How air conditioning changed the world

95995836_gettyimages-509032804Imagine we could control the weather – pushing a button to make it warmer or cooler, wetter or drier. The implications would be enormous. No more droughts or floods, no heat waves or icy roads. Deserts would become verdant. Crops would never fail.

In fact climate change has sparked some crazy-sounding ideas for hacking the climate, such as spraying sulphuric acid into the upper atmosphere, or dumping quicklime in the oceans.

Clever as humans are, however, we’re nowhere near precision control of the weather. Outside, at least. Since the invention of air conditioning, we have been able to control the weather inside, and that has had some some far-reaching and unexpected effects.

Air conditioning as we know it began in 1902, but it had nothing to do with human comfort. New York’s Sackett & Wilhelms Lithographing and Printing Company became frustrated with varying humidity levels when trying to print in colour.

The same paper had to be printed four times in four colours, and if the humidity changed between print runs, the paper would slightly expand or contract. Even a millimetre’s misalignment looked awful. The printers asked heating company Buffalo Forge to devise a system to control humidity.

Read the full article in BBC News