Russia has formally joined the Kyoto Protocol on global warming, after President Vladimir Putin signed Russian ratification into law earlier this month.
This means the agreement will become legally binding on its signatories in 90 days, on February 16, 2005.
The protocol commits 55 industrialized nations to making significant cuts in emissions of gases like carbon dioxide by 2012.
The pact could not come into effect without Russia, since the United States pulled out in 2001.
Moscow's permanent representative to the United Nations turned over the ratification documents to U.N. Secretary-General Kofi Annan Thursday in Nairobi, Kenya, where Mr. Annan is attending a special U.N. Security Council meeting.
Mr. Annan called Russia's action a historic step in the effort to combat a truly global threat.
Some information for this story provided by AP and AFP.