Will historians look back at the summer heatwave of 2006 and declare it a turning point in the hearts-and-minds battle against global warming? Much of the northern hemisphere was united in discomfort. At the same time, the tone of public debate seemed to shift. Not many people followed the bishop of London, Richard Chartres, who declared that flying away on holiday was sinful. But few of the energy-consuming machines that dominate life in the west have been able to escape critical scrutiny.
Except for one. There is a piece of 20th-century technology—seldom discussed or even noticed because it is practically invisible when working as it should—which has played a role in shaping the modern world almost as big as the motor car or the aeroplane. Its contribution to carbon emissions and climate change has been just as disastrous, in its way, and is set to make an even bigger impact in the near future. Step forward, please, the humble air-conditioning unit.
Everyone knows that the US is easily the biggest per capita consumer of electricity on the planet. Less appreciated is that country's dependence on air-conditioning. Americans, representing less than 5 per cent of the world's population, consumed roughly one quarter of all the electricity generated in the world in 2003; and fully a third of that, according to Energy Bulletin, an independent energy information exchange, went towards power for air-conditioners. That's 8 per cent of the world's total electricity supply. Meanwhile, air-conditioners in American vehicles use 7bn gallons of petrol a year, equivalent to the total oil consumption of Indonesia with a population of 240m. About a third of European cars now have air-conditioning. The proportion is growing fast, but there is a way to go before we catch up with the US, where automotive aircon has been standard equipment for years.
The acknowledged father of air-conditioning is Willis Carrier (1876-1950), a farmer's son from Angola, New York, who is said to have come up with the idea while waiting for a train early one morning in Pittsburgh. He observed a bank of fog rolling over the lip of the station platform and conceived the all-important theory of "dew-point control." The patent was granted exactly a century ago. His invention was essentially a refrigerator without the insulated box. A refrigerant gas was compressed until it liquefied, then passed through an expansion valve that caused it to evaporate; the cool air that resulted was distributed by fan. Carrier's original refrigerant was ammonia. These days Freon is used, although the principle underlying the technology is unchanged.
Carrier's story reads like an archetype of the American dream: a stirring tale of visionary brilliance and business acumen that leads to success against the odds. Carrier tinkered endlessly with old clocks and sewing machines as a child, and eventually won a mechanical engineering scholarship to Cornell University. His first job on graduation was with the Buffalo Forge Company, a manufacturer of heaters and blowers, where he was quickly put in charge of an experimental department. In 1902, at the age of 25, he devised and installed the world's first air-conditioner for the Sackett-Wilhelms Lithographing and Publishing Company in Brooklyn. The firm had been unable to print reliable colours because of the effects of heat and humidity on paper and ink. Carrier eventually left Buffalo and set up on his own.
His first clients were mostly commercial. Landmark installations that did much to bring air-conditioning to the attention of the general public included Madison Square Gardens and the US Senate, along with cinemas, department stores, offices and even trains. The depression and then the second world war were setbacks for Carrier's young company. It was not until the 1950s that the technology was introduced into houses. The effect of air-conditioning on worker productivity had already been demonstrated before the war; now it was marketed as a form of empowerment at home. "There's something masterful about flipping switches and turning knobs," ran the copy on one Carrier advertisement from 1959, "and then seeing and feeling how your air conditioning responds. That's part of the mastery a homeowner can now enjoy."
Americans demanded it in their millions. What had originally been considered a luxury soon became one of the must-haves of modern life. "Weatherlessness" was perceived as a step towards a technology-driven vision of utopia.
Because of the weight and size of the early units, the final frontier for air-conditioning was the automobile. As with the early car phones in the 1980s, the first air-conditioned vehicles carried immense social status. In Texas in the 1950s, some people drove around with their windows shut tight in 100-degree heat, just to fool their neighbours.
Since the 1950s air-conditioning has been partly responsible for the economic development of America's sunbelt, internal migration towards which continues to this day. Never mind the cowboys out west: aircon was how the south was won. The same is true of many other parts of the world. The financial centres of Japan, the capitals of the Asian tiger economies, the hubs of the Gulf like Dubai—all would be almost unthinkable without temperature control. So too would the software that links and underpins them, since computer technology does not function well in hot and humid conditions. Without air-conditioning, the information superhighway would buckle in the heat. In South America, Spain and elsewhere in southern Europe, air-conditioning has killed the midday siesta. And the war on terror depends on it. Hi-tech, precision weaponry requires low and stable temperatures for its manufacture.
A more visible legacy of air-conditioning are those clusters of sealed-window, high-rise offices that dominate our city skylines. It's a dark thought, but it took the force of two (air-conditioned) airliners to open the windows of the World Trade Centre in 2001. One of the forerunners of the World Trade Centre was the Johnson Wax Building in Racine, Wisconsin, built by the futuristic architect Frank Lloyd Wright in 1936. The building's most notable feature is its almost complete lack of windows, and so its total reliance on air-conditioning. Not everyone agreed with the space-cooling revolution that this building symbolised. Its critics included HL Mencken, Sinclair Lewis and JK Galbraith. Henry Miller visited the new Johnson building during a tour of America in 1940; an account of his journey, entitled The Air-Conditioned Nightmare, was published in 1945. "This place is flawless—deathlike," he wrote. "Man has no chance to create once inside this mausoleum. Down with Frank Lloyd Wright!" These writers' wrath, according to Marsha E Ackerman, author of Cool Comfort: America's Romance with Air-Conditioning, was focused on "the perceived complacency of a surging middle class full of Babbits who smugly added foolish comforts to their way of life." The dehumanising influence of technology threatened "to banish from American life all that was natural, passionate and spontaneous." It was a futile rearguard action against the march of progress. Today, 83 per cent of US households contain one or more air-conditioning units, and the Carrier Corporation employs 45,000 people in 172 countries.
