"I think we need a 'carbon freeze,'" Gore told policy and business leaders at a conference organized by a venture capital firm. "I intend to launch an ongoing campaign of mass persuasion at the beginning of 2007."

Gore said the grass-roots campaign would put heat on leaders in Washington to come up with more sophisticated policies to address global climate change.

"I think we need a mass movement in the United States. I think it ought to start at the grass roots," said Gore, author of the book, "An Inconvenient Truth," which was made into a hit documentary film on global warming.

Gore said the power of the freeze demand is that it can operate at every level of society -- individuals can take steps to cut their use of nonrenewable energies, and so can businesses and local and state governments.

As a US senator and arms control expert, Gore had opposed the nuclear freeze movement two decades ago because he thought it was "naive and simplistic."

He said he has since come around to recognize its impact on political leaders.

Gore was appearing at a two-day closed-door meeting of a group called the Greentech Innovation Network organized by Kleiner Perkins Caufield and Byers, Silicon Valley's most powerful venture capital firm.

The group, credited with helping convince California Gov. Arnold Schwarzenegger to sign into law a model carbon emissions cap in September, is made up of environmental entrepreneurs, policymakers and academics.

John Denniston, a Kleiner Perkins partner, told reporters that his firm, which has pledged to invest US$200 million to fund green technology start-ups, is prepared to help finance Gore's political efforts.

Gore spoke on a panel that included Andy Karsner, US assistant secretary for renewable energy.

Karsner said he agrees with Gore's call to make environmental issues a moral imperative, but said the righteous tone of such advocacy was counterproductive.

"In fact, what we lack in abundance is the ability to listen to one another and engage in civic discourse," the Bush administration official said.