Agence France-Presse: China said Wednesday countries have a “common duty” to tackle global warming, pointing to a rift between rich and developing nations on climate change policy in the run-up to a UN meeting on the issue. Governments of industrialised and developing countries — including the world’s biggest polluters China and the US — have been battling over who should carry the burden for curbing the greenhouse gases blamed for global warming. “Developed countries have their historic responsibility over climate…