How Cooling Things Down Is Heating Things Up

By Michael Thomas

A visual essay about how cooling equipment like air conditioning and refrigerators cause climate change and what to do about it.


A bad feedback loop

For most Americans, this week is bound to be a hot one. Thanks to a heat wave sweeping across the country, 90% of the population will experience temperatures above 90 degrees. 

Summers are always hot. But due to climate change, they’re getting hotter every year in most of the US. Over the last century average temperatures on Earth have risen by 1 degree celsius. If you’ve asked yourself recently, “Was it always so warm this time of year?” the answer is probably no. 

Fortunately for many people in America, air conditioning protects from the discomfort (and in some cases lethality) of unbearably hot temperatures. 

Air conditioning, like other cooling technology, is essential to modern life and easy to take for granted.  

But we’ve got ourselves into a little pickle. The same cooling technology that keeps us comfortable on a hot day is one of the biggest reasons for global warming. In fact, air conditioners and refrigerants are responsible for about 12% of all C02 emissions globally. 
This creates a bad feedback loop. As we emit more CO2, the planet gets warmer, and as the planet gets warmer the need for air conditioning grows.
In this story we’ll explore how we got ourselves into this problem and what some of the world’s smartest scientists say we need to do in order to get ourselves out.

A brief history of keeping cool

Humans have been trying to beat the heat since the beginning of civilization. For example people everywhere from the steppes of Kyrgyzstan to the Sonoran Desert of Arizona have been using a building material called adobe to keep their homes cool during the day and warm during the night.  

At the beginning of the 20th century a New Yorker named Willis Carrier invented the first modern electric air conditioner. At first, units were expensive and bulky, so only large buildings like movie theaters had AC. But by the middle of the century costs and sizes dropped and adoption of in-home air conditioning skyrocketed in America. 

Not everyone was so quick to accept air conditioning, however. In fact, for a short time, the technology was morally controversial. As the Smithsonian’s Peter Liebhold wrote, “There was this notion that trying to control the environment was going against God’s will.”

90% of homes have air conditioning and a fridge 

The first in-home refrigerator was invented in 1917. Ten years later in 1927, GE released the “Monitor-top” fridge, which would go on to sell one million units. By 1960 nearly every American home had a fridge. Around that time the first window-unit air conditioner was invented, which made air conditioning more accessible. In the following decades adoption skyrocketed in America. 

The solution isn’t as simple as turning down the thermostat

It’s easy to dismiss air conditioning as an unnecessary comfort (especially if you grew up in a house without it, like I did). But for many air conditioning and other cooling technologies are a matter of life and death, especially in low-income countries.

It protects against heat waves

According to the World Health Organization (WHO), 12,000 people die from heat waves globally every year. Due to climate change, that number could rise as high as 250,000 as cities around the world heat up. 

It enables modern medicine

Cooling technology is also essential to modern medicine. The WHO estimates that 150,000 people die every year due to broken “cold chains.” 

It prevents food-born illnesses

If you haven’t had food poisoning recently, you can thank the cold chain. 420,000 people weren’t so lucky in the last year and died due to contaminated food.  

How cooling technologies cause climate change

While air conditioning and refrigerants make modern life possible, the greenhouse gases they emit contribute significantly to climate change. 

These technologies cause climate change in two primary ways.

Energy usage
Air conditioners make up about 20% of electricity usage in the average American home. And today most of that electricity is generated from fossil fuels like coal and natural gas.  

Leaky hydrofluorocarbons 

A lesser known cause of climate change are hydrofluorocarbons (HFCs).

Prior to the 1980s most AC units and fridges used chlorofluorocarbon (CFC) coolants as a refrigerating fluid. But then scientists discovered their link to ozone depletion. In 1987 world leaders gathered in Montreal and agreed to ban the use of these gases (Ah, what a simple time… When world leaders listened to scientists). 

Most companies replaced CFCs with hydrofluorocarbons (HFCs), which was bad news for the stability of Earth’s climate. As a greenhouse gas these new HFCs are anywhere from 1,000 to 3,000 times more potent than CO2. Today HFCs account for 1% of global emissions. But they are growing at an alarming rate of 10-15% per year.

30% of transportation emissions come from leaky HFCs (not burning gasoline)

Cooling Could Use Up About Half of Our Remaining Carbon Budget

According to the United Nations, the population will grow by 2 billion people by 2050. This growth, combined with rising incomes across Africa and Asia, means we’re going to need a lot more air conditioning units and fridges. 

None of this is good news considering that in order to avoid 1.5 degrees of warming, we need to cut emissions 50% by 2030 and 90% by 2050. That’s why we need to do something to solve this problem fast. 
air conditioning emissions

The Most Effective Things You Can Do To Help Solve This Problem

To take effective climate action you don’t need to be a climate scientist or policy wonk. Everyone reading this can do something to help reduce emissions from the cooling sector. Below I’ll cover:

  1. A summary of the best proposed solutions to this problem 
  2. The most effective steps you can take to be a part of the solution (ranked by impact)

The best proposed solutions

On July 16, 2020, the UN released a report detailing how we can cut 460 billion tons of cumulative global emissions over the next four decades. For context, that’s as many emissions as the world produces in eight years. The report can be broken down into two primary recommendations:

  1. Increase efficiency — Right now most cooling equipment sold isn’t the most efficient. In the United States the most efficient model on the market is 3x more efficient than the least. 
  2. Phase out HFCs — If we banned HFCs today like we did CFCs during the ozone crisis, we could avoid 53 billion tons of emissions over the next 40 years.

Ok so that’s what we — as in the big, global we — need to do. But what can me and you do?

The most effective thing you can do is get involved politically.

The most effective lever we as a world have to dramatically cut emissions is policy. 

But before your eyes glaze over, hear me out. Policy isn’t some thing that wonks in windowless rooms write and then pass into law. Most barriers to policy are political. And most politicians don’t pass bold climate policy because they think you don’t want it (and many of them get lobbied by fossil fuel companies). 

But no amount of fossil fuel money could prevent bold climate action if everyone who cared about the environment voted. 

Today less than half of Americans vote. About a quarter of young people vote. So the most effective thing you can do is vote for green candidates, then get your friends to vote, and then organize your community to vote. 

Erika Reinhardt put together a great guide on how to do this effectively. 

The second best thing you can do is reduce your home’s emissions

The average American emits 20 tons of CO2 every year. About 5 of those come from your home. And the vast majority of those emissions come from three places: your air conditioning, heater, and hot water heater.

If you can afford to replace any of these pieces of equipment with more efficient equipment, you can make a big impact. But some of these systems cost thousands of dollars. So if you can’t just remember to prioritize efficiency when you eventually have to replace them. (In my next story I’m going to go over this in more detail).

Don’t buy fridges or AC units with HFCs

Remember how I mentioned that HFCs are 1,000-3,000 more potent as a greenhouse gas than CO2? Well, the odds are pretty good that you have some of them in your house. That’s because most AC units and fridges sold until recently used them. 

And amazingly, while most countries have banned them, the United States hasn’t. 

Here’s a quick guide to the good and bad ones to watch for:

Good refrigerants

Bad refrigerants

Share this with a friend or sign up to read more

If you learned something new from this post and want to support my work, please do me a favor and share this story or sign up for the next one. You’ll also be helping grow awareness for climate change and what we can all do to be a part of the solution. 

Subscribe to our newsletter

Don't miss new updates on your email