Air-conditioning has avoided the opprobrium attached to cars and planes, but as use of the technology grows rapidly so does its contribution to climate changeby James Fergusson / September 24, 2006 / Leave a comment
Published in September 2006 issue of Prospect Magazine
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.