About 175 nations agreed a plan Sunday to salvage climate talks after the Copenhagen summit but the U.N.’s top climate official predicted a full new treaty was out of reach for 2010.

Delegates at the April 9-11 talks, marred by late-night wrangling between rich and poor nations on how to slow global warming, agreed to hold two extra meetings in the second half of 2010 after the December summit fell short of a binding deal.

The extra sessions, of at least a week long each, and a linked plan to prepare new draft U.N. climate texts would help pave the way to the next annual meeting of environment ministers in Cancun, Mexico, November 29-December 10.