Talks have continued well past the official close of business on the final day of a key UN climate summit in Peru aimed at advancing a new global treaty.
The negotiators in the capital, Lima, are tasked with preparing a text to serve as the basis for a new compact to be signed in Paris next year.
Long-running divisions between rich and poor countries are hampering progress.
US Secretary of State John Kerry has warned that the world is “still on a course leading to tragedy”.
He said a deal was “not an option – an urgent necessity”.
Negotiators have been meeting in Lima for almost two weeks to prepare the elements of the new treaty.
A new text has been produced by the chairman of the talks in an effort to get a decision.
But environmental groups say that it is far too weak and threatens to leave many issues unresolved.