The transpiration-to-evapotranspiration ratio (T/ET) is a crucial indicator of the carbon-water cycle and energy balance. Despite the marked seasonality of warming and greening patterns, the differential responses of T/ET to environmental changes across the seasons remain unclear. To address this, we employed a model-data fusion method, integrating the Priestley-Taylor Jet Propulsion Lab model with observational datasets, to analyze the seasonal trends of T/ET in China’s terrestrial ecosystems from 1981 to 2021. The results showed that T/ET significantly increased in spring, summer, and autumn, with growth rates of 0.0018 a^-1 (p<0.01), 0.0024 a^-1 (p<0.01), and 0.0013 a^-1 (p<0.01), respectively, whereas the winter trends remained statistically insignificant throughout the study period. Leaf area index dynamics were identified as the primary driver of the increase in T/ET during summer, accounting for 79% of the trend. By contrast, climate change was the main contributor to the rising T/ET trends in spring and autumn, accounting for 72% and 77% of the T/ET increase, respectively. Additionally, warming is pivotal for climate-driven changes in T/ET trends. This study elucidated seasonal variations in T/ET responses to environmental factors, offering critical insights for the sustainable management of ecosystems and accurate prediction of future environmental change impacts.

Exploring the spatial heterogeneity of ecosystem services (ESs) and their driving factors under various interaction patterns is essential for informing sustainable development policies. Using Northeast China as a case study, this research investigates eight key ESs, including water yield (WY), carbon storage (CS), food provision (FP), habitat quality (HQ), soil conservation (SC), wind-break and sand-fixation (WS), water purification (WP) and aesthetic landscape (AL). The study examines the complexity of ESs from three dimensions: individual ES, ES pairs and ES bundles, and further evaluates their spatial heterogeneity and socio- ecological drivers. The results indicate that the spatial distribution of ESs remained relatively stable from 2000 to 2020. During this period, WY and FP increased significantly, CS and HQ remained relatively unchanged. SC, WS and AL followed an “increase-decrease-increase” trend, and WP exhibited a “decrease-increase” fluctuation. Overall, synergistic relationships among ES Pairs were more prevalent than trade-offs. Notably, CS showed trade-offs with over 70% of the other ESs, while HQ exhibited trade-offs with SC, WS, WP, and AL. The FP-HQ synergy bundle, primarily located in the Greater Hinggan Mountains and eastern regions, emerged as the dominant ES bundle. Ecological factors—such as solar radiation, temperature, slope, DEM, and NDVI—exerted a stronger influence on ES patterns than social factors like GDP and population density. Furthermore, these ecological drivers had a greater impact on individual ESs compared to ES pairs or ES bundles. These findings offer valuable insights for policymakers to understand the complex interrelationships among ESs and to design more effective and regionally tailored management strategies.

The application of ecosystem services (ES) theories in land consolidation is a confusing issue that has long plagued scholars and government officials. As the upgraded version of traditional land consolidation, comprehensive land consolidation (CLC) emphasizes ecological benefits, but it does not achieve the expected effect during the pilot phase. This study first proposed a theoretical analysis framework based on ES knowledge to answer the three key questions of why, where, and how to implement CLC better. Taking mountainous counties as the study area, we found that ES trade-offs/synergies, bundles, and drivers were significantly affected by scale effects. ES knowledge can play a crucial role in designing multi-scale CLC strategies regarding the objective, zoning, intensity, and mode. Specifically, mitigating the significant trade-offs between recreational opportunities, food production, and other ES is the top priority of CLC. Land consolidation zoning based on the ES bundles analysis is more rational and can provide the scientific premise for designing locally adapted CLC measures. Land consolidation can be classified into high-intensity direct intervention and low-intensity indirect intervention modes, based on the major drivers of ES. These findings help narrow the gap between ES and CLC practices.

Ecosystem services in urban agglomerations are the environmental conditions under which human survival and development are sustained. Quantitative assessment of ecosystem services and complex interactions can contribute positively to the achievement of the Sustainable Development Goals (SDGs) for urban agglomerations. However, studies on the future contribution of multi-scenario ecosystem services to the SDGS are lacking. We propose novel integrated modeling framework that integrates the CLUES, InVEST, SOM, and GWR approaches to address the complex relationship between ecosystem services over a long “past-present-future” time series. We construct a novel ecosystem service bundle-based approach for measuring urban agglomerations progress towards achieving ecologically relevant sustainable development goals at multiple scales. In the future scenario, the water yield (WY), habitat quality (HQ), and soil conservation (SC) show similar spatial patterns, with comparable spatial grids, while carbon stock (CS) remains predominantly unchanged and the ecological protection scenario (EPS) improves more significantly. The high-synergy regions are mainly distributed in bundle 4, and most of the trade-off regions appear in bundles 1 and 2. Over the last 30 years, all but the water-related SDGs are declining in bundle 1 of the two urban agglomerations, which are 15% higher in the Guangxi Beibu Gulf (GBG) than in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA). From 2020 to 2035, the three scenarios demonstrate that the optimization of the SDGs progresses most effectively under the future ecological protection scenario (EPS). In particular, bundles 3 and 4 are significantly improved. This critical new knowledge can be used in sustainable ecosystem management and decision-making in urban agglomerations.

