The fuel and engine for the sub-prime mortgage meltdown and the credit crunch was Allen Greenspan and the doubling of the global monetary supply, according to the This American Life episode “The Giant Pool of Money” I just got around to listening to. Basically, a bunch of poor countries got rich all of a sudden selling TVs and the like, and in 6 years, doubled the worldwide supply of money. The giant pool of money was hungry for places to invest itself.