Hello and welcome to The Anthropocene Reviewed, a podcast where we review different facets of the human-centered planet on a five-star scale. I’m John Green, and today I’ll be reviewing air conditioning and a family of tree species known as Sycamore trees.

Let’s begin with air conditioning. Over the last hundred years, the weather for humans has gotten considerably hotter, and not only because of global warming, but also because of where we are choosing to live. Here in the United States, for instance, the three fastest growing states over the last century—Nevada, Florida, and Arizona—are also among the warmest states. This trend is perhaps best exemplified by the U.S.’s fifth largest city, Phoenix, Arizona, which had a population of 5,544 people in 1900. Today, Phoenix is home to around 1.7 million people. Phoenix’s average high temperature in August is 105 degrees Fahrenheit, or over 40 degrees Celsius, and yet they have a professional ice hockey team, the Arizona Coyotes. Until 1996, the Coyotes were known as the Jets, and they played their hockey in Winnipeg, Manitoba, where the weather is considerably cooler, but the NHL followed the money toward the equator.

One of the reasons for this huge shift in human geography is the miracle of air conditioning, which allows people to control the temperature of their interior spaces. It’s hard to even get your head around the extent to which air conditioning has changed human life in rich countries—from small things, like the declining percentage of time that windows are open in our homes, to large things, like the availability of medication. Insulin, many antibiotics, nitroglycerin, and many other drugs are heat sensitive and can lose their efficacy if not stored at so-called “room temperature,” which is defined as between 20 and 25 degrees Celsius, or 68 and 77 Fahrenheit, temperatures that no rooms in summertime Phoenix could hope to achieve before air conditioning. Indeed, climate-controlled drug storage remains one of the big challenges for health care systems in poor countries, where many health facilities have no electricity.

Even the very experience you’re having right now is contingent upon air conditioning—this podcast is stored along with the rest of the world’s digital information on computer servers, which require artificially cool and dry air to prevent corrosion and overheating. 

Temperature has long been a worry for humans, of course. In a 2015 New Yorker story about the sexism of air conditioning—more on that in a moment—Anthony Lydgate points out that one of the central bummers of being expelled from Eden in John Milton’s Paradise Lost is that God tilts the Earth on its axis, causing ‘“scorching heat” in summer and “pinching cold” in winter. In ancient Egypt, houses were cooled by hanging reeds from windows and trickling water down them. The eighth century Chinese emperor Xuanzhong had a “cool hall” built in the imperial palace that featured water-powered fans. In an essay with the catchy title An Account of the Extraordinary Heat of the Weather in July 1757, and the Effects of It, the English physician John Huxham wrote that heat caused, “sudden and violent pains of the head, and vertigo, profuse sweats, great debility and depression of the spirits.” He also noted that the urine of heat wave victims was “high-colored and in small quantity.”

In many countries today, including the United States, heat waves cause more deaths than lightning, tornadoes, hurricanes, floods, and earthquakes combined. A 2003 European heatwave that was concentrated in France led to the deaths of over 70,000 people. Deadly heatwaves from Australia to Algeria and from Canada to Argentina have been common throughout history, but one of the weirdnesses of the Anthropocene is that in the wealthier parts of the world, heat is now more of a health problem in mild climates than in hot ones. Over the past 20 years, people living in usually cool central France, where home AC is uncommon, have been far more likely to die from heat waves than people living in usually sweltering Phoenix, where over 90% of homes have air conditioning.

And then there is the other weirdness of modern air conditioning: cooling the indoors warms the outdoors. Most of the energy that powers air conditioning systems comes from fossil fuels, the use of which warms the planet, which over time will necessitate more and more conditioning of air. According to the International Energy Agency, air conditioning and electric fans combined already account for around 10% of all global electricity usage, and they expect AC usage will more than triple over the next thirty years. And like most other energy-intensive innovations, AC primarily benefits the people in rich countries, while the burdens of climate change are borne mostly by those in poor ones.

Contemporary air conditioning began with an accident: In 1902, a young engineer in Buffalo, New York named Willis Carrier was tasked with solving a problem: A printing company’s magazine pages were warping due to summertime humidity. Carrier created a device that essentially reversed the process of electric heating, running air through cold coils instead of hot ones. This effectively reduced humidity, but it also had the very useful side effect of decreasing indoor temperatures. Carrier went on to make many more inquiries into what he called “treating air,” and the company he co-founded, The Carrier Corporation, remains one of the largest air conditioning manufacturers in the world.

