U.N. Secretary-General Ban Ki-moon is attending the climate talks in Copenhagen.  Before leaving for the Danish capital, he said rich and poor countries must "stop pointing fingers" and must press forward to reach a strong deal to combat climate change.  Ban Ki-moon said he is optimistic a robust agreement will be reached at the Copenhagen conference.

"Copenhagen can and must be the turning point in the world's efforts to prevent runaway climate change and usher in a new era of green growth for all," Ban said.

Tuesday marks the eighth day of climate talks and with world leaders arriving, analysts say it is time to make serious progress with the major issues.

Bob Ward is from the Grantham Institute for Climate Change at the London School of Economics.

"There is a sense that when the political leaders arrive in the next few days, that they will be able to overcome some of the stumbling blocks, because I believe the leaders will be able to really grab this issue by the scruff of the neck and get down to the substance and bridge the remaining gaps," Ward said.

The main goals of the summit are to agree on targets to cut to greenhouse-gas emissions and to set up a mechanism to provide developing countries with the billions of dollars needed to cope with climate change.

But talks were put on hold for much of Monday, after African delegates walked out saying the poor nations most affected by climate change are being ignored.  Before returning to the talks they said developed nations are trying to sideline the Kyoto Protocol - a legally binding deal that set reduction targets for 2012.

The G77-China bloc, which negotiates on behalf of 130 countries including some of the poorest nations - want the Kyoto agreement to continue beyond 2012 with new emissions targets.

But Ward says focusing on the mechanisms for reaching a climate deal are counter-productive right now.  He says world leaders need to focus instead on the major goals.

"That is an issue that can be hammered out after Copenhagen, once we have got the important agreement about exactly how much we are going to cut emissions and how much money is going to be given to those developing countries to help them with their efforts," Ward said.

The European Union has pledged more than $10 billion to help poor countries deal with climate change - a figure developing nations have described as "insignificant".  The World Bank has predicted adjusting to the effects of climate change will cost up to $100 billion a year until 2050.