At present, the trend of global warming is still continuing, and the extreme low temperature events in China have decreased significantly in recent decades. However, since the 1990s, the occurrence of extreme low temperature in China has increased, the number of strong low temperature events and the total amount of snowfall have both increased. This trend is expected to continue in the future. In 2024, the most extreme ice and snow event occurred since 2009 occurred, and freezing rain as a kind of low temperature disaster, in this context, it is necessary to conduct research. Based on daily freezing rain (rime) data from January 1961 to December 2022, the spatio-temporal characteristics of freezing rain frequency were systematically investigated across China. The distribution and variation patterns of freezing rain in the whole country were analyzed and a significant large-scale freezing rain event anticipated in February 2024 was examined. The findings indicate that with exceptions for certain high-altitude regions, freezing rain predominantly occurs between September and following May, peaking during winter (December to following February). The average frequency of freezing rain exhibited an initial rise from 1961 to 1975, followed by a rapid decline between 1980 and 1990. Since 2000, the frequency of freezing rain in China has transitioned from a gradual decline to a sharp increase, accompanied by heightened interannual oscillations. Five primary regions were identified as experiencing significant occurrences of freezing rain: Xiang-Gui (Hunan-Guizhou), Ji-Lu-Yu-E (Hebei-Shandong-Henan-Hubei), Shan-Gan-Ning (Shaanxi-Gansu-Ningxia), Hei-Ji-Liao (Heilongjiang-Jilin-Liaoning). As global changes intensify, the frequency of freezing rain in various regions has experienced new variations, with notable variations observed particularly within the Xiang-Gui and Hei-Ji-Liao regions. The analysis of the large-scale freezing rain process projected for February 2024 reveals that under the background of Arctic warming, the path, intensity and influence range of cold air entering China have changed, accompanied by a significant inversion layer and abundant water vapor, which is prone to cause large-scale freezing rain events.

Accurately quantifying and reducing the uncertainty of climate and hydrological projections is a prerequisite for subsequent climate change impact assessment and adaptation strategy development. For the quantification of projection uncertainty, the development history of different methods is systematically reviewed, and the realization process and applicability of methods, including the HS09, the L20, and the analysis of variance are stated. Further the necessity and ideas to reduce the model uncertainty are elucidated, and the constraint projection methods are classified into four categories: detecting attribution constraints, weighting constraints, emergent constraints, and correction constraints. The principle of each method are comprehensively introduced, and the characteristics of the constraint methods in terms of the establishment of the relationship, the applicability of the scales and variables, are analyzed. Then the implementation process of testing different constraint methods and evaluating the results are summarized. Finally, the key points that need urgent attention in this field are discussed, and the possible future trends are prospected, with a view to providing reference for improving the accuracy and reliability of climate and hydrological variables projections.

Poverty-alleviated regions are particularly vulnerable to reverting back to poverty due to natural disasters. However, there is limited understanding of the potential future risks posed by record-breaking extreme weather in China’s poverty-alleviated counties. Data from 22 models, based on the NEX-GDDP-CMIP6 global downscaling climate scenarios and combined with 8 extreme weather indices, were used to analyze the spatio-temporal distribution patterns of extreme weather across 832 poverty-alleviated counties and other counties in China. The results are as follows. China faces significant threats from extreme heats. From 1950 to 2014, the frequency of extreme heat events increased rapidly. Under the SSP3-7.0 high-emission scenario, it is projected that 84.82% of Chinese counties will experience a record-breaking possibility greater than 80% for warm nights (TN_90p) by 2040, while 83.40% are expected to surpass this threshold for warm days (TX_90p) by 2050. Poverty-alleviated counties face a more severe threat from extreme heats than other counties. The record-breaking probability of heatwave (HW) in these counties is significantly higher than in other counties. Between 2030 and 2040, the probability of TX_90p record-breaking events in poverty-alleviated counties is projected to exceed 50%, a decade earlier than in other counties. The analysis of compound drought and heatwave (CDHW) events from 1950 to 2014 shows that poverty-alleviated counties west of the Hu Line experienced a growth rate more than ten times that of other regions. The record-breaking probability of CDHW in western poverty-alleviated counties is 1 to 2 times higher than in eastern poverty-alleviated counties in the future. Specifically, poverty-alleviated counties in Xinjiang, western Inner Mongolia, Qinghai, and southern Yunnan are identified as high-risk areas for record-breaking CDHW probabilities. Regions along the Hu-Line (especially its northern and southern flanks), Hainan Island, the coastal zones of the Yellow Sea and Bohai Sea, and northwestern Xinjiang exhibit significantly higher record-breaking possibility for sequential precipitation-humid heatwave (SFH) events. The study indicates that China’s poverty-alleviated counties are more vulnerable to record-breaking extreme weather. To effectively mitigate and adapt to extreme weather, policy recommendations are proposed on water infrastructure, disaster mitigation, catastrophe insurance, and public awareness and education.

