How Air-Conditioning Creates a Climate Conundrum

Summer is here in North America, which means in many places it’s too hot for comfort. To escape the sweltering heat, birds pant, take a dip in the water, and hide from the sun. Humans have an additional edge over biology: air-conditioning. With access to electricity, we are able to alter the air temperature itself.

Air-conditioning is expensive: It costs U.S. homeowners a whopping $29 billion each year. But it saves lives. In summer 2021, a heatwave sent the mercury soaring to record temperatures in the Pacific Northwest, a region that’s relatively under-air-conditioned: In Seattle 44 percent of households have AC, compared to 91 percent nationwide. The North American death toll surpassed 1,000.

Scientists say this heatwave would have been “virtually impossible” without global warming. And heatwaves will become only more frequent, prolonged, and deadly as the decades march on. That makes air-conditioning a life-saving adaptation to climate change. However, it’s hard to feel good about it because AC also makes global warming worse.

The Feedback Loop

As long as our electricity comes from fossil fuels, air-conditioning will present a troubling climate conundrum. Today, two-thirds of the world’s electricity is produced by burning coal and natural gas, which emit carbon dioxide and other greenhouse gases that warm our planet.

“There’s this really interesting loop,” says energy and climate researcher Shelie Miller, from the University of Michigan. The more we run AC, the more electricity we use; more electricity releases more greenhouse gases, heating the planet and requiring even more AC to stay cool. “It’s both a response to what is happening and also a driver,” says Renee Obringer, an energy researcher from Penn State University.

Current AC technology incurs another climate cost: hydrofluorocarbons (HFCs), the industrial chemicals in AC units that cool our rooms. Once in the atmosphere, the five most commonly used HFCs absorb 150 to 5,000 times more of the sun’s energy than carbon dioxide does.

Uncool Inequities

Across the globe high temperatures and heatwaves are growing more common, but not everyone has equal access to room-cooling tech. Today, ACs are clustered mostly in wealthier countries. In the United States and Japan, 9 out of 10 households have AC units. In contrast, only 1 in 10 households have ACs in emerging economies like India and Indonesia, and about 3 in 10 in Brazil and Mexico.

These tropical countries have the most need. They already suffer hotter weather year-round and are experiencing deadlier heatwaves due to climate change. Then, as wealth increases in these countries, “we're actually going to see really rapid expansion of air-conditioning across the world,” Miller says. Scientists predict that the global demand for room ACs will surge from 1.2 billion units in 2018 to beyond 5 billion units by 2050 among those who can afford it, including a fivefold increase in the tropics and subtropics. If all cooling needs were met, regardless of wealth, 14 billion AC units would be needed by 2050.  

“Now it really becomes a matter of adaptation,” says Doug Ahl, executive vice president at Slipstream, an organization invested in climate solutions. “How do we make sure that all citizens have access to everything that the wealthy have access to?”

The Way Out of It

One of the most effective ways to reduce AC emissions is to power our grid differently, using clean energy instead of fossil fuels, Miller says. “Anytime we can green the electricity grid, we’re going to do much better in all sectors of society.” Ahl places his bets on technologies to manage the grid, such as better energy storage and artificial intelligence, which could help regulate electricity use and send it where it’s most needed.

We’ll also need new, more efficient air-conditioning tech. Phasing out HFCs is key. In 2016, 170 countries agreed to cut HFC production and consumption over 30 years under the Kigali Amendment to the Montreal Protocol. To meet those targets, manufacturers will have to switch to climate-friendly refrigerants like propane, as well as use new desiccants to reduce humidity—a process that uses a third of the energy in today’s air-conditioners.

Crucially, people will need to adjust their habits—particularly in wealthy countries with more temperate climates, which face less danger from climate-charged heatwaves. “There are technological solutions that are coming into play,” Miller says, “but a lot will come down to behavior and human acceptance.”

“To me it’s not an economic issue,” Ahl says. “Do we have the will to do it?”

This story originally ran in the Summer 2022 issue. To receive our print magazine, become a member by making a donation today.