How do you convince the American public that the entire country, and indeed the entire world, could generate all of its energy from the wind, the sun and water? Go on The Late Show with David Letterman, be earnest, present the plan you published in Scientific American and have Letterman smile at you.

That’s what Mark Jacobson did on October 9. Jacobson is a civil and environmental engineering professor at Stanford University, and he wrote our November 2009 cover story, A Path to Sustainable Energy by 2030. Although he didn’t mention the magazine on the show, and he has of course continued to advance his research, he unveiled the same plan he laid out in his highly visual article. The Late Show clip is below. As it begins, it’s easy to feel that familiar force coming—that Letterman is going to mock this geek or give him a hard time. But Letterman becomes spellbound by Jacobson’s vision and lets the interview go for 10 minutes—a long time in the TV biz. At the very end Letterman asks Jacobson to look directly into the camera and "tell people everything is going to be okay." Jacobson does! And without missing a beat he throws in a little speech, and Letterman just sits there and smiles at him.

Read the Scientific American cover story: A Path to Sustainable Energy by 2030.