Key Points:

Seven years after he lost the US election, Al Gore has more influence on US global warming policy than the man who defeated him, President George W. Bush.

As talks on a new world emissions treaty opened yesterday in Bali, companies and investors such as General Electric, Chevron and Lehman Brothers are backing Mr Gore's push for global limits on climate-changing carbon emissions, a strategy Mr Bush opposes.

A new accord limiting global warming, to be in place by 2012, will affect the way US$11.6 trillion is spent on new power generation, the International Energy Agency says.

Clean energy may be the "biggest business opportunity there's ever been," says billionaire Ted Turner.

Business leaders including GE's Jeffrey Immelt say they need clarity on the cost of carbon emissions to steer "green" investment decisions.

The official US delegation to the United Nations-sponsored Bali talks will probably continue President Bush's opposition to mandatory emissions curbs and preference for voluntary measures.

Mr Bush leaves office in January 2009, before a new accord will be ready.

Anticipating the post-Bush diplomatic era, a shadow delegation of American business and political leaders will advocate mandatory limits. The conference, which runs for two weeks, is intended to help set the stage for more than two years of negotiations on a treaty that would replace the emissions-limiting Kyoto Protocol when it expires in 2012.

Mr Bush walked away from the Kyoto accord in 2001 without offering an alternative.

The unofficial US group in Bali will include Mr Gore, winner of the Nobel Peace Prize for his work on climate change, and Democratic Senator John Kerry of Massachusetts, whom Mr Bush defeated in 2004.

Republican California Governor Arnold Schwarzenegger, who favours limits and the trading of carbon-emission credits, may also attend.

"Clearly, the US position is much more advanced than the White House position," says economist Jeffrey Sachs, director of the Earth Institute at Columbia University in New York and a special adviser to the UN.

"They are there in case the White House really does try to pull a fast one because there's so little trust."

The central idea for slowing global warming involves setting limits on the amount of greenhouse gases, mainly carbon dioxide, that each country's factories, vehicles and generating plants can pour into the atmosphere.

Companies are granted permits for emissions, or need to buy them. Those with spare permits can sell for a profit, while high producers of greenhouse gases need to buy additional permits.

A potential US$300 billion US market for such pollution permits may develop under a new accord, congressional budget office director Peter Orszag said last month. The value of existing global emissions trading tripled last year to US$30.1 billion, 81 per cent of it in the European Union, according to the World Bank.

Bush Administration officials taking part in the Bali talks say they will emphasise spurring development of low-carbon technologies and push for each nation to set its own mix of solutions.

- Bloomberg