The sixth annual Tribeca Film Festival opened on Wednesday with a gala presented by former Vice President Al Gore.  This year's festival has a slate of global warming-themed films making the man who was almost president perfect for the kick-off.

"Art, music, film, dance, poetry—all the arts—have long been our greatest tools to explore the regions of imagination that defy our efforts to think rationally about subjects that our emotions tell us are too painful to contemplate," Gore said at the opening ceremonies.

Al Gore, of course, also starred in the Oscar-winning documentary "An Inconvenient Truth."  Gore spoke optimistically of the potential for change. "Somehow, we do have to penetrate that shell of denial," he said.

Tribeca held its first festival in 2002 to help revive lower Manhattan after the September 11th attacks.  It was founded by Robert De Niro, his producing partner, Jane Rosenthal, and her husband, the entrepreneur Craig Hatkoff.