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Meteorological disasters are one of the major risks to agricultural production, causing huge losses to agriculture. Agricultural insurance is an important part of the agricultural security system and can effectively spread agricultural risks and losses. Weather index insurance, which emerged in the late 1990s, has received a lot of attention, research, and applications due to its objectivity, standardization, and robust liquidity. In this paper, authors analyzed the advantages and disadvantages of weather index insurance compared to traditional agricultural insurance. The development of weather index insurance technology at home and abroad was reviewed. Authors introduced the development and practical application of weather index insurance model for Anhui grain crops (winter wheat, one season rice, summer corn), and discussed and prospected the future development of weather index insurance. [ABSTRACT FROM AUTHOR]

Droughts are increasing in frequency and intensity as the global climate changes. Risk assessment for agricultural drought disasters is an important approach for disaster prevention and mitigation. Based on the formation mechanism of natural disaster risk, the index system model of agricultural drought risk assessment in North China was constructed, and the robustness of the established risk assessment model was tested by using the internal test method. Then based on the characteristics of agricultural drought risk formation in North China, the paper proposes corresponding risk prevention recommendations. The conclusions were as follows: when adjusting the indices and methods in the risk assessment model, the range of changes in the agricultural drought risk ranking for each city was mostly 1-2.5 places, and the model was relatively robust. With the exception of Beijing and Tianjin, which had the highest disaster prevention and mitigation capacity, central and northern China had the highest agricultural drought risk, which was previously linked to the high risk and vulnerability of these regions. The agricultural drought risk in northern Henan and southern Shandong is low, mainly due to the low risk. The 34 cities in North China can be divided into 6 agricultural drought risk clusters, which are not dispersed in space and cross-city distribution, and have good aggregation. Cluster 4, located in the northernmost mountainous areas, has the highest risk of drought, which is associated with high environmental vulnerability and low capacity for disaster prevention and mitigation, so agricultural areas should be reduced and agricultural input should be increased. Clusters 2, 5 and 6, located in the central and southern regions, have higher grain acreage and yields due to drought, so agricultural drought risk can be further reduced by increasing agricultural input and improving irrigation guarantee rate. [ABSTRACT FROM AUTHOR]

Climate change will lead to an increase in extreme weather events and economic losses, which will further affect financial stability and require timely assessment and response by relevant departments. Therefore, it is of great theoretical and practical significance to construct a reasonable climate financial analysis framework, analyze how climate change affects financial variables in detail, and formulate targeted policies and measures in combination with transmission paths. This paper constructs a DSGE model including carbon cycle, climate change factors, and multiple economic entities under the framework of financial accelerator and simulates the impact of climate change on output, asset prices, corporate default rate, and total credit. The results show that: ① The impact of climate change reduces output, capital price, and return on capital, increases the level of external financing premium, and pushes up the leverage ratio and credit default rate of enterprises, which in turn leads to a credit crunch and reduced investment. ② The impact of carbon intensity increases output, capital price, and return on capital, reduces the level of external financing premium, reduces the leverage ratio of enterprises and the default rate of corporate credit, and then causes credit expansion and investment increase. ③ The impact of emission reduction intensity mainly affects the macro-economy through cost drives. In the short term, the economy is negatively affected by the impact of emission reduction. In the long term, with the rapid recovery of output, the demand for investment and credit increases, thus promoting economic growth. Based on this, this paper puts forward the following suggestions: ① Assess the scale of climate change risk in the financial system timely and accurately, and prevent the impact of non-traditional systemic risks on the financial market. ② Actively promote the rapid development of green and low-carbon technologies, and promote the win-win results of pollution and carbon reduction and output increase. ③ Improve the analysis framework of the economic model of climate change and enhance its practical explanatory power and theoretical guidance. [ABSTRACT FROM AUTHOR]

Under the background of climate change, vegetation restoration in arid area ecosystem is faced with great challenges, which has important research value and is also an important research direction of ecology. In this paper, CiteSpace software was used to carry out data mining and econometric analysis on the research progress of vegetation restoration in arid area ecosystem. Besides, the number of papers published under this topic, the trend of change, the main research strength and the development path of the research topic were presented. The study found that (1) the overall volume of papers showed a significant growing tendency on the whole, and generally experienced three growth stages of slow, steady and rapid growth. The research hotspots were different at different stages. At present, the research mainly focuses on clustering topics such as “soil moisture”, “abandoned farmland”, “biological soil skinning” and “layered soil”, and the cross-study of engineering, hydrology, geosciology and other related disciplines is increasing day by day. (2) China, the United States and Spain were the countries with the largest number of publications, and the Chinese Academy of Sciences was the research institution with the largest number of publications. Li Xinrong and others constituted the core group of authors under the research topic. (3) The strategies of vegetation restoration in response to drought stress and the changing rules of the structure and function of different restored ecosystems under the background of climate change may be the research hotspots of vegetation restoration in arid areas in the near future. [ABSTRACT FROM AUTHOR]

Assuming responsibility for emission reduction is an important part of participating in the global governance of climate change. Countries with a carbon neutrality target now cover about 75% of global greenhouse gas emissions. Carrying out fairness evaluations of their carbon neutrality targets provide a strong basis for the global carbon inventory. In this paper, the target years of carbon neutrality for major countries and regions under the global target of 2 °C and 1.5 °C are studied using the burden sharing model. On this basis, this paper simulates the possible pathways of carbon neutrality and evaluates the ambition of emission reduction targets in terms of annual emission reduction, per capita emission, and cumulative per capita emission. The results show that, from the perspective of equity, most of the developing countries cannot meet the global goal of 1.5 °C. The United States and the European Union nations could achieve carbon neutrality by 2050 by continuing their annual emission reductions under their existing NDC targets. However, to achieve carbon neutrality by 2060, China's annual emission reduction rate from 2030 to 2050 will be 6.7%, and the annual amount of emission reduction accounts for 51% of the global amount under the 1.5 °C target. Meanwhile, China would become the main force behind global cumulative emissions in the following decades. Thus, the emission reduction pathways China chooses will have an important impact on global climate mitigation progress. Based on the above research conclusions, this paper proposes that developed countries and developing countries should explore bilateral or multilateral cooperation in technology and finance in the field of climate change. Under the great pressure to achieve carbon neutrality, China needs to carry out research on the overall emission reduction pathways as soon as possible and clarify the paths at the scale of sectors, industries, provinces, and time stages. [ABSTRACT FROM AUTHOR]

