IPCC AR6 WGIII report was published in April 2022. Similar to previous IPCC assessment reports, one of the chapters is long-term mitigation pathways, which play an important role in every assessment report process. Long-term mitigation pathways provide basis for understanding on warming levels or warming targets, and support the international collaboration on GHG mitigation. AR6 again made assessment on emission scenarios published by 2021, majority of these emission scenarios were taking warming targets in Paris Agreement. This report focused on assessment on pathways, policies, cost-benefit and linking with SDGs (Sustainable Development Goals) under the Paris Agreement warming targets. This paper presents the key findings from the Chapter 3 of the report. Achieving the warming targets in Paris Agreement, global emissions need to peak before 2025, and then make rapid decrease. Negative emission technologies are needed in future, and effective emission reductions in all sectors are essential, and the mitigation could bring negative effects on economy development.

Urban systems play an important role in climate change mitigation. Chapter VIII of Working Group III (WGIII) contribution to the IPCC Sixth Assessment Report (AR6), ‘Urban Systems and Other Settlements’ provides a systematic and comprehensive assessment on how urban systems can help in the mitigation of climate change. It includes co-benefits and trade-offs of urban mitigation strategies, urban systems and greenhouse gas (GHG) emissions, urban mitigation options, governance, institutions and finance, and a roadmap of mitigation strategies for different urbanization types. The report shows that the growing concentration of people and activities by urbanization is an opportunity to simultaneously increase resource efficiency and decarbonize at scale. The urban share of global GHG emissions is substantive. It continues to increase, with much inter-region variation in the magnitude of the increase. In 2030, the construction of new, and upgrading of existing urban infrastructure will result in significant emissions. The increase in urban land areas will also create significant implications for future carbon lock-in. There is an urgent need to integrate urban mitigation strategies to address climate change, given the dual challenges of rising urban GHG emissions and more frequent extreme climate events. Deep decarbonization and systemic transformation are critical for cities to achieve net zero GHG emissions. Based on the report’s conclusions, China needs to pay more attention to climate change mitigation in urban systems. Three broad urban mitigation options can be used, including spatial planning and infrastructure, electrification urban energy systems, and enhancing carbon stocks through urban green and blue infrastructure, to achieve sustainable urbanization from a multi-dimensional and across-sectoral nexus perspective. In addition, China needs to develop urban-scale mitigation goals and carbon peaking pathways and strengthen cooperation and linkages between cities, in order to achieve climate change mitigation.

IPCC published the Working Group III Report of its 6th Assessment on 4th April, 2022. The report pointed out the gap between current climate governance activities and targets, and called for immediate and comprehensive transitions in economic, social and technological systems. There are extensive interactions between climate governance, economic and social developments and public governance. Enhancing the coordination of multi-dimensional, multi-level and multi-objective policy tools, including laws and plans, national and sub-national actions, regulatory and economic policies, direct and indirect climate policies, is crucial for achieving an in-depth low-carbon transition. Under the guidance of the long-term transition path, strengthening the co-benefits of climate policies on health, economic growth, income distribution, social concepts and extensive participation will help to maximize the comprehensive effect, to minimize the resistance, so as to build a good policy environment for climate governance. As for China, it’s important to harmonize cross-system, cross-department, and multi-level policies aiming at carbon peaking and neutrality, and to coordinated economic, social, ecological developments and climate governance. Key activities include connecting carbon market with other relevant policies; encouraging and guiding regional actions and strengthening national support as well as inter-regional coordination; exploring ways to promote high-quality development with low-carbon transition; and planning the long-term path for carbon mitigation, sinking and decarbonization from a perspective of coordinated regional developments.

Solar energy is considered as the most promising renewable energy source with extensive application prospects. A reliable and accurate evaluation of solar resources is a primary and essential step before developing and utilizing solar resources. However, in most regions, solar radiation observations are too finite to evaluate solar resources directly. The solar energy resource evalution by other meteorlogical records is available. This paper reviews fundamental theories, the technology roadmap and the advances of four main solar energy resource evaluation methods in domestic and abroad studies. We also investigate errors of each method and discuss their disadvantages. The future development trend of the four methods in China has been prospected. The empirical model and artificial intelligence model highly depend on the characteristics of data. The description of the impacts of the cloud on the solar radiation is inaccurate in the phyical model. The data assimilation and parameterization scheme are critical in the numerical weather forecasting models. Developing hybrid evaluation model with various methods is one of the future directions of solar energy resource assessment.

