The Kyoto Protocol to combat global warming will take effect from 16 February next year.
The protocol will become legally binding on its 128 parties after Russia submitted its instrument of ratification to UN chief Kofi Annan in Nairobi.
Russia's move ends years of uncertainty over the future of the
landmark agreement, which aims to curb carbon gas pollution blamed for disturbing the Earth's climate system.
Kyoto's framework was agreed in 1997, but it took four years to
agree its complex rulebook.
In 2001, the US walked away from Kyoto, saying the cost of meeting its targets would be too high for the US economy.
Russian President Vladimir Putin signed the protocol on 5 November, just over a week after his country's parliament voted to ratify it.
