Delegates at UN climate talks in Qatar have agreed to extend the Kyoto Protocol until 2020.
The deal, agreed by nearly 200 nations, keeps the protocol alive as the only legally binding plan for combating global warming.
However, it covers only developed nations whose share of world greenhouse gas emissions is less than 15%.
The 12-day meeting in Doha overran by more than 24 hours because of differences over whether rich nations should have to compensate poorer states for losses due to climate change.
AFP reports a deal was finally agreed on Saturday after the European Union, Australia and several other industrialised nations agreed to binding CO2 cuts by 2020.
However, the BBC reports the protocol excludes some major polluters, including the United States, China and India.
The US has never ratified the original 1997 protocol, which was due to expire later this year.
The BBC reports the conference also cleared the way for the Kyoto protocol to be replaced by a new treaty binding all rich and poor nations together by 2015 to tackle climate change.
The final text "encourages" rich nations to mobilise at least $US10 billion per year up to 2020, when the new agreement is due to begin.
The US, EU and China accepted the agreement with varying degrees of reservation.
The talks were chaired by Abdullah bin Hamad al-Attiyah, a former head of OPEC. He was widely criticised for his laid-back style earlier in the week, but was cheered by environmentalists by the end.