By Richard Black
Environment correspondent, BBC News website, Copenhagen
Developing nations want rich nations to make deeper emission cuts
Rich countries are being asked to raise their pledges on tackling climate change under a draft text of a possible final deal at the Copenhagen summit.
Documents prepared by the summit's chairmen call on developed nations to cut greenhouse gas emissions by 25-45% from 1990 levels by 2020.
Analyses suggest that current pledges add up to about 18%.
The document leaves open the exact target for limiting temperature rise, amid disputes between various blocs.
Small island states and poorer nations of Africa and Latin America have called for the document to endorse the target of keeping the temperature rise since pre-industrial times below 1.5C (2.7F).
This is below the figure of 2C (3.6F), which was endorsed by the G8 and major developing economies in July, and implies the need for drastic emission cuts.
An analysis by the UK Met Office, released at this meeting, showed that meeting 1.5C would be "almost impossible" to meet without implementing measures to take carbon dioxide out of the air.
The temperature figures are listed as alternatives in the draft documents.
Work in progress
The texts are a long way short of constituting a final outcome document, as they leave open some of the most difficult points of the negotiations so far, including the legal form of any new agreement.
A pledge by EU leaders could boost chances of a deal in Copenhagen
However, in a major concession to developing countries, it spells out that pledges for further reductions for developed countries inside the Kyoto Protocol - all except the US - will be managed under the protocol.
Developed countries would prefer an entirely new agreement.
The draft also leaves open the scale of financing to assist developing countries to curb emissions growth and to protect themselves against climate impacts.
Developing countries are demanding far more than richer countries currently believe is necessary, and are likely to demand a lot more clarity on the issue.
Small island states are particularly concerned about the need for firm, predictable adaptation funding.
They also want any final agreement to set a target year for when global emissions should peak and begin to fall - a concept that is presently absent from the draft.
At a European Council meeting in Brussels, EU leaders have agreed to pay 7.2bn euros ($10.6bn; £6.5bn) over the next three years to help developing nations adapt to climate change - a figure described by delegates from small island states and the Least Developed Countries bloc (LDCs) as "inadequate".
The temperature target is the biggest unresolved item in the texts.
But controversy is also likely over proposals to allow money from the Clean Development Mechanism (CDM) to be used for nuclear power.
CDM funds are raised through levies on carbon trading, and are designed to help lower emissions at the lowest possible cost while assisting economic development in poor countries.