As the largest source of anthropogenic greenhouse gas (GHG) emissions, cities are the basic unit and important space carrier to promote carbon emission reduction. In the face of increasingly severe climate challenges, on one hand, the degree of cooperation among cities is not enough, and most cities choose to conduct urban GHG emission accounting and formulate mitigation policies independently; on the other hand, there are still differences in accounting boundary, accounting content and double counting, types of GHG, and accounting methods among different urban GHG emission accounting guidelines, which increases the complexity of urban GHG emission accounting and is not conducive to the comparison of GHG emission accounting results among cities. The methodological framework for urban GHIG emission accounting is the basis for understanding and evaluating urban GHG emissions. In this paper, we reviewed the domestic and foreign urban GHG accounting standards, databases and cases, which covered the comparison and difference analysis of international urban GHG accounting standards, the application research of three different city-level GHG emission accounting perspectives (including accounting based on administrative division boundaries, cross-border infrastructure, and urban consumption respectively). The core of domestic urban and regional GHG accounting guidelines are clearly proposed to establish a framework of urban GHG emission accounting methods that are prioritized for domestic benchmarks. In the new framework, scopes 1-3 in the framework represents the urban GHG emissions from different perspectives, and reflects the urban GHG emissions to the maximum extent. The indispensability and comparability of Scope 1 emissions within administrative divisions are emphasized. Importantly, the accounting for Scope 2 and Scope 3 emissions is a specific supplement to the urban GHG emissions that are matched to fully meet the actual needs of the city. The framework solves some of the pain points. For example, the accounting boundary is within the boundary of China administrative divisions, covering 7 types of greenhouse gases, and scopes 1-3 are for different accounting emission subjects. In view of the emission sources not covered or disputed by the current urban GHG accounting guidelines, difficulty of data acquisition, uncertainty and so on, the author believes that these problems can be addressed by means of scientific and technological progress, and the impact on the urban GHG emission accounting is not major, but for the long-term development of the city, these pain points must be deeply considered and solved by the decision-making managers. It is necessary to incorporate them into the framework at first, and then gradually solve them. Benchmarking-oriented GHG accounting framework can help decision-making managers understand the flow of embodied GHG emissions between cities, determine appropriate emission reduction policies, and meanwhile consider and plan low-carbon transition paths, optimize urban management methods, and promote exchanges and cooperation between cities from the perspective of GHG emissions. Finally, this paper points out that the effective implementation of the framework requires the linkage of the whole society, multi-industry and cross-department, the overall government-enterprise-people-commerce cooperation, the close industry-university-research cooperation. 

This paper uses energy values to establish an estimation method of oceanic ecosystem service based on non-monetary ecosystem service values evaluation, which is used to estimate China's oceanic ecosystem service values in 2012 with objectives of providing reference for governmental managements in planning oceanic resources. According to oceanic ecosystem service values in 2012, China's 13 coastal provinces (cities) are ranked as follows: Guangdong, Shandong, Taiwan, Fujian, Hainan (Sansha city excluded), Liaoning, Zhejiang, Jiangsu, Shanghai, Guangxi, Hebei, Tianjin and Sansha city (only coral reef and sea grass bed considered). Seven categories of oceanic ecosystems whose unit service values are in a decreasing order are mangrove, salt swamp, tidal flat, estuary, sea grass bed, warm water coral reef and 12 sea miles water, suggesting a bigger unit ecosystem service value in shore wetland, compared to coastal water. So protection of existing shore wetland ecosystem or expansion of its area helps increase oceanic ecosystem service values. The major ecosystem services include increasing biological diversity, fixing carbon and releasing oxygen, and natural power generation with their contribution over 70%.