Background, aim, and scope In the past hundred years, the global environmental change has developed from the influence of natural factors in the Holocene to the influence of human activities in the Anthropocene. The characteristics of the time limit of the Anthropocene and the global boundary stratotype profile and point (GSSP) are the problems that are being solved by the scientific community. An ombrotrophic bog is a domed peatland in which the surface peat layers are hydrologically isolated from the influence of local ground and surface waters, and has been proved to be a good continental geochemical archive of the past environmental changes. The aim of this study is to provide a multi-proxy record of environmental evolution history by a typical ombrotrophic peat bog in China, aiding the clarification of the timing of the Anthropocene. Materials and methods This study was based on the previous investigated peat records of Motianling in the Great Hinggan Mountains in Northeast China. Motianling, located in the upper reaches of the Daheigou Stream northeast of A’ershan City, Hinggan League, Nei Mongol Autonomous Region, is the highest peak of the Great Hinggan Mountains (geographic coordinates: 47°22ʹN, 120°39ʹE; elevation: 1500—1700 m). The sampling site is located on the north slope of Motianling (with a slope of approximately 30°), about 2600 m southwest of Songye Lake. In October 2008 and June 2009, six peat cores (labeled as MP1, MP2, MP3, MP4, MP5, MP6) were collected using a Russian corer and directly excavated trench profiles, with lengths (40—78 cm) covering the entire peat deposit. The peat cores (MP1, MP2, MP3) were dated by ²¹⁰Pb and ¹³⁷Cs techniques and the chronologies were calculated using the constant rate of ²¹⁰Pb supply model (CRS), thereby establishing a sedimentary chronological framework for the past 200 years. All six peat cores were analyzed for ash content, dry bulk density, and water content. For cores MP1 and MP3, polychlorinated biphenyls (PCBs) were analyzed at 1 cm or 2 cm intervals, and core MP2 was analyzed for fossil pollen at 4 cm intervals to reconstruct local ecological conditions and the plant communities that formed the peat. These parameters were comprehensively compared them with previous indicators such as Pb content, ²¹⁰Pb radioisotope activity, and stable lead isotopes (²⁰⁷Pb/²⁰⁶Pb). Results Physicochemical properties of the peat (i. e., dry bulk density, ash content, total organic carbon) as well as other proxies reported elsewhere before have indicated its ombrotrophic character in the upper sections and minerotrophic character in the lower sections. PCBs were detected in both peat profiles from the Motianling peatland with mean concentrations of (10.07±8.34) ng/g and (23.72±17.47) ng/g, respectively. In both profiles, the total PCB content showed an increasing trend with decreasing depth and PCB accumulation was significantly higher after than before 1950. A total of 45 palynological taxa were identified from the peat samples, including 24 woody plant genera, 15 terrestrial herb genera, 2 aquatic vascular plant genera, and 4 fern spore genera, along with the aquatic bryophyte genus Riccia. Based on the percentage changes of major pollen types and the results of CONISS cluster analysis, the pollen spectrum was divided into three pollen zones. Discussion These high-resolution comprehensive geochemical and palaeoecological records of the ombrotrophic bog indicated a significant increase in the impact of human activities on the regional environment since 1950. By comparing with the candidate profiles, Sihailongwan Maar Lake in Northeast China determined by the Anthropocene Working Group of the International Stratigraphy Commission, the best choice for identifying the lower boundary of the Anthropocene was in the 1950s. Conclusions This study provides new evidence support for obtaining the global synchronization signal of the Anthropocene through the reconstruction and comparison of the environmental pollution history recorded by the China’s typical rain fed peat records over the past century. Recommendations and perspectives Peatland studies are presenting a thriving development trend and provide a broad suite of information on the occurrence of ecological conditions and anthropogenic disturbances, especially for missing long-term monitoring data in remote regions. Therefore, peatlands, especially the ombrotrophic bogs play an important role in the study of environmental evolution in the Anthropocene]]> 2026/6/30 0:00:00 Background, aim, and scope Salinity is a key factor affecting population structure, biocenosis, and biodiversity of lake ecosystems. Reconstruction of paleosalinity is crucial for understanding the historical evolution of lake environment, and also provides critical information for predicting future lake dynamics. However, most previous studies have focused on oceans or saline lakes, and thus our understanding of salinity changes in freshwater lakes in the past, especially over the past 200 a, is extremely insufficient. The Sr/Ba ratio in sediments has been widely accepted as an ideal proxy for paleosalinity. This study aims to evaluate whether Sr/Ba is available for reconstructing salinity of freshwater lakes. Materials and methods A sediment core (CHX) was collected from west part of the Chaohu Lake, the fifth largest freshwater lake in China. The core is 143 cm in length, and can be divided into two sedimentary units. The upper part (0—20 cm) of the core is greyish black, while the lower part (below 20 cm) is dark grey. The samples of the core mainly consist of fine-grained particles. The core was sectioned at intervals of 1 cm, and a total of 143 samples were obtained, among which 70 even-numbered samples were analyzed. This study focused on the sediments above the 28 cm depth (the past ca. 210 a) of the core. Grain size compositions, low-frequency magnetic susceptibility, and concentrations of some major and trace elements (including Sr, Ba, Al, Ca, and Na) of the well-preserved sequential sediments were measured. To examine its sedimentary history, chronology of the core was established based on techniques of ²¹⁰Pb and ¹³⁷Cs dating. Results Based on the dating results, sedimentation rate at the sampling site is approximately 1.3 mm/a. The core dates back approximately 1100 a, and age of the the botton sample of the core is around AD 910. It is found that concentrations of Sr in samples of the core vary between 104 mg/kg and 147 mg/kg, with a mean of 121 mg/kg, which is significantly lower than that of marine sediments. The range of Ba concentration in the core is 510—740 mg/kg, with an average of 605 mg/kg. The mean concentration generally falls within the range of Ba concentrations in terrestrial detritus samples (300—750 mg/kg), and similar to those reported for lake sediments in the lower reaches of the Yangtze River. The Sr/Ba ratios in samples of the core CHX range from 0.16 to 0.26 (mean=0.20), much lower than threshold value of 1 for saline environment, indicating clear terrestrial characteristics. These values are consistent with previously reported Sr/Ba ratios in freshwater sediments. Discussion Although Chaohu Lake is a freshwater lake with small salinity variations, the vertical profile of Sr/Ba shows considerable fluctuations, suggesting that Sr/Ba is sensitive to salinity changes even in freshwater environment. Therefore, it can serve as a useful proxy for reconstructing freshwater salinity. The profile of Na/Ca follows a pattern similar to that of Sr/Ba, indicating that Na/Ca may also have a potential to be an ideal indicator for salinity of freshwater lakes; however, more data in future research are needed to confirm its applicability. In combination with ²¹⁰Pb and ¹³⁷Cs dating techniques, a 210-a record of paleosalinity of the Chaohu Lake based on Sr/Ba was reconstructed and the record shows significant variability. Based on the reconstructed record of paleosalinity, the salinity shows an overall rapid decline over the past 210 a. A strong correlation is observed between salinity and precipitation, suggesting that precipitation is a major controlling factor. Increased rainfall results in raises of lake water level, which further increase volume of the lake basin. This dilutes dissolved salts in lake waters and ultimately reduces lake salinity. Conclusions Based on geochemical analyses of the CHX core from Chaohu Lake, it is found that Sr/Ba ratios of sediments show significant variations. These results demonstrates that Sr/Ba ratio could be an effective proxy for salinity in freshwater lakes. And precipitation is a possible control on historical salinity of the Chaohu Lake. Recommendations and perspectives Reconstructing salinity in freshwater systems remains challenging. This study provides a new perspective on reconstruction of paleosalinity in freshwater lakes. The Sr/Ba ratio has strong potential for application in other freshwater lakes.]]