Nearly 200 countries will meet in Doha, Qatar, next week to work for a new climate deal to curb greenhouse gas emissions.
The new deal should be signed by 2015 and come into force by 2020, Reuters reports.
Delegates will also discuss an extension to the 1997 Kyoto protocol, the world's current climate pact, which expires at the end of this year.
Most countries agreed last year to extend the protocol, but are yet to agree on whether it should last for five or eight years, or on the level of various nations' emissions cuts under the pact.
The United States never ratified the Kyoto deal. Japan, Russia and Canada did, but have signalled they will not sign up to any further cuts in emissions in an extension.
In October, New Zealand said it would not sign the second phase of the Kyoto protocol, but will meet its obligations under the first phase.
