JIM LEHRER: This is make-or-break week for negotiators at the climate summit in Copenhagen. Ray Suarez is there, reporting for the NewsHour.
The word from him tonight is that efforts to craft a deal are moving very slowly.
RAY SUAREZ: It was one more demonstration of how tough it will be to get an agreement in Copenhagen. A 1997 treaty, the Kyoto protocol, threw the 2009 talks into temporary disarray.
WOMAN: I think there is a good meeting to get out of the meeting.
RAY SUAREZ: A bloc of developing nations, led by African countries, walked out. They said developed nations had done too little to cut greenhouse gases under Kyoto.
Lumumba Di-Aping of Sudan heads the 135-nation bloc.
LUMUMBA DI-APING: We are not afraid. We know that the developed countries have made that decision that they would want to kill Kyoto protocol in order to change the balance of obligations between developing countries and developed countries. And that is absolutely unacceptable.
RAY SUAREZ: The protest had the support of China, the world's largest emitter of greenhouse gases, and still considered a developing nation under Kyoto. The developing nations are looking to extend Kyoto and work out a new deal for poorer countries.
Developed nations want to fold the 1997 agreement into a new, overarching framework to fight global warming. The new compact would include the U.S. and China, which never ratified Kyoto.
Antonio Hill is the senior climate change adviser to Oxfam, the international aid group.
ANTONIO HILL: Well, in this tit for tat, there's accusations that developing countries, the poorest countries, the ones that most need urgent action on climate change, are blocking the talks.
And I think, in respect of that, we need to be clear that they're not putting blockages in front of -- on the tracks in front of the train. What they're doing is pulling the emergency cord to stop the train before it runs off the cliff at the end of this week.
RAY SUAREZ: By the end of this week, the leaders of 110 countries will arrive here at the Copenhagen conference, President Obama among them, trying to hammer out a compromise to curb global emissions.
Today's impasse was resolved after several hours of informal talks. The developing nations won assurances that wealthy nations are not trying to weaken commitments to emission cuts.
YVO DE BOER, executive secretary, United Nations Framework Convention on Climate Change: They weren't blocking. They were just trying to understand the procedure. But it took a very long time. But now everybody at least understands, is comfortable. And that is really important in a process like this, where there is quite a lot of tension. So, -- but it is -- it is worth investing in everybody being clear.
RAY SUAREZ: But gaining that clarity took time. And British Climate Secretary Ed Miliband and others suggested, the boycott didn't help.
ED MILIBAND: The priority now is to get down to the substantive conversations. I said earlier today that negotiators and ministers need to get their act together. I think that remains the case. I don't we are doing a very good job of it so far today.
RAY SUAREZ: Earlier, former Vice President Al Gore presented out a new slide show report on arctic ice melt. He said the Arctic ice caps could disappear during summer months five to seven years from now.
AL GORE: It's almost like blood spilling out of a body along the east coast of Greenland there. And so it's gone in less than 30 years from this to this. So, on a regional basis, this means a dramatic change in the heat absorption from the sun during the summertime.
RAY SUAREZ: And again today, there were protests by those who warned, failure means catastrophe. Greenpeace protesters marched outside the conference dressed as the four horsemen of the apocalypse.