In the context of climate change, nature-based solutions (NbS) are an advanced concept for human society to cope with climate risks and challenges; they can also help to build a scientific and standardized management system and an efficient and green social and economic system for the achievement of sustainable and high-quality development goals. Besides, it provides the fundamental guidelines and directions for the Xiong' an New Area, which has been planned and constructed with high standards and provides an important realistic scenario for the study of stormwater management modes. This paper introduces the concept and development process of NbS, summarizes its principles and approaches, and systematically analyzes the characteristics of rainstorm and flood disasters in the Xiong' an New Area and the tight situation of water supply and demand caused by rapid socioeconomic development against the background of frequent extreme weather events caused by climate change. Based on the moderate greenhouse gas emission scenario (RCP4.5) of the regional climate model, the numerical simulation results of 1980--2099 with a horizontal resolution of 25 km, and the reference period of 1986--2005, the future climate change prediction analysis and rainstorm and flood risk assessment in the Xiong' an New Area were carried out. According to the Xiong' an New Area' s stormwater management and the current extreme rainfall situation, the paper combines the future social and economic development and urban-rural ecological spatial pattern of the Xiong' an New Area, as well as the concept and construction goals of 'building an ecological city where human and nature coexist harmoniously in the lake city featuring blue sky and verdant fields,' and proposes nature-based solutions to strengthen climate risk management in the area and reduce the risk of extreme precipitation. The proposed stormwater management model for the Xiong' an New Area based on NbS includes three dimensions: ① We should adhere to the overall plan of ecological protection and restoration of the whole basin and improve the capacity of systemic climate governance. ② We should advocate the multi-scale vertical system design at the city level and improve the carrying capacity of urban resilience. ③ We should adhere to the general principle of seeking advantages and avoiding disadvantages and strengthen the development of ecological infrastructure. On the basis of effective engineering and institutional defense measures, actively implementing the concept of nature-based solutions in the stormwater management of the Xiong' an New Area is conducive to fully exploring and rationally utilizing the special water system conditions of the area and the integrated environmental advantages of urban lakes, seeking advantages and avoiding disadvantages, and minimizing the impact of extreme precipitation on the stable operation of the cities and the safety of people' s lives and property. [ABSTRACT FROM AUTHOR]

Since the signing of the United Nations Framework Convention on Climate Change in 1992, the United States has shown a sometimes conservative and sometimes radical pendulum in its position on several key subsidiary climate treaties. For example, in 1997, the United States Congress refused to approve the Kyoto Protocol signed by former US vice president Al Gore. In 2015, President Obama used executive power to bypass Congress to sign the Paris Agreement. In 2017, President Trump announced the withdrawal of the US from the Paris Agreement. These seemingly confusing behaviors actually reflect the contradictions and conflicts in the formulation of climate policy of the United States. Using neoclassical realism theory as the analytical framework, the authors of this paper explore how such several key variables as leader image and perception, partisan politics, and civil society and lobbying groups shape the climate policy of the United States. [ABSTRACT FROM AUTHOR]

In the context of climate change, economic globalization and rapid urbanization, the multi-hazard risk has become a major threat to human society. Risk assessment is the foundation of risk prevention. Based on an in-depth examination of literature, this paper summarizes the theories and methodologies for assessing multi-hazard risk in the past two decades. The compre‐ hensive risk assessment has two significant theory foundations: the conceptual models which in‐ dicate the combination way of multi-hazards and the risk frameworks which describe the risk ele‐ ments and their relationships as well as developing the assessment models. The key to multi-haz‐ ard risk assessment is the integration of single hazard risk, and the method for integration can be classified to two categories: integration of risk values and integration of hazard processes. It de‐ serves closer attention to investigate both the complex relationship between various disasters and risk elements as well as the complex impact of environmental changes on disaster risk. The sce‐ nario-based modeling and risk assessing method may be a better choice for meeting the demands of the current era. It is feasible to take the single hazard risk analysis as a starting point, the in‐ terrelationships between various hazards as traction, and the scenario analysis method as a pro‐ pellant to implement multi-hazards risk assessment. [ABSTRACT FROM AUTHOR]

Kunming-Montreal Global Biodiversity Framework proposes to protect 30% and restore 30% of the land with high quality and maximize the goal of conserving biodiversity and mitigating climate change. Succession theory and vegetation restoration can serve the targets of 30% protection and restoration. Succession theory is the core theory in vegetation ecology. Succession refers to the process that the structure or composition of a group of different species in a site change with time. Vegetation restoration is the process of restoring or recovering or naturally renewing plant communities, mainly based on plant planting and configuration. Vegetation restoration is the process of changing the structure and function of ecosystem from simple to complex, from low level to high level, and the ultimate goal is to establish healthy and stable plant communities. Succession is the foundation of vegetation restoration, and vegetation restoration can be seen as the manipulation of the succession process to achieve the goal of restoring damaged vegetation ecosystem. Succession theory can guide vegetation restoration. Vegetation restoration is also beneficial to the development of succession theory. Succession theory and vegetation restoration differ in scale, theme and paradigms. Succession often emphasizes disturbances related to nature, while vegetation restoration focuses on disturbances related to humans. The succession can be divided into primary succession and secondary succession according to the nature of bare land. The restoration process is suggested to be regarded as the tertiary succession, which will help to understand the management options for promoting the success of vegetation restoration through human intervention, especially by emphasizing the management options which may improve success, especially by addressing environmental and biological legacies. Artificial intervention based on succession theory can accelerate vegetation restoration, avoid early positive promotion of degraded vegetation ecosystems to pre-degraded levels in poor habitats, and also avoid resource waste caused by disordered competition and low efficiency among communities. This paper also puts forward the scientific and technical issues on the theories of vegetation restoration and succession in the future. [ABSTRACT FROM AUTHOR]

