The economic costs of the spotted owl: $46,000,000,000 or . . . $0 ??

Felix Salmon gives the story. I haven't read the research articles, but it's an interesting story. As Salmon frames the book, it's Freakonomics-the-book vs. Freakonomics-style empirical analysis.

P.S. I'm assuming that both numbers above have been rounded to the nearest billion.