EAST RUTHERFORD, N.J. — Former Vice President Al Gore yesterday asked millions of concertgoers not for their votes but to save the planet.
Live Earth — a 24-hour concert spanning all seven continents — was Mr. Gore's brainchild and was designed to raise awareness for climate change in the spirit of Live Aid, which in 1985 worked to end famine in Ethiopia.
The Democrat took the stage here yesterday afternoon to cheers from the sold-out crowd of 52,000, lauding the musicians from Madonna to the Dave Matthews Band for "taking a stand."
"Times like these demand action," Mr. Gore said. "Please sign the Live Earth pledge."
The seven-point oath calls for participants to plant trees, buy from eco-friendly businesses and change their mode of transportation more often to biking or walking. It also urges government action, calling for the pledge-taker's country to sign an international treaty to reduce greenhouse gases.
Musician after musician encouraged fans in stadiums from Sydney to Tokyo to take small steps such as unplugging cell-phone chargers when they are not in use, using cloth grocery bags and buying organic, locally grown produce.
"In saving ourselves from global warming, there are no borders," said model Petra Nemcova, whose boyfriend, Simon Atlee, drowned in December 2004 in the tsunami in Thailand.
Celebrities including Julia Louis-Dreyfus and Ken Watanabe appeared in brief videotaped spots in between performances, giving tips such as reusing plastic water bottles as ways to "answer the call."
Fans were greeted by advocacy groups of all sorts — Pepsi rewarded recyclers with Lance Armstrong LiveStrong-style bracelets, and biodiesel buses transported concertgoers across the grounds. Vendors insisted the caps from every bottle of beer were recycled and hot dogs were wrapped in recycled brown paper.
Even Mr. Gore, who has faced criticism for his own carbon footprint, took a train from the Smithsonian's component of Live Earth in Washington to New Jersey, instead of his usual jet, and appeared onstage in Tokyo as a hologram to deliver his message there.
"Today, folks, we are 2 billion strong," actor Kevin Bacon told the crowd at the New York event, which was held across the state line in New Jersey at Giants Stadium. Mr. Bacon called Live Earth the "biggest global event ever" and asked concertgoers: "Are you ready to answer the call?"
Some of the "calls" were bizarre. Opening act KT Tunstall told fans to "pull your phone chargers out of the wall and, I don't know, eat more soil or something."
Actor Leonardo DiCaprio, whose forthcoming documentary, "11th Hour," outlines what he calls a "tipping point" in the planet's history, told the crowd that they can help shape the future.
"Our actions from this day forward will help determine just what sort of future we pass on to our children and their children," Mr. DiCaprio said.
Politics also made an appearance. Musicians urged fans to demand action from their elected officials. Plenty here at Giants Stadium said they would love to see Mr. Gore make another bid for the White House.
"I'll vote for Al Gore if he runs," said Brant Schweinsberj, 28, of Somerset, N.J. "Why? I think he is the most capable candidate, and I don't have a second choice."
James Boyce, who was blogging live for Huffington Post yesterday, said a New Hampshire poll showing that Mr. Gore would win the state's primary if he ran for president is a key indicator.
"The support is real," said Mr. Boyce, a Democratic political strategist who was a senior adviser to presidential nominee Sen. John Kerry in 2004. "Polling and the sincere public support clearly show that if Al Gore wants to be president, he will be the nominee and he will be the president."
"I would be thrilled. If he ran, he would win," said yogurt magnate Gary Hirshberg, the chief executive officer of Live Earth sponsor Stonyfield Farm in New Hampshire.
Mr. Hirshberg, a longtime Democratic activist whose group offered concertgoers free yogurt and the environmental scores of major companies, said he thinks a presidential campaign "might not be anything but a distraction" for Mr. Gore.
"He's doing an immense amount of good right now," he said.
Mr. Gore initially wanted his U.S. show to be on the Mall in Washington, but the venue was taken for the Smithsonian Folklife Festival. He opted instead for the U.S. Capitol grounds, but Senate Republicans blocked a bipartisan resolution authorizing the show, calling it a "partisan political event." Mr. Gore then took Live Earth to New Jersey.
The Museum of the American Indian, also on the Mall, agreed at the last minute to host a small arm of the concert with Garth Brooks and Trisha Yearwood.
Mr. Gore told the Associated Press that his nonprofit, the Alliance for Climate Protection, will act as a "PR agent," and he views the concerts as the beginning of a three-year effort to make a difference. The goal is to get millions of people around the globe to pressure their government leaders on the environment and policy.
Organizers stressed that the environment shouldn't be a partisan issue.
"It would be a huge mistake if this became a Democratic or Republican issue," said Tom Lalley of the World Wildlife Fund, who traveled with a giant panda and distributed paper fans reading, "I'm hotter than I should be."
Critics noted the massive carbon footprints of the jet-setting musicians.
Miss Tunstall, wearing a "Save the Future" tank top, fired back, saying she is putting solar panels on her apartment in London and travels eco-friendly Virgin Airlines.
A band member from Taking Back Sunday said he runs his old Volkswagen Rabbit on used vegetable oil dumped by a Chinese restaurant. Rock star Dave Matthews said his family uses cloth diapers but also stressed the call to action for elected leaders.
The stadium had separate containers for waste, compost and recycling bottles and cans. The lights were energy-efficient, and the floorboards over the New York Giants field were made of a bioproduct instead of plywood. Organizers also plan to buy carbon offsets from a green energy company.
Event partner MSN handed out packets of spruce and pine tree seeds.
The event here featured two reunited groups — the Police and the Smashing Pumpkins — and capped 24 hours of climate-change fanfare.
The shows, dubbed "concerts for the climate in crisis," were in Sydney, Australia; Tokyo; Shanghai; Hamburg, Germany; London; Johannesburg; and Rio de Janeiro and featured artists such as the Black Eyed Peas, Jack Johnson and Shakira. A group of researchers in Antarctica performed, and their images were beamed to stages at the other shows.