The reliance on air conditioning, widespread in the United States, is explored in Eric Dean Wilson’s book After Cooling: on Freon, Global Warming, and the Terrible Cost of Comfort. The book examines how air conditioning has become one of the most effective ways of cooling down – and explains how harmful chemicals that make our lives comfortable also contribute to the climate crisis.

The modern refrigerant – gas in refrigerators, freezers, and air conditioning systems – was first introduced in the 1930s in the form of a chemical called chlorofluorocarbons (CFCs), better known as freon. This chemical escaped into the air over time, tearing a hole in the ozone layer. In 1987 a worldwide agreement was reached to ban the production of CFCs – although every year in October an ozone hole appears over the Antarctic.

HFCs, the chemicals that replaced the banned refrigerant, are not ozone depleting, but their global warming potential can be hundreds to a thousand times that of carbon dioxide. Today HCFC is the most common refrigerant used in air conditioners and automobiles, which has a much lower ozone-depleting potential.

Wilson’s book is not a call to abolish air conditioning. He admits that refrigerants can save lives in a heatwave. Prolonged high temperatures can affect people’s mental and physical performance, and air conditioning is an effective thermal management tool in classrooms. But before the widespread use of commercial air conditioning, our world was cooler – and in search of comfort, we warmed our planet.

In an interview, Wilson ponders the cost of American comfort.

So if I sit 3 feet from a window AC unit, am I throwing harmful chemicals into my home or into the atmosphere?

Air conditioning systems do not consume refrigerants or dispense them directly. But what the chemical industry that made air conditioners claimed was that they did not send freon into the atmosphere. According to the industry, it was perfectly safe because it would never leak. Well that doesn’t happen. What happens especially with car air conditioning systems is that when a refrigerant is poured into a system, an air conditioning system, it slowly starts to leak over the course of about 15 years.

And even if they don’t, when they get rid of an air conditioner, the vast majority of people simply walk past it on the street, or toss it in the dump or something like that, which is technically illegal. But there is no way to really regulate it. As I was walking down the street today, I saw two air window units that had just been smashed on the street. It is expensive to have someone to look after them properly. And these units most likely have HFCs.

What was the alternative to CFCs after the ban?

There are substitutes such as HFOs (fluoroolefins) that do not deplete the ozone layer. All evidence suggests they are fine, but with each successive generation of CFC refrigerants, we thought they were fine and they weren’t. I’m not a chemist or an atmospheric scientist, but I see a pattern here that I’m quite skeptical about.

Can you talk about addiction to AC during a heatwave?

In a heat wave, you have people who are prone to heat-related illnesses. These are people who tend to live in neighborhoods that have less access to natural shade, fewer trees, less access to parks, more asphalt that absorbs heat and can make parts of the city 10F hotter in some places.

Low-income residents are also more vulnerable. Even if they can afford the device, they may be reluctant to turn it on because they are behind on their energy bills. What also happens during the heatwave is everyone in the city turns on their air conditioning, overloading the electrical grid, and there is a risk of power outages.

One of the things that I write about very briefly in the book is to point out the need for things like community solar or community controlled energy, rather than having a monopoly to control them. Because if profit is the driving force, monopolies are not interested in saving lives.

What if we don’t want or can’t afford AC?

The technically less complex solution is to plant more trees. I think initiatives to ensure that there is lush vegetation on every street in New York, especially in working-class neighborhoods, which tend to have fewer trees, are crucial. Another solution is a sustainable design with passive cooling. There are innovative architects who are into nature, things like termite mounds, beehives, things that exist in the wild that regulate temperature.

Understand how to shade, how to give light, but without direct sunlight that heats a room. Things like bringing natural wind into a room and using better building materials. And these cooling strategies don’t have to be enormously expensive, so I have great faith in good design.

What do you hope people will take away from your book?

The vast majority of cooling in the United States is not intended for emergency situations. And it’s not even for situations that I would say improve our lives. So I ask us to really give thought to how our level of comfort and what we define as comfort are constructed. And whether our level of comfort has actually resulted in an uninhabitable planet. I am not calling for all of us to suffer, I am actually calling for us to redefine what it means to feel good.

This article was amended on July 28, 2021 to remove an erroneous reference to the use of building materials “that do not absorb heat” as an alternative to using air conditioning.