Forest ecosystem, as a predominant component of terrestrial ecosystem carbon sinks, has a high potential for carbon sequestration. Accurate estimation of the carbon sequestration rate in forest ecosystems at provincial level is a prerequisite and foundation for scientifically formulating the technical approaches of carbon neutrality and associated regulatory policies. However, research on future carbon sequestration rates (CSRs) for forest ecosystems for provincial-level regions (hereafter province) in China has rarely been reported. This paper quantitatively assesses the carbon sequestration rates of existing forest ecosystems of all the provinces from 2010 to 2060 using the Forest Carbon Sequestration model (FCS), in combination with large quantities of measured data in China under three future climate scenarios (RCP2.6, RCP4.5, and RCP8.5). Results showed that CSRs across provinces varied from 0.01Tg C/a to 36.74 Tg C/a, with a mean of (10.09±0.43) Tg C/a. There are apparent inter-provincial differences in view of forest CSRs. In terms of the spatial variations in CSRs on unit area basis within provinces, the eastern region has larger capacity to sequestration than the western region, while the western region has greater CSR per unit GDP and per capita. Moreover, there are significant negative correlations between the CSRs per capita in each province and the corresponding GDP per capita, under an assumption that GDP per capita is constant across provinces. In summary, there is a significant regional imbalance of the CSR among provinces, and major technical and policy changes are needed to realize their carbon sink potential sustainably. In view of the overlap between China's poor areas and high ecological carbon sink areas, it is indicated that the existing policies to support the traditional carbon trading are far from sufficient. It is urgent to take China's regulatory measures such as "regional carbon compensation" in line with the Chinese characteristics, so that people in western or underdeveloped regions can voluntarily/consciously strengthen forest protection and enhance forest carbon sinks on the basis of ensuring coordinated regional development, thus China's forests can play a greater role in carbon neutrality strategies.

Six vegetation dynamic models, provided by the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), are selected and verified for net primary productivity (NPP) in China based on remote sensing retrials. Then the goodness of fit of each model is used as the weight to synthesize a new sequence to estimate the future change pattern of China's NPP under the RCP2.6 and RCP6.0 scenarios. This study aims to solve inaccuracy of the estimation on the change pattern of China's NPP due to differences in data and methods. The results show that the single model has a poor fitting effect on NPP in most regions of China (R² < 0.4), the average NPP is 33%-97% higher than the remotely sensed value, but it can well reflect the decreasing trend from southeast to northwest China. The overall goodness of fit of the proposed NPP data is 0.85, and the goodness of fit in most vegetation zones is basically greater than 0.3. In the future 30 years, China's average NPP will continue to decrease from southeast to northwest, and the average value will show a fluctuating growth, which is expected to reach 8.8 μg/(m² s) in 2035 and 9.7 μg/(m² s) in 2050. With the elaspe of time, the main growth area under the RCP2.6 scenario will shift from southern to northern China. This is reflected in the fact that NPP in north China will increase significantly at a rate greater than 0.15 μg/(m² s) per year, but the growth rate will slow down and the area of significant growth will decrease in the southwestern and central-south regions. Under the RCP6.0 scenario, the main growth areas will retreat to the northeastern, southeastern and western regions, and the growth in the central and eastern regions will become insignificant. The high emission scenario will promote the growth of NPP before 2035 and inhibit the growth after 2035. The NPP will be extremely distributed under the RCP 6.0 scenario. For instance, the alpine desert grassland, temperate desert, shrub and semi-shrub desert in the northwest of Qinghai-Tibet Plateau will grow slowly or even stop growing.