he ' Scientific Understanding of Climate Change' part of China' s Fourth National Assessment Report on Climate Change reflects a series of new evidence and new understanding of climate change in China since 2015, based on scientific analyses such as climate system observations, paleoclimate archives, theoretical research, and climate modeling. This report summarizes the basic climatic variables of the atmosphere, ocean, cryosphere, and biosphere, as well as the characteristics of climate change seen in extreme events and typical regions in China. It also analyzes the changes in natural and human driving factors affecting climate change and estimates the future trends of climate change in China. Compared with the Third National Assessment Report on Climate Change, this paper identifies the new features of this assessment report in terms of the structure and conclusions. At the same time, it is pointed out that the system of China' s climate change assessment report is continuously enriched and the understanding of scientific basis is constantly deep -ened. The paper also makes a preliminary comparison between this report and the report of Working Group I to the Sixth Assessment of the Intergovernmental Panel on Climate Change (IPCC) and proposes solutions to issues concerning climate change monitoring and diagnosis, detection and attribution, simulation estimation, instruments, and methods that China may face in the future. [ABSTRACT FROM AUTHOR]

The ability of methane-oxidizing bacteria to oxidize methane significantly affects the total global methane emissions. To study the response of methane-oxidizing bacteria community to temperature rise in river source wetland is helpful to further explore the methane cycling mechanism in river source wetland ecosystem. In this paper, high throughput sequencing method was used to study the changes of methane-oxidizing bacteria community characteristics in river source wetland of Qinghai Lake after temperature rise. Proteobacteria were the dominant phylum of methane-oxidizing bacteria in the headwater wetlands of Qinghai Lake; warming treatment did not significantly affect the community diversity of methane-oxidizing bacteria in the river source wetland. The community structure of methane-oxidizing bacteria in river source wetland responded significantly to temperature rise; warming significantly increased the dominant microflora at the genus level (relative abundance > 0.1%). LEfSe analysis showed that there were 23 different microflora between the warming group and the natural control group; the warming significantly increased the relative abundance of Methylococcus and significantly decreased the relative abundance of Methylobacter. The function of methane-oxidizing bacteria community was closely related to carbon and nitrogen metabolism in river source wetland. In general, the community structure of methane-oxidizing bacteria in river source wetland was more sensitive to temperature rise, and the relative abundance of some bacteria changed significantly. [ABSTRACT FROM AUTHOR]

In the process of vegetation restoration of mine slope, the slope direction has a great influence on the effect of plant regreening. In this paper, Parthenocissus quinquefolia(L.) Planch brocade was taken as the research object, planting troughs were arranged at the foot of the high and steep bedrock slope facing east, south, west, and north. Parthenocissus quinquefolia(L.) Planch was planted in the planting troughs. The slope heterogeneity and suitability of functional traits of Parthenocissus quinquefolia(L.) Planch leaves were studied by analysis of variance and principal component-membership function evaluation. Partial correlation analysis was used to reveal the effect of climatic factors on the changes of leaf functional traits to understand the adaptability of Parthenocissus quinquefolia(L.) Planch to slope climate change. The results showed that in the characteristics of leaf structure, the order of the leaf dry matter content(LDMC) was as east slope > west slope > north slope > south slope. Leaf water content (LWC) and specific leaf area(SLA) are north slope > east slope > west slope > south slope, leaf thickness(LT) is south slope > east slope = west slope > north slope, and leaf tissue density(LTD) is south slope > west slope > east slope > north slope. In the leaf photosynthetic characteristics, the order of net photosynthetic rate(Pn), stomatal conductivity(Gs), transpiration rate(Tr), and water utilization efficiency(WUE) was as east slope > west slope > north slope > south slope, intercellular CO2 concentration (Ci) was opposite to the order. In the leaf fluorescence characteristics, the initial fluorescence(Fo) on the south slope and est slope were large, and the value on the est slope and the north slope were small. Maximum fluorescence(Fm), PSⅡquantum efficiency (Fv/Fo), and PSⅡ maximum photochemical efficiency(Fv/Fm) were in the order of north slope > east slope > south slope > west slope. The comprehensive order of slope adaptability of Parthenocissus quinquefolia(L.) Planch was as follows: east slope (2.67) > north slope(1.66) > west slope(0.07) > south slope(-1.60). The effects of different climatic factors on the functional characters of Parthenocissus quinquefolia(L.) Planch leaves were different. The structural characteristics of leaves were greatly affected by environmental humidity, followed by photosynthetic radiation. The photosynthetic characteristics of leaves were greatly affected by environmental temperature, followed by photosynthetic radiation. The fluorescence characteristics of leaves were greatly affected by environmental humidity, followed by environmental temperature and water evaporation. From the above results, it can be known that in the environment of high and steep rock, the growth of Parthenocissus quinquefolia(L.) Planch grew the best on the east slope. Under the conditions of high temperature, strong evaporation, and strong photosynthetic radiation, the functional traits of Parthenocissus quinquefolia(L.) Planch leaves showed stress resistance. [ABSTRACT FROM AUTHOR]

