BONN, Germany, March 29 (Reuters) - The United States promised closer cooperation with the rest of the world on a United Nations climate treaty on Sunday but cautioned it had no magic wand to fix global warming.
"My team came here determined to make up for lost time," U.S. special envoy for climate change Todd Stern told a news conference at the opening of 175-nation U.N. climate talks, the first since President Barack Obama took office in January.
"The United States is going to be a partner -- we need to be a partner to developed countries and to developing countries, he said at start of the March 29-April 8 meeting in Bonn.
"But we are all going to have to do this together, we don't have a magic wand," he said.
Obama has promised to cut U.S. greenhouse gas emissions by about 16-17 percent from current levels to take them back to 1990 levels by 2020 as part of a new U.N. climate deal meant to be agreed in Copenhagen in December.
Under former President George W. Bush, the United States was isolated among industrialised nations in opposing caps on emissions under the U.N.'s existing Kyoto Protocol. Delegates even booed U.S. delegates at a meeting in Indonesia, in 2007.
"Everyone is very excited" by signs of a stronger U.S. commitment, Yvo de BVoer, head of the U.N. Climate Change Secretariat, told a news conference. China and the United States are the top greenhouse gas emitters.
The U.N. Climate Panel projects more floods, droughts, more powerful storms, heatwaves and rising sea levels from a gradual build-up of heat-trapping gases from burning fossil fuels.
-- For Reuters latest environment blogs click on: blogs.reuters.com/environment/ (Editing by Louise Ireland)