Regionalization, spatiotemporal differentiation and uncertainty are featured in the process of humanistic-natural interaction in Chinese mountain areas, making them typical mountainous transitional geospace (MTGs). Quantitative identification of MTGs types and consequent differentiation characteristics analysis can build a solid decision-making foundation for high-quality development of land space in mountainous areas under the background of rural revitalization strategy of China. This study introduced a spatiotemporal variability index based on the concept of geographic uncertainty, which was designed to work out identification, delineation and division of MTGs, and then it used the Geodetector to analyze the driving factors spectrum of the geographic spatiotemporal variability in each division of MTGs. It concludes the following points: (1) The total area of MTGs was 238.32×10⁴ km² (about 1/4 of the land surface area of China), with MTGs variability index in a decreasing trend from the First Gradient Terrain to the Third Gradient Terrain of China. (2) MTGs in China could be divided into 12 segmentations, of which the area of the Kunlun-Qilian Mountains subzone is the largest. (3) Humanistic driving factors had the strongest analytical power on spatiotemporal variability of population density and land-use intensity. The analytical power of the basic topographic variables, such as DEM, DEM_Relief, DEM_Slope and Topography index, had significant analytical effect on the spatiotemporal variability of vegetation coverage (NDVI) and MTGs geographic uncertainty, and the analytical driving force of altitude and night lighting brightness was the strongest among all the driving factors. (4) Generally, the spatiotemporal dynamics of human factors, such as the time variations and the spatial heterogeneities of humanistic geographical features, had a significant shaping effect on MTGs in the southeastern China, whereas in the northwestern China MTGs was mainly driven by the temporal variations of natural geographical features and the spatial heterogeneities of humanistic geographical features. This research provides an insight for quantitative analysis of geographical uncertainty and diversity in MTGs of China, and reveals the regionality of the human-nature interaction.

Research on the spatiotemporal correlation between the intensity of human activities and the temperature of earth surfaces is of great significance in many aspects, including fully understanding the causes and mechanisms of climate change, actively adapting to climate change, pursuing rational development, and protecting the ecological environment. The north slope of Tianshan Mountains, located in the arid area of northwestern China, is a typical area that is extremely sensitive to climate change. This paper takes the area as an example to retrieve the surface temperature of the mountain based on MODIS data, characterized by the effect of the intensity of human activities on the night light, population distribution and land use. The evolution characteristics of human activity intensity and surface temperature in the study area from 2000 to 2018 were analyzed, and the spatiotemporal correlation between them was further explored. It is found that: (1) The average human activity intensity (0.11) has kept relatively low since the beginning of the 21st century, and it has been slowly rising in a stepwise manner (0.0024 a^-1); in addition, the increase in human activity intensity has lagged behind that in construction land and population by 1-2 years. (2) The annual average surface temperature in the area is 7.18 ℃ with an obvious growth. The rate of change (0.02 ℃·a^-1) is about 2.33 times that of the world. The striking boost in spring (0.068 ℃·a^-1) contributes the most to the overall warming trend. Spatially, the surface temperature is low in the south and high in the north, due to the prominent influence of the underlying surface characteristics, such as elevation and vegetation coverage. (3) The intensity of human activity and the surface temperature are remarkably positively correlated in the areas with intense human activity, showing a strong distribution pattern in the east section and a weak one in the west section. The expression of its spatial differentiation and correlation is comprehensively affected by such factors as scopes of human activities, manifestations, and land-use changes. Vegetation-related human interventions, such as farming and forestry planting, urban greening, and afforestation, can effectively mitigate the surface warming caused by human activities. This study not only puts forward new ideas to finely portray the intensity of human activities, but also offers a scientific reference for regional human-land coordination and overall development.