Situated in the semi-arid regions of North China, the Nihewan Basin documents the fluvio-lacustrine sequence and Pleistocene archaeological sites, offering an excellent opportunity to investigate human adaptation to environmental change in East Asia, especially in North China. However, paleoenvironmental datasets from Middle Pleistocene archaeological sites are not fully understood. Focusing on the evidence from the 0.63-0.49 Ma-old site of Jijiazhuang (Nihewan Basin, North China), this paper presents the results of various environmental indicators from the site context. Moreover, it explores the links between hominin behavioral adaptations and ecological variability during the extra-long interglacial period in North China. Sedimentological features of the excavated section indicate that the site was formed in the margin of the Nihewan paleolake. Based on well-constructed pollen, sediment grain size, color reflectance, and major geochemical element analyses, five stages of environmental changes were identified during site formation. This study indicates that hominins occupied the site at the early part of Stage 2, when the Nihewan paleolake had a relatively low water level and the climate was temperate, with strong weathering intensity dominated by wooded grassland landscapes. In conclusion, the results suggest that the extra-long duration of interglacial or mild stadial climate events (MISs 15-13) in the Northern Hemisphere may have provided favorable conditions for increased technological innovations and adaptive strategies among Middle Pleistocene hominins in the Nihewan Basin even in North China.

Uncovering the evolution process of rural revitalization level (RRL) in China and elucidating the complex driving mechanism hold significant implications for implementing rural revitalization strategy and advancing rural modernization. This study analyzes the spatio-temporal evolution of China’s RRL from 2002 to 2022 and reveals its complex driving mechanism. The results show that China’s RRL steadily increased from 0.1083 to 0.4463, and the provincial RRL exhibited the characteristic of decreasing successively in the eastern region, the central region, and the western region. The overall differences of RRL are shrinking, and intra-group differences contribute almost 1/3 of the overall variation, more than the contribution of inter-group differences. Although the influencing factors show nonlinear characteristics, on the whole, economic level and human capital exhibit positive effects, while relief degree, urbanization, industrialization, and opening degree exhibit negative effects. Farmland resources and investment intensity exhibit the characteristics of positive effect and negative effect equilibrium. At the regional scale, influencing factors exhibit significant spatio-temporal heterogeneity. In the future, to achieve comprehensive rural revitalization, it is vital to implement systemic policy measures, such as enhancing industrial competitiveness, supplementing rural talents, and optimizing the relations between urban and rural areas as well as between industry and agriculture.

Understanding the evolutionary trends and driving factors behind extreme hourly precipitation (EHP) in typical urban agglomerations is crucial for predicting and preventing rapid floods. We collected hourly precipitation datasets from 31 observation stations in the Central Yunnan Urban Agglomeration (CYA) spanning from 2004 to 2020. Urban and rural observations were dynamically classified based on impervious surface fraction. Linear (Granger) and nonlinear causal methods(convergent cross-mapping and Liang-Kleeman information flow) were used to identify the causal impact mechanisms of large-scale circulation, environment and urbanization on EHP. Moreover, geo-detector further reveals the spatial influence of these factors and their interactions on EHP. Our findings revealed that EHP mainly occurred in the afternoon and at midnight. Also, the frequency and intensity of EHP in the CYA significantly (p≤0.05) increased from 2004 to 2020, especially in urban areas. The increasing rate in urban areas was higher than that in rural areas. However, the duration of EHP/hourly total precipitation exhibited a significant/nonsignificant decreasing trend with no significant difference between urban and rural areas. Causality tests and geo-detector indicated that EHP was impacted by natural variability and urbanization. Large-scale circulation indices such as the Pacific Decadal Oscillation, El Niño-Southern Oscillation, and Indian Ocean Dipole nonlinearly influenced EHP. Additionally, urban landscape layout, vegetation, and population variation may strengthen EHP by changing environmental factors such as temperature and relative humidity. Interactions exist between these factors and influence EHP, although large-scale circulation remains the dominant influence. With global climate warming and rapid urbanization in the CYA, the frequency and intensity of EHP may further amplify in the future.

