Mark Perry's Carpe Diem blog has an item fact-checking Paul Krugman's recent New York Times column about rising commodities prices. Professor Perry writes:
Over a very long period of time (76 years), there has been a significant downward trend in the real prices of commodities (see red trend line in graph), and the decline in commodity prices has taken place during a period when the world population increased by more than three times, from 2 billion in 1934 to the current population of 7 billion in 2010.
I'd like to know a little more about the inflation adjuster that Professor Perry is using, but it's a nifty little post.