The capitalization of ecological resources and ecological asset is an important way to realize the transformation to "Lucid Waters and Lush Mountains are Invaluable Assets". The accounting of ecological asset and its gains and losses is conducive to the effective protection, scientific management and sustainable utilization of the ecosystem. Based on relevant domestic and foreign research on ecological asset, this paper developed a technical accounting system of ecological asset and its gains and losses at the county level, analyzed the spatial and temporal variations of ecological asset in China from 1990 to 2018, and then identified the influencing factors which caused the gains and losses of ecological asset. The optimization and promotion paths were finally proposed for counties with different types of ecological resources, gain and loss status and varied driving factors. The results showed that about 45% and 37% of counties were dominated by farmland and forest ecological resources, respectively. From 1990 to 2018, the quality of county-level ecological stock asset showed an increasing trend with fluctuation, while the change trend of ecological flow asset was significantly different, showing decreased water conservation volume in nearly 70% of the counties. The number of counties with the gains and losses of ecological flow asset accounted for approximately 44% and 37%, respectively. The spatial distribution of the gains and losses of ecological flow asset showed the same segmentation characteristics as "Hu Line", that is, the counties in the vastness of northwest China experienced significant gains, while decreases were widespread in eastern and southern China. Over the study period, the change of ecological asset in more than 70% of the counties in China was driven by climate change and human activities. The average impact degree of human activities affecting the gains of ecological asset in counties was about 80%, while that of climate change affecting the losses of ecological asset in counties was about 60%. Through comprehensive analyses, counties in China can be classified into five types, which consist of climate change mitigation, climate change adaptation, ecological resources restoration, ecological resources protection, and ecological resources management. And differentiated optimization and promotion paths can be adopted to achieve the gains of ecological asset.

Key ecological functional zones provide continuous ecosystem services and play an indispensable role in ensuring national ecological security and social sustainable development. From the perspective of ecosystem service trade-off and synergy, this paper discusses and analyzes the protection characteristics of key ecological functional areas. The data includes multi-source datasets such as ecosystem types, meteorological data, elevation data and soil data from 2000 to 2019. Methods of the dynamic degree of ecological spatial change, ecosystem service model and partial correlation coefficient were used for evaluation and analysis. This research selects the Qinling-Daba (Qinba) Mountains region with high similarity of natural and geographical conditions as the reference unit, takes ecosystem supply services and regulation services as the core content, and analyzes the trade-off and synergy relationship of ecosystem services based on the quantitative analysis of the characteristics of ecological spatial changes from 2000 to 2019. The results showed that the ecological status of the study area gradually improved, and the ecosystem tended to be stable after the delimitation of key ecological functional zones. The service capacity of key ecological functional zones is gradually increasing, and the average net primary productivity, total soil conservation and total water conservation are higher than those outside the key ecological functional zones by 25.95 gC/m², 5.81×10⁸ t and 24.95×10⁸ m³, respectively. The synergy between soil conservation services and ecosystem supply services was positively correlated with the improvement of ecological status. Due to the impact of precipitation, the synergistic relationship between water conservation services and ecosystem supply services after 2010 became worse. Overall, the designation of key ecological functional areas in the Qinba Mountains has driven the "quantitative growth" of regional ecological space and the "qualitative improvement" of ecosystem services. However, the "synergy" of the relationship between ecosystem services is not obvious, and even changed to "trade-off", which requires the country to make more targeted ecosystem protection and management decisions in the future, and improve the overall benefits of ecosystem and support the sustainable supply of regional ecosystem services.