> 2026/6/30 0:00:00 Background, aim, and scope The nitrogen isotopes (δ¹⁵N) in lake sediments can record information on human activities and climate change, making them of great significance in the study of lake nitrogen cycling and paleoenvironment. However, due to the nitrogen cycle process accompanied by nitrogen isotope (δ¹⁵N) fractionation, there is some controversy over the interpretation of nitrogen isotopes (δ¹⁵N) in lakes. This study focuses on nitrogen isotopes of different components in surface sediments to clarify the main influencing factors of nitrogen isotopes and their geochemical implications in the Sihailongwan region. Materials and methods This study takes Sihailongwan (42°17′00″—42°17′24″N, 126°35′51″—126°36′24″E) as the object, and explores the changes and influencing mechanisms of nitrogen isotopes (δ¹⁵N) in 15 surface sediments (D1—D15) of the lake through surface sediment nitrogen isotopes (δ¹⁵N), nitrogen and oxygen isotopes of nitrate (δ¹⁵N-NO₃^- and δ¹⁸O-NO₃^-) in 29 lake water (W-1—W-29). Results The research results show that the variation amplitude of nitrogen isotopes (δ¹⁵N) in surface sediments is relatively small, ranging from 2.4‰ to 3.1‰. The variation range of nitrogen and oxygen isotopes of nitrate (δ¹⁵N-NO₃^- and δ¹⁸O-NO₃^-) in pore water is 1.4‰ to 4.9‰ and 3.3‰ to 33.9‰, respectively, and no obvious change pattern is shown. The variation range of nitrogen and oxygen isotopes of nitrate (δ¹⁵N-NO₃^- and δ¹⁸O-NO₃^-) in surface sediments is 0.4‰—7.0‰ and 11.7‰—33.5‰, respectively. Discussion We found that nitrogen isotopes of nitrate (δ¹⁵N-NO₃^-) of water-soluble in the sediment decreased with increasing sediment organic nitrogen isotopes. It indicates that the depletion of organic nitrogen in sediments is accompanied by the process of nitrate production. Firstly, organic nitrogen is mineralized to ammonia nitrogen, and the residual particulate organic nitrogen isotopes in the sediment become progressively more positive as the mineralization process proceeds. Then, both the nitrification and the anaerobic ammonia oxidation process could convert the mineralized ammonia nitrogen to nitrate. We also found that as the depth of the lake water increases, the nitrate content in surface sediments increases, and the nitrate nitrogen isotope is positively correlated with the depth of the lake water. Based on the isotope fractionation mechanism during nitrogen conversion, it is inferred that anaerobic ammonia oxidation is the main pathway for nitrate production in the surface sediment. Conclusions Based on this linear relationship, it is preliminarily proposed that the water-soluble nitrogen and oxygen isotopes of nitrate (δ¹⁵N-NO₃^- and δ¹⁸O-NO₃^-) in the surface sediments of Sihailongwan Lake have the potential to become geochemical indicators for inverting changes in lake water depth. Recommendations and perspectives This study provides fundamental research support for the application of nitrogen isotopes (δ¹⁵N) in lake sediment in paleoenvironmental research.]]> 2026/6/30 0:00:00 Background, aim, and scope Variations in lake hydrological conditions inevitably exert profound impacts on the regional environment; consequently, investigating the relationship between hydrological environments and climatic factors has long been a central focus in academic research. To date, however, the relationship between fluctuations in lake area and water volume across the Qinghai-Xizang Plateau and regional temperature changes has not yet been fully elucidated. Against this research context, the present study focuses on the source region of the Yangtze River (SRYR) on the Qinghai-Xizang Plateau as the study area, with an aim to disentangle the causal linkage between long-term hydrological evolution of lakes and regional thermal variations. Materials and methods This study utilized a multi-decadal time series (1986—2021) of Landsat TM, ETM+, and OLI imagery to characterize the annual spatiotemporal variations in the surface area of 33 major lakes (each >10 km²) within the SRYR (32°25′—36°15′N, 89°25′—97°45′E). The normalized difference water index (NDWI), integrated with rigorous visual refinement, was employed to ensure high-fidelity shoreline extraction. Furthermore, lake volume dynamics and concurrent meteorological records from proximal stations were collected. To quantify the complex interactions, correlation analysis, abrupt change detection, and Liang-Kleeman information flow analysis were applied to elucidate the causal linkages between lake morphometric fluctuations and regional air temperature shifts. Results The analysis demonstrated that between 1986 and 2021, the total surface area and typical water volume of lake clusters in the SRYR first exhibited a declining trend, followed by a pronounced increase. Notable shifts in lake area and water volume occurred around 2003, aligning closely with abrupt changes in annual mean temperature recorded at nearby meteorological stations. A significant positive correlation was observed between variations in lake area and water volume and regional temperature fluctuations. However, the timing of abrupt temperature changes differed among meteorological stations located in the northern and southern parts of the SRYR, showing noticeable lead-lag relationships. Furthermore, Liang-Kleeman information flow analysis confirms a unidirectional information flow from lake area and water volume dynamics to regional temperature variation, indicating that lake hydrological conditions exert a considerable influence on regional air temperature patterns. Discussion The SRYR experiences intense solar radiation owing to its thin atmosphere, exerting a substantial influence on surface temperatures. Concurrently, lakes in the region possess considerable thermal storage capacity due to the high specific heat of water. Specifically, during summer when solar radiation is strongest, lake water absorbs and retains substantial amounts of heat, thereby attenuating the rise in regional air temperature. Conversely, in autumn, as solar radiation weakens and ambient temperatures decrease, the lakes release previously stored heat, moderating the cooling rate across the SRYR. Conclusions This study reveals a significant “heat reservoir effect” of expansive lake clusters in the SRYR on regional temperatures. We propose that the projected expansion of these lake groups in the coming decades will further moderate regional air temperature fluctuations, thereby mitigating climate variability in the SRYR. Recommendations and perspectives This study advances our understanding of the linkages between the hydrological conditions of lakes on the Qinghai-Xizang Plateau and regional air temperature dynamics. It also provides invaluable insights for informing environmental protection strategies and climate adaptation and mitigation policies in the SRYR.]]