Before a rapt audience, Al Gore flashed slides on a giant screen bearing the logos of 11 clean energy companies he predicted could help slow climate change.

“We can’t wait. . . . We have a planetary emergency,” the former vice president told industry leaders and scientists at the 2008 conference. “Here are just a few of the investments that I personally think make sense.”

Today, several of those clean tech firms are thriving, including a solar energy start-up and a Spanish utility company that has dotted rural America with hundreds of wind turbines.