Here is the relevant part of the transcript:

QUESTION: If we could turn to another one of those key questions: climate change. That’s obviously going to be a key issue in your talks with the Chinese. Just on the subject of climate change, could we ask you whether you are intending to go to Copenhagen for the talks? You went there for Chicago’s bid for the Olympics; are you intending to go there for the climate change summit?

OBAMA: Well, here’s what I’ll say. Since before I was sworn in, I was very clear that I think dealing with climate change is vital to our security interests, is vital to our economic interests. It is an opportunity, as well as an enormous challenge, for us to shift to a clean energy economy. And after eight years in which there was resistance to even acknowledging the problem, I think my administration has been very clear that we intend to be a leader on this issue internationally.

Now, getting to a deal internationally is difficult. This will be one of the top subjects for our conversations with the Chinese. In my previous conversations with President Hu Jintao, I think he acknowledges that this is an area of great interest to the Chinese. The effects of climate change could be devastating on their agricultural systems and their ecology. And the key now is for the United States and China as the two largest emitters in the world to be able to come up with a framework that along with other big emitters, like the Europeans and those countries that are projected to be large emitters in the future like India, can all buy into.

And I remain optimistic that between now and Copenhagen, that we can arrive at that framework. It’s hard work. And one of the things that I’ve come to believe based on a lot of summits this year is that the work is really not done at the summit; the work is done before the summit. And if I am confident that all the countries involved are bargaining in good faith and we are on the brink of a meaningful agreement and my presence in Copenhagen will make a difference in tipping us over the edge, then certainly that’s something that I would do. But I’ve got to make sure that over the next three weeks, pressure is continually applied on our teams and everybody else’s teams to actually create a framework that people can sign off on.

QUESTION: Do you think there’s more you can bring, apart from what’s happening on the Hill, sort of legislation which may not indeed be ready by then, but I mean –

OBAMA: Well, I think everybody understands that the Senate won’t have acted on climate change legislation before Copenhagen. And our key partners, including Prime Minister Rasmussen of Denmark, the host, who’s taken a very constructive and active role on this issue, I think recognizes that not every “t” is going to be crossed and “i” dotted in the next three weeks. I think the question is, we can create a set of principles, building blocks, that allow for ongoing and continuing progress on the issue, and that’s something I’m confident we can achieve.

And I am confident also — last point I’d make — I’m confident that the American people will recognize the enormous opportunity around a clean energy economy and the ability for us to reduce our greenhouse gas emissions.

But it takes time. In meetings with world leaders, I’ve repeatedly explained that America is not a speedboat; we’re a big ocean liner. And you can’t reverse course overnight. But what we can do and we are doing is I think changing the trajectory of how we approach this issue, both in terms of public opinion, attitudes on Capitol Hill, and certainly among businesses who really understand that for America to lead in this issue ultimately will create enormous economic opportunities.