Russian President Vladimir Putin (R) speaks with German Chancellor Angela Merkel during the opening day of the World Climate Change Conference 2015 (COP21), on November 30, 2015 at Le Bourget, on the outskirts of the French capital Paris. World leaders opened an historic summit in the French capital with "the hope of all of humanity" laid on their shoulders as they sought a deal to tame calamitous climate change. AFP PHOTO / ALAIN JOCARD