Around-the-world Live Earth concert kicks off in Sydney

To the drone of a didgeridoo, the six bare-chested aboriginal dancers took to the stage at Sydney's Aussie Stadium under a clear bright blue sky and before a less-than-sell-out crowd of 45,000.

Al Gore later appeared on a screen urging all those watching to be better global citizens and do their part to reduce global warming - the overriding theme of all the day's concerts.

The former US vice president, one of the principal organizers, is hoping to persuade fans to adopt a seven-point pledge to reduce their own carbon footprint and to press for meaningful legislation that would cut carbon output by 90 per cent by the year 2050.

Hollywood actor Toni Collette, fronting a band called Finish, thanked the crowd for braving the chill of the southern hemisphere winter.

"Just by being here today, just by turning up, is helping to create awareness of this very life-threatening situation," Collette told the Sydney crowd. "So I take my hat off to you."

Local dance band Sneaky Sound System admitted to being new to environmentalism.

"All we can do is put on a show that people will come and enjoy and let others give the message," band leader Angus McDonald said.

Headlining the Sydney concert is a re-formed Crowded House. The band broke up after a farewell concert on the steps of Sydney Opera House in 1996 but are back playing together.

From Sydney, the 24-hour event spread to official venues in Tokyo, Shanghai, Hamburg, Johannesburg, New York, Rio de Janeiro and London, as well as to more than 7,000 local events, including one in Antarctica.

Australian Live Earth promoter Michael Chugg said the event had "put global warming and the future of the earth on the front pages of newspapers for the past five months."

It was a claim not borne out by reality. Ticket sales have been slow, the line-up lacklustre and Sydney's dailies consigned concert coverage to the middle pages.

Proceeds from the event, subtitled Concerts for a Climate in Crisis, are to benefit the Alliance for Climate Protection, a group chaired by Gore.

Deutsche Presse-Agentur