As Tony Blair and Arnold Schwarzenegger launched their new pact on global warming in Los Angeles last week, they were watched by a young man in a grey T-shirt with a solar-panelled rucksack at his feet.
Instead of being collared by secret service agents as an eco-protester, he was invited on-stage for a photo-call. But then this was Sergey Brin, the Russian-born entrepreneur and co-founder of Google who has made $11bn (£5.8bn) from the internet search engine. The rucksack that powers his phone and MP3 player is just one of his latest investments.
Brin, 32, is typical of the new breed of wealthy, powerful tycoons piling into environmental issues - including media moguls, nightclub owners, hoteliers and property barons. The dollars they have in vast quantities are known to Americans as greenbacks. That's why the new rich greens are being called the Greenback Pack.
Perhaps the most quietly influential member of this set is James Murdoch, 33, the son of the global media magnate Rupert Murdoch and the chief executive of satellite broadcaster BSkyB. He has made Sky "carbon neutral" by using renewable energy for its power, cutting electricity use and air travel, and rewarding staff who switch to bicycles, buy green "hybrid" cars and install low-energy bulbs at home. It is a message, claim Sky executives, that he wants to spread to Sky's eight million subscribers.
Ten days ago, he persuaded his father to screen Al Gore's acclaimed film on climate change to News Corporation executives at their annual summit in Pebble Beach, California. Sources present say the environment was a key topic, and its impact was very quickly felt throughout the Murdoch empire.
Last week, The Sun newspaper announced its conversion to the green cause with two dramatic pieces warning about climate change. On Friday, the paper's 8.5 million readers were urged to watch Gore's film, An Inconvenient Truth, which one writer branded "more hair-raising than any Hollywood horror".
Tony Juniper, the director of Friends of the Earth, said this marked a "high-water mark" for the green movement. "I've lived and worked through several green waves, and these things do come and go. But this time it's a bit different with the depth and seriousness of the things now going on."
Britain has its own Greenbacks, such as Zac Goldsmith, the millionaire editor of The Ecologist and wannabe Tory MP. Over the past few days, many of them have been on a farm near Bristol for the annual Big Green Gathering. The festival ison the new green society circuit, on which charity raffles are held at exclusive Christmas parties to raise funds to promote organic farming; names such as Pink Floyd's David Gilmour turn up at FoE rallies; and the music Svengali Malcolm McLaren pops into Soil Association events.
Mr Goldsmith - the son of the maverick tycoon Sir Jimmy Goldsmith and the nephew of one of Britain's most charismatic early environmentalists, the founder of The Ecologist, Teddy Goldsmith - is at the centre of the network of elite greens. It includes Elizabeth Hurley, who is converting her 400-acre farm in the Cotswolds to organic production and has mused about launching an organic baby-food range.
Donna Air, the former actress and TV presenter, is also in the set, together with her husband, Damian Aspinall, scion of the Aspinall zoo-owning family. In four weeks' time, Ms Air, a supporter of Fairtrade produce, will be unveiled as the "face" of this year's Soil Association Organic Food Fortnight.
Another prominent member is Robin Birley, 47, the owner of Annabel's and four other exclusive London clubs. Mr Birley, who is Zac Goldsmith's half-brother, remembers watching the first edition of The Ecologist running off the presses in the early 1970s.
He has run environmental projects in Africa for the past decade and five years ago launched an EU-funded programme costing some £500,000 a year to support ecologically sound farming and forestry in Mozambique. It offers polluting companies the chance to "offset" their damaging release of global warming gases by supporting these farming and forestry projects - a system known as "carbon trading".
Mr Birley helped to launch a "green" lobbying outfit, Consensus Environmental Group, with a friend, the Iranian property developer and Hilton hotels owner, Vincent Tchenguiz, last month. The new group will invest in environmentally friendly ventures such as tree-planting in Africa.
Mr Birley told The Independent on Sunday that the rise in green awareness among his friends was sincere. Its catalyst was "unquestionably" global warming. "I think people are now aware of it. They know that they're contributing to it. It's something where people can do things on an individual basis. I think there's been a complete and utter sea-change. No one is as openly disdainful as they once were."
Other tycoons and industrialists are also bidding hard to establish their green credentials. Sir Richard Branson - ever one to smell a trend - is seeking to establish his Virgin airline as the first to be powered by greener biofuels. And the couple behind another famous brand in British industry, Lord and Lady Bamford, who own the JCB digger and construction machinery company, are becoming equally well known for championing organic farming and promoting the English rural economy.
The Bamfords' pride and joy is a "farm shop" known as Daylesford Organic, on their Gloucestershire estate, near Ms Hurley's manor. Daylesford has won a host of awards - including Luxury Small Business of the Year 2005 - and has outlets in Selfridges and Sloane Square. Bryan Ferry, Kate Winslet, Kate Moss and Gwyneth Paltrow are all said to be regular customers.
Being green - and loaded - is most definitely in.
The Greenback Pack
James Murdoch Chief Executive of BSKYB
The youngest son of Rupert Murdoch, and a former News Corp executive, he became chief executive of BSkyB in 2003. He has made Sky "carbon neutral" and is an ally of Al Gore, the former Democrat presidential candidate and climate campaigner
Sergey Brin Co-founder of Google
Brin is now one of the world's wealthiest men, worth $11bn, after co-founding the web search engine Google in 1998. He is investing in advanced solar technology and electric cars, has a solar-panelled rucksack for his phone and MP3 player and drives a Prius "hybrid" car
Arnold Schwarzenegger Governor of California
"Arnie" started out as Austria's world champion bodybuilder and went on to become a Hollywood blockbuster action star. As Governor of California, he is championing the environment, and wants major cuts in CO 2 emissions
Donna Air and Damian Aspinall
AGE: 26 and 45
The TV presenter and former actress hooked up in 2001 with Aspinall, who is worth some £42m and is the son of the maverick tycoon and zoo owner John Aspinall. She is the new "face" of the Soil Association, which certifies organic produce, and is a supporter of fair trade. He is a conservationist and owns Howlett's Zoo
Robin Birley Nightclub owner
Owns Annabel's nightclub, established in the 1960s by his father Mark, and four private members' clubs in west London. Set up African environmental charity and promotes 'carbon-trading' schemes to help tackle global warming
Lord and Lady Bamford
AGE: BOTH 60
Worth £950m as owner of the JCB digger company, Anthony Bamford is Britain's 56th richest man. The couple have an organic farm in Gloucestershire and run Daylesford Organic, an award-winning "farm shop"
Elizabeth Hurley Actress
Known for her acting roles, "that" Versace dress and her one-time relationship with Hugh Grant, Hurley is converting her 400-acre Cotswolds farm to organic production and has floated plans to make an organic range of baby foods
Vincent Tchenguiz Property Tycoon
Starting out letting flats in London, the Iranian property and hotels tycoon and his brother Robert have amassed a fortune worth £490m. Now an investor in renewable energy, he has founded a new conservation arm, the Consensus Environmental GroupReuse content