On the opening day of the Tribeca Film Festival, former V.P. Al Gore, NYC Mayor Michael Bloomberg, director Rob Reiner, joined by Live Earth creator Kevin Wall and Tribeca fest co-founder Jane Rosenthal, talk about global warming and kick off the 2007 festival. In these clips from Wednesday's press conference, they address the issue of a potential backlash against artists who support global warming awareness programs like Live Earth and SOS. Get the latest in an iW Video segment (via YouTube).