And my, how AC has grown—here in Indianapolis, the high temperatures are above 90 degrees Fahrenheit—or 32.2 Celsius—only about thirteen days per year, and yet most of our homes and office buildings are air conditioned. This is in part because architecture has changed dramatically in the last 50 years, especially when it comes to commercial buildings, to assume the existence of air conditioning—a phenomenon explored wonderfully in an episode of the podcast 99% Invisible. But AC is also becoming more common because more of us expect to be able to control our interior environments. When I’m outside, if I can adjust my wardrobe a bit, I feel very comfortable anywhere between 60 and 85 degrees Fahrenheit—about 15 to 29 Celsius. But inside, my comfort zone drops dramatically, down to a couple of degrees. I loathe sweating while sitting, as I often did when I lived in an un-air-conditioned apartment in Chicago. But I also find it very uncomfortable to feel goosebumps of chill on my arms when I’m indoors. Like an expensive painting or a fragile orchid, I thrive only in extremely specific conditions.

And in that respect I am not alone: A Cornell University study in 2004 found that office temperatures affect workplace productivity—when temperatures were increased from 20 degrees Celsius to 25, typing output rose by 150% and error frequency dropped by 44%. This is no small matter—the author of the study said that it suggested “raising the temperature to a more comfortable thermal zone saves employers about $2 per worker, per hour.” Why, then, are so many summertime office environments so cool when it is both more expensive and less efficient to keep summertime temperatures so low? Perhaps because the definition of “room temperature” has historically been established by analyzing the temperature preferences of forty-year-old, one-hundred-fifty-four pound men wearing business suits. Studies have consistently found that on average women prefer warmer indoor temperatures. Also, men who don’t wear business suits enjoy warmer indoor temperatures—all of which is to say that our office buildings are, on the whole, too cold.

Now, we’re not here to review the 2-star practice of wearing a business suit on a hot summer’s day, but I do find it odd and a bit distressing that so many of us—myself included—have to wear multiple layers to feel comfortable in our overly air conditioned commercial spaces. Like, I remember as a kid growing up in Orlando, Florida, I almost never needed a sweatshirt—except for when going to the absolutely frigid movie theater. But that seemed natural to me. 

Air conditioning, like so much else in the Anthropocene, has become a background hum that reshapes our lives without our much noticing it. Still, I’m immensely grateful for air conditioning. It makes human life vastly better. It does so unsustainably, and I know our descendants may be unable to forgive our cooling excesses, but God help us, we just want to be comfortable. I give air conditioning three and a half stars.

After the break, we’ll turn our attention to the sycamore tree, but first . . . 

Ad Break

My children like to play an age-old game with me called, “Why?” I’ll tell them, for instance, that I need them to finish breakfast, and they’ll say why, and I’ll say so that you receive adequate nutrition and hydration, and they’ll say why, and I’ll say because as your parent I feel obligated to protect your health, and they’ll say why, and I’ll say partly because I love you and partly because of evolutionary imperatives baked into my biology, and they’ll say why, and I’ll say because the species wants to go on, and they’ll say why, and I’ll pause for a long time before saying, “I don’t know. I guess I believe in spite of it all the human enterprise has value.” And then there will be a silence. A blessed and beautiful silence will spread across the breakfast table. I might even see a kid pick up a fork. And then, just as the silence seems ready to take off its coat and stay awhile, one of my kids will say, “Why?”

My brain likes to play a somewhat similar game. That game is called, “What’s even the point?” There’s an Edna St. Vincent Millay poem I’ve quoted in two of my novels and will now quote again, because I’ve never come across anything that describes my depressive blizzards so perfectly. “The chill is in the air,” the poem begins, “which the wise know well and have even learned to bear. This joy, I know, will soon be under snow.”

I’m in an airport when suddenly I feel the chill in the air. What’s even the point? I’m about to fly to Milwaukee on a Tuesday afternoon, about to herd with other moderately intelligent apes into a tube that will spew a truly astonishing amount of carbon dioxide into the atmosphere in order to transport us from one population center to a different one. Nothing that anyone has to do in Milwaukee really matters, because nothing really matters. There’s no point to the human endeavor in the largest sense. We will leave no permanent legacy in this impermanent universe, and our central lasting contribution to Earth will be that we were the first species to grow powerful enough to muck up the planet.

When my mind starts playing What’s Even the Point, I can’t find a point to making art—which is just using the finite resources of our planet to decorate, and I can’t find a point to planting gardens, which is just inefficiently creating food that will sustain our useless vessels for a little while longer, and I can’t find a point to falling in love—which is just a desperate attempt to stave off the loneliness that you can never really solve for, because you are always alone in what Robert Penn Warren called, “the darkness, which is you.”

Except it’s not really a darkness. It’s much worse than that. The writer Jacqueline Woodson has said that we need to consider carefully what we construct as dark, and she’s right. When my brain plays What’s Even the Point, what really descends upon me is a blizzard of blinding, frozen white light. Being in the dark doesn’t hurt, but this does, like staring at the sun. That Millay poem refers to “the eye’s bright trouble.” It seems to me that bright trouble is the light you see the first time you open your eyes after birth, the light that makes you cry your first tears, the light that is your first and greatest fear. 

