Abstract: The IPCC assessment reports play an important role in the international climate change negotiation process. The IPCC Fifth Assessment Report (AR5) has been identified as one of the important information sources for the negotiation of a new agreement by the end of 2015 and will have significant influences on the ongoing negotiations on mode of international cooperation to address climate change in the post-2020 period. Based on new and comprehensive observations and advanced model simulations, the newly released IPCC Working Group I (WGI) report reaffirms the fact of global warming trend, strengthens the causality between anthropogenic emissions and global temperature rise and establishes the quantitative relationship between cumulative greenhouse gas emissions and global temperature rise. This paper identifies some key conclusions of the WGI report and analyzes their policy implications, especially their influences on the ongoing negotiation process and the new agreement. It also discusses the role of scientific information in decision-making process, and how this information could be absorbed and used in a scientific manner so that it could better serve the purpose of assisting us in the process of international negotiations and domestic decision making.

Key words: IPCC, assessment reports, international climate change negotiations, uncertainties, decision-making process