Why air-conditioning is making us hotter
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“In the Spring, a young man’s fancy turns lightly turns to thoughts of love.” I’m not young anymore and can’t remember if Alfred Lord Tennyson was right about that. What I do know, however, is that, in Summer, my fancy turns to thoughts of air-conditioning.

Normally, the English Summer is so fleeting that those thoughts don’t last for very long – but this year is proving to be an exception. With climate change we can expect the exceptional to become the usual. If that’s the way it does go, Europe may follow America’s example and see ‘air-con as standard’ spread from south to north.

It’s no exaggeration to say that air-con has reshaped America. You can see this on a map that shows the evolution of the country’s ‘mean centre of population’ – i.e. the point at which there are equal numbers of people to the north and south, and to the east and west. In 1800, the mean centre was in Maryland, just north of Washington DC. Then, with the settlement of interior and Pacific coast, it moved due west, reaching southern Indiana in the early 1880s. It has since continued to move westwards, reaching Illinois the end of Second World War and Missouri by the 1980s. However, since the War, it’s also been heading southwards, putting it on course for Oklahoma. 

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It’s not hard to work out what made the Sun Belt suddenly so attractive. With air-conditioning in every room – what Americans call ‘central air’ – the long hot Summers are bearable.

In a New York Times piece from last Summer, Emily Badger and Alan Blinder explain the multilayered effects of an under-appreciated revolution:

“Southern cities that boomed in the era of air-conditioning typically did not have the transit systems of older, Northeastern cities like New York and Boston. But even car commutes there have their own air-conditioned rationale: People are willing to cope with the traffic created by sprawl because their cars are air-conditioned.”

And that’s not the only way that air-con facilitated sprawl:

“In 1950, barely 100,000 people lived in [Phoenix, Arizona]. Today, 1.5 million do.

“…during that time… the region strayed from the types of ‘passive design’ and concrete-block exteriors that once made the desert’s large daily temperature swings tolerable (if not entirely pleasant). Air-conditioning enabled faster wooden housing construction.

“And in offices, central air systems demanded that buildings be sealed off from the outside. Windows couldn’t be opened even if you wanted to — requiring people, again, to turn up the air-conditioning.”

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The authors argue that air-con therefore creates demand for itself – “a feedback loop environmentalists fear”. Furthermore, this is no longer an issue for sunniest states alone:

“Decades after air-conditioning made much of the Sun Belt liveable, it has now become standard nearly everywhere. Eighty-six percent of new single-family homes in the Northeast are now built with it; 94 percent in the Midwest are. Parts of the United States whose historical development never depended on air-conditioning increasingly resemble the regions whose growth wouldn’t have been possible without it.”

However, the real growth opportunity for air-con is not in America or Europe, but in the rapidly expanding cities of the developing world. Growing prosperity combined with temperatures rising from an already high base equals an enormous new market, but also a vast source of new demand on the world’s energy resources. That, of course, means more carbon dioxide emissions, higher temperatures and therefore further demand for air-conditioning.

We’d better hope that solar power out-competes coal on price and reliability, otherwise we can expect a feedback loop from hell.

Further reading

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