The article discusses how to engage China and other developing countries in climate policy. It looks at whether joint participation in a global cap-and-trade system would benefit China, and why China has been hesitant to discuss this in international negotiations. The paper explores China's perspective on unity with other developing countries, lessons from past negotiations with the U.S., and the fairness of emissions caps. It also considers the political implications of CDM investments and emissions trading. The findings suggest that setting emissions targets for developing countries is complex and must consider future levels compared to historical levels for industrialized countries.