Regular quantitative assessments of regional ecological environment quality (EEQ) and driving force analyses are highly important for environmental protection and sustainable development. Northern China is a typical climate-sensitive and ecologically vulnerable area, however, the changes in EEQ in this region and their underlying causes remain unclear. Traditional evaluations of EEQ rely primarily on the remote sensing ecological index (RSEI), which lacks assessments of indicators such as greenness (NDVI), humidity (WET), heat (LST), and dryness (NDBSI). To address these issues, this study employs the principal component analysis method and the Google Earth Engine to construct an RSEI suitable for long-term and large-scale applications and analyzes the spatio-temporal variations in the RSEI, NDVI, WET, NDBSI, and LST. Additionally, geographical detectors are utilized to analyze the driving factors affecting EEQ. The results indicate the following. (1) The RSEI shows a fluctuating upward trend, with an average value of 0.4566, indicating a gradual improvement in EEQ. The EEQ exhibited significant spatial heterogeneity, with a pattern of lower values in the west and higher values in the east. (2) The NDVI and WET exhibit fluctuating increasing trends, indicating improvements in both indices. The NDBSI shows a fluctuating decreasing trend, whereas the LST presents a fluctuating increasing trend, suggesting an improvement in the NDBSI and a slight deterioration in the LST. NDVI and WET demonstrate a spatial pattern characterized by low values in the west and high values in the east. NDBSI and LST demonstrate a spatial pattern characterized by low values in the east and high values in the west. (3) Land use types and precipitation are the primary driving factors influencing the spatial differentiation of the EEQ. The explanatory power of these driving factors significantly increases under their interactions, particularly the interaction between land use types and other driving factors. This study fills the gap in existing EEQ evaluations that analyze only the RSEI without considering the NDVI, WET, NDBSI, and LST. The findings provide new insights for EEQ assessments and serve as a scientific reference for environmental protection and sustainable development.

The Liaohe River Valley was one of the key centers of the origination and development of agriculture in northern China during the Holocene. To understand the long-term interaction among the evolutions of climate, agriculture, and human activities, it is essential to quantitatively reconstruct the spatiotemporal changes in regional prehistoric human land use. In this study, known archaeological sites and a prehistoric land use model (PLUM) were combined to reconstruct changes in land use in the Liaohe River Valley during 8-2 ka BP from a quantitative perspective. The land use area experienced two stages of increase (during 8-5 ka BP and after 4 ka BP) and one stage of decrease (during 5-4 ka BP); these periods were characterized by spatial expansions and contractions. The land use intensity level differed significantly in the western and eastern parts of the valley before 4 ka BP, but the situation changed as the distribution center of the human activity shifted to the southern part of the valley around 5-4 ka BP. Overall, the spatial and temporal changes in the land use areas in both the western and eastern parts of the valley responded well to variations in precipitation during 8-2 ka BP, which potentially provides useful insights into understanding the responses of human activity to future climate change.

Understanding the characteristics and driving factors behind changes in vegetation ecosystem resilience is crucial for mitigating both current and future impacts of climate change. Despite recent advances in resilience research, significant knowledge gaps remain regarding the drivers of resilience changes. In this study, we investigated the dynamics of ecosystem resilience across China and identified potential driving factors using the kernel normalized difference vegetation index (kNDVI) from 2000 to 2020. Our results indicate that vegetation resilience in China has exhibited an increasing trend over the past two decades, with a notable breakpoint occurring around 2012. We found that precipitation was the dominant driver of changes in ecosystem resilience, accounting for 35.82% of the variation across China, followed by monthly average maximum temperature (Tmax) and vapor pressure deficit (VPD), which explained 28.95% and 28.31% of the variation, respectively. Furthermore, we revealed that daytime and nighttime warming has asymmetric impacts on vegetation resilience, with temperature factors such as Tmin and Tmax becoming more influential, while the importance of precipitation slightly decreases after the resilience change point. Overall, our study highlights the key roles of water availability and temperature in shaping vegetation resilience and underscores the asymmetric effects of daytime and nighttime warming on ecosystem resilience.

Green roofs play a vital role in promoting sustainable urban development and achieving carbon neutrality by enhancing carbon sequestration, oxygen release, and efficiency of land use. Despite these benefits, living roof coverage in China remains limited. To address the challenges in policy formulation, operational monitoring, and the absence of multi-scale retrofit strategies supported by robust assessment methods, this study develops a comprehensive evaluation framework. The framework integrates vector data, building age information, and point-of-interest (POI) data, and applies an optimized Prophet model to classify six major climate zones. This approach facilitates the selection of appropriate plant species and substrates while quantifying the potential for carbon sequestration and oxygen release. An assessment of 90 cities reveals approximately 1.3861 billion square meters of rooftop area suitable for green roof implementation, with an estimated annual carbon sequestration potential of 67.30 million tons and oxygen release of 30.36 million tons. Commercial buildings contribute significantly, comprising 65% of the total suitable area. Climate zones 2 and 3 exhibit the most favorable outcomes. The current study provides a reliable quantitative reference for evaluating the carbon sequestration and oxygen release capacities of green roofs and supports the formulation of effective retrofit policies.

