The goal of reaching global agreement on addressing climate change has been postponed beyond a December summit in Denmark.

President Barack Obama and other world leaders in Singapore for the ASEAN summit this weekend endorsed a more scaled-back climate goal for the upcoming meetings in Copenhagen.

"We agreed to work closely to ensure the success of the United Nations Climate Change Conference in Copenhagen and that the agreed outcome should incorporate long-term cooperative actions to address climate change," the leaders said in a statement at the conclusion of the summit.

"We also recognized the critical importance of adapting to the increasingly severe effects of climate change in the region," they added.

The postponed deadline reflects concerns that the U.S. is unlikely to come to the table with climate legislation on the books by next month.

"There was an assessment by the leaders that it was unrealistic to expect a full internationally legally binding agreement to be negotiated between now and when Copenhagen starts in 22 days," Deputy National Security Mike Froman told reporters.

The House passed its climate bill in June, while senators have begun work on marking-up their own bill, though many Democratic leaders in the Senate have conceded that the effort is likely to slip into 2010.