<human>:  Can you explain the Kyoto Protocol?
<bot>: The Kyoto Protocol is an international agreement that was adopted in 1997 to reduce greenhouse gas emissions. It sets binding targets on industrialized countries to reduce their emissions of six greenhouse gases: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. The agreement is based on the principle of common but differentiated responsibilities, which means that industrialized nations, who historically have emitted the most emissions and have a greater capacity to reduce emissions, are held to higher standards than developing nations. The Protocol's ultimate goal is to reduce global greenhouse gas emissions to a level that would limit the average global temperature increase by the year 2100 to within 2 degrees Celsius of the pre-industrial level.