As a major climate forcing factor, CO₂ is closely related to human activities, but many studies have overlooked the carbon absorption of terrestrial ecosystem to anthropogenic carbon emissions. China, the United States, Russia and Canada are the four countries with the largest area in the world at different socio-economic development stages. Quantifying the global radiative forcing contribution of CO₂ emissions is important for assessing the climate effects of human and natural factors. Based on CO₂ assimilation data, this study used a "carbon-climate" parameterization scheme to analyze the anthropogenic carbon emissions and its climatic effects while considering the climate effects of carbon sinks of terrestrial ecosystem. Then we obtained the net global radiative forcing contributions of the four countries. The results showed that the anthropogenic emissions of CO₂ in all the four countries showed a significant increase (0.125 Pg C a ^-1). Meanwhile the carbon uptake of terrestrial ecosystems increased at a growth rate of 0.003 Pg C a ^-1. During the study period, the total anthropogenic carbon emissions of China and the United States accounted for 87.19% of the four countries while Russian terrestrial ecosystems had the strongest carbon absorption capacity, 14.69 Pg C. Correspondingly, as of 2016, the cooling effect of terrestrial ecosystems is -0.013 W m ^-2, which can offset 45.06% of the whole warming effects of anthropogenic carbon emissions, indicating that if the terrestrial ecosystems are not considered, the warming effect of anthropogenic carbon emissions will be significantly overestimated. Overall, the total anthropogenic carbon emissions of the four countries contributed 0.32 and 0.42 W m ^-2 of global radiative forcing, respectively, relative to the CO₂ concentration levels before 2000 (initial year of this study) and before the Industrial Revolution. This study further explored the linear relationship between air temperature and radiative forcing. Compared with a single climate effect of anthropogenic or natural carbon emissions, the combined radiation forcing and the temperature change in the corresponding period had the highest consistency (30.3%).

Glaciers provide essential resources and services for human well-being and socio-economic development in arid regions, and estimation on service value of glaciers and its spatiotemporal characteristics are vital for socio-economic sustainable development and environmental protection. Based on the first and second glacier inventories, this research firstly constructed an assessment system of glacier service value. The glacier service value and its variation with time and space were then estimated by combining the unit area service price method, equivalent factor method and glacier service change index. The total glacier service value in the Qilian Mountains for 2016 was 24354 million yuan. The main parts were climate regulation and runoff regulation, which occupied 60.58% and 33.14% of the total value, respectively. The minor parts were freshwater supply and hydropower, which contributed 3.47% and 1.75% to the total, respectively. The service value of the rest parts was about 259 million yuan. For glacier service value of the watersheds in the Qilian Mountains, Shule River ranked first with 7771 million yuan, or 31.91%, followed by Haerteng River with 4321 million yuan (17.74%) and Beida River with 3281 million yuan (13.47%). From an administrative perspective, the glacier service value of the Qilian Mountains in Qinghai province was 1138 million yuan higher than that of Gansu province. For Qinghai, Haixi Mongolian Tibetan Autonomous Prefecture had the highest glacier service value with 11124 million yuan, accounting for 45.68%. For Gansu, the correspondent value was Jiuquan with 7758 million yuan, or 31.86%. During the period of 1956-2010, the loss of glacier service value in the Qilian Mountains increased faster from west to east, reaching 435 million yuan. This suggested that the change of glacier service value in the study region showed an obvious longitudinal and zonal differentiation.

The individual exposure level of fine particulate matter (PM_2.5) is a key issue in the study of health effects. However, the lack of historical data and the small coverage of ground monitoring stations have hindered the development of related research. Based on the aerosol optical depth (AOD) provided by NASA remote sensing data, multi-source data such as ground monitoring and meteorological data were integrated for modeling to estimate near-ground PM_2.5 concentration. The results have wide spatial coverage, strong time continuity and low method cost. Based on the Beijing-Tianjin-Hebei-Shandong region in 2018, this paper introduces 50 features such as meteorological elements, NDVI, time nodes and spatial markers to analyze the relationship between AOD and PM_2.5. In view of the information loss caused by the single traditional interpolation method, the spatiotemporal multi-view interpolation method is used to improve the accuracy and coverage of interpolation. Considering the complex relationship caused by hysteresis of features, and the correlation and partial correlation between features, this paper uses a distributed perception deep neural network model (DP-DNN) to separately capture higher-order features between multiple-source features. The results show that: (1) The relative error of the spatiotemporal multi-view interpolation method is 27.5%, and the average proportion of missing data decreases from 52.1% to 4.84%. (2) In terms of time prediction, mean absolute error, relative error, mean square error and root mean square error of DP-DNN are 7.7 μg/m ³, 46.8%, 766.2 μg ²/m ⁶ and 26.9 μg/m ³, respectively. In terms of space prediction, they are 16.6 μg/m ³, 41.8%, 691.5 μg ²/m ⁶ and 26.6 μg/m ³, respectively. In aspects of accuracy, robustness, generalization ability and time consuming, the results are superior to linear statistical models and common deep learning architecture.

