The UN climate chief has encouraged negotiators to complete work in the first week so a historic pact could be agreed to fight climate change.

Yvo de Boer said big issues such as emissions targets for rich nations and funds for poor countries would have to wait for the final summit of 100 world leaders to be held on December the 18th. Negotiators are now struggling to reach agreement on the depth of emissions cuts. They are also worried about the cost to economies of switching from fossil fuels to cleaner energy.

Yvo de Boer, executive sevretary of UN Framework Convention on climate change, said, "First of all we need, in terms of the short-term finance, a list of pledges from individual industrialized countries specifying what each individual country will contribute. So not a collective promise where you don't know who will be paying what at the end of the day but individual announcements of contributions from individual countries. Secondly, we will have to ensure that we establish a clear and effective tracking mechanism that allows us to be absolutely sure that individual industrialized countries are meeting their financial commitments."