Live Earth kicks off in Australia

The performance was immediately followed by a video greeting from former US Vice President Al Gore, whose campaign to force global warming onto the international political agenda inspired the event.

Gore invited the crowd to take Live Earth's seven-point pledge to reduce their personal environmental impact and support policies to reduce greenhouse gas emissions.

"Thank you for being the very first to launch this movement to help solve the climate crisis," Gore said, standing before the Capital building in Washington. "Enjoy the show."

Australian actress Toni Collette, taking a break from Hollywood to pursue a singing career, dedicated a song called 'Cowboy Games' to world political leaders.

Her band, the Finnish, ended their set with a grinding guitar-driven version of the 1970s T-Rex hit 'Children of the Revolution'.

"It's heartwarming to see so many people here today for the cause of going green," said Collette, who was Oscar-nominated for her role in The Sixth Sense. "I take my hat off to you all."

On a cool but sunny midwinter day, the crowd danced and sang along with some songs, and at one point chanted Zero Seven, Zero Seven - a reference to the 07/07/07 date of the shows.

"It's a rowdy rabble of green people out there," former Midnight Oil drummer Rob Hirst said.

The Tokyo concert in Japan kicked off with a high-tech, laser- and light-drenched performance by virtual-reality act Genki Rockets.

Gore got into the spirit, appearing as a hologram to deliver another save the planet message.

"With Live Earth, we hope to connect people through the power of music and engage them with a simple universal message: SOS. Answer the call," Gore said.

Popular Japanese vocalist Ayaka urged the crowd to recognise that global warming was a serious problem for everyone.

"We can start helping by doing something small," she said between songs. "I started to carry my own eco-bag so I don't have to use plastic grocery bags, and use my own chopsticks instead of disposable ones."

Madonna and Metallica in London and the Police and Kanye West in New Jersey are among the top billed of more than 150 acts due to appear in the series of nine concerts.

More modest lineups of mostly local and regional acts are playing in Australia, Japan, China, South Africa, Brazil and Germany.

Problems and changes to the series continued right down to the last minute, with a ninth concert - in Washington, DC - added yesterday and a court battle continuing in Brazil to decide whether the show there could go ahead as planned.

Critics say Live Earth lacks achievable goals, and that bringing in jet-setting rock stars in fuel-guzzling airliners to plug in amplifier stacks and cranking up the sound may send mixed messages about energy conservation.

Organisers say the concerts will be as green as possible, by using biodiesel for power and recycled products where possible. Proceeds from ticket sales will go toward distributing power-efficient light bulbs and other measures to offset the shows' greenhouse gas emissions, they say.

The series rolls west today, from Sydney to Tokyo, Shanghai, Johannesburg, Hamburg, London, Rio de Janeiro, New Jersey and Washington.

Organisers were predicting live broadcasts on cable television and the internet could reach up to two billion people, including public service announcements giving tips about how to conserve energy.

Retired five-time Australian Olympic champion swimmer Ian Thorpe was among the high-profile supporters of the event, though he told an interviewer today his efforts to help the environment stopped short of becoming a vegetarian.

"I've thought about it," Thorpe said. "But I like steak. I figure that we've got to the top of the food chain ... and I'm going to enjoy my time now that we're there."