, New York. The publishing company was most concerned about humidity warping their paper supplies. Carrier is still a going concern.

A little over a century after Scientific American’s helpful hints, The Science News-Letter’s “Keeping Cool in Summer Heat” (1961: 318 ppmv) wasn’t so very different.

“If you suffer from heat frustration when the mercury hits the 90’s, a little scientific knowledge of summer heat can help your body temperature and state of mind remain well within the comfort zone,” the editors claim.

These hints were essential for those without air conditioning, that wonder of the twentieth century. Try to imagine cars, theaters, restaurants, the suburbs, office towers, apartment blocks, malls, et cetera, without A/C. The post-World War II population growth across the Sun Belt, stretching from Southern California to North Carolina, would most likely not have been possible without it.

In his exploration of how A/C transformed the South, Raymond Arsenault quotes a Floridian circa 1982 (341 ppmv).

“I hate air conditioning,” the woman confirmed. “It’s a damnfool invention of the Yankees. If they don’t like it hot, they can move back up North where they belong.”

But most people—in the South and elsewhere—welcomed A/C with a passion. Arsenault notes that historians tended to shy away from writing about the transformative power of air-conditioning on the South because they were leery of falling into an old climate-is-destiny paradigm. In the first three decades of the twentieth century, the South’s climate was held responsible for everything from the Southern drawl to plantation slavery. Climate determinism faded by mid-century (1950: 311 ppmv), as the “long hot summers” of the Civil Rights years transitioned into the “New South,” supposedly post-racial but definitely all indoor-cooled.