The Kyoto Protocol, the only binding agreement aimed at cutting greenhouse-gas emissions, expires at the end of this year. Above, a coal-fired power plant in Germany. Patrik Stollarz / AFP
The Earth summit in Rio de Janeiro, Brazil in June 1992. Getty Images
An Indian demonstration against nuclear production at the summit. Getty Images
The EU has signed on to a second round of the Kyoto Protocol, the treaty to cap greenhouse-gas emissions, while the US and developing nations pledged to create a legal mechanism to succeed Kyoto by 2020. AFP
From left to right: BG Group CEO Helge Lund, Eni CEO Claudio Descalzi, Pemex CEO Emilio Lozoya, BP CEO Bob Dudley, Saudi Aramco CEO Amin Nasser, Total CEO Patrick Pouyanne, Statoil CEO Eldar Saetre and Repsol CEO Josu Jon Imaz, pose before starting a meeting of the Oil and Gas Climate Initiative (OGCI) in Paris on October 16, 2015. AFP
John Cridland, deputy director general of the Confederation of British Industry, addressing the CBI National Conference 2003. Business leaders warned the government that power prices could rise in the UK faster than elsewhere in Europe and competitiveness could be hit because of new environmental targets. PA
EU environment ministers, angered at Washington's abrupt pull-out from the Kyoto protocol on global warming, are seated at the start of the meeting in Kiruna to take stock of the battered treaty and consider alternatives, in March 2001. AFP
Former US president Bill Clinton speaks about the agreement to cut greenhouse gas emissions brokered in Kyoto at JFK Airport in New York before flying to Miami. He was immediately warned of a battle with Congress to get it passed. AFP
Convention Against Climate Change in Kyoto, Japan on December 1, 1997. Getty Images
Former US vice president Al Gore, centre, shakes hands with former Japanese prime minister Ryutaro Hashimoto, right, as former Japanese foreign minister Keizo Obuchi looks on prior to their talks in Kyoto. AFP
Environmentalists and citizens hold banners calling for a reduction of green house gas emissions in front of the Heian shrine in Kyoto, in December 1997. The Kyoto Protocol set carbon pollution cuts for developed countries but not poorer nations. AP photo
Cyclists passing through thick pollution from a factory in Yutian, 100km east of Beijing in China's north-west Hebei province, in July 2006. AFP
Former US vice president Al Gore, right, shakes hands with former Japanese Prime Minister Ryutaro Hashimoto, left, prior to the high-level segment attended by ministers for the UN conference on climate change at the Kyoto International Conference Hall. Former Costa Rican president Jose Maria Figures looks on. AFP
Kjell Larsson, left, former Swedish environment minister, hands over his country's ratification of the Kyoto Protocol to Hans Correll, former UN assistant secretary general, at UN Headquarters in New York on May 31, 2002. The 15 members of the EU all handed over their ratification of the Kyoto Protocol, aimed at reducing global emissions. AFP
Negotiators from nearly 200 nations are in South Africa to try to find a successor to the Kyoto Protocol, the binding agreement between 37 countries to cap greenhouse gas emissions that expires next year. Above, a power plant in China. EPA
Former president Bill Clinton with Mr Gore at a White House function in Washington, in February 1998. Getty Images
The Kyoto Climate Conference. Getty Images
The Kyoto Protocol, the only binding agreement aimed at cutting greenhouse-gas emissions, expires at the end of this year. Above, a coal-fired power plant in Germany. Patrik Stollarz / AFP
The Earth summit in Rio de Janeiro, Brazil in June 1992. Getty Images
An Indian demonstration against nuclear production at the summit. Getty Images
The EU has signed on to a second round of the Kyoto Protocol, the treaty to cap greenhouse-gas emissions, while the US and developing nations pledged to create a legal mechanism to succeed Kyoto by 2020. AFP
From left to right: BG Group CEO Helge Lund, Eni CEO Claudio Descalzi, Pemex CEO Emilio Lozoya, BP CEO Bob Dudley, Saudi Aramco CEO Amin Nasser, Total CEO Patrick Pouyanne, Statoil CEO Eldar Saetre and Repsol CEO Josu Jon Imaz, pose before starting a meeting of the Oil and Gas Climate Initiative (OGCI) in Paris on October 16, 2015. AFP
John Cridland, deputy director general of the Confederation of British Industry, addressing the CBI National Conference 2003. Business leaders warned the government that power prices could rise in the UK faster than elsewhere in Europe and competitiveness could be hit because of new environmental targets. PA
EU environment ministers, angered at Washington's abrupt pull-out from the Kyoto protocol on global warming, are seated at the start of the meeting in Kiruna to take stock of the battered treaty and consider alternatives, in March 2001. AFP
Former US president Bill Clinton speaks about the agreement to cut greenhouse gas emissions brokered in Kyoto at JFK Airport in New York before flying to Miami. He was immediately warned of a battle with Congress to get it passed. AFP
Convention Against Climate Change in Kyoto, Japan on December 1, 1997. Getty Images
Former US vice president Al Gore, centre, shakes hands with former Japanese prime minister Ryutaro Hashimoto, right, as former Japanese foreign minister Keizo Obuchi looks on prior to their talks in Kyoto. AFP
Environmentalists and citizens hold banners calling for a reduction of green house gas emissions in front of the Heian shrine in Kyoto, in December 1997. The Kyoto Protocol set carbon pollution cuts for developed countries but not poorer nations. AP photo
Cyclists passing through thick pollution from a factory in Yutian, 100km east of Beijing in China's north-west Hebei province, in July 2006. AFP
Former US vice president Al Gore, right, shakes hands with former Japanese Prime Minister Ryutaro Hashimoto, left, prior to the high-level segment attended by ministers for the UN conference on climate change at the Kyoto International Conference Hall. Former Costa Rican president Jose Maria Figures looks on. AFP
Kjell Larsson, left, former Swedish environment minister, hands over his country's ratification of the Kyoto Protocol to Hans Correll, former UN assistant secretary general, at UN Headquarters in New York on May 31, 2002. The 15 members of the EU all handed over their ratification of the Kyoto Protocol, aimed at reducing global emissions. AFP
Negotiators from nearly 200 nations are in South Africa to try to find a successor to the Kyoto Protocol, the binding agreement between 37 countries to cap greenhouse gas emissions that expires next year. Above, a power plant in China. EPA
Former president Bill Clinton with Mr Gore at a White House function in Washington, in February 1998. Getty Images
The Kyoto Climate Conference. Getty Images
The Kyoto Protocol, the only binding agreement aimed at cutting greenhouse-gas emissions, expires at the end of this year. Above, a coal-fired power plant in Germany. Patrik Stollarz / AFP