> 2026/6/30 0:00:00 Background, aim, and scope Climate change poses significant risks to socio-economic systems worldwide. This study aims to investigate the relationship between economic development and climate change in the Yangtze River Delta (YRD), and to assess the economic impacts under various future warming scenarios. Specifically, we examine how variations in annual temperature, precipitation, monthly rainfall anomalies, and the number of wet days influence economic growth. Materials and methods A fixed-effects panel model is employed to analyze long-term data on climate variables and economic indicators, including gross domestic product (GDP). In addition, the dynamic integrated model of climate and the economy (DICE) is applied to project future economic impacts under different climate scenarios. Results The results indicate that economic development in the YRD is highly sensitive to temperature changes. When temperature increases remain below 18 ℃, no significant negative economic impacts are observed. However, beyond this threshold, higher temperatures exert increasingly detrimental effects on the economy. Projections further suggest that economic impacts remain minimal only under the RCP2.6 scenario. In contrast, under the RCP4.5, RCP6.0, and RCP8.5 scenarios, economic losses are projected to range from 7% to 40%, increasing in line with temperature rise. Discussion A key finding of this study is the pronounced threshold effect of temperature on economic performance. While impacts remain limited below 18 ℃, economic damages escalate rapidly once this threshold is exceeded. For instance, in the agricultural sector, extreme heat can damage crops, reduce yields, and increase irrigation demand, leading to substantial economic losses. In the industrial sector, elevated temperatures may reduce labor productivity due to increased cooling requirements and may disrupt supply chains. These findings highlight the critical importance of limiting temperature increases below the identified threshold. Conclusions This study demonstrates that constraining global warming to within 2 ℃ is essential for minimizing economic losses in the YRD. The results provide strong evidence supporting aggressive emission reduction strategies to safeguard economic development against climate risks. Recommendations and perspectives We recommend urgent and comprehensive emission reduction measures to limit warming below 2 ℃. Future research should focus on developing adaptive strategies for the YRD and other economically critical regions. Policymakers are encouraged to integrate climate risk assessments into economic planning to enhance long-term resilience.]]> 2026/6/30 0:00:00 Background, aim, and scope River sediments contain abundant weathering products, holding valuable information about silicate weathering. However, the prorpotions of primary rock fragments and secondary weathering minerals vary across grain size fractions, leading to differences in how they reflect the weathering process. In traditional research, a combination of methods such as sieving, sedimentation, and elutriation is often used for particle size separation of various types of samples, but methods for micron-scale river particle separation remain unstable and underdeveloped. This study aimed to establish a simple and reliable micron-scale particle separation process for use in watershed silicate weathering research. Materials and methods This study developed a simple and reliable micron-scale particle separation process using ultrasonic dispersion and multistage microporous filtration. Seven floodplain sediments (YL-3, YL-4, YL-5, YL-18, YL-23, YL-30, and YL-31) were sampled from upstream to downstream along China’s Yalong River. Separation experiments and elemental composition analysis were performed on four particle size fractions (<2 μm, 2—41 μm, 42—100 μm, >100 μm) of these sediment samples. Results The results showed that the separation process established in this study enabled high-precision separation of different particle size fractions in river sediments. Elemental composition analysis showed that the fine particles smaller than 2 μm contained a higher concentration of insoluble elements and relatively lower concentrations of soluble elements, with a composition more characteristic of secondary clay minerals. Additionally, those <2 μm fine particles had a lower Na/Al ratio and a higher chemical index of alteration (CIA) value, with significant spatial variations across the Yalong River watershed. Discussion Our research indicated that the relation between the mineral-element composition of river sediments and particle size fractions was influenced not only by chemical weathering but also by the source material. During chemical weathering, soluble elements like Na and Ca gradually leach out through water–rock interactions, whereas insoluble elements like Al and Fe are retained in secondary minerals. Because the particles smaller than 2 μm were rich in secondary weathering products such as clay minerals and Fe-Al oxides, those fine particles had lower concentrations of soluble elements. Additionally, particles of different sizes might have originated from different lithological sources. For instance, the fraction smaller than 2 μm often contained more sedimentary debris that had undergone multiple sedimentary cycles, gradually accumulating insoluble elements such as Al, resulting in higher Al concentrations. Further analysis of the Na/Al ratio and CIA values found that the fine particles smaller than 2 μm had undergone more intense chemical weathering than coarse particle fractions, and their chemical weathering intensity varied between the up- and downstream regions along the Yalong River. The higher altitudes and steeper terrain in the upstream areas lead to more pronounced mechanical erosion and relatively less chemical weathering. In contrast, the downstream regions, characterized by gentler terrain and longer sediment retention times, experience stronger water-rock interactions and, consequently, more intense chemical weathering. This spatial variation reflects the effect exerted by river topography and sediment retention time on the weathering process. Our research found that fine particles smaller than 2 μm might have recorded paleo-weathering information because they incorporated ancient weathering products in sedimentary cycles. That highlighted the importance of considering both weathering intensity and the sediment source area and deposition history when using fine particles to trace weathering. Conclusions Overall, the fine-grained fraction held extensive chemical weathering information, making it particularly valuable for silicate weathering studies. Recommendations and perspectives Because the particle fraction smaller than 2 μm also contained a considerable amount of sedimentary rock debris and was strongly influenced by sedimentary cycles, it is essential to carefully distinguish between modern and ancient weathering signals when using those particles for tracing weathering processes.]]> 2026/6/30 0:00:00 Background, aim, and scope Water resources are crucial for maintaining the ecological balance and supporting sustainable vegetation construction in the wind-blown sand area of Northern Shaanxi Province. Revealing the water uptake sources of sand-fixing plants and their influencing factors in this region can provide a scientific basis for vegetation construction and rational water resource utilization. While previous studies have examined plant water uptake sources in different regions, little is known about the water sources of typical sand-fixing plants under conditions of seasonal drought and periodic groundwater fluctuation in the wind-blown sand regions of Northern Shaanxi Province. This paper analyzed the root water uptake patterns of a typical sand-fixing plant (Prunus pedunculata) and their influencing factors in the wind-blown sand area of Northern Shaanxi Province. The aims of this study were to (1) determine the variation in isotopic composition among different water potential sources, (2) quantify the relative contributions of these water sources to the plant, and (3) identify the key drivers controlling root water uptake. Materials and methods The study area (38°48′—38°54′N, 109°11′—109°29′E) is located in the Gechougou small watershed of Yulin City, Northern Shaanxi Province. During the growing seasons (May to October) from 2019 to 2021, plant xylem water and its potential water sources (soil water at different depths and groundwater) were collected and measured monthly for δD and δ¹⁸O, and a total of 324 soil water samples were collected from six depths (0—20 cm, 20—40 cm, 40—60 cm, 60—90 cm, 90—140 cm, and 140—200 cm), along with 54 xylem water samples and 54 groundwater samples. Precipitation samples were collected after each rainfall event during the growing seasons, and 53 precipitation samples were collected in total. The variation characteristics of hydrogen and oxygen isotope compositions examined. Based on the principle of isotope mass balance and using the MixSIAR model, the sources and influencing factors of root water uptake in P. pedunculata were further investigated. Results The results showed that during the growing season, the δD values of xylem water, soil water and groundwater were in the range of -91.96‰——-44.72‰, -91.80‰——-30.29‰ and -63.30‰——-58.35‰, respectively. The corresponding δ¹⁸O values were in the range of -12.74‰——-6.35‰, -15.06‰——-2.21‰ and -8.58‰——-7.84‰, respectively. The average rainfall amount and groundwater level during the rainy season (July to September) were 25.61% and 3.35% higher than those during the dry season (May, June and October), respectively. During the dry season, P. pedunculata mainly absorbed soil water from the active layer (0—60 cm) and moist layer (140—200 cm), accounting for 59.39%±11.99% of total uptake. In contrast, during the rainy season, P. pedunculata mainly relied on soil water from the active layer (0—60 cm) and stable layer (60—140 cm), constituting 64.43%±2.85% of total uptake. The contribution of active layer water to root water uptake was significantly positively correlated with monthly cumulative precipitation and the proportion of fine root biomass (p<0.01), but significantly negatively correlated with groundwater table depth (p<0.05). Discussion The clear seasonal shift in water sources demonstrates the high plasticity of P. pedunculata's root system in response to changing water availability. During the dry season, the depletion of shallow soil moisture forces the plant to rely on deeper, more stable water sources. The significant positive correlation between the contribution from the active layer and monthly cumulative precipitation, and the significant negative correlation with groundwater table depth, indicate that rainfall replenishment and groundwater level fluctuations are key environmental controls. Moreover, the strong positive correlation between active layer water contribution and the proportion of fine root biomass in that layer (which accounted for 60.9% of total fine roots) provides direct evidence that root distribution is a major biological factor determining water uptake depth. Conclusions During the dry season, P. pedunculata primarily relied on soil water at depths of 60—200 cm, whereas in the rainy season, it mainly drew from soil water with the 0—140 cm layer. The contribution of active layer water to root uptake in P. pedunculata showed a significant positive correlation with monthly cumulative precipitation and the proportion of fine root biomass (p<0.01), and a significant negative correlation with groundwater table depth (p<0.05). Seasonal precipitation variation, fine root biomass proportion, and periodic fluctuations in groundwater level were identified as the principal factors influencing root water uptake from the active soil layer. Recommendations and perspectives This study offers useful insights for informing rational vegetation restoration practices in the wind-blown sand areas of Northern Shaanxi Province, and can support the formulation of management strategies and policies aimed at achieving sustainable development goals.]]> 2026/6/30 0:00:00 Background, aim, and scope Vegetation is a fundamental component of terrestrial ecosystems, playing a key role in climate regulation and carbon sequestration, thereby contributing significantly to ecosystem quality and stability. Understanding the long-term dynamics of vegetation and its responses to climate change and human activities is essential for developing rational ecosystem management strategies. Net primary productivity (NPP) serves as a robust indicator of vegetation growth dynamics, offering valuable insights for regional vegetation restoration and ecosystem management. Previous studies have often simply attributed vegetation changes to either climate change or human activities, without sufficiently disentangling the combined mechanisms driven by both natural and socioeconomic factors. This study analyzed vegetation NPP changes and their influencing factors on the northern slope of the Tianshan Mountains (NSTM) (41°11′—46°12'N, 79°54′—91°34'E) from 2000 to 2020, aiming to (1) reveal the spatiotemporal patterns of vegetation NPP, (2) clarify the relative contributions of climate change and human activities to vegetation dynamics, and (3) elucidate the driving factors and constraint effects on vegetation NPP changes across different regions. Materials and methods Using an improved Carnegie-Ames-Stanford Approach (CASA) model, residual analysis, trend analysis, correlation analysis, and constraint line analysis, this study integrated meteorological data, land use types, and the normalized difference vegetation index (NDVI) to investigate vegetation dynamics and their influencing factors on the NSTM from 2000 to 2020. Results From 2000 to 2020, vegetation NPP on the NSTM was generally higher in the northeast and lower in the northwest, southwest, and southeast. Over the 21-year period, the area of vegetation restoration area (68.60%) was substantially larger than that of vegetation degradation (31.40%). Climate change and human activities were identified as the predominant drivers of vegetation restoration and degradation, respectively. Between 2000 and 2016, NPP showed a fluctuating upward trend, with an average increase rate of 1.35 g/(m²·a) (calculated as carbon, same below). However, from 2016 to 2020, vegetation NPP declined rapidly at an average rate of 11.35 g/(m²·a). Increasing gross domestic product (GDP) and population density were associated with a nonlinear decrease in the potential maximum value of vegetation NPP. Constraint effects of precipitation and temperature on vegetation NPP exhibited thresholds, approximately 378 mm and 2 ℃, respectively. Discussion The spatial distribution of vegetation NPP was mainly related to climate change and land use types on the NSTM. The fluctuating increase in NPP from 2000 to 2020 was attributed to the combined effects of ecological restoration projects and agricultural practices. In contrast, the decline from 2016 to 2020 was linked to reduced precipitation, land use conversion, rapid economic development, and population growth. Decreasing precipitation and rising temperature were found to be detrimental to long-term vegetation restoration. Human activities mainly affected vegetation changes through economic development and the implement of ecological protection measures. Conclusions Vegetation NPP on the NSTM exhibited significant spatiotemporal heterogeneity from 2000 to 2020, characterized by a fluctuating increase trend before 2016 followed by a rapid decline. Overall, the vegetation restoration area was more than double the vegetation degradation area during 2000—2020. Climate change and human activities were the leading factors driving vegetation restoration and degradation, respectively. However, the positive effects of ecological restoration projects may not always offset the negative impacts of rapid climate change, land use conversion and economic development, particularly during 2016—2020. Recommendations and perspectives This study helps reveal the response mechanism of vegetation to climate change and human activities in arid Northwest China under global warming. By applying an improved CASA model, it clarifies the spatiotemporal changes of vegetation NPP on the NSTM and its key influencing factors, confirming the differential effects and constraint thresholds of climate change and human activities. The findings provide a scientific basis for the recovery and management of degraded ecosystems in the region.]]