In this paper, the development process of the IPCC National Greenhouse Gas Inventory Guidelines is systematically reviewed, and the evolution characteristics of its four stages are summarized, namely, from the initial stage framework construction to the systematization and department improvement stage, and then to the stage of system upgrade based on scientific research breakthroughs, further, to refine and finalize the latest guidelines. Based on the Modalities, Procedures and Guidelines (MPGs) for the transparency framework for action and support referred to in Article 13 of the Paris Agreement, and using the 2006 IPCC National Greenhouse Gas Inventory Guidelines, the specification and requirements for the preparation of greenhouse gas inventories are systematically elaborated, the mandatory requirements (“shall”) and non-mandatory requirements (“should”, “may” and “encourage” ) in MPGs are compared and analyzed, and the institutional construction based on the design of “mandatory regulations plus flexibility mechanism” are revealed. Finally, it highlights the challenges China faces in transition from the 1996 Guidelines to the 2006 Guidelines while preparing the Biennial Transparency Report (BTR) and National Inventory Document (NID). It also proposes measures to address these issues and recommends accelerating the establishment of a greenhouse gas accounting and reporting system that meets the requirements of the MPGs with Chinese characteristics.

The current global average sea level rise is experiencing an acceleration. This study assesses the risk of permanent inundation in coastal China caused by sea-level rise under the extreme scenario of rapid ice sheet retreat. The bath-tub approach is employed to simulate the inundation extent due to future sea-level rise. Under the SSP1-2.6 and SSP5-8.5 scenarios, the newly added static permanent inundation area along the coast of China increases from 0.32%-2.29% in 2100 to 1.14%-6.33% in 2150. Existing coastal defenses can effectively cope with the process of gradual permanent inundation, with major risks lying in high-tide flooding and backwater effects caused by the rise in baseline water levels, as well as the amplification effect on the frequency of extreme coastal floods. It is necessary to promptly assess the capabilities of coastal defense levels and take corresponding measures, emphasizing the impact of amplification effects from extreme compound disasters. In the Black Swan scenario of ice sheet instability, the range of sea-level rise far exceeds coastal defense capabilities, leading to widespread static inundation. By 2300, the inundation areas will account for 6.26%-18.89% of coastal regions. The destabilization of polar ice sheets can lead to extremely high rates of sea-level rise, leaving a relatively short window for coastal adaptation measures, such as enhanced defenses, and increasing the risk of systemic failures. Coastal regions need to prioritize emerging risks under the Gray Rhino and Black Swan scenarios of sea-level rise to meet the demands of climate change adaptation planning and risk management decisions.

As agricultural production faces an increasing risk of climate change, there is an urgent need to strengthen adaptive capacity building in order to promote extensive agricultural adaptation actions. This paper synthesizes the progress of scientific understanding on agricultural adaptation to climate change and the scientific support on adaptation actions with literature review, and then summarizes the progress and shortcomings in the capacity building for agricultural adaptation to climate change according to the logical layers of efficient utilization of agro-climatic resources, agricultural disaster prevention and alleviation, ecological governance and climate risk management. Presently, the description on adaptive capacity building in the published literatures, reports, and policy documents is too general. This paper presents an effort on in-depth investigation how to increase agricultural adaptive capacity. The capacity building for efficient utilization of agro-climatic resources, agro-meteorological disaster reduction, ecological governance, and agricultural management is clarified as utilizing thermal climatic resources and water resources; lowering the climatic hazards, diminishing exposure, decreasing vulnerability of climate change-affected agricultural systems; increasing the agricultural ecosystem services of food production and supply, regulation, supporting, and cultural function; enhancing the research and development of agricultural adaptation technologies, innovating the financing mechanism, and improving policies and legislation, respectively. Finally, it proposes a series of recommendations for the enhancement of future agricultural adaptive capacity building, including the systematic evaluation of agricultural climate risk, identification of adaptation priorities, construction of agricultural adaptation technology system, formulation of agricultural adaptation plan, and raising public awareness regarding adaptation to climate change.

With the continuous impact of climate change, the frequency of compound hot and dry events is increasing, which impacts global food production. Wheat, as a major food crop, is crucial for ensuring global food security and economic development. This review summarizes the temporal and spatial patterns of compound hot and dry events in major wheat-producing regions worldwide, assesses their impacts on wheat yield, and clarifies the mechanisms and research methods associated with extreme hot and dry conditions. The results indicate that the frequency and intensity of compound hot and dry events in the major wheat-producing regions of the world have increased during the period from 1960 to 2020. Compound hot and dry events have become a serious threat to wheat yields, and are expected to increase and intensify further in the future. The interaction between land-atmosphere systems and crop physiological stress further complicates the impacts of these events on wheat. Future research should focus on developing compound hot and dry indicators with physiological relevance for crops, employing statistical and crop growth models to explore the response mechanisms to compound hot and dry events, and integrating different dimensions, methods, and models to gain a deeper understanding of the impacts of compound hot and dry events. This will enhance adaptation strategies and risk assessments for such events, providing a scientific basis for understanding the impact of compound hot and dry conditions on wheat yield and offering guidance for the sustainable development of agricultural production.

