After Cooling

On Freon, Global Warming, and the Terrible Cost of Comfort

Eric Dean Wilson

• Publisher: Simon & Schuster
• Year: 2021
• ISBN:
  9781982111328
• Topic: Biological Sciences
• Subtopic: Global Warming & Climate Change
• Index: Biological Sciences

This "ambitious [and] delightful" ( The New York Times ) work of literary nonfiction interweaves the science and history of the powerful refrigerant (and dangerous greenhouse gas) Freon with a haunting meditation on how to live meaningfully and morally in a rapidly heating world. In After Cooling, Eric Dean Wilson braids together air-conditioning history, climate science, road trips, and philosophy to tell the story of the birth, life, and afterlife of Freon, the refrigerant that ripped a hole larger than the continental United States in the ozone layer. As he traces the refrigerant's life span from its invention in the 1920s—when it was hailed as a miracle of scientific progress—to efforts in the 1980s to ban the chemical (and the resulting political backlash), Wilson finds himself on a journey through the American heartland, trailing a man who buys up old tanks of Freon stockpiled in attics and basements to destroy what remains of the chemical before it can do further harm.Wilson is at heart an essayist, looking far and wide to tease out what particular forces in American culture—in capitalism, in systemic racism, in our values—combined to lead us into the Freon crisis and then out. "Meticulously researched and engagingly written" (Amitav Ghosh), this "knockout debut" ( New York Journal of Books ) offers a rare glimpse of environmental hope, suggesting that maybe the vast and terrifying problem of global warming is not beyond our grasp to face.

I. Before Freon On the Trouble with Personal Comfort

A sudden cold breeze in the long, dim corridor chilled the five workers and gave them gooseflesh. It was like a blast of winter wind of late-night air. They turned every which way to see where the wind was coming from but saw nothing.

—Abdelrahman Munif, Cities of Salt (1984)

There is no document of culture which is not at the same time a document of barbarism.

—Walter Benjamin, “On the Concept of History” (1940)

1.

Its structure is simple. Four atoms—two of chlorine, two of fluorine—surround one of carbon: dichlorodifluoromethane. We know it better as Freon, a DuPont brand name, but “Freon” refers to a number of different chemical refrigerants, which can confuse us if we want to attend to the particularities of certain chemicals (which we do). If we mean dichlorodifluoromethane specifically, “Freon-12” gets us closer, but many companies besides DuPont manufactured this refrigerant under other names. In the industry, it flies from the mouths of mechanics as “R-12,” short for “Refrigerant-12,” which, for the uninitiated, invokes the wonders of science fiction, like Kurt Vonnegut’s ice-nine, which destroyed all life on Earth by freezing everything it touched. But the most accurate name for what Sam bought is “CFC-12,” which reveals the kind of refrigerant we’re dealing with: a chlorofluorocarbon, the ozone-depleting kind.

Unlike the numeral in, say, Chanel’s perfume, the “12” here describes not a series of inventions but its molecular structure. Following a standard three-digit system, the first is the number of carbon atoms minus one (in this case, the substraction gets us “0”); the second is the number of hydrogen atoms plus one (with no hydrogen, this makes “1”); and the third is the number of fluorine atoms (a straightforward “2”). Thus, 12.

Nontoxic, nonflammable, and noncorrosive, all CFCs nearly elude our senses. Only when huffed directly (which I don’t recommend) does the nose note a slight sweetness of ether. With boiling points as low as −81°F, these colorless refrigerants are invisible gases at room temperature. Their escape into the air, though complicit in world destruction, is a total nonevent. It’s almost as if they’re not there.

Though the structures of CFCs are simple, their effects on the planet have been complex. Freon radically transformed the world, yet it’s hardly known beyond its name. It’s as invisible to most historians of the twentieth century as it is to the human eye. I find it important, then, to make visible this invisibility. Like the carbon dioxide we continue to shovel into the air, CFCs have changed the chemical composition of the atmosphere. This is indisputable. But CFCs changed far more than the physical makeup of air. The arrival of CFCs on the market in the early 1930s marked a gradual shift in Western culture and political economy that’s evident in our architecture, in our transportation, in our medicines, in our entertainment, in our capacity to secure and seek information, in our expectations of bodily comfort, and even (or especially) in the ways we relate—or fail to relate—to one another. Regardless of any one individual’s access to air-conditioning and refrigeration, Freon changed the world for everyone. It redefined what we mean by “world.”