Petrocodon Hance is one of the famous ornamental flowers, but most of them are assessed as extremely dangerous (CR), or at least above vulnerable (VU) due to climate turbulence and strong interference of human activities. To reconstruct the temporal and spatial changes of the potential suitable areas of Petrocodon since the last interglacial period, and explore the response of the suitable areas to environmental changes, which provided theoretical guidance for the origin of Petrocodon, the study of geographical differentiation, the conservation of unique germplasm resources in China, and the development and utilization of gardens. In this paper, combined with 120 distribution records and 17 environmental variables, the optimal MaxEnt model and geographic information technology (ArcGIS) were used to simulate the suitable areas and distribution pattern of Petrocodon in China and Indo-China Peninsula. Based on stepwise multiple linear regression analysis, redundancy analysis and Monte-Carlo test, the dominant variables affecting the current geographical distribution of Petrocodon were evaluated. The results were as follows: (1) The prediction accuracy of the optimized MaxEnt model was high, and the AUC value was greater than 0.96. The potential suitable areas of Petrocodon for the present distribution are continuous from Southwest China to North Vietnam, scattered in central and southern China and blocky in North Myanmar, of which the South Yunnan-Guizhou Plateau in China was the most suitable. (2) The environmental variables which restrict the geographical distribution of Petrocodon included precipitation of the driest month (bio14), precipitation of the warmest quarter (bio18), precipitation of the wettest quarter (bio16), SD of the temperature seasonality (bio4), min temperature of the coldest month (bio6) and altitude (alt). (3) Under the climate change scenario, the expansion and contraction areas of the suitable habitat of Petrocodon were located in the north and northeast of the current potential distribution area, which were sensitive areas susceptible to climate change. During the last interglacial period, the suitable area of Petrocodon expanded on a large scale, but there was almost no suitable distribution area of Petrocodon in the dry and cold environment during the last glacial maximum. After that, with the aggravation of climate warming, the suitable habitats of Petrocodon increased rapidly to high latitudes, while the suitable habitat in low latitudes decreased. (4) The centroid position of the suitable area for Petrocodon migrated northwards from Yongfu County, Guangxi (110.10° E, 24.69° N) to Chengbu County, Hunan (110.29° E, 26.05° N). To sum up, global warming has a positive impact on the potential distribution area of Petrocodon, but extreme warming will cause the suitable habitat of Petrocodon to shrink, and the niche of Petrocodon will narrow. Southwest China to North Vietnam, which has the advantage of mature karst landform, may be its main refuge. [ABSTRACT FROM AUTHOR]

The aims of this paper is to illustrate the importance of grain production in China's food security strategy based on the three Northeastern provinces (NEP) in the new period, which quantitative assessment of climate change under the background of the loss caused by meteorological disasters of regional food production is clarify. In this paper, using grain planting area, yield and agricultural disaster statistics from 1981 to 2020, comparison analysis grain production and disaster characteristics between NEP and the whole country respectively. The disaster-yield assessment model was used to estimate the disaster-yield loss and final yield of the NEP by inputting disaster data in recent 10 years, and the sensitivity and stability of the disaster-yield assessment model were re-tested. The results showed that :(1) from 1981 to 2020, the grain planting area and total output in NEP increased significantly, and the proportion of the total output of NEP increased steadily, and the proportion of the total output of the three northeast provinces reached 1/5 of the total output of the whole country by 2020. (2) The disaster situation in NEP showed a significant trend of first increasing and then decreasing. The incrasing of average grain yield during the past 40 years was 65.96kg⋅ha-1 and 252.5kg⋅ha-1 per year for NEP and the whole country, while the incrasing of average grain yield during the past 10 years was 52.6kg⋅ha-1 per year for NEP significantly. (3) From 2011 to 2020, the average affected area and affected area in China were 23704.5x10³ha and 11204.7x10³ha, respectively, and 3899.1x10³disasters of the whole country and the three northeastern provinces were significantly lower than those of the previous three years, making it the decade with the least severe disasters in 40 years. (4) The simulation accuracy of the disaster-yield assessment model was high. The linear regression coefficients (R²) of simulated grain yield and measured grain yield in Heilongjiang, Jilin and Liaoning provinces were 0.98, 0.90 and 0.88, respectively. The slopes were 1.05, 1.02 and 0.98 (P < 0.01), respectively. The loss rate of grain yield due to agro-disaster was 10.4%, 17.9% and 18.0% respectively in the three province, while which was more than 8.0%, 17.0% and 16.0% for 20a.years. (5) The model slightly overestimated the grain yield of Jilin and Liaoning in recent 10 years due to the overall light disaster situation. Based on the data from 1981 to 2010, the regional grain disaster loss assessment model was proved to be able to evaluate the loss of grain yield caused by meteorological disasters well, and had the performance of predicting grain yield, and has the feasibility of operational application. The impact of meteorological disasters on the grain output in northeast China is higher than the average level of disasters in the whole country. Considering that the grain output in Northeast China accounts for a high proportion of the national grain output, preventing the risk of agro-meteorological disasters in Northeast China in the new period is of great importance to guarantee the national food security. [ABSTRACT FROM AUTHOR]