Based on 24 global climate models participated in the Coupled Model Intercomparison Project Phase 6 (CMIP6), future climate changes in the west route of the South-to-North Water Transfer Project (divided into two parts of the water source and receiving areas) was projected under the three scenarios of SSP1-2.6, SSP2-4.5 and SSP5-8.5. Results show that under different emission scenarios, the annual mean temperature presents a significant increasing trend in the water source and receiving areas, and the annual mean precipitation and extreme precipitation (characterized by the maximum daily precipitation) are mainly increasing, with greater magnitude under higher emission scenarios. Relative to 1995-2014, increased annual mean temperature, precipitation and extreme precipitation in the water source and receiving areas at the near (2021-2040), mid (2041-2060) and end (2081-2100) of the 21st century can be found, with greater increase as time progresses. In the future three time periods, relative to 1995-2014, all the models show an increase in the annual mean temperature averaged in the water source and receiving areas, and the consistency among the models is good; The simulated annual mean precipitation and extreme precipitation present significant uncertainty, but increases can be mainly observed. Overall, the future changes in precipitation in the water source area are beneficial for the planning and implementation of the west route of the South-to-North Water Transfer Project. Meanwhile, the uncertainty of the projection should be noted.

Long-term warming and extreme weather events will have significant impacts on energy supply and demand. Understanding and assessing the effects of climate change on energy systems is crucial for mitigating risks associated with energy transition. Based on the Climatic Impact Drivers (CID) framework proposed in the IPCC Sixth Assessment Report (AR6), the impacts and mechanisms of climate change on energy supply and demand are systematically combed in this review. The findings indicate that the CID framework is effective in comprehensively evaluating the impacts and risks of climate change on energy systems. Key CID types, including wind, heat and cold, wet and dry, snow and ice, and other, have significant effects on energy systems. It is essential to incorporate the impacts and risks of climate change into the regular planning of energy and power systems, considering long-term warming and extreme weather events as critical factors, to build climate-resilient energy and power systems.

Based on life cycle analysis (LCA) method, representative facilities and typical technological processes were selected, new survey data and evaluation parameters were investigated, and the normalized greenhouse gas (GHG) emissions of the current nuclear energy system were calculated. The result was 5.31 g CO₂/(kW.h), with the nuclear power plants account for 27% and nuclear fuel cycle facilities account for 73%. Taking the main pressurized water reactor types (Hualong-1, AP1000, VVER1000, CNP1000, CNP650) as the research subjects, the GHG emissions of nuclear power plants was 1.40 (ranging from 0.94 to 1.85) g CO₂/(kW.h). Focusing on nuclear fuel cycle front-end facilities based on CO₂+O₂ in-situ leaching uranium technology, the integrated process of uranium purification and conversion, and the new generation of centrifugal uranium enrichment technology, the GHG emissions from the front end was 2.18 (ranging from 2.01 to 2.59) g CO₂/(kW.h). The GHG emissions from spent fuel reprocessing and waste disposal were 1.71 (ranging from 0.68 to 1.91) g CO₂/(kW.h) and 0.02 g CO₂/(kW.h), respectively. China’s Double-Carbon (carbon peak and carbon neutrality) policy had promoted energy conservation and consumption reduction across all industries. The average reduction in comprehensive energy consumption for steel and cement had reduced over 9% in the past decade. China’s power energy structure had continued to undergo green and low-carbon transformation, with the average carbon emission factor of the national power grid continuously decreasing by about 35%. As a result, the emissions caused by the purchase of electricity or raw materials used in the nuclear energy system had also continued to decrease. Under the goal of carbon neutrality, the nuclear energy system had a further vision of decarbonization. The research on nuclear facilities decommissioning and waste recycling and reuse technologies should be strengthened, and the carbon footprint management should be further improved.

Solving the problem of source-sink matching of Carbon Capture, Utilization and Storage (CCUS) can provide scientific support for the optimal layout of CCUS clusters. Based on the full consideration of transport distance, capture-transport-storage and utilization costs, a CCUS source-sink matching model was constructed with the carbon neutrality target as the emission reduction constraint and based on the principle of minimizing the cost of CCUS deployment. A comparative analysis was conducted on the optimal CCUS source-sink matching pathways and the economic costs of cluster layout options before and after considering the carbon utilization scenarios. The results show that achieving the carbon neutrality target requires the annual capture scale of CCUS to reach 513.33 Mt CO₂. Compared with the scenario that only considers CO₂ sequestration in saline aquifer, gas field and CO₂-EOR, the number of carbon sources that need to be transformed by CCUS will increase from 332 to 434, the number of carbon sinks involved will increase from 49 to 276, and the length of the transport pipeline construction will increase from 21237.96 km to 31473.33 km, assuming the consideration of the mineralization of steel slag and the chemical conversion technology using CO₂. The total abatement cost of deploying CCUS over the 30-year planning period would decrease from $760.4 billion to $514.1 billion, and the unit abatement cost would decrease from $49.38/t CO₂ to $33.38/t CO₂. The demonstration of carbon utilization technology can optimize the cluster layout options, play the cluster scale advantage, reduce the layout cost, and help form characteristic clusters. The Su-Lu cluster and Meng-Ning-Shaan-Jin-Ji cluster are the primary regions for CCUS deployment in the future, and the deployment of CCUS in the Bohai Bay and Northeast clusters is the most feasible.