To get a sense of the totality of this quiet revolution, it’s important to understand the world before Freon. Rather than telling this story at the typical tempo—that is, at the velocity of human life, discretely narrative and individually heroic—we should attempt to see it from the perspective and velocity of the chemical itself. Fragmented. Sweeping. CFCs waft into the stratosphere thousands of miles above us. There they live for up to 140 years until, finally, they’re broken down by the rays of the sun. I’ll try to calibrate the origin story that follows to this particular ticking. From the point of view of CFCs, we’ll see the people and cultures and ideas that pulled us into our air-conditioned world from high above and far away. From here, they resemble flies. And from here, human history seems to clip along at dizzying speeds, in fits and starts, in vignettes of triumphs and failures, so that from our place above the clouds, we can better understand the crisis of shifting climate, a crisis both new and old whose visage is new but whose motivating forces, bred on the European continent, have been ongoing for hundreds of years.

I don’t claim that the world before Freon was “better.” Only a fool would see a world of polio and starvation, of deaths in droves by heat and work exhaustion, and call it “better.” Neither do I claim, necessarily, that it was worse. I mean only to show how the world before Freon was fundamentally different. It’s important to remember this difference not so that we succumb to nostalgia or paint the past as some Edenic paradise but so that we remember, instead, that it wasn’t always this way.

Before Freon, other worlds were still possible.

Which is to say that, after Freon, other worlds still are.

2.

The history of cooling is about as long and far reaching as recorded history itself, spanning six continents and thousands of years. From ancient Egypt to imperial China, clothing and building design were two of the most common and successful methods of mitigating indoor heat. Loose, lightweight fabrics—or little clothing at all—allowed the heat generated by the body to escape. Architectures across Persia and India as well as in the southwest regions of Turtle Island reflected a sophisticated understanding of how building design can resist heat absorption in some of the hottest places on Earth, a strategy we now call “passive cooling,” the regulation of indoor temperatures without consuming much additional energy. (Interestingly, passive cooling, which nearly vanished in the Global North’s buildings of the twentieth century, has slowly crept back into recent design in structures like Zaha Hadid’s King Abdullah Petroleum Studies and Research Centre in Riyadh, Saudi Arabia, which keeps cool in temperatures as high as 113°F through its heat-reflective materials and its hivelike cellular roof, which shades the building from direct sun and reroutes desert winds into numerous open courtyards.)

Apart from building design, preindustrial peoples cooled with ice, snow, underground bunkers, cool river water, and subterranean canals that changed the course of that water—sometimes in combination and with varying degrees of success. They gathered ice and snow from nearby mountaintops or imported them from far-off frozen lakes, carried carefully in insulated chests across vast distances and stored in cellars deep in the ground, away from the rays of the sun. Though rarely used to cool the indoors, natural ice typically preserved food and drink. There were easier means of preserving—salting, pickling, or dehydrating—but often at the expense of nutrients and flavor. The means of preserving food and chilling perishables expanded with the increased mobility of early-modern Europe, and a bustling trade in imported ice developed. At the height of summer, ships would sail to Svalbard, to Greenland, to Labrador. They would cut frozen blocks from rivers, mountaintops, glaciers, and lakes, and the ships would return full of ice.

For thousands of years, the only method known for actively lowering temperature was evaporative cooling. We need only look as far as our own skin to observe evaporative cooling in action. When it’s hot, we sweat. When that sweat dries, we find our skin has cooled. (We also notice this when we emerge from a pool or shower and our bodies, shivering in the dry air, plead for a towel.) The evaporation of a liquid cools both the air around it and the surface from which it evaporates. Many cultures of the past understood that this happens, though they wouldn’t have understood the process of evaporation in the way we do today. As early as 2500 BCE, the ancient Egyptians built a device that could cool—or maybe even freeze—food and water. A glazed, clay jar was placed in a larger, porous pot filled with water. Enslaved people were forced to fan the pot, which caused the water to evaporate more quickly. As the water evaporated in the outer pot, it cooled the inner jar and whatever was held inside that jar—the first fridge. The same principle drove another cooling strategy in desert climates, where a wet blanket over the entrance of a door cooled the air around it as it dried.