Research on urban health constitutes an important issue in the field of health geography and also a strong propeller of the Healthy China Initiative. As the main form that realizes new-type urbanization, urban agglomerations should become the primal sites for the construction of a “Healthy China”. The evaluation of healthy cities’ development in urban agglomerations has both theoretical and practical values. Based on the concept of urban health and its evaluation models, this paper developed an evaluation framework for healthy cities that involved multiple data sources. With 19 urban agglomerations in China as the research subjects, we used CRITIC weighting and geographical detectors to examine the geographies of healthy cities and their influencing factors in 2010 and 2020. The results were fourfold. Firstly, the urban health level of China significantly increased from 2010 to 2020, and the comprehensive health index developed towards a positive skewed distribution, along with a shift from “low in the hinterland - high in the coastal areas” to a “multipolar” pattern led by the coastal and southwest urban agglomerations. Secondly, among various dimensions of urban health, the healthy environment index became improved with narrowed regional differences; while the health services index was still polarized; health collaboration was upgraded with a strengthened intercity health network; the healthy population index slightly declined and converged to the middle. Thirdly, urban health in China has initially demonstrated the characteristics of a H-H pattern in the Yangtze River Delta and Chengdu- Chongqing regions, as well as L-L clusters in the northern urban agglomerations, the narrowed regional differences, and increasing coordination within each urban agglomeration. Fourthly, the geographical detector found that economy, urbanization and the human capital were significant external factors that affected urban health development. The explanatory power of technological innovation and opening to the outside world were also increasing. The development of healthy cities is yet to be transformed into regional health integration.

Cropland suitability analysis is a vital tool for ensuring food security and sustainable agriculture, coordinating ecological space with human activity space on the Qinghai-Tibet Plateau (QTP). However, there are few studies on complete and accurate cropland suitability assessments on the QTP, let alone on identifying key potential areas for cropland development. We used a novel assessment model to generate a 30-m cropland suitability map for the QTP. The identification of areas with cropland development potential and the evaluation of potentially available cropland were further integrated into a unified analytical framework. We found that only 10.18% of the study area is suitable for large-scale and permanent cropland. Moreover, approximately 72.75% of the existing cropland was found to be distributed in suitable or marginally suitable areas. Considering the trade-offs related to irrigation water supply convenience, approximately 1.07% of the study area was identified as having high potential for cropland development. Four key potential areas were further identified: the Shannan Valley, the Nyingchi Valley, the Zanda Valley, and the Gonghe Basin. These areas boast abundant potentially available cropland resources and ecological resettlement capacities, which leads us to recommend strategic priorities for comprehensive land consolidation and water development. This study has practical significance for optimizing land resource allocation and guiding decision-making related to ecological migration on the QTP.

Data centers operate as physical digital infrastructure for generating, storing, computing, transmitting, and utilizing massive data and information, constituting the backbone of the flourishing digital economy across the world. Given the lack of a consistent analysis for studying the locational factors of data centers and empirical deficiencies in longitudinal investigations on spatial dynamics of heterogeneous data centers, this paper develops a comprehensive analytical framework to examine the dynamic geographies and locational factors of techno-environmentally heterogeneous data centers across Chinese cities in the period of 2006-2021. First, we develop a “supply-demand-environment trinity” analytical framework as well as an accompanying evaluation indicator system with Chinese characteristics. Second, the dynamic geographies of data centers in Chinese cities over the last decades are characterized as spatial polarization in economically leading urban agglomerations alongside persistent interregional gaps across eastern, central, and western regions. Data centers present dual spatial expansion trajectories featuring outward radiation from eastern core urban agglomerations to adjacent peripheries and leapfrog diffusion to strategic central and western digital infrastructural hubs. Third, it is empirically verified that data center construction in Chinese cities over the last decades has been jointly influenced by supply-, demand-, and environment-side locational factors, echoing the efficacy of the trinity analytical framework. Overall, our findings demonstrate the temporal variance, contextual contingency, and attribute-based differentiation of locational factors underlying techno-environmentally heterogeneous data centers in Chinese cities.

Drought significantly constrains vegetation growth and reduces terrestrial carbon sinks. Currently, the spatiotemporal patterns and mechanisms of the differential impacts of soil and meteorological droughts on vegetation productivity remain inadequately understood. In this study, we analyzed soil moisture (SM), vapor pressure deficit (VPD), and gross primary productivity (GPP) to investigate their spatiotemporal patterns and the combined effects on GPP over China. The results revealed that: (1) Soil drought and meteorological drought generally exhibited temporally synchronous trends across China. (2) GPP was predominantly affected by the combined and synchronous effects of both SM and VPD, although their effects displayed directional variability differences in certain regions. (3) SM demonstrated a greater relative importance on GPP than VPD across more than half of the regions in China, whereas deciduous broadleaf forests were the only vegetation type primarily affected by VPD. (4) Under the lag effects, both SM and VPD exhibited bidirectional Granger causality with GPP, with the interaction between VPD and GPP proving more pronounced than that of SM. Our research provides valuable insights into the mechanisms through which SM and VPD influence GPP, contributing to improved predictions vegetation productivity and implementing ecological restoration.

