The world should cut greenhouse gas emissions by 50% by 2050 from 1990 levels with the bulk of the reduction coming from rich countries, according to a draft proposal by Denmark.
The draft says rich countries should account for 80% of the global emission cuts by 2050.
The proposal which could become the basis of a political agreement at the end of the climate talks in Copenhagen suggested the world adopt 2020 as the year when global emissions will peak.
It did not specify any mid-term emission target for developed countries, a key demand from poorer countries.
The UN climate talks are to take place in Denmark from 7 to 18 December.
