•  Time now the enemy as UN climate talks struggle for deal

The deal follows years of failed attempts to impose legally-binding, international cuts on emerging giants, such as China and India.

The developed world had already accepted formal targets under a first phase of the Kyoto Protocol, which runs out at the end of next year, although the US had never ratified its commitment.

After days of emotional debate, the chairwoman of the UN climate talks, Maite Nkoana-Mashabane, who is South African Foreign Minister, urged delegates to approve four packages, which have legal force.

"We have made history," she said, bringing the hammer down on more than two weeks of sometimes fractious talks in the South African port of Durban, the longest in two decades of UN climate talks.

The Durban talks had been due to wrap up on December 9, but dragged into a second extra day on December 11 because of disputes over how to phrase the legal commitment.