The global environment issue resulting from carbon emissions has aroused worldwide concern for governments, the public and scientific communities. A precise measurement of the time-resolved and spatial distribution characteristics of carbon dioxide (CO₂) and carbon footprint as well as its long-period evolution mechanism, can help clarify the relationship between environmental carbon load and economic growth, and are critical references to the formulation of scientific carbon emission reduction targets with reasonable and differential emission reduction policies. In this study, the mainland of China is taken as the research object. According to the quantitative correlations between DMSP-OLS nighttime light image data and carbon emission statistics, the carbon emission panel data model was simulated for China's carbon emissions in the period 2000-2013, and then the spatiotemporal evolving trend and spatial distribution characteristics of carbon emissions in the 14-year research period were discussed using Theil-Sen Median trend analysis and Mann-Kendall test method. Based on the framework of exploratory spatial-temporal data analysis (ESTDA), the spatial pattern and spatiotemporal dynamic evolution of carbon footprint from 2001 to 2013 were analyzed from the perspective of spatiotemporal interaction. In the three periods, the decoupling effect between environmental carbon load and economic growth of 336 prefecture-level cities were analyzed using the improved Tapio decoupling model. The results show that the overall carbon emissions in China had been on the rise from 2000 to 2013, in which the stable-slow rise type was dominant. China's carbon footprint and carbon deficit increased year by year, and the central and western regions became the focus of the growth of carbon footprint and carbon deficit from 2001 to 2013. At different administrative city scales, the spatial distribution pattern of carbon footprint and carbon deficit show obvious administrative orientated and spatial zonal differentiation characteristics. The annual average of global Moran's I index of each level unit is 0.491, which indicates that there is a significant spatial auto-correlation feature in the carbon footprint of China's prefecture-level units. The relative length of the LISA time path is greater in the north than in the south, and it tends to increase from the coastal areas to the central and western regions. The curvature of LISA time path decreases from coastal areas to inland areas on the whole. The curvature of northeast and central regions is higher, while that of eastern and western regions is lower. There is a different trend of the decoupling effect of environmental carbon load in China. Meanwhile the expansion-connection and expansion of negative decoupling regions continuously increased and spatially agglomerated, presenting an "E"-shaped distribution pattern from the north to the south. The national average decoupling elastic value is gradually increasing, while the coefficient of variation continues to decline, and the decoupling type has a significant evolution trend. Therefore, the unbalanced trend of economic growth and carbon emissions in China will continue for a certain period.

Forest ecosystems play important roles in provisioning and regulating services. In China, forest ecosystems have been facing problems such as poor quality, simple structures, and weak ecological functions. Scientific, reasonable, and applicable forest management strategies are concerned with optimizing the structure of forests, achieving sustainable development, and promoting ecological functions while meeting production requirements. Therefore, a coupling path of the ecosystem progress model (PnET-II) and landscape model (LANDIS-II) were used to simulate dynamic changes in the area and aboveground biomass (AGB) of the plantations over the next 100 years, considering from the initial year (2009). The variables of the designed factorial experiment were cut-block size, cutting area ratio, as the initial year cutting age and cutting frequencies. It was found that the cutting age and cut-block size had limited impacts on the forest area, although they affected the levels of AGB. Both the cutting area ratio and cutting frequency, however, had significant impacts on forest area and AGB. Moreover, the cutting area ratio was a crucial variable with the greatest influence on forests among the four variables. The management strategy of a harvest scenario with a 20% cutting area ratio, 5 ha cut-block size and 10-year cutting frequency on 21-year-old Chinese fir, 26-year-old pine and 41-year-old broad-leaved forests provided the optimal results among all the tested scenarios. This ensured that the AGB of the forest remained relatively stable during the simulation. Therefore, it is an effective way to maintain the ecological functions of artificial forests while producing wood.