Dryland regions face complex interactions between urbanization and ecological changes, where effective coordination is essential for enhancing sustainability and resilience. However, most studies concentrate on the national or provincial scales, with insufficient research on county-level coordination, limiting the ability to provide targeted policies from a precise perspective. This study addresses this gap by analyzing 39 counties within the Hohhot-Baotou-Ordos-Yulin Urban Agglomeration (HBOYUA), a typical dryland urban cluster in China. We use daytime and nighttime remote sensing images to track the spatio-temporal evolution of urbanization and ecological conditions from 1992 to 2023. A novel quantitative framework based on an improved coupling coordination degree (CCD) is proposed to assess their coordination relationship. The results reveal that: (1) Urbanization and ecological quality both exhibited fluctuating upward trends, with spatial heterogeneity increasing for urbanization and decreasing for the eco-environment. Regions with better ecological conditions had higher urbanization levels. (2) The overall coordinated level improved from imbalance (0.36) to low-level coordination (0.55), although its spatial distribution remained uneven, with central urban areas showing higher CCD than surrounding counties. (3) Socioeconomic factors exerted greater effects on CCD than natural factors, with GDP and land surface temperature (LST) playing a significant role in interaction analysis. (4) In western arid regions, urbanization did not necessarily harm ecosystems; instead, ecological conditions improved alongside urbanization. This research offers targeted and valuable references for county and city governments in resource allocation and sustainable development. The proposed methodology is also adaptable for urban resilience studies in other regions.

As the largest desert in China, the Taklimakan Desert features unique mobility and alternating mega-dune and inter-dune landscapes with rich dune types. Most areas of the sand sea were explored in the early 20th century. However, the eastern Taklimakan Desert characterized by extremely tall dunes, had received little attention until 2022 owing to transportation inconveniences. This study examined the alternating mega-dune and inter-dune landscapes in the eastern Taklimakan Desert, through spatial analysis and field surveys. Results demonstrate that the tallest mega-dunes are distributed primarily to the east of the central desert, with the occurrence of approximately 240 mega-dunes exceeding 150 m in height. The height-spacing relationship of mega-dunes with different orders exhibits a weak correlation, suggesting that the dune formation and evolution are more complex than previously documented; this could be attributed to the factors other than solely the wind regime. Additionally, from the field survey, we found that sand availability is the dominant factor for constraining the sustained growth of mega-dunes. A pattern coarsening may be responsible for the development of the dune fields in the eastern Taklimakan Desert, thus yielding constraints on the development of mega-dunes, and other dune fields on Earth as well.

Agricultural greenhouse gas (GHG) emissions are influenced by a combination of climate, soil and agricultural management practices. Over the past 30 years, approximately 5% of China’s cropland has shifted from the south to the north. This shift has significantly altered the geographical environment, with potential substantial impacts on agricultural GHG emissions. This study used the DeNitrification DeComposition (DNDC) process-based model to simulate GHG emissions (CH₄ and N₂O) from the production of China’s 10 major food crops and explored changes in agricultural GHG emissions caused by the spatial shift of cropland in China. Results from the validated DNDC model indicate that total emissions from the major food crop production in China were approximately 343 Tg CO₂-eq yr^-1 with CH₄ emissions accounting for about 74%. Meanwhile, the spatial shift of cropland from 1990 to 2020 resulted in a 3% decrease in average CH₄ emissions per unit cropland area and an 8% increase in average N₂O emissions per unit cropland area, respectively. The expansion of dryland in the Northwest Arid Region emitted less CH₄ but significantly more N₂O, thereby driving changes in national GHG emissions. This study provides a scientific foundation for the sustainable use of cropland and the formulation of strategies to reduce agricultural GHG emissions.

The uneven distribution of medical resources has led to increasingly frequent patient mobility; however, the interaction between this phenomenon and the healthcare supply-demand relationship remains underexplored. The present study constructed the 2023 Cross-City Patient Mobility Network in China using one million patient mobility data records obtained from online healthcare platforms. We applied urban network analysis to uncover mobility patterns and used the coupling coordination degree model to assess healthcare supply-demand relationships before and after patient mobility. Explainable machine learning further revealed the impact of supply-demand coupling on patient mobility. The results indicated the following: Patient mobility followed administrative boundaries, although megacities serve areas beyond provincial borders; The scale of healthcare supply and demand displayed a multi-centric spatial pattern with a general decline from east to west, and these characteristics of demand distribution were further solidified by patient mobility; Cities with low supply-demand coupling and undersupply experienced patient outflows, while cities with high coupling and oversupply attracted them. In turn, patient mobility helped balance healthcare supply and demand, optimising the coupling relationship across cities. Thus, this research not only provides a methodological reference for understanding the interaction between patient mobility and healthcare systems but also offers empirical insights for public health policy.

