The Kyoto Protocol is an international treaty adopted on December 11, 1997, in Kyoto, Japan, that extends the 1992 United Nations Framework Convention on Climate Change (UNFCCC). It commits state parties to reduce greenhouse gas emissions based on scientific consensus about human-made CO2 emissions driving global warming, with legally binding emission reduction targets for developed countries (Annex I parties). These targets aimed for a 5.2% reduction below 1990 levels by 2012, while allowing developing countries more flexibility. The protocol entered into force on February 16, 2005, after ratification by Russia. It regulates six key greenhouse gases: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, sulfur hexafluoride, and perfluorocarbons, and includes mechanisms like emissions trading, the Clean Development Mechanism, and Joint Implementation. The United States signed the protocol in 1998 under President Clinton but did not ratify it, citing concerns over economic harm and lack of binding commitments for developing nations, as expressed in the 1997 Byrd-Hagel Resolution. The protocol's first commitment period ended in 2012, followed by the Doha Amendment extending targets to 2020. It laid groundwork for subsequent agreements like the Paris Agreement, influencing global climate policy despite criticisms over differentiated responsibilities and limited scope.