Reuters: China Wednesday urged rich countries to agree to cut their CO2 emissions by 25-40 percent by 2020 as part of a new global climate change pact that negotiators hope to seal by the end of the year. Here are some facts about China’s role in climate change policy: * China is the world’s biggest emitter of carbon dioxide (CO2), the main greenhouse gas from human activity, outstripping the United States. The U.S. Oak Ridge National Laboratory has estimated China emitted 1.8 billion …