Objectives: As an emerging airborne remote sensing system, unmanned aerial vehicle (UAV) falls into multiple categories with various payloads, such as the multi ⁃ rotor and fixed ⁃ wing ones. Despite the harsh climatic condition, UAV is widely used in many Antarctic fields of basic and applied science, which still lacks a comprehensive and systematic literature review. Methods: We firstly discuss the special impact of Antarctic environmental conditions (meteorology, electromagnetic field, light, etc.) on the UAV operation. A comprehensive literature retrieval is subsequently presented on the current application of UAV in Antarctic research and expedition. We sort out 104 papers according to the time of publication, main journals, study areas, nations, and institutions. Representative literature is reviewed in seven application areas, including aeromechanics, atmosphere, sea ice and iceberg, glacier, geomorphology and geomagnetism, ecology-vegetation as well as ecology-animals. We retrospect the development and achievement of UAVs applications in the Chinese national Antarctic research and summarize the limitations of the research on the application of UAV in Antarctica. Results: A number of environmental factors need to be considered before the UAV missions, such as the meteorological conditions, electromagnetic field, solar radiations, and flight regulations. According to the review, half of the literature belongs to the journal paper, mostly in Polar Biology, Polar Science, and Remote Sensing. The earliest UAV research in Antarctica was published in 2004, followed by a productive period of International Polar Year in 2008. The first-tier countries including the USA, Australia, and Germany, led the progress in the research on UAVs in Antarctica. Meanwhile, the dominant role of top universities stood out via various collaborations. The UAV can also be classified into multiple categories according to the payload, such as the industrial⁃ or consumer-grade optical cameras, radiosonde, synthetic aperture radar, and light detecting and ranging （LiDAR), among which consumer-grade camera is widely used in Antarctic investigations. China􀆳s Antarctic expedition team initiated the Antarctic UAV program in 2007 and had carried out at least 18 flight missions by 2020. The flights covered Zhongshan Station, The Great Wall Station, Inexpression Island, and the inland ice sheet, from which the collected data were employed to support the glaciological, geomorphic, and biological studies. Conclusions: The UAV remote sensing, as the essential technology in the “Air ⁃Space ⁃Ground” polar observation system, has been increasingly upgraded in the recent decade. The flight experiments covered the primary research topics and research fields in Antarctic science. In general, the application and development of Antarctic UAV in China lie in the second tier, falling behind the USA and Australia. In the end, according to the current development of Antarctic UAV in China, this paper provides guidance for China's Antarctic expedition team in the future: (1) Develop new UAV models; (2) Make breakthroughs in the battery technology; (3) Couple multiple sensors; (4) Encourage trans ⁃disciplinary collaboration; (5) Pro-mote foreign communication and sharing; (6) Participate in the international management. [ABSTRACT FROM AUTHOR]

Climate warming has become the direction of future climate change. Climate warming and terrestrial ecosystem will interact and influence each other. Grassland ecosystem accounts for about 1/3 of land surface area. Observing and analyzing the responses of plant community and ecosystem carbon exchange in grasslands to climate warming will help to further predict changes in grassland ecosystem in the future. This paper reviewed the effects of climate warming on plant physiological and ecological processes, plant community and ecosystem carbon exchange of grasslands. Various results were obtained in different regions and by different experimental methods. Overall, climate warming had a positive effect on alpine grassland ecosystem, a negative effect on tropical grassland ecosystem, and positive/negative effects on temperate grassland ecosystem. In the future, long-term observational studies and mechanism studies on a global scale should be considered to further clarify the responses of grassland ecosystem to global warming. [ABSTRACT FROM AUTHOR]

In 2022, The United Nations' Intergovernmental Panel on Climate Change (IPCC) released the Sixth Assessment Report (AR6) of Climate Change 2022: Impact, Adaptation and Vulnerability and China Meteorological Administration issued China Climate Chang Blue Book (2022). This paper presents a brief summary of the assessment report on the ecological impacts of climate change and adaption strategies, and related studies of China by reviewing additional literature. The AR6 report and related studies indicate that the ecological impacts of climate warming are significant, including advancement of phenology, extension of plant growing season; species range shift towards high latitude or elevation, tree line moving towards the top of the hill; local extinction of species or habitat loss; increase in frequency, severity and range of disease outbreaks. These ecological impacts of climate change may differ between species or regions. The AR6 report and related studies highlight the urgent need to take necessary measures of adaption and mitigation and to deal with the damages or challenges of climate change to the ecosystems which humans live on. These reports and studies also provide important enlightenment to China in dealing with climate change. We need to strengthen studies of climate change biology so as to take scientific and effective measures of adaptation and mitigation to climate change. [ABSTRACT FROM AUTHOR]

To achieve the goal of 'Net-zero Europe' by 2050, the European Union (EU) has set up detailed policies in the fields of energy and climate. This paper summarizes the main characteristics of relevant policies in the EU and UK and their implications for China by reviewing these policies in the achievement of the carbon neutrality goal and other goals in the energy and climate fields. The characteristics of these energy and climate policies include: ① Top-down and bottom-up approaches are adopted to distribute the EU' s overall emission reduction targets to member states in accordance with the principle of fairness, and each member state formulates and adjusts its own goals to ensure the realization of the overall goals. ② Detailed transition plans are formulated for the power, industry, transportation, and building sectors; importance is attached to the application of new and renewable energy technologies such as solar, wind, and hydrogen energy; specific goals are set concerning coal power transition, nuclear energy development, energy efficiency improvement, carbon capture and storage, electrification, and building renovations; and the importance of energy security in transition planning is stressed. ③ A sound and mature emissions trading system and a fair transition mechanism are established to support the realization of the transition goals, and developing countries are helped to reduce emissions through technical dialogues and climate financing. To reach peak carbon emissions and achieve carbon neutrality, China should develop relevant roadmaps at national, sectoral, and provincial levels and strengthen R&D of key decarbonization technologies. At the same time, China should enhance its regulatory regime, and improve the carbon emissions trading system, the green financial system, and the just transition mechanism. [ABSTRACT FROM AUTHOR]

The ' Policies and Actions to Address Climate Change' part of China' s Fourth National Assessment Report on Climate Change comprehensively summarizes the policies and actions implemented to tackle climate change during the middle and late stages of the 12th Five-Year Plan and the 13th Five-Year Plan, and makes an in-depth and systematic assessment of the effects of the policies. This paper mainly introduces the overall framework and main features of this part of the report, interprets its main conclusions, and proposes prospects for future policies. Since the middle and late stages of the 12th Five-Year Plan, China has adopted a series of policies and actions to tackle climate change, continued to promote the establishment and improvement of climate policies, and formed a policy system with distinctive Chinese characteristics involving the planning objectives, the administrative measures, the market-based policies, the pilot and demonstration actions, etc. During this period, China made great achievements in tackling climate change, fulfilled the 2020 carbon emission reduction target in advance, and reversed the rapid growth of carbon dioxide emissions. To achieve the goal of reaching peak carbon emissions by 2030 and achieving carbon neutrality by 2060, China needs to make climate change solutions a part of the overall goal and strategy for national modernization in the future, formulate and implement stronger climate policies, and put them into action. [ABSTRACT FROM AUTHOR]