The one thing that air-conditioning's early detractors didn't mention, but might have, was the cost to the environment. Despite all the improvements since Carrier's day, air-conditioning remains hopelessly inefficient. In a typical unit, as much as 40 per cent of the energy used is lost in the form of heat. A humming locust plague of air-conditioning plants, blasting out hot air in urban backyards and on the roofs of big buildings, are themselves significant local contributors to warming, and one reason that many cities are often several degrees hotter than their immediate environs. Air-conditioning, in the words of one environmentalist, is the SUV of the electricity world. And it contributes to global as well as local warming—according to the US Environmental Protection Agency's own figures, 3,400 pounds of carbon dioxide are emitted each year to cool the average American home: about two thirds of the annual emissions from an average British car.
And what of the emerging economies in the east—particularly the "surging middle classes" of Asia and the far east, whose potential numbers dwarf the air-conditioner users of the US? In China, the pattern set in 1950s America is already repeating itself. Exactly the same social issues of status, worker productivity and domestic comfort apply. The Chinese have worked hard for the trappings of western affluence. Just as in the US half a century ago, the environment counts for little in the face of such aspiration. There are already more than 100m residential air-conditioners in China, triple the number of five years ago. Sales are slower this year than last, but are still expected to reach a staggering 27m units. According to figures published in the People's Daily, air-conditioning already accounts for 15 per cent of national power consumption annually. In summer, that figure jumps to as much as 40 per cent.
Like Californians, the Chinese have grown used to seasonal electricity shortages as demand exceeds supply, especially in Shanghai, where there are regular government decrees obliging shopping malls, offices and hotels to set their thermostats no lower than 26 degrees Celsius. Two thirds of China's electricity generation is still coal-fired. Every ten days, it is said, another coal-fired power plant opens somewhere in China that is big enough to serve all the households in Dallas. China uses more coal than the US, the EU and Japan combined, and is home to five of the ten most polluted cities in the world—and partly because the Chinese want their homes to be as cool and as comfortable as those of the Americans.
The local market leader in air-conditioner manufacture is the Haier Corporation, whose factories cover a square kilometre in the coastal city of Qingdao, south of Beijing. Haier's sales have grown by an average of 70 per cent every year over the last two decades, and are now worth around $10bn per annum. Its boss, Zhang Ruimin, was recently rated by Fortune magazine as one of the most powerful businesspeople outside America. He is lionised at home, too. His management style is based on the former head of General Electric, Jack Welch, but he is also a member of the Communist party central committee. Ruimin is—or so he seems to perceive himself—one of the new masters of the universe. His corporate literature sounds crazed. "Haier should be like the sea," it reads, "because the sea can accept all the rivers on earth, big and small, far and near, coming all the way to empty into it… Haier is the sea."
The clock of progress is seldom turned back. "The best attribute of air-conditioning is its addiction," Salil Kapoor, the head of marketing in India for the South Korean company LG Electronics, the world's largest manufacturer of air-conditioners, once told Reuters. "It's a romance." Yet addictions can be broken; romance does not always last. Mankind not only survived for many millennia without Carrier's invention, but developed all sorts of effective strategies for dealing with the conditions it was designed to beat. Mesopotamian despots built double-walled palaces, and packed the cavities with imported ice. The street plan of medieval Korcula, a Venetian town on an island off the Dalmatian coast, follows a unique fishbone pattern that maximises shade and cleverly channels any available sea breeze. To this day, certain Pashtuns in northern Afghanistan spend the hottest hours of the day on a raised, shaded platform hung about with palm fronds that are periodically dipped in a nearby stream—a technique known as evaporative cooling that was widely practised in 18th-century France. Even the British rulers of imperial India deployed high ceilings and enough punka-wallahs to prevent their wing-collars from wilting. Air-conditioning, in other words, is not the only means we have of cooling ourselves down.
In the meantime, the technological utopia once envisioned for America by Willis Carrier is in danger of becoming all the world's dystopia. Air-conditioning sits at the centre of what physicists call a "positive feedback loop," by which they mean that the hotter it gets, the more inclined people are to turn up the dial on their air-conditioners, with the result that it gets hotter still. In the understated words of Energy Bulletin: "Positive feedback loops are a form of amplification, and when left uncontrolled, lead to a circumstance called saturation… This result is normally an undesirable outcome." Just how undesirable was hinted at this summer, when high temperatures in California created such a demand for power that the state was forced to ration it in a series of "rolling blackouts." The same thing happened in Texas, and even, briefly, in London. Demand for electricity in California, the world's sixth largest economy, has grown by 6 per cent a year for the past five years, according to the utility company Pacific Gas and Electric, who partly blamed the blackouts on the large number of digital and internet companies with headquarters in the state, and the levels of air-conditioning these businesses notoriously require.
In Long Beach in early August, Tony Blair and Arnold Schwarzenegger, governor of California, met to discuss climate change. They agreed to "share experiences," to find "new solutions," and to "work to educate the public on the need for aggressive action to address climate change." The roundtable of businessmen at which they sat was, naturally, bathed in conditioned air. Nobody is seriously proposing bringing back the punka-wallahs, but it is time that air-conditioning was more publicly recognised as one of those technologies that, while liberating us, increasingly threatens us too.