BANGKOK/LONDON - Carbon emissions from a group of richer developing nations including Russia, China, Brazil and the Middle East must stop growing by 2020 to control global warming, the International Energy Agency said on Tuesday.

The estimate is far more ambitious than goals offered by emerging economies such as China in United Nations talks meant to agree a new climate pact in Copenhagen in December.

China -- the world's biggest carbon emitter -- on Monday accused rich nations of killing the present Kyoto Protocol by proposing more flexible strategies for cutting their own greenhouse gas emissions, at preparatory two-week climate talks in Bangkok.

Carbon emissions will fall by as much as 3 percent this year, following the economic crisis, aiding the effort to cut carbon, said the IEA, which is an energy adviser to 28 industrialized countries.

This gives us a chance to make real progress toward a clean-energy future, but only if the right policies are put in place promptly, said IEA Executive Director Nobuo Tanaka in a statement.

The report, an early release from the IEA's annual World Energy Outlook, said $10 trillion extra energy investment would be needed from 2010-2030 to control carbon emissions, or between half and 1 percent of global economic output, but that could be almost entirely made up from fuel savings following efficiency gains.

The investments the world has to make to shift to a low-carbon economy will pay off and result in lower energy bills, less air pollution and help keep climate change under control, said John Nordbo, WWF technology and climate change expert, speaking in Bangkok.

Limiting global warming to 2 degrees, which scientists say may avoid the most dangerous extreme weather and sea level rise, would require global carbon emissions from burning fossil fuels to stop rising before 2020, the IEA report said.

Rich country emissions must fall steadily from 2007 levels. Other major economies classed as Brazil, China, the Middle East, Russia and South Africa, would have to stop emissions growth by 2020, the IEA said.

Global use of fossil fuels should peak before 2020 under a scenario to limit global warming to 2 degrees Celsius, it said.

Oil demand will increase much less in our (2 degrees) scenario, said Fatih Birol, IEA chief economist.

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