Gibbs: Obama is working the phones for Copenhagen deal

Asked whether Obama might change his plans to arrive days earlier, in order to take a more personal role in the talks, Gibbs replied “I think when the President picks up the phone and calls world leaders, I would define that as personally involved.”

Negotiators are still grappling with a host of disputes at the talks on issues including aid from industrialized nations to help developing countries tackle climate change, and major rifts over binding emissions targets between rich and poor countries.

“The President is committed to pursuing an accord that requires countries to take meaningful steps to address the climate change problem,” Gibbs said.

“I don't think there's any doubt that there are still – there will be issues left to resolve when he lands – that developing nations are going to have to do their part; they're going to have to recognize the part that they have to do; that we have worked strongly and diplomatically to bring countries like India and China along to the point where it's possible to get some type of agreement; that the President will continue to work throughout this week to see – to make sure that that happens,” Gibbs added.