The global dominance of air conditioning was not inevitable. As recently as 1990, there were only about 400m air conditioning units in the world, mostly in the US. Originally built for industrial use, air conditioning eventually came to be seen as essential, a symbol of modernity and comfort. Then air conditioning went global. Today, as with other drivers of the climate crisis, we race to find solutions – and puzzle over how we ended up so closely tied to a technology that turns out to be drowning us.

Evolution of air conditioning

• A century ago, few would have predicted this. For the first 50 years of its existence, air conditioning was mainly restricted to factories and a handful of public spaces. The initial invention is credited to Willis Carrier, an American engineer at a heating and ventilation company, who was tasked in 1902 with reducing humidity in a Brooklyn printing factory. Today we assume that the purpose of air conditioning is to reduce heat, but engineers at the time weren’t solely concerned with temperature. They wanted to create the most stable possible conditions for industrial production – and in a print factory, humidity curled sheets of paper and smudged ink.
• Carrier realised that removing heat from the factory air would reduce humidity, and so he borrowed technology from the nascent refrigeration industry to create what was, and still is, essentially a jacked-up fridge. Then as now, air conditioning units work by breathing in warm air, passing it across a cold surface, and exhaling cool, dry air. The invention was an immediate success with industry – textile, ammunition, and pharmaceutical factories were among the first adopters – and then began to catch on elsewhere.
• The House of Representatives installed air conditioning in 1928, followed by the White House and the Senate in 1929. But during this period, most Americans encountered air conditioning only in places such as theatres or department stores, where it was seen as a delightful novelty.
• It wasn’t until the late 1940s, when it began to enter people’s homes, that the air conditioner really conquered the US. Before then, according to the historian Gail Cooper, the industry had struggled to convince the public that air conditioning was a necessity, rather than a luxury. In her definitive account of the early days of the industry, Air-Conditioning America, Cooper notes that magazines described air conditioning as a flop with consumers. Fortune called it “a prime public disappointment of the 1930s”. By 1938 only one out of every 400 American homes had an air conditioner; today it is closer to nine out of 10.
• What fuelled the rise of the air conditioning was not a sudden explosion in consumer demand, but the influence of the industries behind the great postwar housing boom. Between 1946 and 1965, 31m new homes were constructed in the US, and for the people building those houses, air conditioning was a godsend. Architects and construction companies no longer had to worry much about differences in climate – they could sell the same style of home just as easily in New Mexico as in Delaware. 
• By the 1950s, that future had arrived. Electric utilities ran print, radio and film adverts promoting air conditioning, as well as offering financing and discount rates to construction companies that installed it.
• In 1957, Commonwealth Edison reported that for the first time, peak electricity usage had occurred not in the winter, when households were turning up their heating, but during summer, when people were turning on their air-conditioning units. By 1970, 35% of American houses had air conditioning, more than 200 times the number just three decades earlier.
• In the 1990s, many countries across Asia opened up to foreign investment and embarked on an unprecedented urban building spree. Over the past three decades, about 200 million people in India have moved to cities; in China, the number is more than 500 million. From New Delhi to Shanghai, heavily air-conditioned office buildings, hotels and malls began to spring up. These buildings were not only indistinguishable from those in New York or London, but were often constructed by the same builders and architects.
•  In Delhi in the early 1990s older forms of building design – which had dealt with heat through window screens, or facades and brise-soleils – were slowly displaced by American or European styles.
• The builders  want 10- to 20-storey blocks close to one another. That’s just how business works now, that’s what the cities are forcing us to do. It’s all driven by speculation and land value.”This reliance on air conditioning is a symptom of what the Chinese art critic Hou Hanru has called the epoch of post-planning. 
• Today, planning as we traditionally think of it – centralised, methodical, preceding development – is vanishingly rare. Markets dictate and allocate development at incredible speed, and for the actual inhabitants, the conditions they require to live are sourced later, in a piecemeal fashion.

Currrent scenario

There are just over 1bn single-room air conditioning units in the world right now – about one for every seven people on earth. Numerous reports have projected that by 2050 there are likely to be more than 4.5bn, making them as ubiquitous as the mobile phone is today. The US already uses as much electricity for air conditioning each year as the UK uses in total. The IEA projects that as the rest of the world reaches similar levels, air conditioning will use about 13% of all electricity worldwide, and produce 2bn tonnes of CO2 a year – about the same amount as India, the world’s third-largest emitter, produces today.

Steps taken at global level

One step towards solving the problem presented by air conditioning – and one that doesn’t require a complete overhaul of the modern city – would be to build a better air conditioner. There is plenty of room for improvement. 