Since 2000, China’s investment in Africa has grown rapidly, following a steady upward trajectory. However, this influx of Chinese capital has sparked both economic and political controversies. By integrating multi-source data—from micro-level individual projects to national statistics—this study examines the impact of Chinese investment on African economic development between 2000 and 2022. The results reveal a significant positive correlation between Chinese investment and economic growth across different scales, with investment-intensive regions achieving stronger economic outcomes. The DID analysis indicates that the Belt and Road Initiative has contributed positively to Africa’s economic development. Both static and dynamic panel models confirm that Chinese investment significantly stimulates growth, exhibiting notable lag effects. Furthermore, β-convergence models demonstrate that Chinese investment fosters economic convergence among African countries. Regarding regional inequality, the findings suggest that Chinese investment helps to narrow disparities across Africa, promoting a more balanced economic landscape. Overall, this research underscores the constructive role of China’s investment in fostering economic growth and reducing inequality within the African context.

The amplitude of the annual temperature cycle (ATC) is a crucial component of Earth’s climate and profoundly influences its phenology and ecosystem dynamics. However, most previous studies on ATC amplitude have been confined to the post-industrial instrumental period. Although a few studies have reconstructed ATC amplitudes over the past few centuries using proxy data, these efforts have been limited to regional scales, leaving the global profile of ATC amplitude from the pre- to post-industrial periods poorly understood. Here, leveraging rigorous evaluation and screening of monthly mean air temperature data derived from eleven CMIP5/CMIP6 models spanning the last millennium, combined with grid-based weighted averaging, we produced reliable ATC amplitude series for global and hemispheric land areas since 850 CE. Our analysis reveals a significant reduction in ATC amplitude since the 1860s across global and Northern Hemispheric lands, whereas the Southern Hemisphere has been relatively stable. The unprecedented decline in ATC amplitude since the late 19th century stands in stark contrast to the modest increases observed during the Medieval Climate Anomaly (ca. 1000-1300 CE) and the Little Ice Age (ca. 1400-1850 CE). These findings, particularly the distinct shift in ATC amplitude between the pre- and post-industrial periods, provide an early global fingerprint of anthropogenic forcing on climate change.

In recent years, the uncontrollable risks of urban production-living-ecological (PLE) space have increased sharply, making resilience enhancement essential for sustainable urban development. Based on the social-ecological system (SES) theory, this study constructs an assessment framework for urban PLE space resilience by analyzing its inherent characteristics. The central urban area of Ganzhou city is taken as a case study to evaluate urban PLE space resilience and diagnose its obstacles. The results are as follows: The PLE space resilience in the central urban area of Ganzhou exhibits gradations and substantial spatial differentiation. The ecological space resilience in the study area was the highest, followed by that of production space, while living space resilience was the lowest. The primary factors influencing PLE space resilience are concentrated in the dimensions of robustness and adaptability. In particular, the robustness of the PLE space is relatively low. Based on these results, targeted spatial resilience governance strategies for the PLE space have been proposed. These strategies serve as theoretical and technical references for the study area. By adopting the PLE space perspective, this paper enriches resilience research and provide theoretical support for sustainable urban development.

The agro-pastoral ecotone in northern China (APENC) is an ecologically fragile region with a variable climate and unbalanced socioeconomic development. Identifying the spatial range and transitional dynamics of the APENC is crucial for understanding the delicate balance between regional ecology, the economy, and society. The human-Earth system provides a comprehensive research framework in which human activities and the natural environment are viewed as interdependent and dynamically interactive. Guided by the principles of human-Earth system science, in this study, the boundaries of the APENC are identified by integrating core parameters, including water, land, climate, ecology, and human factors. Raster-based spatial data analysis is employed to examine the spatial and temporal evolution of the APENC from 1990 to 2020. The APENC extends from northeast to southwest along the central axis of northern China, displaying trends of contraction and fragmentation over time, with its centre of gravity shifting closer to the Hu Huanyong Line. The peripheral areas exhibit heightened sensitivity to environmental and ecological changes, highlighting the region’s vulnerability to external pressures. In this study, management strategies grounded in sustainable development principles are proposed, a framework for integrating ecological changes with socioeconomic strategies is established, and actionable guidance for policy- makers to promote sustainable development in this fragile and dynamic region is provided.

