IPCC WGIII AR5 is developed in the context of deeply restructuring the strategic profile of the world’s economy, energy, GHG emission, technologies, and the global climate governance, and when the new round of international climate talk, known as Durban Platform process, has been underway. Starting from a discussion on the different understandings of the storyline for the IPCC WGIII AR5, this paper reviews and explores varies of issues, including framing concepts for socioeconomic assessment of climate mitigation, historical trends and corresponding drivers of greenhouse gases emission trajectories, transformation pathways to achieve a target of temperature rise less than 2℃, institutional and policy options to support the pathway transformation, as well as evolution of knowledge system and methodologies for socioeconomic assessment of climate mitigation. Based on reviewing the key messages from WGIII AR5, the authors come up with several recommendations on developing China’s strategy and policy options for its low carbon development and correct interpretation and application of knowledge and information from AR5 in the future studies on the socioeconomic assessment of climate mitigation in China.

The IPCC assessment reports serve as important policy basis for the international society and national decision makers. Conclusions related to historical emission trends and future mitigation scenarios are the core subjects in IPCC WGIII report issued in April 2014, which will substantially influence the national positioning, mitigation responsibility allocation and national groupings in international negotiation, as well as global and national mid/long term mitigation targets setting and future global emission budget allocation. Based on comprehensive review and analysis of the key conclusions regarding historical emission trends and its drivers, emission budget and allocation, pathway, cost and technology choices under 2 degree target, etc. in the assessment report, this article further discuss the potential impacts of related conclusions on international climate change negotiation and domestic low-carbon development, as well as how to understand and apply these conclusions in decision making in an accurate and scientific manner.

Based on the IPCC WGIII AR5, this paper analyzed the conclusions of CO2 and greenhouse gas (GHG) reduction pathway and counter-measures contributions in the fields of energy supply, industry, transportation, building, agriculture, forest and other land use (AFOLU). Except the AFOLU, the GHG emissions of all the sectors above have been increasing since 2000, and the energy supply, industry, transportation, and building contribute 47%, 30%, 11%, and 3% respectively. In the future, these four sectors will be the main emission sources and GHG reduction fields. By developing and updating technologies, improving energy and raw materials efficiency, refining energy structure, strengthening the management of waste, optimizing products and service demand, and applying the carbon capture and storage (CCS) and the carbon dioxide removal (CDR), the GHG emissions from these four sectors will reduce by 15%-80% compared with the BaU scenario. All of these emission reduction measures have reference significance for China’s CO2 emission reduction.

As an independent chapter for the first time, international cooperation on mitigation is assessed comprehensively in the Fifth Assessment Report of IPCC. The major conclusions include: United Nation Framework Convention on Climate Change (UNFCCC) is the main multilateral forum, however, the basic principle of UNFCCC should be evolved as pattern of development, emission and impacts change, and the Kyoto Protocol together with CDM has not been as successful as intended; international cooperation on climate change has become more institutionally diverse over the past decade, varying in the degree to which their authority is centralized; the lessons from existing agreements are participation and compliance. A “bottom-up” mechanism and finance/technology incentives encourage broad participation, so does trade measures, which can also be used to enhance compliance. Through policy linkage, the diversified mechanisms outside UNFCCC can complement a binding international agreement on climate change. The assessment has significant impacts on international cooperation after 2020.

Sustainable development and equity are key framing and cross-cutting issues in Working Group III contribution to the IPCC AR5, mentioned in quite a few of chapters. Based on the previous reports and the latest research work, AR5 has highlighted the interacted relationship between climate change, sustainable development and equity, emphasizing comprehensive assessment of climate policies under the framework of sustainable development and equity. There are synergies and/or trade-offs between climate responses and broader sustainable development goals. Thus, AR5 has also highlighted to optimize them to identify co-benefits and reduce adverse side-effects and risks, meanwhile promoting transition of the development pathways.

