The World Wildlife Fund for Nature (WWF) said in a statement by the organisation's US director Jennifer Morgan that "President [Vladimir] Putin has to decide if he wants to be climate killer number 2 after [US President] George [W.] Bush or if he wants to be on the side" of the rest of the world.
The United States withdrew from the 1997 Kyoto treaty in March 2001, having initially signed it. The treaty now requires Russia's ratification to pass the threshold that will enable it to become effective.
The WWF statement, to be released late Sunday but handed to AFP by its Russian section, also criticised Russia's "attempt to link ratification to Russia's accession to the World Trade Organisation" (WTO).
It called for a ratification bill to be sent to the Russian parliament as soon as possible, with a decision to be made before the end of the present parliamentary session on November 20 which is to be followed by legislative elections on December 7.
So far "118 countries have ratified [the Kyoto accord] and are just waiting for Russia to complete ratification," Morgan said ahead of the five-day World Conference on Climate Change that Putin is due to open on Monday in Moscow.
"The so-called World Conference on Climate Change has been down-scaled to a purely scientifc meeting ... It is of no importance for the Russian ratification process and it is unlikely to give any new scientific insights," Morgan said.
Ukraine last week became the 118th nation to ratify the Kyoto protocol.
Last week the WWF, along with the Greenpeace environmental protection group, wrote to the leaders of six Group of Eight leaders asking them to put pressure on Putin over the Kyoto treaty.
A Western diplomat confirmed to AFP that the letter had been received.
The WWF and Friends of the Earth organisation have refused to attend the Moscow conference, while Greenpeace is to send just two delegates instead of the several dozen it usually sends to climate conferences.