Tammemagi (2009, p.192) claims that “To become international law, the (Kyoto) protocol had to be signed by at least 55 developed countries whose cumulative greenhouse gas emissions in 1990 formed at least 55 percent of the world’s total. Canada signed the Kyoto agreement in late 2002, to become the 99th nation to join. But without the ratification of the United States, Russia’s signiture was necessary. In 2004, Russia reversed its previous position and, much to the delight of European countries and environmentalists, signed the Kyoto Protocol, bringing it into force on February 16, 2005. Initially, Australia refused to sign the Kyoto Protocol. In December 2007, Australia’s newly elected prime minister Kevin Rudd reversed the previous policy and commited his country to joining the agreement.”
Tammemagi, H. Y. (2009). Air: our planet’s ailing atmosphere.