Agence France-Presse: The United States is to announce concrete targets for cutting greenhouse gas emissions as pressure mounts on polluters to find a formula for success two weeks ahead of a crucial climate summit. China has put the issue on the agenda of a summit meeting with the European Union next week and leaders of the 53 members of the Commonwealth, representing around two billion people, are set to address it at their weekend gathering in Trinidad. And Australia, the world’s heaviest per …