JEREMY GRANTHAM’S GOT A TRACK RECORD that’s impossible to ignore—he called the Internet bubble, then the housing bubble. While moves like those have earned the famed forecaster the nickname “perma-bear,” in early 2009 he also told clients at GMO, his $100 billion, Boston-based money-management firm, to jump back into the market. It was the same week that stocks hit their post-Lehman low. Now, however, the outspoken Yorkshireman, who is chief investment strategist at GMO, is making headlines with a new prediction: Dire, Malthusian warnings about environmental catastrophe. To hear him tell it, the world is running out of food. Resources will only keep getting more expensive. And climate change looms over it all. Indeed, at times he sounds like someone Greenpeace would send door-to-door with a clipboard. (He’s not above likening the coal-industry spin to the handiwork of Goebbels.) If it were anyone else, Wall Street would probably laugh him off. But because it’s Jeremy Grantham, they just might listen.