The Qinghai-Tibet Plateau (QTP) is known as the “Water Tower of Asia” and is also the origin of major rivers in China. Study on changes in precipitation properties is crucial to assessment of climate change impact on water resources, agriculture and husbandry, ecosystems, and disasters such as drought, flash floods, and landslides. However, due to the complex of topography, and lack of spatial coverage of long-term in-situ observations, our understanding on changes in precipitation amount, frequency and related extremes is limited. In recent years, various precipitation analysis or derived datasets have been developed, but we do not have much knowledge on if these multi-source datasets are representative in reflecting actual climate change and consistent with in-situ observations in the QTP. The consistencies and differences in changes of the rainy season precipitation amount, frequency and extreme precipitation (R95ptot and R95pday) are comprehensively analyzed between the in-situ rain gauge observations and five analytical precipitation datasets (APHRO、CN05.1、CMFD、TRMM and GPCP) in this paper. In addition, changes of precipitation prosperities in three different climatic regions of QTP are assessed. It concludes that: (1) CN05.1 and CMFD datasets are generally consistent with the in-situ observations in terms of the trend of the regional average precipitation, the spatial distribution of precipitation, R95ptot and the trends, but have discrepancies in changes of precipitation days and extreme precipitation days. APHRO dataset underestimates increasing trends in precipitation total and frequency and gives opposite trends for extreme precipitation and frequency as compared to the in-situ observations on average. GPCP and TRMM datasets are too short for climate change study, overestimates change in number of rain days and exhibit opposite trend in total precipitation, but they are acceptable for trend estimates for extreme precipitation amount and frequency. (2) Based on the in-situ precipitation observations and with consideration of consistency of other analytical datasets, rainy season precipitation total and extreme amount, and number of extreme precipitation days over QTP show overall increasing trends from 1961 to 2019. However, uncertainty still exists in the understanding of precipitation frequency due to the large discrepancy between the in-situ observations and other analytical datasets. Regionally, the arid zone and the semi-arid zone seem to have experienced increasing trends in rainy season precipitation amount and frequency, and in extreme precipitation and frequency. For the semi-humid zone, a slight increase trend is detected in number of extreme precipitation days, and significant increase trends are found in precipitation total and extreme precipitation amount except for slight decrease trends in some of its eastern and central parts. In addition, regional averaged number of precipitation days has reduced mainly due to significant decrease in its eastern and southern parts.

The carbon peaking and carbon neutrality “1+N” policy system of China proposes to transition from dual control of energy consumption to dual control of carbon emissions, and establish a total carbon emission control system. Most of the existing studies focus on the methodology of total emission target setting and carbon emission allocation, or the analysis of the object of the system, but lacking the discussion on the key issues of the system, such as the decomposition mode, the coordination of different responsibility subjects, and the matching of responsibility subjects and emission sources. From the perspective of system implementation, this paper arranges the relevant institutional practices of carbon emission control at domestic and abroad, proposes the whole process management and elements of the total carbon emission control system “target decomposition → policy introduction → action implementation → assessment and adjustment”, and puts forward specific suggestions for each process. First, target decomposition adopts the mode of “combining regional and industrial decomposition”. The key emission units such as power generation included in the carbon market industry are decomposed and controlled by industry, and other emission sources (including general emission enterprises, buildings, transportation, etc.) are decomposed and controlled by region. Second, the policy tools should match the management mode of the responsible subjects and the emission reduction priorities of the emission sources, which can give play to the synergy between different responsible subjects, and avoid duplication of management. Third, we should build a corresponding data accounting and support system, and form an evaluation, feedback and adjustment mechanism.

The Paris Agreement proposed to control the global temperature rise within 2℃ at the end of the 21st century and strive to control it within 1.5℃. To this end, as of November 2021, more than 140 countries had proposed or were considering to propose carbon neutrality targets, covering 90% of global emissions. This fully reflects the ambition of these countries to reduce emissions in depth under the new climate governance system. As an important final energy consumption sector, the transportation sector plays an important role for all regions towards carbon neutrality targets. In this paper, the Global Multi-regional Energy Transition and Carbon Neutrality Analysis Model (GTIMES 2.0), which was developed and used to explore the transition pathways of the transportation energy towards carbon neutrality. Results show that carbon neutrality requires profound transitions in the global transportation energy system. Transportation carbon emissions will peak at 8.5 billion t in 2030 and drop to 2.7 billion t in 2050. Meanwhile, electricity and hydrogen will account for more than 60% of transportation energy in 2050. The road transportation will still be the biggest carbon emissions source in the future and the proportion of aviation will increase significantly because of the rapid growth of demands and the difficulty of decarbonization. Transportation carbon emissions in 11 of the 31 regions/countries, including European Union, the United Kingdom, Japan, Korea etc., have already peaked in 2018, while China, the “the Belt and Road” countries, India, etc., will peak around or after 2030. In 2050, the transportation carbon emissions of 23 regions/countries will decrease by more than 50% compared with 2018 with Brazil and Japan approaching net zero, while India even higher than 2018.

