The Kyoto Protocol was an international summit held in Kyoto, Japan, in December 1997. Its goal was for governments around the world to reach an agreement regarding emissions of carbon dioxide and other greenhouse gases. The Kyoto Protocol called for industrialized nations to reduce national emissions over the period 2008–2012 to 5 percent below the 1990 levels; they also made a second commitment period to lower emissions between 2013 and 2020, but as of this writing, it has not been legally verified. The protocol covers these greenhouse gases: carbon dioxide, methane, and nitrous oxide, with other chemicals such as hydrofluorocarbons, perfluorocarbons, and sulfur hexa fluoride added in subsequent years. Of course, without most people signing on, the Kyoto Protocol is essentially one-sided, with some of the major polluters in the world not adhering to the lowering of greenhouse gases. Unfortunately, by 2010, the countries signing on to the second commitment period emitted a mere 13.4 percent of the total troubling greenhouse gases each year.