•  In the mid-1980s, Geneva, which has a warmer climate than much of the US, the local government banned the installation of air conditioning except by special permission. This approach is relatively common across Switzerland and, as a result, air conditioning accounts for less than 2% of all electricity used. The Swiss don’t appear to miss air conditioning too much – its absence is rarely discussed, and they have largely learned to do without.
• The New York City council recently passed far-reaching legislation requiring all large buildings in the city to reduce their overall emissions by 40% by 2030, with a goal of 80% by 2050, backed with hefty fines for offenders. Costa Constantinides, the city council member spearheading the legislation, says it is “the largest carbon-emissions reduction ever mandated by any city, anywhere”. The Los Angeles mayor’s office is working on similar plans, to make all buildings net-zero carbon by 2050.
• In countries where air conditioning is still relatively new, an immense opportunity exists to find alternatives before it becomes a way of life. The aim, in the words of Thomas, should be to avoid “the worst of the west”.
• Recently, the Indian government adopted started its countrywide national residential building code . It allows higher indoor temperatures based on Indian field studies – Indian levels of comfort – and notes the “growing prevalence” of buildings that use air conditioning as a technology of last resort.
• Global Cooling prize  to encourage engineers to build a more efficient air conditioner was launched last year by the Rocky Mountain Institute (RMI), a US-based energy policy thinktank, and endorsed by the UN environment programme and government of India. They are offering $3m to the winner of the inaugural Global Cooling prize. The aim is to design an air conditioner that is five times more efficient than the current standard model, but which costs no more than twice as much money to produce. They have received more than a hundred entries, from lone inventors to prominent universities, and even research teams from multibillion-dollar appliance giants.

Concerns

• But, as with other technological responses to climate change, it is far from certain that the arrival of a more efficient air conditioner will significantly reduce global emissions. According to the RMI, in order to keep total global emissions from new air conditioners from rising, their prize-winning efficient air conditioner would need to go on sale no later than 2022, and capture 80% of the market by 2030. In other words, the new product would have to almost totally replace its rivals in less than a decade. Benjamin Sovacool, professor of energy policy at Sussex University and a lead author on the next Intergovernmental Panel on Climate Change (IPCC) report, describes this ambition as not impossible, but pretty unlikely.
• New air-conditioner technology would be welcome, but it is perhaps “the fourth, or maybe fifth thing on the list we should do” to reduce the emissions from air conditioning, says Diana Ürge-Vorsatz, a professor of climate change and energy policy at Central European University, and a lead author on the forthcoming IPCC report. Among the higher priorities that she mentions are planting trees, retrofitting old buildings with proper ventilation, and no longer building “concrete and glass cages that can’t withstand a heatwave”. She adds: “All of these things would be cheaper too, in the long run.”
• But while these things are technically cheaper, they require changes in behaviour and major policy shifts – and the open secret of the climate crisis is that nobody really knows how to make these kind of changes on the systematic, global scale that the severity of the crisis demands.

What are the options

• Less use of air conditioning- But that need to change our lifestyle and any serious proposals to change our lifestyles – cutting down on driving, flying or imported avocados – are considered “beyond the pale, heretic, almost insane”. This is especially true of air conditioning, where calls to use it less are frequently treated as suggestions that people should die in heatwaves, or evidence of a malicious desire to deny other people the same comforts that citizens in wealthy countries already enjoy.

• Cut the over-reliance on air consitioning-  suppose ideal indoor temperature has long been determined by air-conditioning engineers, using criteria that suggest pretty much all humans want the same temperature range at all times. The underlying idea is that comfort is objective, and that a building in Jakarta should be the same temperature as one in Boston, this means that the temperature in most air-conditioned buildings is usually “low-20s plus/minus one”.But not everyone has accepted the notion that there is such as thing as the objectively “right” temperature. Studies have suggested that men have different ideal temperatures from women. In offices around the world, “Men toil in their dream temperatures, while women are left to shiver,

• Researchers have also shown that people who live in hotter areas, even for a very short time, are comfortable at higher indoor temperatures. They contend that, whether it is a state of mind or a biological adjustment, human comfort is adaptive, not objective. This is something that seems obvious to many people who live with these temperatures. At a recent conference on air conditioning that I attended in London, an Indian delegate chided the crowd: “If I can work and function at 30C, you could too – believe you me.”

• once people are open to the idea that the temperature in a building can change, you can build houses that use air conditioning as a last resort, not a first step. “But there is no broad culture or regulation underpinning this,” he says. At the moment, it is the deterministic camp that has control of the levers of power – and their view continues to be reflected in building codes and standards around the world.

How, then, can we get ourselves out of the air-conditioning trap? 

• On the continuum of habits and technologies that we need to reduce or abandon if we are to avoid the worst effects of the climate crisis, the air conditioner probably falls somewhere in the middle: harder to reduce than our habit of eating meat five times a week; easier than eliminating the fossil-fuel automobile.

• UN programme  aims to improve the efficiency – and thus reduce the emissions – of all air conditioners sold worldwide. It falls under the unglamorous label of consumer standards. Currently, the average air conditioner on the market is about half as efficient as the best available unit. Closing that gap even a little bit would take a big chunk out of future emissions.

• Finally there is urgency to changes in behaviour and major policy shifts – and the open secret of the climate crisis is that nobody really knows how to make these kind of changes on the systematic, global scale that the severity of the crisis demands it.