In what amounts to an admission that the Copenhagen climate summit ended in failure, President Barack Obama says people are "justified" in being disappointed with the lack of a comprehensive deal for emissions reductions.

But the president added that "an important principle" was established with the last-minute, non-binding agreement signed in Copenhagen late last week: By having China and India agree to emissions reductions, Obama said, it was established that developing countries, and not just wealthy ones, share responsibility for cutting emissions.

"I think that people are justified in being disappointed about the outcome in Copenhagen," Obama told PBS's Jim Lehrer in a year-end interview for NewsHour. The president said:

It didn't move us the way we need to. The science says that we've got to significantly reduce emissions over the next - over the next 40 years. There's nothing in the Copenhagen agreement that ensures that that happens.

What did occur was that at a point where there was about to be complete breakdown, and the prime minister of India was heading to the airport and the Chinese representatives were essentially skipping negotiations, and everybody's screaming, what did happen was, cooler heads prevailed.

And we were able to at least agree on non-legally binding targets for all countries - not just the United States, not just Europe, but also for China and India, which, projecting forward, are going to be the world's largest emitters.

So that - that was an important principle, that everybody's got to do something in order to solve this problem. But I make no claims, and didn't make any claims going in, that somehow that was going to be everything that we needed to do to solve climate change.

Read the full transcript of the interview here.

The following video was broadcast on PBS' NewsHour with Jim Lehrer, December 23, 2009.