Secretary of State Condoleezza Rice challenged the world's biggest polluters Thursday to "cut the Gordian knot of fossil fuels" by shifting toward energy sources that will reduce global warming — without harming their economies.

"Ultimately we need to answer just one fundamental question: What kind of world do we wish to inhabit and what kind of world do we wish to pass on to future generations?" Rice said at the start of a two-day climate meeting called by President Bush.

The United States has lined up with China, India and other major polluters in opposition to the mandatory cuts in Earth-warming greenhouse gases sought by the United Nations and European countries.

Rice said the challenge of global climate change cannot be dealt with entirely as an environmental question, but "in a way that does not starve economies of the energy that they need to grow."

"Though united by common goals and collective responsibility, all nations should tackle climate change in the ways that they deem best," she said. "Managing the status quo is simply not an adequate response. ... We must cut the Gordian knot of fossil fuels."

A White House statement said the meeting will emphasize creating more diplomatic processes to find a solution to global warming, rather than setting firm goals for reducing carbon dioxide and other gases blamed for heating up the atmosphere.

The nations summoned by Bush will seek agreement on how the nations might set their own strategies beyond 2012, when the U.N.-brokered Kyoto Protocol expires, but also could include "a long-term global goal," the statement says.

Despite the emphasis on bureaucracy, James Connaughton, chairman of the White House Council of Environmental Quality, told participants: "This has to be about more than presentations."

European leaders, who concede that the biggest polluting nations must be part of any solution, walked a thin line between skepticism and optimism.

"We can't do this on the basis of talking about talking or setting goals to set goals," John Ashton, a special representative on climate change for the British foreign secretary, said in an interview. "We know that a voluntary approach to global warming is about as effective as a voluntary speed limit sign in the road. We don't just need an approach that works; we need an approach that works very quickly."

Bush's meeting notably includes the fast-emerging economies whose exclusion from the group of industrialized nations participating in Kyoto has been cited by his administration as reasons for rejecting that international climate accord.

"This relatively small group of countries holds a key to tackling a big part of the problem," said Yvo de Boer, the top U.N. climate official.

Yet Bush also has competed for attention with the climate change summit that was held Monday in New York City at which U.N. Secretary-General Ban Ki-moon warned 80 world leaders that "the time for doubt has passed" and urged fast action to save future generations from potentially ruinous effects of global warming.

The U.S.-led talks Thursday and Friday unite countries at both ends of the economic spectrum, the haves and have-nots, in opposition to mandatory cuts in greenhouse gases, but for different reasons. The already-industrialized nations do not want to harm their economies, as Bush has argued. Developing nations do not want to give up ground toward industrializing — and meeting basic human needs.

"For a developing country, the main task is to reduce poverty," Xie Zhenhua, vice chairman of China's national development and reform commission, told a forum Wednesday sponsored by the Center for Clean Air Policy, a think tank.

Mexico's environment minister agreed. "We have always to bear in mind that half our population is at the poverty line," said Juan Rafael Elvira Quesada. "We are also extremely concerned about the consequences, the adverse effects of climate change."

They expressed a strong preference for the climate negotiations later this year sponsored by the U.N. Framework Convention on Climate Change, for which Ban's summit Monday was intended to build momentum.

"All these discussions should be taken within the framework of the UNFCCC and the Kyoto Protocol," Xie said.

But developing countries still are trying to curb their emissions while lifting the welfare of their citizens, said Sergio Serra, Brazil's first ambassador in charge of global warming issues.

"It is a myth to think the developing countries are doing nothing to address climate change," he said.