> 2026/6/30 0:00:00 Background, aim, and scope The Dabie Mountains (DBM), located on the eastern flank of the Qinling Mountains, is an important ecological barrier and water conservation area in Central China. Climate change in the DBM is closely linked to regional natural ecology and social-economic development. While previous studies have explored climate change characteristics in this region based on meteorological records and proxy data, systematic research on the spatial and temporal patterns of climate change, as well as the variations of the annual temperature cycle (ATC) and diurnal temperature range (DTR), remains limited. This study aims to comprehensively characterize the spatial and temporal patterns of climate change in the DBM over the past seven decades, with particular attention to altitudinal and slope variations, and to examine the long-term trends of ATC and DTR. Materials and methods Based on monthly climate data from 12 meteorological stations (Xiaogan, Shouxian, Fuyang, Gushi, Taihu, Anqing, Huoshan, Lu'an, Macheng, Dawu, Xinyang, Yingshan) in the DBM (30°—33°N, 113.72°—117.47°E) from AD 1951 to 2020, this study analyzed the characteristics of climate change across different altitudes and slopes using linear regression and the Mann-Kendall (M-K) nonparametric test. ATC and DTR analyses were further carried out to assess temperature variability patterns. Results Over the past 70 a, the warming rates of annual mean temperature (T_mean) were 0.199 ℃/(10a), 0.178 ℃/(10a) and 0.222 ℃/(10a) from low to high altitudes (≤50 m, (50, 100] m, (100, 150] m), respectively; the warming rates of annual maximum mean temperature (T_max) were 0.151 ℃/(10a), 0.170 ℃/(10a) and 0.179 ℃/(10a); and the warming rates of annual minimum mean temperature (T_min) were 0.254 ℃/(10a), 0.186 ℃/(10a) and 0.276 ℃/(10a), respectively. When it comes to slopes, the warming rates of T_mean were 0.145 ℃/(10a) (southern) and 0.209 ℃/(10a) (northern); T_max were 0.190 ℃/(10a) and 0.136 ℃/(10a); T_min were 0.125 ℃/(10a) and 0.262 ℃/(10a). T_mean on both slopes showed fluctuating upward trends. Specifically, the change of each temperature factor was relatively small before the 1990s, and then there was a clear upward trend. Seasonally, T_mean on the northern slope exceeded that on the southern slope across all four seasons, with warming rates ranking as spring>winter>autumn>summer. ATC and DTR showed a downward trend in the past 70 a. For precipitation, change rates of annual precipitation amount (P) across altitudes were 16.730 mm/(10a), 22.344 mm/(10a) and 3.947 mm/(10a) from low altitude to high altitude, respectively. On slopes, the rates were 13.449 mm/(10a) (northern) and 16.901 mm/(10a) (southern). Annual mean relative humidity declined significantly on both slopes at rates of −0.41%/(10a) (northern) and −0.38%/(10a) (southern). Mutation analysis revealed that T_mean on both slopes underwent a mutation in AD 1997, whereas precipitation showed no significant mutation. Discussion ATC and DTR, two key climate change indicators, have not been studied and discussed in depth. This study reveals an overall declining trend in ATC at 0.24 ℃/(10a), indicating a gradual reduction in the seasonal temperature contrast. Although this decline rate is lower than that in most middle and high latitudes of the Northern Hemisphere, the regional differentiation of seasons is weakening. The overall DTR also showed a downward trend, with a more significant decrease on the northern slope than on the southern slope. Significant negative correlations exist between DTR and cloud cover on both slopes, suggesting that decreasing DTR coincides with slowly increasing cloud cover. The reason may be that the DBM is affected by the monsoon, and the temperature rises with more precipitation and sufficient water vapor supply, resulting in a slow upward trend in cloud cover. Conclusions (1) Temperature changes in the DBM demonstrate generally consistent spatial characteristics with an overall warming trend. The warming trend of T_min is significantly higher than that of T_mean and T_max, and the warming rate of T_min is the most significant at the high altitudes (>100 m). In contrast, the warming rate on the northern slope is higher than that of the southern slope. On the seasonal scale, warming rates on both slopes are spring>winter>autumn>summer. The M-K mutation test revealed that annual T_mean on both slopes underwent a mutation in AD 1997. (2) Although total annual precipitation increases from the northern to the southern slope, the precipitation did not show long-term significant trends in terms of altitudinal gradients or slopes. (3) Over the past 70 a, annual mean relative humidity on both slopes showed a significant downward trend, indicating a drying trend in the DBM. (4) Both ATC and DTR in the DBM have shown a weakening trend over the past 70 a, and the weakening trend in the northern slope was more significant than that on the southern slope. Recommendations and perspectives Given the short duration of the meteorological data, it is still necessary to strengthen the analysis of high-resolution climate proxies in the future, and to evaluate modern observations under a longer time scale framework to fully reveal the characteristics and laws of climate change in the DBM.]]> 2026/6/30 0:00:00 Background, aim and scope Climate variability during Mid- to Late Holocene represents a critical interval for understanding Earth-system responses to external forcing under relatively stable boundary conditions. The Chinese Loess Plateau (CLP) lies on the northeastern margin of the Qinghai-Xizang Plateau, bounded by the Taihang Mountains to the east, the Qinling Mountains to the south, and the Tengger Desert and Mu Us Sandy Land to the north, and is commonly divided into three sub-regions (eastern, central, and western) along topographic-climatic gradients. Diverse archives, including loess deposits, lacustrine sediments, stalagmites, and tree rings, provide key evidence for orbital- to decadal-scale East Asian summer monsoon (EASM) variability. While previous work has substantially advanced understanding of orbital- to millennial-scale changes, centennial and shorter-timescale variability remains poorly constrained, partly due to limitations in proxy resolution and chronology. Here we synthesize and review CLP climate records spanning the last 6 ka, with the aims of quantifying long-term trends, characterizing the spatiotemporal expressions of millennial- to centennial events, and evaluating potential drivers. Materials and methods Based on proxy continuity, chronological reliability, and temporal resolution, we compiled 25 high-quality paleoclimate records covering ≥6 ka with sub-centennial (≤100 a) resolution from loess-paleosol sequences, lake sediments, stalagmites, and tree rings. Multi-archive comparison was used to assess Mid- to Late Holocene climatic trends and the spatiotemporal differentiation of abrupt events at millennial- to centennial-scale. Results (1) Long-term trends: The CLP experienced a progressive cooling and drying trend over the past 6 ka. Temperature variations are consistent with temperature syntheses at global and regional (China) scales, and precipitation changes broadly match EASM simulations. However, stalagmite records from the western CLP suggest a precipitation increase over the last ca. 400 a. (2) Abrupt climatic events: the 5.5 ka, 4.2 ka, and 2.8 ka events show pronounced regional differences in onset/termination, duration, and internal structure. While the 5.5 ka event shows variable structures (single- or double-pulsed), the 2.8 ka event uniformly exhibits a double-pulsed morphology. In contrast, the 4.2 ka event displays a clear north-dry/south-wet contrast, often manifesting as a dry–wet–dry sequence in northern records. Discussion Mid- to Late Holocene trends on the CLP were primarily forced by declining mid- to high-latitude summer insolation. The spatiotemporal heterogeneity of abrupt events likely reflects both differential proxy sensitivities and chronological uncertainties. Although the three weak-monsoon intervals generally manifest as aridification, their driving mechanisms differ: the 5.5 ka and 2.8 ka events are associated with solar minima and North Atlantic ice-rafting activity (Bond events), whereas the 4.2 ka event may have been modulated by North Atlantic Oscillation (NAO) phase variability. Conclusions (1) The CLP exhibits broadly coherent cooling and drying trends since 6 ka, dominated by insolation forcing, while the western CLP shows a Late-Holocene wetting tendency over the last ca. 400 a, indicating regional heterogeneity. (2) The 5.5 ka, 4.2 ka, and 2.8 ka events differ in spatiotemporal patterns and amplitudes, implying distinct forcing involving solar variability, North Atlantic ice-rafting activity, and NAO-related dynamics. (3) Inter-archive comparability, including proxy sensitivity, temporal resolution, and dating precision, is critical for resolving the fine structure of abrupt events. Recommendations and perspectives Future work should prioritize high-resolution reconstructions in data-sparse areas (e. g., the central CLP), strengthen proxy – model comparisons, and improve chronological constraints to better resolve centennial-scale event structures and mechanisms.]]