Last week I was one of many who highlighted an old Lee Kuan Yew quote in which he argued that Singapore's development had a lot to do with air conditioning, because it made 'development possible in the tropics. Without air conditioning you can work only in the cool early-morning hours or at dusk.'
Paul Krugman also noticed the quote, and blogged on it for the NY Times, with evidence from the American south backing up LKY's claim about the link between air conditioning and development in warm climates. Tyler Cowen at Marginal Revolution pushes back gently at Krugman's argument, citing this paper which argues that Krugman's argument may be backwards: as consumers have become wealthier, it argues, they have placed a higher premium on 'nice weather', so they move to warmer climates and buy air conditioners. There's also this post, which argues that air conditioning may have been an important early factor in the development of America's south, but not so much lately.
Lastly, my thanks to Elliot Brennan, who points out that there was an entire book written on LKY's theory about air conditioning and Singaporean development.
(PS. On the broad subject of unexpected reasons for major social trends, check out some recent articles on the link between lead exposure and crime.)
Photo by Flickr user Choo Yut Shing.