LONDON - The world needs to build 100 major projects for capturing and burying greenhouse gases by 2020 and thousands more by 2050 to help combat climate change, the head of the International Energy Agency said on Tuesday.

Nobuo Tanaka said the drive, mostly to capture emissions from coal-fired power plants, would cost $56 billion by 2020 alone. Carbon capture funding could be a key part of a new U.N. climate treaty due to be agreed in Copenhagen in December.

We will need 100 large scale projects by 2020, 850 by 2030 and 3,400 in 2050, Tanaka told energy ministers from around the world at a carbon capture and storage (CCS) conference.

A few industrial-scale projects are in operation, including in Norway, Canada and Algeria, but none test all parts of the capture process. Heat-trapping carbon dioxide can be trapped from the exhausts of a coal-fired power plant, for instance, then piped underground into porous rocks.

Tanaka said rich nations in the Organization for Economic Cooperation and Development would have to take the lead.

But the technology must quickly expand in the developing world where we see the vast majority of emissions growth, he told the Carbon Sequestration Leadership Forum.

By 2050 our estimates suggest that 65 percent of CCS projects must be located in non-OECD countries, he said. The IEA estimates $56 billion of investment will be needed in CCS globally from 2010-2020, then $646 billion from 2021 to 2030.

U.N. studies have indicated that CCS could do more to limit greenhouse gas emissions this century than a shift to renewable energies such as wind or solar power. CCS has been limited by high costs.

COPENHAGEN SUCCESS

The world's biggest coal-using nations recognize we cannot continue with business as usual on coal, British Energy Secretary Ed Miliband said.

I think we are sending a very clear signal to the Copenhagen talks that coal and carbon capture and storage need to be a very important part of the final agreement, he added, summing up two-day of talks among 15 ministers in London on promoting the technology, including China and the United States.

We need a mechanism which will at least provide the opportunity for developing countries to get help with financing some of the incremental costs of their projects.

A promise of big aid via technologies such as CCS could encourage developing nations led by China and India to sign up for more action to limit rising emissions in Copenhagen.

Talks on the new U.N. climate deal made little progress at a two-week session that ended in Bangkok last week, partly because of disputes between rich and poor nations about sharing out the burden of curbs on greenhouse gas emissions.

And it is unclear if the U.S. Senate will pass laws before Copenhagen to cut national emission. And recession is dampening willingness to act.

In Australia, a survey on Tuesday indicated that saving jobs was the top priority for voters and that fighting climate change had fallen to seventh two years after Prime Minister Kevin Rudd was swept to power on a pledge to tackle global warming.

The government said it was committed to an emissions trading scheme which, if defeated in November, could bring a snap election.

Our policy is not determined by polls, Climate Minister Penny Wong said of the survey by the Sydney-based Lowy Institute for International Policy.

So far, few nations have agreed to invest heavily in carbon capture technologies -- nations including the United States, Australia, Britain and China have projects.

Still, in a national budget on Tuesday, Norway said it would almost double funding of carbon capture research to $620 million next year. Norway has the oldest commercial carbon capture site, set up in 1996 at the Sleipner gas field in the North Sea.

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