Air conditioning transformed the world. Cities such as Singapore and Dubai would not have risen without it. In the United States, artificial cooling enabled the blockbuster growth of the Sun Belt. All over the planet, AC enabled expansion of the manufacturing plants and office buildings, the semiconductor fabrication plants and server farms, on which the global economy relies.
And, yet, the cooling technology remains unacceptably scarce. One study found that only 8 percent of the 2.8 billion people living in the hottest parts of the world currently have air-conditioned homes. In 2018, only 5 percent of Indian households were equipped with AC, according to the International Energy Agency (IEA), compared to over 90 percent in the United States and Japan. The share in South Africa was 6 percent; in Indonesia 9 percent.
The idea of ubiquitous climate control might strike some in the environmental movement as immoral; another bit of evidence, as Pope Francis put it, of people’s failure to curb “their harmful habits of consumption which, rather than decreasing, appear to be growing all the more” at the expense of the planet.\
But extreme heat stunts development. Studies in several nations have found that it lowers workers’ productivity, national output and income. Given current trends, the International Labour Organization estimates that 2 percent of working hours worldwide will be lost either because it is too hot to work or because workers have to labor at a slower pace. In Southern Asia and Western Africa the resulting productivity loss might even reach 5 percent.
Heat also kills. Heat-related deaths jumped 68 percent over the past two decades. Today, heat waves cause 12,000 deaths a year. They are preventable: Mortality from excessive heat in the United States fell from about 3,600 a year in the first six decades of the 20th century to 600 per year between 1960 and 2004. It was all due to the adoption of AC. For billions of people in poorer, hotter countries — over 90 percent of urban households in India and Indonesia will need air conditioning — AC will be a necessity, not a luxury.
Such countries were always bound to deploy air conditioning at higher rates, as they moved up the income ladder. Longer and more intense heat waves, driven by climate change, will require that process to accelerate. The IEA projects the number of AC units in the world will hit 5.5 billion in 2050, from around 2.3 billion today.
Other than the cost of deployment, the challenge is that all this AC will use a lot of energy, boosting the carbon dioxide emissions that are warming the planet in the first place. Researchers project emissions from residential cooling alone will warm the world by 0.5 degrees Celsius by the year 2100. Today, AC consumes about 7 percent of the world’s power. A study of the 25 countries that account for about three-fourths of global electricity use estimated that air-conditioning ownership increases households’ power consumption by 34 percent, on average. It projected that, as AC penetration grows, carbon dioxide emissions from air conditioning in those 25 nations, which include Mexico, the United States and Indonesia, could triple by 2050, hitting 948 million tons, more than three times the current emissions of France.
This year is already on track to be the hottest on record. Some optimists still believe global temperatures can be kept from rising 1.5 degrees Celsius above the average for the late 19th century. More realistic observers suggest the world might be heading toward 3 degrees of warming by the year 2100. That will make the Earth a more dangerous place. Research by the World Resources Institute concluded that at 3 degrees of warming, 1 in 6 of the world’s largest cities would suffer at least one heat wave per year lasting over a month. Delhi would suffer a minimum of 140 days with temperatures hitting at least 95 degrees Fahrenheit.
The project to combat climate change cannot condemn billions to broil. The moral response to the challenges confronting the world — including climate change, but also poverty and inequality — must include expanding access to lifesaving air-conditioning technology to billions of people who currently lack it.
Providing it to them doesn’t require a technological moonshot. The IEA reports that the average efficiency of air conditioners sold today is less than one-third of the best available technology. Just improving efficiency could cut power demand for cooling in 2050 by 45 percent.
That would still be a lot of electricity for cooling. But the world can’t do without it.