STAN LEHMAN, RIO DE JANEIRO

A BRAZILIAN judge decided yesterday that South America's Live Earth concert could go ahead as planned after organizers convinced her there would be adequate security at the Copacabana Beach event.

The office of the prosecutor who had sought to cancel the concert confirmed Judge Maria Galhardo had reversed her earlier decision to cancel the show, ensuring the worldwide music fest against global warming will happen on all seven continents.

"We still don't know if she will appeal the judge's latest decision," said Daniel Brunet, a spokesman for prosecutor Denise Tarin.

Under Brazil's multi-layered court system, judges' decisions can be repeatedly reversed, often within hours.

Chances for the show featuring Lenny Kravitz, Macy Gray and Pharrell Williams got a boost from police who said they could guarantee security for the show expected to draw 700,000 people.

Promoted by former US Vice President Al Gore, Live Earth concerts are also scheduled for London; Tokyo; Johannesburg, South Africa; Shanghai, China; Sydney, Australia; Hamburg, Germany, and East Rutherford, New Jersey. A band of scientists also will perform in Antarctica.

But Rio's free show tomorrow was scratched this week after Galhardo agreed with Tarin who argued police would not be able to provide concert security because they are stretched thin with the upcoming Pan American Games and a huge crackdown on slum-based gangs.

Organizers appealed to Galhardo after authorities reversed course and said police were now available because an open-air gospel music show scheduled for the same time was switched to a site where fewer officers will be needed.

Tarin last year imposed restrictions on a free concert by the Rolling Stones on Copacabana that drew a million people. She said at the time that Copacabana is not appropriate for huge concerts because the setting makes it difficult for police to craft "the slightest viable security plan."

The Rio event is the only free concert for Live Earth, founded by Kevin Wall, who is an Emmy-winning concert producer.

Proceeds from the other concerts will go toward the Alliance for Climate Protection, a nonprofit organization chaired by Gore.