To explore the impact of climate change on the lake area of Selin Co, this paper used maximum likelihood method to extract the lake areas of Selin Co for the past 33 years (1988-2020) from Landsat data, then analyzed the variations in lake area, temperature, precipitation as well as snow cover depth in Selin Co basin using linear regression and Mann-Kendall test, and discussed the correlation between lake area and climate change by Pearson correlation. The results showed that, in the past 33 years, the Selin Co Lake expanded by 650. 70 km² at the rate of 203. 34 km²/ (10 a),mostly at northward and southward directions. The average annual temperature and precipitation increased significantly at the rates of 0. 50℃/ (10 a) and 17. 32 mm/ (10 a) (p<0. 05),while the average maximum snow cover depth decreased significantly at the rate of 0. 65 cm/ (10 a) (p<0. 05) during 1988-2020. An extremely significant correlation was found between the change of lake area and the rise of air temperature in the basin as well as the decreasing maximum snow cover depth in cold season (p<0. 001),indicating that the Selin Co lake’s expansion in the past 33 years was a consequence of the increasing water supply from ice-snow meltwater due to the rising air temperature in Selin Co basin. [ABSTRACT FROM AUTHOR]

Based on the assessment report of the Intergovernmental Panel on Climate Change (IPCC) and recent research literatures, from the perspective of the impacts and risks of climate change, this paper attempts to interpret several climate tipping points that may be exceeded due to global warming and explain mitigation measures such as carbon dioxide emission peak and carbon neutrality taken by the international community. The importance and urgency of adaptability research in different systems or regions are discussed. The main conclusions are as follows: ① In the past century, especially since the 1970s, global warming has been increasing rapidly, while the warming rate of China􀆳s land and sea is higher than that of the global average. ② In 2019, the atmosphere concentration of CO2, the main driver of global warming, has reached 410.5 ppm, which was 148% of the pre⁃industrial (1750) level and the highest at any time for at least 2 million years. ③ The risks of climate change will increase disproportionately as global temperature quickly increases. The climate tipping points (thresholds) of some systems may be exceeded or occur earlier than expected, causing abrupt and irreversible changes. ④ With the increase of global warming, nine global climate tipping points may being exceeded, including large⁃scale bleach⁃ ing and death of warm water coral reefs, accelerated melting of Greenland and Antarctic ice sheets, slowdown of the Atlantic Meridional Overturning circulation, etc., and there is also a risk of domino effect. ⑤ In order to address the impacts and risks of climate warming, it is necessary to limit global temperature rise in this century to 2 ℃ (preferably 1.5 ℃) above pre⁃industrial levels (1850-1900). Com⁃ pared with 2010, the global net anthropogenic CO2 emissions need to be reduced by about 25% (45%) by 2030 and achieve carbon neu⁃ trality in around 2070 (2050). ⑥ Taking warm water coral reefs as an example, this paper discusses and analyzes that the tipping point of damaged coral reefs in China may be firstly exceeded due to the high warming rate of the China Seas. Therefore, it is urgent to restore and strengthen the climate resilience of different systems or regions such as damaged coral reefs, so as to improve their ability to adapt to climate change. In addition, a breakthrough has recently been made in the research on in situ sexual reproduction and restoration of damaged coral reefs in China, which provides a positive prospect for reconstructing the resilience of damaged coral reefs. [ABSTRACT FROM AUTHOR]

Global climate change is becoming more and more serious, resulting in an increased risk of sea-level rising, extreme weather events, frequent forest fires, and so on. Despite the efforts made by all countries, the trend of global warming has not been stopped, and it is urgent to solve the climate problem. As the largest carbon emission country in the world, China has committed to the international community to achieve peak carbon emissions by 2030 and carbon neutrality by 2060. To explore the synergy mechanism and effect of China's climate policy and promote carbon emission reduction, this paper proposes the concept of 'Sector Consortium'. It is believed that due to the specialization of sector division, a single sector cannot effectively deal with complicated climate problems, and multi-sector climate policy synergy is imperative. Climate policy synergy runs through the process of policy objective formulation, policy detail determination, and policy implementation. All sectors should be fully mobilized to participate in the response to climate change and to enhance the capacity of climate governance by optimizing policy objectives, improving policy details, and strengthening policy implementation. The results show that differences between the central government and the provincial governments in the degree of climate policy synergy are obvious, the central government has a higher degree of climate policy synergy, and the provincial governments have a larger space to improve their climate policy synergy. Based on the provincial panel data from 2003 to 2017, this paper finds that climate policy synergy can reduce carbon emissions, but this influence is reflected by an indirect effect. Climate policy synergy will not have a direct impact on carbon emissions, but will play a role through four types of interaction mechanisms: the synergy of climate policy with measures such as strengthening financial investment, promoting technological innovation, optimizing industrial structure, and reducing energy intensity can reduce carbon emissions more effectively. China's experience of climate policy synergy has important implications for the construction of global carbon emission reduction mechanism. This paper proposes that the global climate governance synergy mechanism should be established based on the effectiveness of climate policy synergy and the behavior logic of 'Sector Consortium', so as to effectively promote global carbon emission reduction and slow down the process of climate change. [ABSTRACT FROM AUTHOR]

The essence of ecological security focuses on ecological risk and ecological vulnerability, and the study of ecological security is the hot points of low-carbon green development, which has important theoretical value and practical significance for optimizing landscape ecological spatial structure and maintaining ecological sustainability. Based on the interdisciplinary principles and methods involved in geography, ecology, remote sensing and GIS, this paper studies the characteristics and laws of climate change and landscape pattern, the coupling relationship between climate change and ecological process, landscape pattern and functional properties. The relationship between landscape pattern, climate factors and soil, hydrological processes and vegetation processes in the ecosystem is analyzed, and the effects of climate change on carbon storage, NPP and ecosystem services are studied to reveal the impact of climate change on ecological processes. The comprehensive analysis shows that climate factors affect the characteristics and changes of ecological security. Meanwhile, landscape pattern is the basis of restricting regional ecological security, and the effects of climate change and landscape pattern on ecological security mechanism are complex. [ABSTRACT FROM AUTHOR]