Based on the four typical global monthly surface temperature datasets, namely the climate research dataset of the University of East Anglia (CRUTEM3), the dataset of the U.S. National Climatic Data Center (GHCN-V3), the dataset of the U.S. National Aeronautics and Space Administration (GISSTMP), and the Berkeley Earth surface temperature dataset, this paper analyzes the status of existing resources through extensive research and international cooperation. Then, China’s first global land monthly temperature dataset was developed by integrating the four global monthly surface temperature datasets and some regional datasets from the major countries or regions. This dataset contains 9519 stations from all over the world with the length no less than 20 years for monthly average temperature, 7073 for monthly maximum, and 6587 for monthly minimum temperature. Compared with CRUTEM3 and GHCN-V3, the station density of this dataset is much higher, especially in South America, Africa and Asia; besides, there are much more stations after the 1990s, which can dramatically reduce the uncertainty of the estimated global temperature trend since 1990.

Based on the simulations from 22 CMIP5 models and in combination with the socio-economic data, the extreme heat risk change during the near term (2016-2035), medium term (2046-2065) and long term (2080-2099) were projected by quantitative estimation under RCP8.5. The results show that the extreme heat hazard risk will gradually increase during different terms in the future, and extreme heat risk will also tend to increase. Class III and above of the extreme heat risk will increase, especially in the northeast, Inner Mongolia, Shaanxi, Ningxia, Guizhou, Fujian provinces (autonomous region). In Shandong, Hebei, Henan, Anhui provinces, Class V of the extreme heat risk tends to appear in the near term, and it will extend to Jiangsu, Hunan, Hubei, Jiangxi, Sichuan, Guangxi and Guangdong provinces (autonomous region) in the medium and long term.

This paper takes the tourism in the city of Xiamen as the research sample, adopting system analysis method, concentrating on the impacts of climate change on tourism’s development, building the relevant index system, and adopting analytic hierarchy process to calculate the weight of each index. Besides, it also applies fuzzy comprehensive evaluation to evaluate each index, performing the quantitative analysis of the impacts of climate change on tourism in the city of Xiamen. According to the research, the maximum membership grade of the impacts of climate change on tourism is 0.309, which is relatively high. According to influential degree, this research can clearly classify various parts which are affected by climate change in the process of tourism’s development. Therefore, it can effectively instruct tourism practitioners to implement risk classification, have a clearer understanding of the impacts, further coordinate the interests of different parties, achieve pertinent promotion and realize the long-lasting utilization of tourism resource and the sustainable development of tourism.

Based on the detailed origins of each province’s electricity consumption, a new method for calculating CO₂ emissions from the power sector at the provincial level in China was proposed. With this so-called consumer responsibility method, the emissions embodied in imported electricity were calculated with source-specific emission factors. Using the new method, the CO₂ emissions in 2005 and 2010 were estimated. Compared with those derived from the producer responsibility method, the power exporters’ emissions decreased sharply. The emissions from the power sector in Inner Mongolia with the largest exported electricity, decreased by 109 Mt CO₂ in 2010. The value is equivalent to that from Shaanxi’s power production or Canada’s power and heat production in 2010. In contrast, the power importers’ emissions increased sustantially. The emissions from the power sector in Hebei, the largest power importer of China, increased by 74 Mt. Emissions of Beijing increased by 60 Mt (320%) in 2010. Thus, we suggest that the Chinese government should take the emissions calculated from consumption perspective into account when formulating and assessing local CO₂ emission reduction targets.

In essence, the international climate negotiation is a kind of serious-minded and responsible global efforts despite the various conflicts. The climate negotiation is designed to establish a reasonable international climate system, and the essence of addressing climate change is to guide the world to adopt a low-carbon, green and circular development road, achieving a sustainable development worldwide. What’s more, climate negotiation should be a process of driving all parties to reach constructive global climate system. To this end, this paper suggests three major aspects that should be addressed to make substantial breakthroughs, and then the “Review” and “Adjustment” mechanism under the Convention principles should be adopted to make gradual supplements and improvements. This is a combination of “Down-Top” and “Top-Down” approach. In addition, the ultimate solution to international climate negotiation lies in collaboration and win-win strategies. The in-depth reasons for China’S proactive and practical participation of international climate negotiation are the internal need for scientific and sustainable development, and a responsible developing power’S performing international obligations.