> 2026/6/30 0:00:00 Background, aim, and scope The Bay of Bengal and the Arabian Sea are two marginal seas in the northern Indian Ocean with distinct physicochemical properties. Due to the isolation by the South Asian continent, material exchange between them occurs primarily through the Indian coastal current. Reconstructing the evolutionary history of the Indian coastal current and understanding its variability are crucial for predicting future marine environmental changes in the northern Indian Ocean. However, reliable reconstruction records of this coastal current have not yet been published. This study aims to reconstruct the evolutionary history of the Indian coastal current and the material exchange between the Bay of Bengal and the Arabian Sea. Materials and methods This study is based on sediment core MD77-191(7°30′N, 76°43′E), collected from the southern margin of the Indian subcontinent. A total of 369 sediment samples, covering 854 cm of the core and spanning the interval from 0.5 ka to 18.0 ka, were obtained for analysis. Grain size compositions of terrigenous clastic sediments were analyzed, and an end-member modeling algorithm was applied to isolate the dominant grain size end-members. Sediment provenance was constrained using previously published Sr-Nd isotopic data obtained from the same core. By further comparing these results with other climatic proxies, we reconstructed the history of sediment provenance shifts and their implications for changes in coastal current direction. Results The results indicate that the mixing of two end members can explain approximately 90% of the grain size variation in core MD77-191. The modal grain sizes of end-members EM1 and EM2 are 8 μm and 16 μm, respectively. Combined with published Sr-Nd isotope data, it was found that during the prevailing summer monsoon, sediments primarily originate from the Arabian Sea, while during the prevailing winter monsoon, they mainly derive from the Bay of Bengal. During 18.0—9.5 ka, the finer end-member EM1 content was higher during the cold periods of the Younger Dryas (YD) and Heinrich Stadial 1 (HS1) when the summer monsoon was weaker. In contrast, EM1 content decreased during the warmer Bølling-Allerød (B/A) and Early Holocene periods when the summer monsoon was stronger. Since 9.5 ka, EM1 content was higher during the warm Mid-Holocene with a stronger summer monsoon and lower during the cold Late Holocene with a weaker summer monsoon. This indicates that sediments from the Arabian Sea were coarser than those from the Bay of Bengal from 18.0 ka to 9.5 ka, but this trend reversed after 9.5 ka. Discussion This phenomenon may be attributed to the broader continental shelf on the western side of the Indian Peninsula (eastern Arabian Sea). During the low sea level period of 18.0—9.5 ka, the continental shelf was exposed, and river mouths extended seaward. This allowed the summer monsoon-driven West Indian coastal current (WICC) to transport coarser sediments from the Arabian Sea more readily. In contrast, the narrower continental shelf on the eastern side of the Indian Peninsula (western Bay of Bengal) was less affected by sea level changes in terms of river mouth positions. Additionally, the southward flow of the East Indian coastal current (EICC) was obstructed and slowed by Sri Lanka. This caused coarser sediments from the Bay of Bengal to be deposited more readily during transport, resulting in relatively finer sediments reaching the core site. During high sea level periods, the grain size of sediments from the Bay of Bengal did not change significantly. However, the western continental shelf was submerged, and river mouths retreated. Combined with enhanced sediment weathering and erosion due to higher temperatures and increased precipitation during the Holocene, sediments from the Arabian Sea became finer overall. Furthermore, during the low sea level period of 18.0—9.5 ka, the positive Indian Ocean dipole (IOD) enhanced the summer monsoon. This promoted the WICC to transport more coarse sediments from the Arabian Sea, while finer sediments from the Bay of Bengal dominated during weaker summer monsoon periods. During the negative IOD phase since 9.5 ka, sediments from the Bay of Bengal increased, and coarser sediments from the Arabian Sea were blocked from reaching the core site. Conclusions In conclusion, sea level changes are the primary controlling factor for grain size variations in the core, while phase changes in the IOD act as a secondary factor. Recommendations and perspectives Based on the hypothesis that global warming may lead to more frequent positive IOD phase, it is expected that the transport of low-salinity water from the Bay of Bengal to the Arabian Sea may be suppressed in the future. This could further widen the salinity differences between the two marginal seas.]]> 2026/6/30 0:00:00 Background, aim, and scope The Quaternary period, closely associated with human evolution, holds pivotal importance in understanding the sensitivity of climate change across different time scales and accurately predicting future climate variations. This study aims to establish an average sea surface temperature (SST) stack over the past 2 Ma and reveal its orbital and long-term trends, as well as the potential driving mechanisms. Materials and methods We compiled SST records from 26 sites across different oceanic regions. To ensure the robustness of the SST stack, several selection criteria were applied: (1) all records span over 800 ka with a temporal resolution finer than 10 ka, suitable for orbital-scale analyses; (2) only SST reconstructions based on Mg/Ca ratios and long-chain unsaturated alkenone (U^K'₃₇) were included, excluding those derived from other proxies; (3) all records are anchored to astronomical ages calibrated by benthic or planktonic foraminiferal δ¹⁸O, providing a unified chronological framework. Results In the long-term trend, the global SST gradually decreased by approximately 3 ℃ before the Mid-Brunhes Event (MBE) and decoupled from atmospheric CO₂. After the MBE, SST slightly increased, while the amplitude of glacial-interglacial cycles increased. SST exhibits clear cycles at orbital time scales, including periods of 41 ka and 100 ka, as well as the 405 ka eccentricity long period. Discussion Despite clear long-term changes in global SST since the Quaternary, the mechanisms behind these trends remain uncertain. Orbital forcing and changes in atmospheric CO₂ alone cannot fully explain the observed cooling, suggesting the involvement of other processes such as ice sheet dynamics. Uncertainties remain regarding the mechanisms behind Quaternary orbital-scale climate variations, including the origins of the 41 ka and 100 ka cycle and the transition from the 41 ka to 100 ka cycle. The 405 ka eccentricity cycle influences SST variability, potentially amplified by ocean carbon reservoirs. Additionally, the linear correlation between ocean heat content and SST suggests a modulation of high-frequency precession signals, enhancing the expression of eccentricity-paced SST variability. Conclusions We investigate the long-term and orbital-scale variability of sea surface temperature of Quaternary and explore its potential driving mechanisms. These findings enhance our understanding of climate sensitivity and the dynamic processes of Quaternary climate changes. Recommendations and perspectives Future research endeavors will necessitate precise atmospheric CO₂ reconstructions and refined fully coupled climate simulations to further elucidate the intricate relationships between SST and atmospheric CO₂. Investigating the evolution of Quaternary climate from the perspective of hemispheric asymmetry may provide fresh insights into the dynamic processes governing climate changes during this epoch.]]