Cancun - Russia stated plainly on Thursday that it would not support a new round of the Kyoto Protocol, backing a position by Japan that has raised controversy at UN-led climate talks.
The Kyoto Protocol requires wealthy nations to cut carbon emissions blamed for climate change through 2012. The European Union has led calls to extend it due to the growing unlikelihood that a new treaty will be reached in time to replace it.
Alexander Bedritsky, an adviser to President Dmitry Medvedev, told the meeting in Cancun, Mexico, that a second Kyoto period "would be neither scientifically, economically nor politically effective."
"Russia will not participate in the second commitment period of the Kyoto Protocol," he told the conference.
Yet Bedritsky allowed that Russia would support extending parts of the Kyoto Protocol other than emission cuts, such as the treaty's establishment of a market trading emission rights.
Japan has stood firm against another round of the Kyoto Protocol, saying it would be unfair and insisting that a new round involve all major emitters.
The Kyoto Protocol only covers some 30% of the world's carbon emissions as the two top emitters are absent. China has no obligations because it is a developing nation, while the United States rejected the treaty.
Russia is a major supplier of fossil fuels, which are targeted in anti-carbon efforts.
Russia's ratification of the Kyoto Protocol in 2004 allowed the treaty to come into force because enough emitters had joined.
Unlike most Kyoto countries, Russia was actually producing less carbon than in 1990 - the baseline for cuts - due to industrial decline since the Soviet Union's collapse.
Besides Russia and Japan, Canada has also been seen as unenthusiastic about a new round of the Kyoto Protocol.