The United States never ratified the treaty, initially adopted in Kyoto, Japan, in 1997.
Canada’s previous Liberal government signed the accord but did little to implement it. Prime Minister
Stephen Harper’s Conservative government never embraced it. George W. Bush rejected Kyoto during his presidency and president's Clinton and Obama never sent the treat to the U.S. Senate for a ratification vote.
The Kyoto Protocol does not cover the world’s largest two emitters, United States and China, and
therefore cannot work. (AP, Wash Post, 12/13/2011)