(Updates after end of meeting)

By Alister Doyle, Environment Correspondent

PARIS, April 16 (Reuters) - Greenhouse gas curbs on industries such as steel and cement could help a U.N.-led drive to fight global warming despite fears they would be hard to implement, delegates at a U.S.-led conference said on Wednesday.

Developing nations objected at the 17-nation talks that such sectoral industrial schemes might throttle their inefficient energy-intensive businesses and said the burden for curbs should fall instead on rich nations.

But many said that such sectoral industrial targets, championed by Japan as a possible element of a planned new U.N. climate treaty beyond 2012, could be help alongside national targets for slowing climate change.

"The sectoral approach, we all agree, is not a substitute for economy-wide targets for greenhouse gases," Brice Lalonde, France's climate change ambassador, told reporters after Wednesday's talks among 17 nations. "It's complementary."

Seventeen nations, the European Commission and the United Nations meet in Paris on Thursday and Friday for a third round of a U.S.-led series of meetings to work out ways to fight global warming.

Experts were at a preliminary workshop on Wednesday on setting global industrial benchmarks for sectors of industry, such as for the amount of greenhouse gases produced by manufacturing a tonne of aluminium, steel or cement.

The Paris talks are partly trying to silence criticism that President George W. Bush is doing too little to fight climate change compared to other industrial allies who have agreed to cut emissions by at least 5 percent below 1990 levels by 2008-12 under the Kyoto Protocol.

2025 GOAL

But in Washington, an official said that Bush was planning to call for halting the growth of greenhouse gas emissions by 2025 -- far short of most nations' targets. The Paris talks ended before the speech and delegates declined comment before hearing the details.

"Quite frankly, we are looking to the next president for answers, not to Bush," one senior European delegate said. The U.N. Climate Panel has urged deep cuts to avert more heatwaves, droughts, floods and rising seas.

India led objections on Wednesday at the workshop, reviewing whether industries could take on sectoral goals such as the amount of greenhouse gases emitted to produce a tonne of steel or aluminium.

Plans by rich nations to cut emissions of greenhouse gases "should not be diluted by a sectoral approach," R. Chidambaram, chief scientific adviser to India's government.

He said that India needed new technologies to help industries that were dirtier than foreign rivals. "You cannot develop a global policy that will throttle these guys," he said.

"We believe a sectoral approach is a solution," said Olivier Luneau of cement maker Lafarge. There was huge room for improvement in an industry where greenhouse gas emissions per tonne of cement by the best producers are half those of the worst, he said.

For steel, Hiroyuki Tezuka, of JFE Steel Corp, said emissions standards had to be global to work since 40 percent of the metal was traded on global markets. If curbs were only on part of the industry, high-polluting exporters would benefit.

-- For Reuters latest environment blogs click on: http://blogs.reuters.com/environment/ (Editing by Giles Elgood)

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