Excessive anthropogenic emissions of greenhouse gas have led to global climate change in recently years. Methane is an important greenhouse gas after carbon dioxide. Methane emissions increase with the global temperature, which further intensifies global warming. Soil is a huge source and sink of methane, and methanotrophic bacteria play a key role in reducing methane emissions. Exploring the effect of temperature on soil methane-oxidizing ability has been a research hotspot in recent years. This paper reviewed the effects of temperature on soil methane oxidation and methanotrophic bacteria; analyzes and compares the soil methane oxidation process and methanotrophic bacteria in various ecosystems at different temperatures, and the growth temperature range of methanotrophic bacteria strains. The results showed that various ecosystems have different temperature ranges for methane oxidation; the rate of methane oxidation increases with increasing temperature in their particular temperature ranges. When the cultivation temperature is closer to the in-situ temperature, the methane oxidation response will be faster. Similar to the effect of temperature on methane oxidation, the diversity and abundance of methanotrophic bacteria also increase with increasing temperature and are closely related to the magnitude of temperature increase and the adaptation temperature of dominant bacteria. Type II methanotrophic bacteria in the soil are more sensitive to temperature. As the temperature rises, the abundance of type II methanotrophs increases. Therefore, temperature affects the abundance and community structure of methanotrophs, thereby affecting the rate of methane oxidation and methane emissions. However, whether temperature can only change the methane oxidation capacity of the soil by regulating the replacement of dominant bacteria is still unconfirmed. This review discussed the response of methane oxidation to temperature and its microbial mechanism, in order to provides a comprehensive analysis for methane oxidation capacity under the context of future climate change. [ABSTRACT FROM AUTHOR]

Climate change potentially increases the severity, frequency, and duration of cyanobacterial blooms in freshwater lakes, thereby threatening the ecosystem service functions of these lakes and negatively impacting human health. This paper provides a comprehensive review of the external environmental factors and internal eco-physiological characteristics that may trigger these blooms. In particular, detailed discussions are provided to explain the processes leading to cyanobacterial blooms caused due to rising temperature, CO2 concentration, and extreme climate change. A preliminary research framework to determine the impact of climate change on the blooms, namely, the “mechanism analysis — model construction — simulated prediction — risk assessment” research framework, is established. Strategies for the control and prevention of bacterial blooms are developed. Several key future research themes, including the construction of big data monitoring platforms, mechanism models for development and risk prediction, and formulations of nutrient control standards and prevention policies, are proposed to tackle the current problem. This review provides scientific evidence for the prevention and control of cyanobacterial blooms in lakes. [ABSTRACT FROM AUTHOR]

Because of global climate change and human activities, the occurrence frequency of extreme precipitation events is increasing steadily, which causes devastating flood disasters. The stability of a human body can be compromised when exposed to floodwaters, which definitely threatens the life of a human being. Therefore, the investigation into mechanisms and criteria of human instability in floodwaters can provide scientific bases for urban flood risk assessments and hazard reduction measures, and can also benefit the ability of emergency response. This paper summarizes existing studies on instability mechanisms and criteria for people in floodwaters. Based on the summarization, the application scope, advantages and disadvantages of these existing criteria for human instability are evaluated in detail. Even though the calibrated formulas based on mechanical analysis and measured data involve some simplifications, they can reflect the critical mechanical condition of human instability in floodwaters, and therefore show better universality in practice. Given the limitations and shortcomings of the existing studies as well as major threats in current urban flood disasters, this study also presents key future research directions, including the instability mechanisms and criteria of pedestrian evacuation in actual flood conditions and from flooded stairs; using big data technologies to obtain and analyze online resources of flood instability videos and images, and reasonably estimate the critical instability state to construct a dataset of body instability in floodwaters; conduct in-depth studies on the influence of body posture adjustment on flood hazard degree. Besides, it is necessary to promote the application of human instability criteria in the field of urban flooding disaster prevention and reduction, in order to minimize the disadvantageous impacts of urban flood disasters. [ABSTRACT FROM AUTHOR]

As the melting of Arctic Sea ice because of global warming creates new shipping routes and energy resources, the post-Cold War peace and stability of the Arctic has been shattered. It has once again become a strategic location for multinational rivalries, attracting widespread attention in international geopolitical circles. Compared to other regions of the world, studying the Arctic region from a Western geopolitical perspective is at the forefront of international research. Although China, as a near-Arctic country, has developed geopolitical research on the Arctic in response to its practical needs, domestic research in this field started late, with room for improvement in its breadth and depth. Therefore, 98 papers in the Web of Science core database that are highly relevant to Arctic geopolitics are selected as the object of the study. Through a literature review, we summarize the development of Arctic research from a Western geopolitical perspective, and the shift in perspective and hot topics; we adopt a forward-looking perspective of future research development trends to provide reference for innovative research in this field in China. The results reveal the following: (1) Research on the geopolitics of the Arctic has been conducted in a wide range of fields and topics in Western academia, with some correlation among the topics, although the links among the studies are not strong, and the research scale generally shows a fluctuating growth trend. (2) The research content, composed of six major fields (boundary and territorial politics, Arctic shipping routes, Arctic resource development, Arctic geo-strategy, Arctic security and governance, and indigenous population issues), focus on politics and economics but is lack of cultural research. (3) Under the influence of aesthetic humanism and the "cultural and institutional turn," the trend in the cross-fertilization of geopolitical, geo-economic, and geo-cultural perspectives has increasingly become more obvious. (4) Research on the Arctic from a geopolitical perspective has been relatively fruitful, although there remain shortcomings in the depth of theoretical research, breadth of research scale, diversity of research methods, and geo-economic and geo-cultural research paradigms, which require further development. Future research will generate new ideas and directions in immaterial areas such as theoretical framework studies, interdisciplinary studies, and emotional culture, and will focus more on the role of multiple actors, such as indigenous peoples and NGOs, in geopolitical knowledge production and power competition. [ABSTRACT FROM AUTHOR]

