The US President, George W Bush, has called on countries to agree on a global emissions target for greenhouse gasses and to reach a consensus by 2008.
Mr Bush unveiled his long-term strategy on climate change in a speech in Washington.
The change in language comes ahead of next week's G8 summit in Germany, where global warning is expected to be a significant issue.
At the summit, Germany is expected to call for cuts in emissions, but the White House has already made it clear that US will oppose demands for it to cut emissions and join a global carbon trading system.
The US has still not ratified the Kyoto Protocol which set out targets on lowering emissions by 2012.
