Global warming has truly arrived in the heartland of cool. If further proof were needed, it's to be found in the May issue of Vanity Fair, the second to be devoted to green concerns in a year.

The issue hails a "green revolution". And manning its barricades is an unlikely citizens' army of rockers, venture capitalists, hoteliers and Hollywood stars alike, all fighting for action on climate change.

Leonardo DiCaprio, Hollywood's leading green man, graces the cover, and he is joined inside by fellow actors Robert Redford and Julia Louis-Dreyfus. Then there are the rockers, including Jack Johnson and Alanis Morissette, who are both members of Musicians United for Safe Energy, founded by Jackson Browne and Bonnie Raitt.

Less well known among the elite environmental movers and shakers identified by the magazine is Barry Sternlicht, chief executive of the Starwood Capital Group, who is creating eco-friendly hotels; the first is to open in Seattle next year. Just five years ago there were only 10 environmentally friendly designers. Now there are more than 500. At 23, fashion model Summer Rayne Oakes has her own think tank and consulting company promoting fair trade clothing.

Students

Meanwhile, more than 500 campuses have signed up to start reducing their carbon emissions, partly as a result of a student campaign, Campus Climate Challenge. Perhaps the greatest green superstar, former vice-president Al Gore, is not included, but then he was prominent in last year's issue, tastefully arranged at Julia Roberts' feet on the cover, along with George Clooney and Robert Kennedy Jnr. But he was all over the news last week anyway, with the announcement of the line-up of stars for a series of Live Earth concerts this summer, which will highlight global warming.

Last week Matt Bellamy, front man for the rock band Muse, criticised the concerts for not practising what they preach. He said, with more passion than eloquence: "Private jets for climate change - not sure about it. That seems to be a bit on the edge really. That's an issue, so we need to think about it."

Mr Gore admits that the concerts will consume a vast amount of electricity, but the organisers are working hard to make the concerts carbon-neutral, and have hired John Picard, a sustainability expert and a former member of Bill Clinton's White House environmental task force, to help make it happen. Electricity at the concerts will be provided from bio-diesel generators and other renewable sources. Food and drink sellers will use biodegradable plastics. And a waste recycling system is promised for each venue.

He himself has also come under attack for hypocrisy. Earlier this month the Tennessee Center for Policy Research revealed that his home consumed more than 20 times as much electricity as a normal home. Mr Gore replied that he pays extra to get it from renewable sources and is installing solar panels.

Madonna, who is set to headline the London leg of the concert, is also prominently in the critics' sights.

John Buckley, managing director of Carbon Footprint.com says: " Madonna's Confessions tour produced 440 tons of CO2 in four months of last year. And that was just the flights between the countries, not taking into account the truckloads of equipment needed, the power to stage such a show and the transport of all the thousands of fans getting to the gigs."

Coaching

Global Cool, an environmental charity which has enlisted celebrities such as KT Tunstall to help make saving energy an "aspira-tional lifestyle" , gives them all "carbon coaching" to help them to reduce their footprints. It aims to encourage a billion people worldwide to take steps to reduce their carbon emissions by one ton per year.

However, the Scissor Sisters decided instead to support a little-known UK charity, the C-Change Trust. Singer Ana Matronic said that C-Change was " our first choice to offset our carbon emissions from our UK tour last year because it is the only carbon-offsetting charity in the UK and we love its education programme.

"Our keyboard player actually went down to Wales to plant some of our trees, and C-Change brought 30 local schoolkids to plant trees with him and a couple of other businesses who were offsetting."

Unfortunately, last week an authoritative scientific study revealed that planting trees in temperate countries, such as Britain, makes global warming worse.

How green are they really?

John Travolta

Serious aviator lectured Press on global warming last week

Arnold Schwarzenegger

Supported green highway; took $$1m from oil industry

Liz Hurley

Her wedding celebrations released 200,000kg of carbon

Sienna Miller

Constantly flying ambassador for Global Cool

Al Gore

Environmental activist slated for size of house and energy it uses

Josh Hartnett

Drives a Prius; has backed Global Cool since its inception

Daryl Hannah

Many environmental awards and blog on ecology

Ed Begley Jnr

Environmentalist since 1960s. Home is solar-powered

How Hollywood has climbed aboard the green bandwagon

Leonardo DiCaprio - the king of the Hollywood 'greens' - is the face of the Vanity Fair annual green edition, which is billed as its first carbon-neutral issue. The magazine chose an image of DiCaprio on an iceberg, with the three-month-old polar bear cub Knut added digitally. The actor is seen as representing the close relationship between Hollywood and the green lobby.

With Academy Award nominations for Blood Diamond and The Departed, DiCaprio's film career is at a peak. But the actor also sees himself as an environmental activist. Currently on the boards of the Natural Resources Defence Council and Global Green USA, he has been campaigning for green causes for the past 10 years. Later this year he will release The 11th Hour, a feature documentary on the state of the environment. And his interest in the environment is shared by his peers. Edward Norton has championed the benefits of solar power, as have Danny DeVito and Brad Pitt, while Daryl Hannah has long promoted green issues on her website.