When economists think about climate change, some think a lot about horse manure. Specifically, they consider the greatmanure crisis of the late 1800s, when the world’s cities relied on horses for transport to such an extent that a public sanitation disaster loomed. Fine minds set to work on a crisis that The Times of London estimated in 1894 was so dire that in 50 years every street in the city would be buried 9ft deep in horse droppings.
As it turned out, a simple solution was at hand: not new laws or policies but the motor car, a technical innovation so successful that the equine pollution problem was swiftly overcome.
The lesson is obvious for anyone worried about climate change, say economists such as Steven Levitt. In 2009’s SuperFreakonomics he and co-author Stephen Dubner used the tale to argue that technological fixes are often far simpler and cheaper than doomsayers imagine; and global warming could be addressed by so-called geoengineering, or manipulating the environment to halt rising temperatures.