> 2026/6/30 0:00:00 Background, aim, and scope During the Paleogene period, the Paratethys Sea invaded the southwest part of the Tarim Basin and was located to the south of the salt lakes within the Kuqa Depression in the northeastern part of the basin. Multiple episodes of sea-level changes of the Paratethys Sea had potential providing abundant water and material source for the salt lake deposition of the Kuqa Depression. However, the genesis and main controlling factors of the salt lakes in the Kuqa Depression is still controversial. Against this geological backdrop, this study investigates the Paleogene Kumugeliemu Group outcropping at the Kuqa River section in the northern Kuqa Depression, and elucidates the response of saline lake sedimentation to Paleogene sea-level change as well as the primary controls on saline lake genesis via sedimentary facies analysis. Materials and methods In this study, we selected the Kuqa River section in the northern Kuqa Depression for sedimentary facies analysis, and collected 43 gypsum samples from the Paleogene Kumugeliemu Group, which has a total thickness of 326.12 mm (section coordinates: 42°06′48.16″N, 83°05′11.43″E) for strontium isotope analysis, to elucidate the response of salt lake sedimentation to Paleogene eustatic sea-level changes and the primary controls on salt lake formation. Results The Kumugeliemu Group of the Kuqa River section can be divided into three third-order ( Ⅲ) cycles. The first Ⅲ cycle was dominated by early alluvial-fan conglomerate-sandstone and late evaporite lagoon gypsum deposits and its gypsum was characterized by low ⁸⁷Sr/⁸⁶Sr values (0.709100 to 0.709132). The second Ⅲ cycle was represented by deposition of early alluvial fan conglomerate-sandstone, middle salt lake gypsiferous mudstone, and late delta sandstone-mudstone deposits. Its gypsum was characterized by higher ⁸⁷Sr/⁸⁶Sr values (0.709267 to 0.709410). The third Ⅲ cycle recorded three small-scale lake transgression and regression and was represented by the deposition of lake playa and mudflat, and high gypsum ⁸⁷Sr/⁸⁶Sr values (0.709320 to 0.709467). Discussion The varied gypsum ⁸⁷Sr/⁸⁶Sr values and lithological association of the Kumugeliemu Group from the Kuqa River section were a combined response of seawater transgression, tectonic activity and climatic changes. The first Ⅲ cycle was affected by the transgression and regression of the Paratethys Sea in the Tarim Basin and the second Ⅲ cycle was collectively affected by the Tianshan uplift, marine transgression and arid climate. Whereas the third Ⅲ cycle was but mainly affected by arid climate and terrestrial sources, without marine transgression of the Paratethys Sea. Conclusions This study reveals that the early two main salt-forming stages of the Kumugeliemu Group in the Kuqa Depression were strongly influenced by marine incursions while the later stage, dominated by terrestrial source supply, was unable to form thick-bedded gypsum-bearing rock deposits. Recommendations and perspectives The depositional response of the Paleogene saline lakes in the Kuqa Depression provides evidence for the transgression range and timing of the eastern Paratethys Sea, Central Asia paleoclimate, and regional tectonics.]]> 2026/6/30 0:00:00 Background, aim, and scope Global warming caused by the greenhouse effect has become one of the most concerning environmental problems in recent years. As a major greenhouse gas, CO₂ plays an important role in the worldwide climate. Understanding alterations in CO₂ concentrations throughout geological history is of great significance for determining the present climate system and predicting future climate development. As indicators of environmental change, plants record important information about climate change during geological periods through their evolution. This study aimed to apply stomatal parameters of fossilized plants to reconstruct paleoatmospheric CO₂ concentrations using the stomatal ratio method. It further explored changes in CO₂ levels during the Middle Jurassic and their paleoclimatic significance. Materials and methods This study employed two plant fossils collected from the coal-bearing strata of the Middle Jurassic Yaojie Formation (J₂y) in the Baojishan Basin (36°40'—36°50'N, 107°47'—105°00'E), Gansu Province, China, as the research material. Their macroscopic morphology was described, and microscopic features were observed. By calculating stomatal parameters and paleoatmospheric CO₂ concentrations, the paleoenvironment of the Baojishan Basin was reconstructed. Results This study reports two plant fossils in Middle Jurassic from the Baojishan Basin. By analyzing their macroscopic and microscopic characteristics, the fossils were identified as Phoenicopsis (Phoenicopsis) angustifolia Heer and Sphenobaiera jugata. The stomatal apparatus of Ph. angustifolia was hypostomatic, elongated, and rectangular, measuring approximately 22—48 μm in length and 9—16 μm in width. The stomata were elliptical, the guard cells were kidney-shaped, and the subsidiary cells numbered 4—8. The stomatal density and index were 39—61 per mm² and 4.86%—6.03%, respectively. The stomatal apparatus of S. jugata was hypostomatic and bore a relatively large number of stomata, arranged in an inconspicuous longitudinal row within the interveinal bands and occasionally on the veins. The stomatal slit was roughly parallel to the veins; the guard cells were sunken, and subsidiary cells numbered 4—6. The stomatal density and index were 23—39 per mm² and 4.89%—5.68%, respectively. Using two fossil materials, the stomatal ratio method was employed to reconstruct paleoatmospheric CO₂ concentrations during the early Middle Jurassic, and they were 1343.01 μL/L and 1353.63 μL/L, respectively. Discussion The two fossil specimens were compared in detail with extant plants and related fossil species belonging to the same genera. One specimen showed 5—8 linear leaves with contracted bases and parallel veins. Based on these morphological characteristics, the fossil was identified as the genus Phoenicopsis. The epidermal cell structure of the fossilized leaves was hypostomatic, suggesting its classification within the subgenus Phoenicopsis. The present specimen closely resembled a narrow-leaved Phoenicopsis type specimen from the Irkutsk Basin of Siberia, which had leaves 4—5 mm wide, with 6—10 veins and lacking fine inter-veins. Therefore, the present specimen was assigned to Ph. angustifolia Heer. The terminal branch system of the second fossil specimen comprised long and short branches; each branch was 6 cm long and about 5 mm wide. Each long branch was 4—5 mm in diameter and had a smooth surface. These branches diverged at an angle of about 50° and bore several short branches arranged in two spiral rows, at a general spacing of 2—3 cm. The present specimen closely related to S. jugata. Previous studies on Middle Jurassic plant fossils from Gansu Province have used the stomatal parameter or stomatal ratio method to reconstruct paleoatmospheric CO₂ concentrations for various plant fossils. This present study further explored variations in Middle Jurassic paleoatmospheric CO₂ concentrations and their paleoclimatic significance using this method. The CO₂ levels of the early Middle Jurassic were 1343.01 μL/L for Phoenicopsis and 1353.63 μL/L for Sphenobaiera, and the two values fall within the reliable error range of the GEOCARB Ⅲ carbon balance model and are consistent with paleoatmospheric CO₂ estimates reported from other regions of the same period. Conclusions The average paleoatmospheric CO₂ concentrations reconstructed employing the stomatal ratio method were close to the simulation curve of the GEOCARB Ⅲ carbon balance model. The values indicate that Ph. angustifolia and S. jugata are suitable materials for reconstructing the volume fraction of CO₂ within the paleoatmosphere. Recommendations and perspectives Further research is needed to verify the accuracy and applicability of the method. Future studies should incorporate wider variety of reconstruction methods and models, covering not only paleoatmospheric CO₂ but also other environmental parameters, to provide a more comprehensive understanding of the regional paleoenvironment.]]