Agence France Presse: The world’s top 20 greenhouse gas emitters agreed Sunday to work together to draft a successor to the Kyoto Protocol but rich and developing nations remained divided on their roles. Envoys from the 20 countries, which are together responsible for 80 percent of the world’s emissions blamed for global warming, were trying to bridge gaps on what to do after Kyoto’s obligations expire at the end of 2012. “We reconfirmed the principle of common but differentiated responsibility …