Climate change is exerting an increasingly profound influence on rice diseases, emerging as a major threat to global rice production and food security. This review synthesizes current understanding of the mechanisms by which climate change affects rice disease dynamics, alongside recent research advances. Rising temperatures accelerate pathogen life cycles, promote spore germination, infection, and dissemination, and impair rice immunity by disrupting hormone signaling pathways. Altered precipitation patterns not only increase field humidity and facilitate pathogen spread, but also reshape rice canopy structure and rhizosphere environments: modifying microclimates and microbial communities that indirectly influence disease outbreaks. Elevated atmospheric CO₂ alters rice carbon and nitrogen metabolism, often reducing the synthesis of defense-related secondary metabolites, while higher O₃ levels induce oxidative stress, weakening physical barriers and interfering with disease signaling networks. Extreme weather events, such as typhoons and droughts, further exacerbate physiological stress and susceptibility in rice, and enhance the long-distance transmission of pathogens. While significant progress has been made in uncovering these mechanisms, key limitations persist particularly the lack of long-term, cross-regional monitoring and integrated analysis. The adaptive evolution of pathogens and their dynamic interactions with host defense systems under changing climates remain underexplored. It is recommended that future research focus on cross-scale and cross-regional systematic studies to uncover the transmission patterns and dynamic responses of rice diseases under various climate scenarios. Efforts should be made to accelerate the breeding of disease-resistant varieties, optimize agronomic practices, and develop intelligent monitoring and early warning systems. This will help establish a comprehensive, multi-level, and coordinated control system that spans from genetic research to field management, and from early warning to intervention, providing strong scientific support for rice disease control in the context of climate change.

Based on daily maximum temperature, monthly leaf area index (LAI), gross primary productivity (GPP), and net primary productivity (NPP) data from 8 CMIP6 models, the changes in heatwave days (HWD) and the ecosystem exposure to HWD were projected over mid-high latitude Asia under the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios. The ensemble projection result indicates an increase in HWD across the mid-high latitude Asian region, with larger increase under higher emission scenario. As the HWD increases, the exposure of LAI, GPP, and NPP to HWD is also projected to increase over mid-high latitude Asia. The largest increase is anticipated under SSP5-8.5. Compared to the reference period (1995-2014), the LAI, GPP, and NPP exposure tends to increase by 12.1 times, 14.9 times, and 14.3 times by the end of the 21st century, respectively. The projected increases are particularly pronounced in the regions such as the Kamchatka Peninsula, southern Central Asia, Xinjiang in China, South Korea, and Japan. In terms of factors influencing the ecosystem exposure, the climate factor is the most dominant contributor, followed by the nonlinear interaction factor, while the contribution from the ecological factor is minimal. With increased greenhouse gas emissions, the contribution of both the climate factor and the ecological factor gradually weakens from the near term to the end of the 21st century. In contrast, the influence of the nonlinear factor gradually strengthens. Consequently, the impact of heatwaves on the terrestrial ecosystem over mid-high latitude Asia will increasingly reflect the combined effects of climatic and ecological interactions.

Heat exposure is a key indicator for assessing the risks of extreme weather and climate events. While substantial research has focused on the attribution of extreme heat events, studies on the attribution of heat exposure remain limited. By using the Coupled Model Intercomparison Project Phase 6 (CMIP6) models and global gridded population (GlobPoP), this paper proposes an attribution method for heat exposure, exemplified by the record-breaking 2022 extreme heat event in China. Using extreme heat and heat exposure to daily maximum temperatures exceeding 35℃ and 40℃ (Tx35E and Tx40E) as indicators, it’s found that both the number of extreme heat days and heat exposure have increased during 1990-2022, with the most pronounced growth in eastern China. Based on bias-corrected model data, human activities increase the probability of early summer Tx35E events in 2022 by 1.4 times in the south of the Yangtze River and 2.4 times in the north of the Yangtze River. Human activities also lead to additional extreme heat exposure and exposure ratio. In summer, with more extreme heat days, the influence of human activities on heat exposure and exposure ratio becomes more evident. Specifically, human activities lead to extra exposure of 46.5 million and 17.9 million person∙d (3.2% and 1.2% of the total population) to temperatures above 35℃ in the south and north of the Yangtze River, respectively. Although extreme heat events above 40℃ are relatively rare, human activities still increase the likelihood of Tx40E events and lead to additional heat exposure.