But beyond this, no one could cool a room at will because no one knew how the cooling happened, though, at times, emerging from the annals of history, some con artist or charlatan, particular to no time or place (since swindling is a classical art), would claim the power to control air temperature. A mystic bets a king he can chill the air of a cave, or an architect builds a “cool room” for a wealthy emperor, claiming supernatural abilities, when, really, the walls are filled with large blocks of ice. And though nothing but innovative design presented as magic, the wonder expressed at such feats reminds us that the power to call forth the mutinous winds of winter in the heat of summer has been a force associated throughout history with sorcery. Even with the rise of Western science, which attempted to demystify the universe as wholly knowable, like some galactic Rubik’s Cube waiting to be solved, the act of temperature control was fantasy more fitting for Prospero than Newton.

Until 1755. In that year, the Scottish scientist William Cullen rapidly dropped the pressure of diethyl ether in a vacuum pump by expanding its chamber. Cullen noticed that, along with the chamber’s pressure, the mercury of a thermometer placed inside had also lowered. Cullen repeated the experiment with different liquids—water, wine, vinegar, oils, ammonium chloride. All resulted in cooling, though to varying degrees of intensity. In his last trials, Cullen set a vessel of ethyl nitrite in a larger vessel of water (much like the ancient Egyptians had done). When he dropped the pressure of the inside vessel, the water around it froze.

What was happening?

Before answering, it will help to define the general physics of a few concepts that we use all the time but may not fully comprehend.

First, what exactly is temperature? Though we don’t always notice it, everything’s in motion all the time. All matter—that which we see and that which we can’t—is made of particles that move randomly. (I picture them as jiggling beads.) The speed at which a particle jiggles (as well as its mass) determines its level of kinetic energy. In one object, the kinetic energy of each bead varies. Temperature, then, is not the measure of energy in one jiggling particle. Temperature is the measure of the average kinetic energy of all particles in an object, the measure of the average motion of jiggling beads. Temperature is also the willingness of that object to transfer its kinetic energy to the space around it.

This definition of temperature as “average kinetic energy” is crucial to understanding how evaporation cools. A glass of water has a uniform temperature, but the individual atoms that make up the water jiggle at different speeds. Energy is required to shift matter from one state to another—from a liquid to a gas, for instance. Once the level of energy of a particle exceeds a certain threshold (a threshold determined by the kind of particle), the particle changes states. If we’re thinking about changing states from liquid to gas, we call this the boiling point. Anyone who’s ever boiled water for tea knows this. If we want tea, we fill a kettle with water and place it over a flame. The flame provides the energy (in the form of heat) needed for the water molecules to jiggle so fast that, at 212°F, they turn to vapor.

But water can turn to vapor without added heat, especially in dry air. Our skin secretes sweat, which is mostly salt water, and some molecules of sweat jiggle so fast that they absorb kinetic energy around them, shifting to vapor. As a water molecule changes states from liquid to gas, it absorbs the heat from our skin and transfers this heat to the air. As a result, the temperature of our skin lowers because its average kinetic energy has now decreased. Constantly shifting atmospheric pressure, temperature, and humidity tend to complicate this simplistic understanding of evaporative cooling, but the point here is this: if a particle has enough energy to change states from a liquid to a gas, it absorbs the kinetic energy around it and carries that energy into the air, leaving whatever it came from cooler than it was before. When air is drier, water evaporates more easily because the air has a greater capacity to hold moisture. This is why a swamp cooler works well in New Mexico or west Texas. When the air is humid, evaporation happens less because the air is already saturated with moisture, like a wet sponge. (Despite its name, a swamp cooler is useless in Florida.)

It may also help to keep in mind the laws of thermodynamics, which were formulated after Cullen but were very much at work in his experiments. The first law of thermodynamics states that energy is always conserved in a closed system. Energy, of which there are many kinds, can convert from one sort to another—from motion to heat, for instance—but energy is never created or destroyed. For example, methane, which fuels most gas stoves, doesn’t appear out of nowhere. Methane is a result of the slow decomposition of plants and animals that lived millions of years ago. While living, those plants and animals took in energy via the rays of the sun (or via other plants and animals that did the same) and converted it into biomass. Methane, then, is decomposed sunshine, dredged from the depths of the earth. The flame on our stove appears suddenly when we turn the knob, but this isn’t the creation of energy from nothing either. Uncombusted methane, which carries the potential energy of the ancient sun in its chemistry, combines with oxygen, and, with the help of a spark, combusts, transforming the potential energy to light and heat. Some of that heat transfers to our kettle, boiling our water. Most of it escapes unused into the air—the reason gas burners are particularly wasteful. But if we could somehow keep track of all this energy before and after it boiled our water, we would find that, even across millennia, the total quantity of energy never changed. Instead, energy changed forms.