Ecosystem services play an important role in regional ecological balance, ecosystem health, land and ecological security, and global climate change. The response characteristics of scale and the spatial differentiation mechanism of the ecological service value are worth discussing. Taking the Dabie Mountain area located in central China as the research object, based on the data of land use classification, this paper applied the methods of spatial statistics, hot spot analysis and geographical detector to examine the dynamic evolution characteristics, scale effect and spatial differentiation mechanism of the ecological service value of Dabie Mountain area from 1970 to 2015. The results show that over the 50 years, the overall value of ecological services in the Dabie Mountain area increased by 951 million yuan, while in recent years it decreased by 395 million yuan, accounting for 41.54% of the total value added. Scale is helpful for understanding the pattern and process of ecosystem. To strengthen the study of scale characteristics in the evaluation of ecosystem service function can improve the objectivity, credibility and practicability of the evaluation results. Therefore, in this paper, we made a comparative analysis through the scale of four types, which includes 9-level amplitude. The results show that the unit scale of township is the characteristic scale of the spatial differentiation of ecological service value in Dabie Mountain area, and the spatial difference information of the ecological service value at the township unit scale is rich, and the type of township unit scale is a more appropriate research scale level in the study area. To strengthen the geographical exploration of the spatial differentiation of ecosystem service value will be helpful to carry out regional ecological planning and ecosystem regulation. In this study, we analyzed the spatial differentiation mechanism of ecosystem service value in Dabie Mountain area by using the geographical detector. The results show that the explanatory power q value of the ecological land use proportion, land use degree and human influence composite index among the 16 influencing factors contributing to the spatial differentiation of ecological service value is nearly 40%, which is the main reason for the spatial differentiation. Elevation and slope factor q value is nearly 30%, which is a secondary factor. There are mainly three categories and 30 types of interaction combinations with an interactive detection q value of more than 50%. The interaction and synergistic effects of natural factors, human disturbance factors and landscape pattern factors enhance the explanatory power of spatial differentiation of ecological service value. Our work may provide a theoretical basis for the precise and diversified regulation of ecosystem functions in Dabie Mountain area.

The sustainable supply of ecosystem services is the basis of the sustainable development. Human beings satisfy the demand and improve their own well-being through the consumption of ecosystem services. It is of great significance for the management of regional ecosystems and the effective allocation of resources to study the demand and consumption of ecosystem services and to analyze the supply and demand characteristics of ecosystem services and their spatial trade-offs. Based on the multi-source data such as land cover, meteorological observation and statistical yearbook in Lanzhou in 2017, the spatial analysis tools including InVEST model, ArcGIS and GeoDA were used to calculate the supply and demand of water yield, food supply, carbon storage and soil conservation. The supply and demand matching of ecosystem services in the study area was analyzed and evaluated. The results show that: (1) The supply and demand of ecosystem services have obvious spatial heterogeneity. The total supply of services is greater than the total demand, but there are differences between different sub-regions and different kinds of ecosystem services. (2) The supply-demand ratio of comprehensive ecosystem services is 0.039. There are differences in supply-demand matching of different kinds of ecosystem services: water yield service (0.098) > carbon storage service (0.066) > food supply service (0.030) > soil conservation service (0.001), and there are significant differences in supply-demand matching between urban and rural areas. (3) There are different kinds of spatial matching pattern between supply and demand of ecosystem services, including "high-high spatial matching", "low-low spatial matching", "high-low spatial dislocation" and "low-high spatial dislocation". (4) There are obvious synergic effects in the balance of supply and demand of services in Lanzhou, which are "high-high synergy" and "low-low synergy".