* U.S. climate envoy praises China's climate efforts
* But Beijing must do "a lot more" - Stern
BONN, Germany, March 29 (Reuters) - The United States gave rare praise to China's efforts to curb emissions of greenhouse gases on Sunday but said Beijing must do "a lot more" under a planned new U.N. treaty to fight climate change.
Todd Stern, U.S. special envoy for climate change, told Reuters on his debut at 175-nation U.N. climate talks in Bonn that all major emitters had to step up action despite recession under a U.N. climate pact due to be agreed in December.
"The Chinese are doing a lot already," he said. China has recently overtaken the United States as top emitter of heat-trapping gases, mainly from burning fossil fuels, blamed for global warming.
"The Chinese have a lot of policy that they have put in place -- energy intensity targets, significant renewable energy targets, they've got auto standards that are good, they've got efficiency standards for their top 1,000 enterprises," he said.
"Yet given the power of their economy and the growth trajectory of their economy they are going to have to do a lot more," Stern said.
Separately, in a speech to delegates at the March 29-April 8 talks, Stern said he was "immensely impressed" by actions by developing nations such as China, India, South Africa, Brazil and Mexico.
Delegates said the tone was unusually conciliatory.
China and the United States, which together account for about 40 percent of global emissions, are often at odds over climate policies. U.S. emissions are more than four times higher per capita than China's.
Former President George W. Bush rejected the U.N.'s Kyoto Protocol, which sets caps on emissions for all industrialised nations except the United States, partly arguing that poor nations such as China were under no obligation to act. That, he said, would cost U.S. jobs.
And earlier this month, U.S. Energy Secretary Steven Chu angered Chinese officials by saying Washington's plans for setting a price on carbon emissions included examination of the possibility of taxing imports from countries that did not.
Stern suggested that China needed to step up action in areas such as energy efficiency, renewable energy, and curbing high polluting coal. But he stopped short of calling for a ceiling by 2020 on Chinese emissions.
"I'm not saying that there needs to be an absolute reduction," he said. China says it cannot consider a cap on emissions because it needs to use more energy to stoke its economy and lift millions from poverty.
President Barack Obama wants to cut U.S. emissions to 1990 levels by 2020, a reduction of about 16 to 17 percent from current levels, Stern said, and to cut to 80 percent below 1990 levels by 2050.
Chinese officials have said the U.S. goal falls far short of advice by the U.N. Climate Panel, which says rich nations need to cut emissions by 25 to 40 percent below 1990 levels by 2020 to avoid the worst of climate change such as floods, droughts, heatwaves and rising sea levels.
Developing nations' emissions, meanwhile, should merely show a "substantial deviation" below projected growth paths by 2020, it says.
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Editing by Jon Boyle
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