NEW DELHI - The world should cut greenhouse gas emissions by 50 percent by 2050 from 1990 levels with the bulk of the reduction coming from rich countries, according to a draft proposal by Denmark, host of Dec 7-18 U.N. climate talks.

The draft, a copy of which was seen by Reuters, said rich countries should account for 80 percent of the global emission cuts by 2050.

The draft, 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 draft also suggested efforts be made to keep the rise in global average temperatures to within two degrees Celsius.

Parties should work together constructively to strengthen the world's ability to combat climate change, the draft says.

The U.N. talks have run out of time to settle a legally binding deal after arguments between rich and poor nations about who should cut emissions, by how much and who should pay. But hopes are growing that a substantive political pact can be agreed at the December meeting instead.

Developing countries led by China and India are also expected to table a text that they would like to be turned into the basis for negotiations.

Danish Prime Minister Lars Lokke Rasmussen says he wants a 5-8 page politically binding agreement, with annexes outlining each country's obligations such as cuts in emissions by 2020 by developed nations.

He also wants also a deadline in 2010 by when the deal has to be translated into a legal treaty text.

(Editing by David Fogarty)