A comprehensive understanding of urbanization impacts on landscape dynamics, eco-environmental consequences, and advancements in human habitation is paramount for effectively advancing urbanization-related sustainable development goals. This study predicted the urbanization process within the Hohhot-Baotou-Ordos-Ulanqab (HBOU) region and its projected implications for ecology, human settlement, and energy consumption in 2020-2050 using multi-source data and models under Shared Socioeconomic Pathways (SSPs). The results revealed that the HBOU region’s urban area grew by 624.66 km² between 1990 and 2020. By 2050, it is expected to reach 1793.49±169.30 km², mainly expanding into cropland (58.95%) and natural ecological land (31.79%). Urban greening is projected to enhance, with the highest urban green space (UGS) predicted under SSP1 (32.42%). Under this scenario, the per capita urban area (PCUA) and per capita urban green space area (PCUGA) are projected to reach 172.66 and 55.63 m²/person in 2050, respectively. Furthermore, the ecological and energy utilization impacts are anticipated to decrease by 3.99% to 37.52% relative to alternative scenarios. Our projections suggest that limiting urbanization area in the HBOU region to 1500-1600 km² would significantly enhance the settlement environment and mitigate ecological and energy consumption effects. These results guide urban strategies balancing ecology, energy use, and habitation in arid regions.

Focusing on investment security along the Belt and Road (B&R) routes, this study analyzes the geopolitical environment (GE) of countries (regions) along the B&R routes from two dimensions: political and business environment (PBE) and political orientation. The results show that since the proposal of the B&R Initiative in 2013, the PBE of these countries (regions) has shown slight improvement but with significant spatial disparities, presenting a pattern of better conditions in the eastern and western regions and poorer conditions in the central regions. There is no strong spatial dependence in the PBE among these countries (regions), but a weak homogenization trend toward improvement is observed. Low-scoring countries (regions) are mainly located in former Commonwealth of Independent States (CIS), the Middle East, and the Indochina Peninsula. These countries (regions) exhibit weak interconnections, demonstrating a characteristic of “similarity without harmony.” (a Confucian concept describing nations sharing superficial traits but lacking substantive cooperation). Therefore, the B&R construction should adopt a clustered and contiguous breakthrough strategy. The evaluation of political orientation reveals significant political divergence among B&R countries (regions), with varying attitudes toward China. Moreover, as pro-China sentiment increases, the PBE tends to deteriorate. This negative correlation suggests that countries (regions) actively engaging in the B&R Initiative generally face political instability and economic underdevelopment, and seek to leverage the B&R Initiative for domestic growth. Consequently, while prioritizing investment security, it is important for the B&R construction to actively promote Chinese values in order to garner support and participation from countries (regions) with more favorable PBE. Given the generally underdeveloped PBE and political polarization among B&R countries (regions), China urgently needs to develop a geopolitical theory aligned with the B&R’s geopolitical model to safeguard its advancement. Simultaneously, China should reshape geopolitical narratives to reclaim discourse power in political interpretation. This study provides preliminary insights into cross-country (regional) political polarization and contributes to advancing GE research.

Human activities have significantly impacted the land surface temperature (LST), endangering human health; however, the relationship between these two factors has not been adequately quantified. This study comprehensively constructs a Human Activity Intensity (HAI) index and employs the Maximal Information Coefficient, four-quadrant model, and XGBoost- SHAP model to investigate the spatiotemporal relationship and influencing factors of HAI-LST in the Yellow River Basin (YRB) from 2000 to 2020. The results indicated that from 2000 to 2020, as HAI and LST increased, the static HAI-LST relationship in the YRB showed a positive correlation that continued to strengthen. This dynamic relationship exhibited conflicting development, with the proportion of coordinated to conflicting regions shifting from 1:4 to 1:2, indicating a reduction in conflict intensity. Notably, only the degree of conflict in the source area decreased significantly, whereas it intensified in the upper and lower reaches. The key factors influencing the HAI-LST relationship include fractional vegetation cover, slope, precipitation, and evapotranspiration, along with region-specific factors such as PM_2.5, biodiversity, and elevation. Based on these findings, region-specific ecological management strategies have been proposed to mitigate conflict-prone areas and alleviate thermal stress, thereby providing important guidance for promoting harmonious development between humans and nature.

