Aboriginal elders, virtual-reality performers and more than 100 of the biggest names in music — including Madonna, The Police and Kanye West — were taking to the stage on seven continents Saturday as Al Gore's Live Earth extravaganza harnessed star power to fight climate change.

The Material Girl was flaunting her eco-friendly side as the headliner of an eclectic show at London's newly rebuilt Wembley Stadium that included the Beastie Boys, the Pussycat Dolls and the Black Eyed Peas.

Click here to read about the scandal surrounding Madonna's not-so-green investments.

The drummers from Queen, the Foo Fighters and the Red Hot Chili Peppers kicked off the London concert, leading a battery of percussion set to flashing images of endangered animals, landfill heaps, wind farms and the Earth seen from space. They performed against a map of the world made from the painted tops of oil barrels.

The crowd — which was expected to swell to 65,000 — immediately rose to its feet as the reunited Genesis used its hit "Land of Confusion" to send an environmental message with Phil Collins urging fans to make the world "a place worth living in."

Will.i.am of the Black Eyed Peas was among a handful of stars who had written songs specifically about the climate crisis for Live Earth.

Click here to see pictures of the concerts.

"The world is dying," he rapped. "If people say it's all right, they're lying."

The London show was one of nine gigs involving some 150 acts around the world aimed at raising awareness about climate change and backed by Gore, the former U.S. vice president turned green campaigner.

With shows in New York, London, Sydney, Tokyo, Kyoto, Shanghai, Hamburg, Johannesburg, Rio de Janeiro — and even a performance by a five-piece band of scientists beamed from a research station in Antarctica — organizers promised Live Earth would be the biggest musical event ever staged, dwarfing the Live Aid and Live 8 concerts.

More than 1 million people were expected to attend concerts around the world and organizers were predicting live broadcasts on cable television and the Internet could reach up to 2 billion people.

The 24-hour music marathon kicked off in Sydney, Australia, where the show opened with a traditional welcome by a group of white-painted Aboriginal tribal leaders.

The London lineup also includes James Blunt, David Gray, 80s chart-toppers Duran Duran, Metallica and spoof metal band Spinal Tap.

Live Earth was to wrap up later Saturday with a New York show — actually held in nearby East Rutherford, New Jersey — featuring The Police, Smashing Pumpkins, Alicia Keys and Bon Jovi.

Gore, whose campaign to force global warming onto the international political stage inspired the event, made a live video appearance from Washington to open the first show on the other side of the world in Sydney.

He took the technology a step further a few hours later, appearing on stage in Tokyo as a hologram to deliver his message.

"Global warming is the greatest challenge facing our planet, and the gravest we've ever faced," said Gore — the only person in sight wearing a suit.

"But it's one problem we can solve if we come together as one and take action and drive our neighbors, businesses and governments to act as well. That's what Live Earth is all about."

For the most part, the diverse range of performers wholeheartedly backed the call. Organizers promised the huge shows were made eco-friendly by using recycled goods and buying carbon credits to offset the inevitable high power bills.

But some pointed out rock 'n' roll stars known for excesses might not be the best eco-role models. Many of the stars were jetting off to perform separate shows afterward. On her tour last year, Madonna produced an estimated 440 metric tons (485 U.S. tons) of carbon dioxide in four months, Britain's Guardian newspaper reported.

The irony did not escape some rock stars.

"Everyone that didn't arrive in a private jet put your hand in the air," Duran Duran singer Simon Le Bon joked as the band launched into its song "Planet Earth."

Aboriginal tribal leaders with white-painted bodies and shaking eucalyptus fronds were the first to take the stage in Sydney, singing and dancing a traditional welcome to the sounds of a didgeridoo, a wind pipe made from a hollow tree branch.

An estimated 50,000 people grooved through a set by former professional surfer-cum singer-guitarist Jack Johnson, banged their heads to afro- haired 1970s retro rockers Wolfmother, and gave a re-formed Crowded House a rapturous homecoming.

"This is so cool," Neil Finn, the singer-guitarist who penned the band's 1987 breakthrough "Don't Dream It's Over" and other hits. "We are the groundswell."

In Tokyo, Linkin Park singer Chester Bennington said in halting Japanese that the U.S. rap-metal act had joined the show "because we can make a difference if we only try."

The Tokyo concert kicked off with a high-tech, laser- and light-drenched performance by virtual-reality act Genki Rockets. Later, popular Japanese singer Ayaka urged fans to take up the concerts' theme of changing their daily habits as a first step to reducing global greenhouse gas emissions.

In Shanghai, a lineup of largely local acts was joined by British singer Sarah Brightman. The show was less a concert than a made for television event, with an audience of just 3,000, seated on bleachers in front of the riverside Oriental Pearl television tower.

Problems and changes to the series continued right down to the last minute. A ninth concert — in Washington, D.C. — was added Friday, and a Brazilian judge rejected a last-minute bid to shut down South America's Live Earth concert after a prosecutor had argued safety could not be guaranteed for an audience of 700,000 on Rio's Copacabana beach.

The Hamburg concert — which opened with Shakira and was to close with Yusuf Islam, the former Cat Stevens — was plagued by cool, rainy weather and low turnout. By the time the event started, only about 28,000 of a possible 45,000 tickets had sold, organizers said.

Bob Geldof, who organized the Live Aid and Live 8 anti-poverty concerts, thought Gore's energies were misplaced.

"I hope they're a success," Geldof said. "But why is he (Gore) actually organizing them? To make us aware of the greenhouse effect? Everybody's known about that problem for years. We are all ... conscious of global warming."