What’s even the point? All this trial and travail for what will become nothing, and soon. Sitting in this airport, I’m disgusted by my excesses, my failures, my pathetic attempts to forge some meaning or hope from the materials of this meaningless world. I’ve been tricking myself, thinking there was some reason for all of it, thinking that consciousness was a miracle when it’s really a burden, thinking that to be alive was wondrous when it’s really a terror. The plain fact, my brain tells me when it plays this game, is that the universe doesn’t care if I’m here. Night falls fast, Millay wrote. Today is in the past.

The thing about this game is that once my brain starts playing it, I can’t seem to find a way to stop. Any defense I try to mount is destroyed instantaneously by the blinding light. It feels like the only way to survive life is to cultivate an ironic detachment from it. If I can’t be happy, I at least want to be cool. When my brain is playing What’s Even the Point, hope feels so flimsy and naïve—especially in the face of the endless outrages and horrors of human life. What kind of mouth-breathing jackass looks at the state of human experience and responds with anything other than nihilistic despair?

But of course the problem with despair is that it isn’t very productive. Like a replicating virus, all despair makes is more of itself. If playing What’s Even the Point made me a more committed advocate for justice or environmental protection, I’d be all for it. But the white light of despair instead renders me inert and apathetic. I struggle to do anything. I often can’t find a reason to get out of bed in the morning.

Philosophical questions—what’s the point of being alive, what should we seek from life, how can we know what we know, how and where should we seek meaning—are often dismissed as pointless. What’s the difference between a philosophy degree and a pepperoni pizza? The pepperoni pizza can feed a family of four. And so on. But I think those questions are genuinely important, because I need to be able to survive my mind playing What’s Even the Point. I don’t want to give it to despair; I don’t want to take refuge in detached ridicule of unironized emotion. I don’t want to be cool if cool means being cold to or distant from the reality of experience. I want to feel what there is to feel while I am here. 

You don’t choose when your kids play the Why game, and you don’t choose when your brain plays What’s Even the Point. It’s exhausting. It gets old so fast, listening to the elaborate prose of your brain tell you that you’re an idiot for even trying. When the game is being played, it feels like it will never end, like you will be in active combat with your brain for what remains of your wretched life.

But no. No. Now always feels infinite and never is. You keep going. You go to therapy. You try a different medication. You meditate, even though you dislike meditation. You exercise. You wait. Your mind keeps playing What’s Even the Point, and you keep refusing to give in to it, battling it with philosophy and self-help books and religion and whatever else that works. And then one day, the air is a bit warmer, and the sky is not so blindingly bright. It’s overcast, and you’re walking through a forested park with your children. Your nine-year-old points out two squirrels racing up an immense American Sycamore tree, its white bark peeling in patches, its leaves bigger than dinner plates. You think, my God that’s a beautiful tree. It must be a hundred years old, maybe more. Later, you’ll go home and read up on sycamores and learn that there are sycamore trees alive today that date back more than three hundred years, trees that are older than your nation. You’ll learn that George Washington once measured a sycamore tree that was over thirteen meters in circumference. You’ll read that Herodotus wrote 2,400 years ago that the Persian emperor Xerxes was marching his army through a grove of sycamore trees when he came across one of “such beauty that he was moved to decorate it with golden ornaments and to leave behind one of his soldiers to guard it.”

But for now you’re just looking up at that tree, thinking about how it turned dirt and water and sunshine into wood and bark and leaves, how it turned nothing into a place where squirrels play, and you realize you are in the vast dark shade of this giant tree, and that’s the point. I give sycamore trees four and a half stars.

Thanks for listening to The Anthropocene Reviewed, which was written by me, edited by Stan Muller, and produced by Rosianna Halse Rojas and Tony Philips. Joe Plourde is our technical director. Hannis Brown makes the music. 

Thanks also to the many of you who’ve written in to suggest a review of air conditioning—Thomas and Jeff, for instance, sent me an email suggesting it while I was writing the review, and Melanie, Tom, and Charlene’s recommendations sent me down fascinating AC rabbitholes. If you’d like to suggest a topic for review, or just say hi, please email us at anthropocenereviewed at gmail dot com. 

My favorite fact that didn’t make it into today’s episode? Annie Dillard writes beautifully of sycamores in her classic book Pilgrim at Tinker Creek. In it, she quotes her friend Roseanne Coggeshall as saying “that “sycamore” is the most intrinsically beautiful word in English.” I’m inclined to agree. 

Last thing: If you are concerned about your mental health, please reach out for help—either by talking to someone you know or by calling your local mental health hotline. Here in the U.S., you can always call 1-800-273-8255. Pull over right now if you need to and write that number down: 1-800-273-8255. I’m so glad you’re here with us. Thanks again for listening. We’ll leave you today with the wind in the leaves of that sycamore tree.