Representatives of more than 180 nations gathered on the Indonesian island of Bali today to kick off a United Nations-sponsored conference on global climate change. The U.N. hopes the meeting will conclude with a road map toward a new agreement on reducing the types of air pollution many scientists believe are driving changes in the earth's climate. From Bali, Trish Anderton reports.

Conference president Rachmat Witoelar of Indonesia told reporters that a detailed proposal is not necessary at this stage, but participation by all nations is vital.

"We will be happy if this Bali road map is general so we will not push for a very detailed in this short time," he said. "The introduction, the process is important."

As the conference opened, Australia's new prime minister, Kevin Rudd, signed the Kyoto Protocol, limiting his country's greenhouse gas emissions. That act earned a standing ovation in Bali, and focused attention on the failure of the United States to sign the protocol - the only developed nation not to have done so.

Alden Meyer of the U.S.-based Union of Concerned Scientists accused the Bush administration of obstructing progress on climate change.

"While the current U.S. delegation will not join in serious negotiations over mandatory limits on global warming pollution, they won't be around when the final deal is made in 2009. A new team will be on the field with a very different game plan," he said. "The other nations must not allow the U.S. to derail, delay or water down the Bali mandate."

Senior U.S. negotiator Harlan Watson denied his country was blocking progress, saying the U.S. had merely chosen a different course.

"It's up to each country to do the analysis and analyze for themselves if the target is do-able. Obviously the U.S. came to a different conclusion," he said. "We respect the decisions other countries have made and of course ask them to respect the decision that we've made."

President Bush says that the Kyoto Protocol threatened U.S. economic growth, and believes that any future climate-change agreement will be ineffective unless it includes rapidly developing nations such as China and India, which are among the world's largest producers of greenhouse gases.

Other subjects on the agenda in Bali include saving the world's remaining forests, and sharing technologies to help developing nations grow in less-polluting ways.

The U.N. also hopes to finalize a fund to help countries affected by global warming to cope with the impacts. The money could go toward flood-proof houses, better water management, and crop diversification.

The Bali conference will continue until December 14. Thousands of government representatives, scientists and activists are attending.