Another reason air-conditioning is a blessing:
A new study just released by the National Bureau for Economic Research [argues]that it is warmer temperatures that may be the real economic cost [of global warming].
The paper, by Tatyana Deryugina of the University of Illinois-Urbana Champaign and Solomon Hsiang of the University of California, Berkeley, shows a fairly dramatic negative influence of heat on economic productivity. In particular, they find that, for every 1.8 degrees Fahrenheit (1 degree C) that a given day's 24 hour average temperature exceeds 59 degrees, economic productivity declines by 1.7 percent. And for a single very hot day -- warmer than 86 degrees F -- per capita income goes down by $ 20.56, or 28 percent.... But the paper also highlights the "well-documented productivity decreases of workers who are exposed to thermal stress." According to Hsiang, on hot days, people working outdoors tend to work as much as an hour less. He also points to research suggesting that in warmer temperatures, workers make more mistakes.