The Kyoto Protocol, adopted in 1997 in Kyoto, Japan, is an international treaty under the UNFCCC that aimed to reduce greenhouse gas emissions by industrialized nations to combat global warming. Critics argued the emission targets were insufficiently ambitious and that major developing economies, like China and India, were not obligated to reduce emissions. Additionally, the United States signed but never ratified the protocol, citing economic concerns and the exclusion of developing countries, sparking debates over its efficacy.