It is an urgent need to explore the spatiotemporal differences in land use carbon emissions and new-type urbanization level and their interaction relations in metropolitan areas, which is of great significance for reducing the pressure of carbon emission reduction and realizing the “dual-carbon” goal as scheduled in China. Taking Nanchang metropolitan area as the study area, the emission coefficient method, Theil coefficient method and geographical detector model were used to explore the spatiotemporal differences, regional differences and influence degree between land use carbon emissions and new-type urbanization level. The research results showed that the growth of land use carbon emissions in the study area gradually slowed down, while the carbon emissions in the central economically developed areas were larger. While the new-type urbanization level increased steadily, and the overall gap decreased year by year. The impacts of different new-type urbanization factors on the spatial differentiation of land use carbon emissions varied greatly. The effects of land use efficiency and population urbanization level on the spatial differentiation of land use carbon emissions continued to increase, while the effects of economic development level gradually weakened. The combined effects of the new-type urbanization factors were nonlinear, and the combined effects of land use efficiency & economic development level and economic development level & population urbanization level have a greater impact on the spatial differentiation of land use carbon emissions. The optimization and adjustment of land use efficiency and labor flow should be focused during the process of low-carbon urbanization, and different policies and measures should be adopted according to local conditions to optimize urban construction, so that the pressure of urban carbon emission reduction will be relieve and the sustainable development of natural ecological environment and social economy will be promoted.

The Tibetan Plateau (TP), a vital ecological security barrier and watershed region on a global scale, plays a crucial role in the global ecological environment and the well-being of humanity. The TP’s sustainable development is currently confronted with numerous challenges due to the compounding effects of global climate change, population growth, and economic development. This paper reviews the state of sustainable development on the TP, synthesizing research findings from both theoretical and policy-oriented studies. It reveals that both domestic and international studies have examined the region’s sustainable development holistically, as well as its various subsystems, through lenses of inter-element interactions, sustainable practices, strategies, and assessments. Nonetheless, the current research still identifies issues such as the absence of spatial and temporal continuity and the lack of a comprehensive multifactorial feedback mechanism.

In the outcome of the first Global Stocktake (GST) under the Paris Agreeemnt, the important role of the Paris Agreement is clarified and affirmed in promoting the collective global climate goals and enhancing the climate actions by all Parties, and the significant collective progress made by all Parties is reaffirmed in achieving the temperature goals of the Paris Agreement through the development and implementation of Nationally Determined Contributions (NDCs). Regarding the progress in formulating mitigation targets by Parties to the Paris Agreement, most Parties have proposed 2030 and long-term climate mitigation targets through their NDCs and long-term low-emission development strategies, the types of 2030 mitigation targets and the expressions of long-term net-zero targets are diverse. Through an assessment of the progress and the prospects of major Parties in implementing their 2030 mitigation targets, it is found that the performance and prospects of developed countries in achieving their 2030 targets are not optimistic, and most developed countries still deviate significantly from the track on achieving their targets even with additional measures. The mitigation targets types that chosen by major developing countries are closely related to their own emission stages and characteristics. Based on the latest emission trends, most developing countries are assessed as on track but with a gap between then and their targets. Developing countries are in need for larger scale of financial, technology, and capacity building support to implement and strengthen their mitigation actions. In the target-setting stage, it is recommended that China’s subsequent NDCs should comply with the requirements of the Paris Agreement and the global trends, and respond how the NDC is informed by the outcome of GST. During the implementation phase of the agreement, it is recommended that developed countries strengthen their mitigation actions, effectively fulfill their obligations of taking the lead on mitigation, and provide sufficient financial, technology, and capacity building support to developing countries. It is suggested to make good use of the dialogue platform such as the mitigation global dialogue to strengthen the exchange of experiences on mitigation policy measures among all Parties, and to enhance international cooperation in carrying out mitigation actions.

The low-carbon transition of high-carbon industries is the key to addressing climate change, and climate transition finance provides support for large-scale financing of high-carbon industries. International organizations and financial institutions are actively advocating and formulating relevant standards, and the formulation of financial standards for climate transition in China is in its infancy. Based on the practice of climate transition finance standards at home and abroad, this paper systematically sorts out their experiences in five aspects: method selection, principles to be followed, support objects, industries covered and financial instruments, and proposes to build a multi-dimensional climate transition finance standard system, and puts forward suggestions on national climate transition finance standards that meet China’s low-carbon development needs from the national, local and industry levels. Finally, it points out the key elements of the formulation of transitional financial standards and the implementation suggestions, aiming to mitigate climate change and promote the achievement of the “dual carbon” goal.