It's official: Former Vice President Al Gore and a group of climate-crisis activists have launched a massive campaign that includes a star-studded, 24-hour Live Earth [ tickets ] concert, which will stretch across all seven continents July 7.

More than 100 acts are expected to draw an audience of 2 billion-plus through concert attendance and broadcasts, according to a press release. Artists on the bill so far are Pharrell Williams [ tickets ], The Red Hot Chili Peppers [ tickets ], Foo Fighters [ tickets ], Snoop Dogg [ tickets ], Lenny Kravitz, Bon Jovi, Paolo Nutini, Sheryl Crow, AFI, Melissa Etheridge, John Mayer, Damien Rice, Corrine Bailey Rae, Duran Duran, Snow Patrol, John Legend, Black Eyed Peas, Akon, Enrique Iglesias, Fall Out Boy, Mana, Keane, Kelly Clarkson, Korn,
Faith Hill with Tim McGraw, and Bloc Party.

The concerts will take place in Shanghai, China; Sydney, Australia; Johannesburg, South Africa; London; and cities to be announced in Brazil, Japan and the eastern US.

Emmy-winning Live 8 Executive Producer Kevin Wall founded Save Our Selves (SOS) - The Campaign for a Climate in Crisis, which was officially launched today (2/15) with the help of Gore, rap artist/producer Pharrell Williams, actress Cameron Diaz and the MSN Network.

SOS hopes to trigger a global movement to combat the climate crisis through television, film, radio, the Internet and the Live Earth concert.

"In order to solve the Climate Crisis, we have to reach billions of people," Gore said in a statement. "We are launching SOS and Live Earth to begin a process of communication that will mobilize people all over the world to take action. The Climate Crisis will only be stopped by an unprecedented and sustained global movement. We hope to jump-start that movement right here, right now, and take it to a new level on July 7, 2007."

Wall added that the 100-plus acts that will perform at Live Earth are all headliners.

"That's what it takes to engage billions of people," he said. "We're not just engaging fans of the Red Hot Chili Peppers and Snoop Dogg, or the Foo Fighters and Faith Hill. We're engaging them and everyone in between. We've been overwhelmed by the response from the artist community and are feverishly working out the logistics for all of the bands that want to be involved."

Live Earth performances will be webcast worldwide on MSN's new Live Earth website.

Proceeds from the event will be used to create a new foundation led by the Alliance for Climate Protection, which Gore heads. The foundation will launch a multi-year global effort to combat the climate crisis.

For those concerned about the impact the concerts will have on the environment, Live Earth organizers assure they will implement a new "Green Event Standard" that will become a model for carbon neutral concerts and other live events in the future.

More information about Live Earth and its cause can be found at the event's website.