A poster of Pope Francis with his handwritten letter is pictured the day when his encyclical on climate change titled "Laudato Sii", a collection of principles to guide Catholic teaching, has been presented on June 18, 2015 at the Sinod hall at the Vatican. Pope Francis calls on the world's leaders to pull together to fight global warming, publishing his hotly-anticipated thesis on the environment which slams profiteers and slaves to progress. Released six months ahead of a key climate change meeting in Paris, Francis's text calls on international actors to take responsibility for "new modes of production, distribution and consumption", according to a leaked draft. AFP PHOTO / VINCENZO PINTO        (Photo credit should read VINCENZO PINTO/AFP/Getty Images)