The second law of thermodynamics states that all energy in a closed system tends toward disorder. But what is disordered energy? Let’s say that after dessert I forget to put the tub of ice cream back in the freezer. The more organized state of thermal energy (the frozen ice cream) will begin to absorb the room-temperature heat around it, allowing it to shift states from solid to liquid. In turn, the ice cream will also cool the air around it a little. By morning, the tub and the air will have reached thermal equilibrium. They’ve integrated. The ice cream has melted. That is, the more organized state (concentrated cold, segregated from the warm room) has taken on the energy of the more disordered state. (And the energy of my partner, who told me to put the ice cream back, has also shifted to a more disordered state, though this is irrelevant, since love, as far as I can tell, doesn’t follow the laws of thermodynamics. Thank goodness.)

This second law of thermodynamics establishes a general rule of irreversibility of energy, what’s sometimes called the “arrow of time.” While energy can transfer from one kind to another, it doesn’t always transfer back. The ice cream melted. But it won’t freeze spontaneously unless we put it back in the freezer, because to do so would violate this second law of thermodynamics. Temperatures do not order (segregate) themselves. They integrate. (This is essentially what time is too: the flow of net energy from order to disorder without reversibility. Which is why Cher can only sing about turning back time.) The second law offers a general explanation for why Cullen’s feat was unprecedented. It’s easy to move from cold to hot through thermal energy (fire) because it’s a move from order to disorder. But you can’t perform the reverse—hot to cold—without hacking the laws a bit.

So what was Cullen’s hack? Pressure. Lowering air pressure can decrease the boiling point of a liquid without added heat. Pressure is the force exerted by (in Cullen’s experiments) the molecules of a gas on the inside of its container. Pressure is also the force of gas molecules pushing on the surface of the liquid in the container. In an open system, typical pressure is atmospheric pressure, and at elevations close to sea level, the temperature at which water boils is its normal boiling point. But if you’ve ever made tea on a mountaintop, you know that it takes much less energy (heat) to boil the water. We usually think of a boiling point as the temperature at which a liquid turns to vapor. This isn’t untrue. But a more accurate explanation is that the boiling point of a liquid is the threshold of average kinetic energy needed for the liquid molecules to overcome the pressure of the air pressing down on it. When the pressure of air above the surface of the liquid is lower, the force of air molecules pushing on the surface of the water is weaker, and the liquid molecules require less kinetic energy to vaporize. The lower the pressure, the lower the temperature needed to boil the water. In a sealed space, lowering the pressure of a gas increases the rate of evaporation, since those jiggling beads can more easily overcome the forces keeping them in their liquid state. Liquid molecules absorb energy as they vaporize. If we think of the heat as simply transferring from the water to the air, we might think there should be no change in temperature within the space, but changing states of matter from liquid to gas converts “sensible heat” (the change in temperature we can measure with a thermometer) to “latent heat” (a sort of “hidden” heat that won’t register on the thermometer). The sensible heat is a kind of energy that fuels the transfer from liquid to gas without raising the temperature. Since more and more of this sensible heat (room temperature) is converted to latent heat, the overall effect of this rapid decrease in pressure and increased evaporation at room temperature is cooling.

And how do you decrease the pressure? By expanding the volume of the container, which, in allowing more room, decreases the frequency that the particles will hit the container and the surface of the liquid. (A few lungfuls of air can burst the balloon at your birthday but not the deflated Snoopy at the Macy’s parade.) As the volume of the container expands, the air around it cools. After a few minutes, according to the second law of thermodynamics, the air inside will warm to the temperature of the air outside as the two reach equilibrium once more.

Cullen’s experiment was the first mechanical cooling of the air to be recorded, harnessing the natural cooling of evaporation by mechanically expanding the space of a volatile liquid. Though his method was impractical for cooling a room, two centuries away from the kind of domestic window unit the Carrier company would eventually sell to millions of Americans, Cullen had mastered the unmastera...