Under the background of climate change and water shortage, the study on the change of vegetation ecological water demand in the middle and lower reaches of Shule Riverbasin is of great significance for water resources allocation, ecosystem balance and sustainable development of Shule River oasis. In this paper, the area quota method and the phreatic evaporation method were adopted to calculate and analyze the temporal and spatial variation trend during the vegetation growth period（April-October） in the middle and lower reaches of Shule River basin from 1980 to 2018. The results show that the average annual ecological water demand of grassland（640 million m³） is higher than that of woodland（50 million m³） in the study area. On the annual, the total ecological water demand of vegetation fluctuated and increased with the change rate of 4 million m3/10 a, among which, the ecological water demand of grassland is increased（7 million m³/10 a） and the ecological water demand of forest is decreased（4 million m³/10 a). During the growing period, the vegetation water demand accounts for 63% of the total amount from April to July, reaches to the maximum value of 138 million m³ in July and gradually decreases from July to October. Spatially, the total water demand in the middle reaches is slightly higher than that of in the lower reaches, among which the ecological water demand of forest land is greater than that in the lower reaches and the water demand of grassland is basically the same as that in the lower reaches. [ABSTRACT FROM AUTHOR]

As a primary tool in climate change research at the watershed scale, the role of horizontal resolution in regional climate simulations needs to be evaluated. This paper investigates the role over the Huang-Huai-Hai (HHH) River basin using a regional climate model, RegCM4, coupled with the National Center for Atmospheric Research (NCAR) Community Land Model, version 4.5 (CLM4.5) including the modules of CN and DV (RCM_CLM4.5). The model is driven by ERA-Interim reanalysis data, and the time period is 1990—2010. Model validation shows that RCM_CLM4. 5 at 50 km and 25 km resolutions can reproduce the present climate well, including the spatial distribution of winter and summer mean temperature and precipitation, the annual cycles of temperature and precipitation, and the climate extremes. However, some biases can also be found. For example, compared with the observation, cold and warm biases are found in the winter and summer mean temperature, respectively; wet biases are found in the precipitation. Comparison between the two simulations, better performance of the magnitude and spatial distribution of mean temperature is found in the simulation at 25 km resolution; while for precipitation, better performance is observed in the one at 50 km resolution; little difference is found for the climate extremes. In general, results from this study indicate a very low sensitivity of present climate in this region to model resolution and can provide a reference for the application of this model in future climate change research over the HHH River basin. [ABSTRACT FROM AUTHOR]

The Yellow River is the mother river of China and the cradle of Chinese culture. The social-economic development of the entire Yellow River basin and the whole country is closely related to the changes in the water resources of the Yellow River. This study tries to disentangle the driving factors of the change in the Yellow River runoff across different reaches and in different periods of time. Using the restored natural runoff data, observed runoff data, rainfall data and potential evapotranspiration data of four typical hydrological stations of Lanzhou, Toudaoguai, Huayuankou and Lijin on the main stream of the Yellow River from 1960 to 2010, this paper analyzed the attribution of the change of the main stream of the Yellow River by using double mass curve and sensitivity coefficient methods based on the Budyko framework. The results show that human activities are the main reason for the significant decline of the Yellow River runoff after 1989 mid their contribution rate to the Yellow River runoff is more than 85%·, while the contribution rate of climate change is less than 15%, and the further downstream, the higher the contribution rate of human activities. In short, the climate change impact of the annual runoff is more prominent in the upstream than that of in the middle mid lower reaches. Finally, it discussed the theoretical and practical issues of the hydrological effects of climate change and human activities. [ABSTRACT FROM AUTHOR]

This paper is based on the meteorological observation data of the five meteorological stations (Shiquanhe, Gerze, Xianza, Bangoin and Amdo) near Qiangtang National Nature Reserve, the climate of Qiangtang National Nature Reserve from 1960 to 1990 and the estimated grid data in the future issued by IPCC5. The Miami model, Thornthwaite Memorial model, and tendency rate were used. The statistical analysis methods were used to study the spatiotemporal evolution of Net Primary Productivity in Qiangtang National Nature Reserve and its response to climate change. The results showed that: (1) the average annual temperature decreases from the west to the east, and the annual precipitation increases from the west to the east. The annual mean temperature(T) showed a significant increasing trend, while the annual precipitation(R) and annual evapotranspiration(E) showed a slight increasing trend. NPP of Temperature(NPPt) and NPP of precipitation(NPPr) showed a slight increasing trend at all stations, and NPP of evapotranspiration(NPPe) and standard NPP(NPPb) showed a slight increasing trend at most stations. (2) NPPt gradually decreased from the west to the east, NPPr gradually increased from the west to the east, NPPe and NPPb first increased and then decreased from the west to the east. The limiting factor of NPP was precipitation in Shiquanhe station and Gerze station, evapotranspiration in Xianza station and Bangoin station, and evapotranspiration or air temperature in Amdo station. (3) The NPPt, NPPr, NPPe and NPPb in different periods of the 21st century were significantly higher than those in all periods of the 20th century. The NPPt, NPPr, NPPe and NPPb were significantly increased in the future under different emission scenarios compared with those from 1960 to 1990. Under the trend of "warming and wetness" in the past 48 years and in the future, the NPP of vegetation increased, and the increase was larger in the cold and humid area in the southeast, but less in the cold and arid area in the northwest. The future climate is conducive to the improvement of local vegetation NPP and the improvement of local ecological environment. Assessing the possible impact of future climate change on the ecological environment of Qiangtang Plateau. The results not only provide a basic method for studying the Net Primary Productivity of vegetation in no man's land at regional scale, but also have important reference value for estimating ecological security research and ecological function planning. [ABSTRACT FROM AUTHOR]