The “Pilot Zones for Green Finance Reform and Innovations” policy is an important tool for local government achieving carbon dioxide peaking and carbon neutrality goal. However, less attention has been paid to the carbon emission reduction effect on the pilot zone policy. Therefore, with the panel data of provincial-level administrative regions from 2013 to 2020, the difference-in-difference model (DID) was first used to analyze the impact of the pilot zone policy on carbon emission intensity, and then, the impact mechanism was examined using the mediating model. Besides, the influence of financial development level on the carbon emission reduction effect of the policy was investigated using the moderating effect model. The results show that the implementation of the pilot zone policy reduces the carbon emission intensity of the pilot area significantly, and the financial development level has a positive moderating effect on the carbon reduction effect of the policy. From the perspective of mechanism, the policy mainly promotes carbon emission reduction by optimizing the industrial structure, while the mediating path of technological innovation has not been verified. Therefore, this study recommends deepening and expanding the pilot policy, optimizing industrial structure, strengthening the support for technological innovation, and formulating green finance policies according to the level of financial development of different areas in the near future.

In the context of achieving the goal of “carbon peaking and carbon neutrality”, corporate carbon information disclosure is the basis for giving full play to the role of market mechanism and social supervision. This paper focuses on the impact of capital market opening on corporate carbon information disclosure, and further analyzes the influencing factors of carbon information disclosure. Taking Shanghai-Hong Kong Stock Connect and Shenzhen-Hong Kong Stock Connect as the background and the data of 2182 A-share listed enterprises in China from 2012 to 2020 as the sample, a multi-dimensional carbon disclosure quality evaluation system was constructed and analyzed using a multi-period difference-in-differences (DID) model. The results show that the opening of capital market has a positive role in promoting corporate carbon information disclosure. Information environment has a moderating effect on its promotion. The combination of external pressure and internal incentives has facilitated enterprises to better disclose carbon information regarding the opening of capital market. This paper puts forward policy suggestions such as bringing the promotion of carbon information disclosure into consideration of capital market opening, cultivating a climate-change-oriented capital market, improving China’s carbon information disclosure framework, and striving to improve corporate governance and enhance corporate governance capabilities. The marginal contribution of this paper lies in: (1) Build a multi-dimensional evaluation index system to evaluate the carbon information disclosure of A-share listed companies in China, so as to analyze its influencing factors based on the practice of Shanghai-Hong Kong Stock Connect and Shenzhen-Hong Kong Stock Connect; (2) Multi-angle mechanism analysis and in-depth analysis of the internal impact mechanism have guiding significance for improving the carbon information disclosure mechanism.

Based on the original improved equal proportion distribution, the dynamic improvement was carried out to meet the needs of the decomposition of the total provincial CO₂ emission target to the cities. This method was applied to the Hebei province case. The results show that high-carbon cities in traditional industries such as coal and steel should strictly control the growth of carbon emissions, and only obtain a small amount of CO₂ relative surplus space; The cities south of Beijing and Tianjin would obtain more CO₂ relative surplus space than other cities. The construction of Xiongan New Area also needs a certain space for CO₂ emission increment. According to the judgment result of carbon peaking control time, Tangshan and Handan should reach the peak before 2025; most cities still reach the peak on time according to 2030, which can meet the overall peaking demand of Hebei province before 2030. Based on the comparative analysis of the old and new methods, the new method is based on fairness and efficiency, and development trend of the cities and carbon control policy orientation are taken into account, which is different from the original method’s decomposition logic. This method can be further optimized to adapt to the decomposition needs of carbon emission targets in provinces with different development characteristics.

The eight climate-related bills proposed by the European Commission in June 2022, including the establishment of the EU Carbon Border Adjustment Mechanism (CBAM) and the “Social Climate Fund”, are important guarantees for the implementation of the European Climate Change Law, the realization of its emissions reduction of more than 55% by 2030 and the achievement of climate neutrality by 2050. From the three dimensions of “active government + effective market + favorable international trade”, the eight climate-related bills decompose emission reduction targets through government means, allocate emission reduction resources through market means, and introduce new trade rules to avoid carbon leakage, which will open the largest regulatory change in the EU carbon market since its establishment, and utilizing “carbon price coercion” against EU trading partners like China by the CBAM. The paper makes an overall analysis and evaluation of eight climate-related bills, and puts forward specific policy recommendations for China such as strengthening the carbon control responsibility of government departments, playing to the role of the fundamental system of the carbon market, and improving the ability to deal with carbon trade barriers.