Leak something outrageous, and then "compromise".

"The future is already here -- it's just not very evenly distributed" William Gibson

Patching up after Copenhagen leak

Danish officials may play down a document implying a stitch-up between rich nations. But their impartiality as hosts looks shaky

[...]It has also provoked sharp reactions from Danish and international environmental NGOs. Kim Carstensen, the leader of WWF's climate delegation, says: "This shows an elitist, selective and non-transparent approach to the negotiations. We understand the developing nations' frustration with the Danish government." Greenpeace's Martin Kaiser agrees: "The document is hurting negotiations and shows Danish prime minister Lars Lokke Rasmussen's lack of good leadership. It is creating mistrust."

Actually, the document dates back to November 27. It is as such already old news in terms of the now ongoing negotiations, and the Danish prime minister on November 30 distanced himself from the now leaked document (the contents of which were already familiar back then). "We have not come with any proposals," Lars Løkke Rasmussen stresses.
[...]
However, the document does raise problems when it comes to the Danish hosts' ability to remain neutral during the complicated and probably difficult process of getting the developing world to agree to an economic deal with the developed world. This is not the kind of publicity Rasmussen and his team has been looking for – far from it. There were always worries that the relatively inexperienced Danish state leader, heading a very small country, might not be up to the enormous and crucial job of hosting such a summit.
[...]