Carbon budgets serve as a crucial policy measure supporting the achievement of China’s “dual carbon” goals, providing institutional safeguards and quantifiable pathways for their realization. A systematic comparison of the design and implementation models of carbon budget systems across different countries holds significant implications for the development of China’s own carbon budget system. In this paper, the carbon budget systems of the UK, Germany and France were compared and analyzed in terms of top-level design, target decomposition, monitoring and evaluation, and adjustment mechanism. The results show that all three countries have established a carbon budget framework through legislation, but there are differences in the implementation modes: the UK adopts a five-year carbon budget system and sets targets based on sectoral emission reduction potentials; Germany implements annual sectoral emission budgets and has a gap-filling mechanism; France refines the five-year budgets according to the sectors and types of greenhouse gases. In addition, all three countries have established independent assessment systems and independent expert committees, but there are differences in the budget adjustment mechanisms. In the future, China can combine carbon emission intensity and total volume control policy practices to steadily advance carbon budget management, improve legal safeguards, adopt a top-down and industry-specific approach, strengthen scientific support, and establish a dynamic adjustment mechanism to provide systematic policy support for the achievement of the “dual carbon” goals.

This paper focuses on the economic evaluation of offshore wind-powered hydrogen production technologies in China based on a levelized cost of hydrogen (LCOH) model. Four hydrogen production and transportation schemes are investigated: onshore hydrogen production via Alternating Current (AC) transmission, onshore hydrogen production via Direct Current (DC) transmission, offshore platform-based hydrogen production with pipeline transport, and offshore platform-based hydrogen production with ship transport. Considering the impact of electrolyzer types and offshore distances on the economic performance of these technologies, a total of eight technological schemes and three offshore distance scenarios (20 km, 60 km, and 100 km) are examined. Additionally, an analysis is conducted on the sensitivity of the wind power price and electrolyzer cost on the economic performance of hydrogen production technologies. The findings indicate that: (1) Offshore platform-based hydrogen production is more economical than onshore hydrogen production. When the offshore distance exceeds 20 km, platform-based hydrogen production combined with ship transport offers greater cost advantages. (2) For onshore hydrogen production, DC transmission is more competitive than AC transmission due to the lower cost and reduced losses of DC cables. (3) Alkaline electrolyzer (ALK) technology has a significant cost advantage over Proton Exchange Membrane (PEM) technology, with baseline scenario LCOH ranging from CNY 38.94 to 44.33 kg for ALK and CNY 53.68 to 60.39 kg for PEM. (4) Both electricity price and electrolyzer capital cost have a linear impact on LCOH, hydrogen production costs are directly proportional to electricity price and electrolyzer investment cost. (5) If the abandoned electricity from offshore wind power is adopted (with a cost of 0), the cost of hydrogen production based on the shore will be significantly reduced, greatly enhancing the economic efficiency of hydrogen. At the same time, it will help improve the current situation of insufficient capacity to accommodate offshore wind power.

Under global warming, forestry has emerged as a critical component in climate change mitigation and adaptation strategies, and has become an important topic in international climate negotiations. The paper reviews the progress of global climate governance and its impact on forestry, with a focus on analyzing the progress of the main forestry-related negotiation topics: LULUCF (Land Use, Land-Use Change and Forestry), CDM (Clean Development Mechanism) forestry carbon sink project, and REDD+ (Reducing Emissions from Deforestation and forest Degradation, plus the sustainable management of forests, and the conservation and enhancement of forest carbon stocks). The LULUCF rules continue to be improved and are currently integrated into national emission reduction systems through NDC (Nationally Determined Contribution); The development of CDM forestry carbon projects has been challenging, yet it has provided valuable practical insights for advancing global carbon market integration; REDD+ promotes forest conservation in developing countries, with significant progress made in implementation, funding, and governance models. Although forestry-related negotiations have achieved remarkable results, they still face challenges such as financing mechanism, carbon sink Monitoring, Reporting, and Verification (MRV), market fluctuations, natural disaster risks, forest community rights protection, and cross-sectoral collaboration. In future global forest governance under the context of climate change, the emphasis should be placed on improving forest financing mechanisms, advancing climate-smart forestry practices, enhancing market-oriented mechanisms for carbon sink value realization, strengthening community rights protection and natural risk resilience mechanisms for forests, deepening cross-sectoral collaboration to curb deforestation, and promoting Nature-based Solutions (NbS) to maximize the multifunctional benefits of forests. These efforts aim to provide references for China’s forestry sector to participate in global climate governance.