African negotiators are worried that if the final deal is still being negotiated when the leaders arrive they will take over the negotiations. This will mean that the leaders of the rich world will be able to put pressure on the leaders of small developing nations to sign. Leaders can use linkage in negotiations to connect an agreement at Copenhagen to other areas of relations, so they could threaten to cut off military aid for example or bribe them with building projects etc.

Linkage can go both ways, developing nations have very little developed nations have in terms of climate change, on the other hand western nations in particular would always like more cooperation against terrorism and piracy, more secure trade routes etc.

The Heads of Government and Heads of State want a big agreement that shows them in a good light with other leaders saving the world from climate change. Without this there is little reason for many leaders to come to the conference at all, why come all the way to copenhagen only to have some discusssions and go home again with no deal?

It would suit leaders vanity even more if they could come and claim to save the world and it was really true, they get the chance to break the deadlock themselves rather than taking the credit for others.

Whether or not a deal is done it will still be a major gathering of world leaders, that in itself makes it worth attending for many. Many will see it as an opportunity to have discussions about things other than climate change, renew friendships etc.

Leaders negotiating is the nightmare of the bureaucrats. What happens has not been sketched out, the leader may not follow his briefing paper, will likely not know all the details and may well find at the end of the negotiations that he has made a deal that is disadvantageous to his country that may even be rejected by his legislature which would be humiliating.

The leader of a nation has much more flexibility in giving concessions. Negotiators have a particular brief they have to stick too, they will often have to refer any possible concessions or concessions given by others back to their home government so wasting time and preventing there being free flowing negotiations. By contrast leaders have the power to make any deal they wish. They can make big concessions to get a deal so someone can step up to break deadlocks with a big concession that in turn brings reciprocal concessions from the other parties. This can lead to a much better deal all round than had been expected.

India has however set a deadline of Tuesday evening to have an agreed text for a deal. Indian Environment Minister Jairam Ramesh insisted "Ministers and heads of state and government cannot negotiate a text. The heads of state and government will be arriving from December 16 and they have to work on adopting a political statement."

There is no time to do a deal before leaders arrive so there is no point in trying and as a result doing a rushed job resulting in making mistakes. Negotiators are worried that they are not far enough along to make a deal by the end of the conference let alone several days before the result. Some of the leaders will begin arriving from tomorrow. There is no chance of having a breakthrough on all the main sticking points by then.