Tropical cyclone activity has undergone significant changes under the impact of global warming since the 20th century. However, the characteristic and trend changes of landfalling tropical cyclones over China still need to be further clarified. The study conducted an analysis of the spatiotemporal characteristics and trends of landfalling tropical cyclones over China from 1949 to 2022 using the dataset of the best tracks of tropical cyclones from the China Meteorological Administration. Additionally, we explored the influences of ENSO and the Pacific Decadal Oscillation (PDO) on landfalling tropical cyclone activities. The results indicate that: (1) The annual average number of landfalling tropical cyclones over China is approximately 8.85, showing a significant decreasing trend, and the decreasing range becomes larger with lower latitude overall. However, both the proportion of landfalling tropical cyclones to the total number and the percentage of higher intensity tropical cyclones increase. (2) The landfall locations of tropical cyclones in China are mainly concentrated between 18°N and 26°N, accounting for approximately 88.2% of the total, and the landfall frequency shows a sharp decline in the regions north of 30°N. The central landfall location of tropical cyclones has shifted significantly northwestward, moving closer to China. Compared to 1949-1969, the central genesis location from 2010 to 2022 shifted 4.5° westward and 2.0° northward. (3) There is a correlation between ENSO and the genesis frequency variation of tropical cyclones in the Northwest Pacific and landfalling over China. El Niño promotes the genesis of strong tropical cyclones and leads to a more southeastern bias in the genesis location of landfalling tropical cyclones, while La Niña has an opposite effect. The PDO also affects the tropical cyclones to a certain extent. During the PDO warm phase, the genesis position of tropical cyclones is westward and the number is smaller than that in the cold phase. This study further clarifies the changing trends and characteristics of landfalling tropical cyclones over China since 1949. It also highlights the impacts of ENSO and the PDO on tropical cyclone activities. The findings can serve as a scientific basis for conducting simulations and assessments of tropical cyclones and for disaster prevention and mitigation efforts.

Soil erosion (SE) is a critical form of land degradation that significantly threatens the health of terrestrial ecosystems worldwide. The Qinba Mountains represent a vital geo-ecological transition zone in China. Therefore, analyzing the dynamics of SE in relation to climate changes and land use/cover (LULC) change is essential for guiding ecological conservation efforts in this region. The soil erosion intensity (SEI) from 2001 to 2020 was estimated using the Revised Universal Soil Loss Equation (RUSLE). For the period of 2021-2040, SEI projections were made based on CMIP6 data, utilizing the Statistical Downscaling Model alongside the CA-Markov model. Variations in SEI under four distinct shared socio-economic pathways were compared. Additionally, statistical methods were employed to evaluate the long-term impacts of climate and LULC change on SE. Findings indicate that between 2021 and 2040, both precipitation and rainfall erosivity are expected to increase by approximately 8%-12% and 3%-14%, respectively. Based on differing socio-economic pathways, the soil erosion rate (SER) is predicted to rise by 12%-32%, with SSP2-4.5 anticipated to result in the highest SER. An analysis of contributing factors revealed that precipitation intensity and total precipitation are likely to escalate SE, while elevated temperatures may mitigate it. Among all types of LULC, barren land is particularly susceptible to erosion and remains a priority for conservation. The generated SEI maps will aid in promoting sustainable land use and provide crucial support for mitigating ecological risks from climate change.

To address the contradiction between the rapid development of ski tourism and effective protection of the ecological environment, this study constructed the DPSIR-EES (Drive-Pressures-State-Impact-Response-Environment-Economy-Society) model and Ski Tourism Destination Ecological Security System (STDESS) framework system. They form an integrated methodology system based on the “entropy weighting-hierarchical analysis-gray correlation projection” composite weighting method that can be used to clarify the intrinsic mechanism of ecological security in ski tourism destinations. Taking Chongli as a case study, this study evaluated the evolution of its ecological security from 1995 to 2023, predicted the ecological security early warning levels from 2024 to 2050, and analyzed the mechanism of influences on regional ecological security. The findings indicate that the ecological security of ski tourism destinations shows a significant “stepped leap - dynamic equilibrium” evolutionary path. The dynamic response mechanism of the subsystems is characterized by significant heterogeneity. The ecological security early warning system revealed the temporal and sequential differentiation of risk transmission. The factors influencing ecological security show the significant dual dominance of policy and climate. This paper enhances the applicability of ecological security systems within ski tourism contexts by analyzing their evolutionary characteristics, predicted future changes and impact factors, and it provides an effective case study for ecological improvement.

Administrative division adjustments serve as crucial policy tools for spatial governance, significantly impacting regional resource allocation, economic development, and administrative governance. However, the impact of administrative division adjustment policies (ADAPs) on air quality is often overlooked. Can these policies improve air quality? By what mechanisms do they achieve this? To address this research gap, in this study, we used a two-way fixed-effects difference-in-differences model to analyze panel data from 192 prefecture-level cities in China from 2000 to 2021 in an effort to examine the effects of China’s ADAPs on haze pollution, utilizing actual implementation as empirical evidence. We analyzed the impact mechanisms from the perspectives of regional industrial structure transformation, technological innovation, and governmental regulatory capacity. We found that first, the implementation of China’s ADAPs significantly improved urban haze pollution, with varying effects observed across different types of policies. Second, ADAPs promote the upgrading of the industrial structure, technological innovation, and the enhancement of governmental regulatory capacity, thereby ameliorating urban haze pollution in China. Third, the influence of ADAPs on urban haze pollution exhibits significant spatial heterogeneity, with differing outcomes observed in regions of varying development levels. Therefore, achieving the dual goals of spatial optimization and environmental improvement necessitates the flexible application of ADAPs tailored to regional realities.