Climate change in Japan and Toyota hybrid electric vehicles were named to have the highest fuel efficiency and lowest emissions. The fuel economy and emissions decrease is due to the advanced technology in hybrid systems, biofuels, use of lighter weight material and better engineering. As a signatory of the Kyoto Protocol, and host of the 1997 conference which created it, Japan is under treaty obligations to reduce its carbon dioxide emissions and to take other steps related to curbing climate change. The Cool Biz campaign introduced under former Prime Minister Junichiro Koizumi was targeted at reducing energy use through the reduction of air conditioning
2011 United Nations Climate Change Conference said: "I salute the countries who made this agreement. They have all laid aside some cherished objectives of their own to meet a common purpose, a long-term solution to climate change." Kumi Naidoo of Greenpeace International said: "Right now the global climate regime amounts to nothing more than a voluntary deal that's put off for a decade. This could take us over the 2 °C threshold where we pass from danger to potential catastrophe." U.S. Senator Jim Inhofe, who opposes government energy regulations such as cap-and-trade and has called man-made climate change a hoax, cheered what he called the setting