POLIS

Last night, I was lucky enough to attend a screening of An Inconvenient Truth, Al Gore's new movie about global warming, at the AMC on Illinois, and the man himself - the former next President of the United States - was there.

Early in the movie, Gore talks about professor Roger Revelle at Harvard, who was the first to blow the whistle on warming, a diligent, careful scientist and clearly a skilled teacher, to judge by Gore's reverence. And at some point later on, after maybe the third or fourth vignette in his lecture, you realize that Gore has become that figure, the great teacher, in command of a vast array of data but never at a lost to explain lucidly. Of course, he's got great material to work with: I've never seen charts and graphs of data have such a visceral reaction from an audience. But Gore walks us through it, the patient teacher, obviously driven by a moral imperative he asks us to share. By the end, you'd be hard pressed to turn it down.

In the Q&A session afterwards, perhaps because he knew he was with the choir - the screening was organized by ELPC and attended by the environmental literati of Chicago - he was a bit flat, gamely trying to field questions that included details such as the amortization of power plants. Which, of course, he's fully capable of answering, just as much a wonk as ever. But towards the end, he seemed to find the fire that's been fueling him since the most powerful position in the world was taken away from him, and looking relaxed and dressed in an all-black suit, he reminded me of Johnny Cash, the Man in Black, up front, daring to tell the inconvenient truth until it becomes history.