It's very nearly a wrap for Arnold Schwarzenegger, whose career as governor of California will come sputtering to an end in January with his approval rating in the 20s, the state budget shortfall at $25bn (£16bn), and unemployment at nearly 13%. But, like the action heroes he has so often played, the man they called the governator is already working on a comeback.

In what is likely his last performance on a world stage as governor, Schwarzenegger this week launched the R20 climate network, an alliance of regional leaders who have pledged to work together to fight climate change. Schwarzenegger is the "founding father" of the new venture, a self-appointed global champion in the war against climate change.

Backstage at the performance hall at the University of California, Davis, Schwarzenegger is moments away from revealing to the Guardian the formula that will jolt the world's jaded and divided populace from their dangerous inertia in the face of great peril. First, though, there is the basket of muffins laid out in his backstage dressing room. "This is where the action is. Right here," he says, grabbing one.

How will he approach the fight against climate change? "I always was a big believer in doing things on a global level," he said. "Everything I have ever done, I always was interested in doing it globally – if it was the fitness, if it was the bodybuilding, if it was entertainment and acting and showbusiness."

Schwarzenegger has had more than 40 years of celebrity since storming the world of bodybuilding. He conquered Hollywood. His marriage to Maria Kennedy Shriver catapulted him into America's elite. But he is 63 now. The action-hero physique is bulkier and swathed in suits and ties – bright green at environmental gatherings like this.

Schwarzenegger said he could see a place for himself mobilising world opinion – and investment capital – in support of clean tech projects around the world that together could help reduce global warming.

"I think that I have the talent of speaking the language in such a way so that the world understands it rather than making it complicated," he said.

But don't expect to see Schwarzenegger touring an Al Gore-style scientific slideshow. The governator's version of environmental leadership hinges on avoiding mention of the words climate change or greenhouse gas emissions, which he thinks are a turn-off for some people. "People get stuck and fall in love with their slogans and with their little agendas," he said. "You've got to make it hip. You've got to make it sexy to be part of this movement."

You've also got to steer clear of party politics. Schwarzenegger, a Republican, refuses to see the environment as a solely Democratic preserve. "People get stuck in this political crap when in fact you don't need to," he said. "Let's just leave politics out and find out what we can do together."

The vehicle for this next stage of his life is the new R20 group of city and state leaders, which Schwarzenegger conjured into being at his climate summit this week.

The group, whose name is a conscious play on the G20 club of major world economies, is devoted to putting together clean energy projects in developing countries by recruiting finance from industrialised countries. The first wave of projects is likely to involve the installation of white roofs, which reflect the sun and keep houses cool, aides said.

After this week's launch, the next stop is Cancun, where aides say the R20 will hold a side event at the UN climate summit. Then there is the prospect of another star turn for Schwarzenegger, who is thinking of putting in an appearance at Davos, the talking shop of the global elite. Then he will see where the R20 takes him.

"It could very well be that this would be the main thing," he said of his new career, but just as immediately mentioned some alternatives. "It could also be that it would be one of five things that I would do. It could be showbusiness. It could be business in general."

Schwarzenegger admits he stumbled into the role of environmental activist when he signed California's ambitious climate change law in 2006 – the same year Gore came out with An Inconvenient Truth. Four years later Schwarzenegger helped defeat an attempt to repeal the law by Texas oil companies in the midterm elections.

He would have liked to be known as an economics guru – but then California's budget deficit just topped $25bn. He would have liked to be seen as a model of post-partisan politics – but then he admits that he has little or no sway over his fellow Republicans in Washington. That left an opening on the environment, at a time when Congress and international climate negotiations had both failed to deliver results – and Schwarzenegger says his whole life has been built on finding such openings.

"My whole life I was always very ambitious, but I was smart enough to always look, what is my talent, what do I have to offer to the world? Then you go with that. You never know. Six years ago, seven years ago I did not know it would drag me into this," he said. "But you go with it."

It's too early to say how R20 will fill the gap in national and international action on climate change. This year's climate summit, the third and last for Schwarzenegger, was a slightly shrunken affair, transplanted from the glitz of Los Angeles to the clean tech hub of the University of California at Davis.

Schwarzenegger managed to rustle up some big names. David Cameron joined in a video satellite conversation. Prince Charles sent a video talking about harmony. The primatologist Jane Goodall sent a rendition of a chimpanzee greeting. Harrison Ford and Deepak Chopra came in person, as did a couple of governors.

But those governors, like Schwarzenegger, will soon be leaving office. Officials from China, the world's largest emitter, were at the meeting, but did not sign on. By lunchtime, a Dutch official, who did sign on, was telling his dining companions he thought it was another empty promise.

However, Terry Tamminen, an adviser to Schwarzenegger who will effectively run the R20, argued that the organisation would help fill the critical gap caused by the failure of the UN to reach a global agreement on climate change.

The organisation hopes to recruit enough members to represent 20% of the world's economies within the next year. "If you start getting to that size in terms of economies of scale and greenhouse gas reductions in one organised effort, then it becomes a coalition of the willing," he said. "Then hopefully even more of the world's economies join in and then you get to the virtuous tipping point where it's easier for the rest of the countries in the world to join in."

Much of that depends on Schwarzenegger's ability to rally celebrities, world leaders and the public. Few personalities can command the support from global leaders that he can – or boast a global fan base many million strong.

Schwarzenegger said he has led his entire life by just waiting for the pieces to fall into place, and then making his move.

"There is a lot of it that falls into place like that," he said. "It all unfolds and you just say, 'OK.'"