> 2026/6/30 0:00:00 Background, aim, and scope Determining to what extent different sources contribute to the total content of urban atmospheric CH₄, the second most prevalent anthropogenic greenhouse gas, is critical for carbon emission mitigation strategies. Carbon isotopes (stable δ¹³C and radiocarbon Δ¹⁴C) are powerful CH₄ tracers as they exhibit distinct signatures in different CH₄ sources. This review aims to synthesize the principles, methodologies, and applications of tracing urban CH₄ sources using carbon isotopes, providing a foundation for further scientific studies in China. Materials and methods The literature on the carbon isotopic composition (δ¹³C and Δ¹⁴C) of major urban CH₄ sources (e.g., natural gas, landfills, wastewater treatment plants) has been systematically reviewed, including fundamental principles behind isotope tracing, experimental techniques for atmospheric CH₄ sampling and isotopic analysis, and key mathematical models (Keeling plot, Miller-Tans, and mass balance) for source contribution assessment. Results Fossil-derived CH₄ (e.g., natural gas leakage) is devoid of ¹⁴C (Δ¹⁴C=-1000‰), so that its emission causes a measurable dilution in atmospheric Δ¹⁴CH₄. In contrast, Δ¹⁴C values of biogenic CH₄ (e.g., from landfills) are close to those of contemporary atmospheric CO₂. Stable carbon isotopes appear in a wide range: microbial CH₄ is typically more depleted in ¹³C, whereas thermogenic and pyrogenic sources are relatively enriched. Discussion The literature survey demonstrates that the sole use of Δ¹⁴C enables an accurate quantification of the fraction of fossil fuel CH₄. On the other hand, using δ¹³C as a tracer can qualitatively identify dominant source types, as demonstrated by the seasonal shifts in the δ¹³C content observed in various European cities. Indeed, combining Δ¹⁴C and δ¹³C isotopes warrants a more detailed CH₄ apportionment; Δ¹⁴C first partitions fossil vs. biogenic CH₄ sources, while δ¹³C subsequently helps differentiate among biogenic sub-sources, like landfills and wastewater treatment. Conclusions Carbon isotopes (Δ¹⁴C and δ¹³C) are indispensable tools for identifying and quantifying the specific emission sources of urban atmospheric CH₄. Recommendations and perspectives To advance this field of CH₄ tracing in China and support the national carbon reduction goals, we recommend a multi-faceted approach. First and foremost, it is essential to continue strategic investing in developing robust and efficient atmospheric ¹⁴CH₄ sampling and analysis technological infrastructure to enable systematic and combined Δ¹⁴C and δ¹³C observations in typical urban environments, thereby allowing a detailed characterization of spatial and temporal CH₄ emission patterns. Furthermore, establishing a national background monitoring framework for Δ¹⁴CH₄ at remote, high-altitude sites is critical for providing reference values necessary for accurate calculations of fossil fuel contribution. At the same time, systematic characterization of δ¹³CH₄ for major emission sources is needed to build regionally representative endmember datasets and to better constrain source apportionment. Finally, future studies should further develop hierarchical isotope-based source apportionment frameworks, in which Δ¹⁴C is used to distinguish fossil from modern biogenic CH₄, while δ¹³C is used to further resolve biogenic sub-sources, with Bayesian mixing models helping to address endmember and observational uncertainties. Pursuing these research directions will provide robust scientific evidence for formulating more goal-oriented and effective CH₄ mitigation policies in China.]]> 2026/6/30 0:00:00 Background, aim, and scope Aerosols can act as cloud condensation nuclei (CCN) or ice nuclei (IN), exerting complex influences on cloud properties and precipitation. Under the prevailing westerlies in winter, a large number of atmospheric pollutants from East Asia are transported to the North Pacific Ocean (NPO) region. The favorable environmental conditions in this region facilitate aerosol-cloud interactions (ACI), leading to significant impacts of the transported aerosols from East Asia. The study aims to quantitatively analyze the effects of increased anthropogenic aerosols from East Asia on cloud properties and precipitation in the NPO region. The research results can provide references for revealing the mechanism of aerosol effects on weather and climate. Materials and methods This study employed a specific version of the Weather Research and Forecasting Model coupled with Chemistry (WRF-Chem), which couples a two-moment bulk cloud microphysics scheme and accounts for the influence of aerosols on CCN and IN. Firstly, a baseline simulation was set up to evaluate the model performance; subsequently, sensitivity simulations were conducted, with anthropogenic source emission factors set at 0.3 (clean-case or C-case) and 3.0 (pollution-case or P-case), to explore the impact of increased anthropogenic aerosols from East Asia on cloud systems and precipitation in the NPO. Results The index of agreement (IOA) for near-surface CO, NO₂, O₃, and SO₂ all exceeded 0.75. The model reproduced the observed spatial patterns of cloud optical thickness (COT), liquid water path (LWP), ice water path (IWP), and precipitation. Under the P-case, the domain-averaged cloud droplet number concentration (CDNC) was 154.1% higher than that in the C-case. In the later stage of the simulation, both the number concentration and mass concentration of ice and snow crystals increased markedly. High cloud fraction increased, whereas low cloud fraction decreased. The intensity and occurrence probability of heavy precipitation (>10 mm/d) both increased, while total precipitation changed by 2.4%. Discussion The large increase in CDNC reduced the effective radius of cloud droplets and suppressed the warm-rain collision-coalescence process. More cloud liquid water was thereby transported to the freezing level, enhancing ice-phase processes (e.g., the Bergeron-Findeisen mechanism and riming) and leading to the observed increases in ice and snow crystal concentrations. The associated latent heat release invigorated deep convection, which promoted the development of high clouds, suppressed low clouds, and altered the macroscopic cloud structure. These microphysical and dynamical changes shifted the precipitation spectrum toward heavier events: total precipitation remained nearly unchanged, but extreme precipitation became both more intense and more frequent. Conclusions Increased anthropogenic aerosols from East Asia markedly modify cloud microphysical processes over the NPO, suppressing warm rain while invigorating ice-phase and deep convective processes. This redistribution of cloud water favors high cloud formation and suppresses low clouds. As a result, total precipitation shows little change, but the intensity and frequency of heavy precipitation events are substantially enhanced, raising the risk of extreme rainfall in the NPO region. Recommendations and perspectives In the future, numerical simulation studies with higher spatial resolution and longer simulation periods should be conducted to more accurately depict small-scale convective precipitation processes and improve the representativeness of the research results.]]> 2026/6/30 0:00:00 Background, aim, and scope Meteoric beryllium-7 (⁷Be, t_1/2=53.29 d) and beryllium-10 (¹⁰Be, t_1/2=1.39 Ma) are natural occurring cosmogenic radionuclides that are widely used as environmental tracers. They are widely used to investigate sediment sources and transport, sedimentation rates, atmospheric deposition fluxes, atmospheric aerosol residence time, and paleoclimatic reconstruction. Their effectiveness as tracers is mainly attributed to their well-defined sources, stable geochemical properties, and dynamic behavior. Both isotopes are produced by interactions between cosmic rays and atmospheric constituents such as nitrogen and oxygen. They subsequently reach the Earth's surface via wet and dry deposition. Current evidence suggests that most of ⁷Be and ¹⁰Be deposition occurs through wet deposition. To ensure their reliable application as tracers, it is essential to understand the variability of ⁷Be and ¹⁰Be in precipitation and the mechanisms controlling their deposition. Therefore, this study aims to review the variation characteristics of ⁷Be and ¹⁰Be in precipitation and to identify the key factors influencing their behavior. Materials and methods In this review, we synthesize and evaluate existing research on the variation characteristics of ⁷Be and ¹⁰Be in precipitation, summarize their regional and seasonal patterns, and analyze key influencing factors. We categorized the compiled datasets based on geographic locations. On this basis, the joint effects of cosmogenic production, large-scale atmospheric circulation, localized wet clearance mechanisms, and vegetation cover were comprehensively evaluated. Results The spatial and seasonal uniformity of ⁷Be and ¹⁰Be fallout remains an open question in tracer applications. Globally, ⁷Be in precipitation shows clear zonal variability. The activity concentration and deposition flux of ⁷Be in precipitation generally reach their maximum at mid-latitudes and decrease toward the equator and the poles. The variation characteristics of ¹⁰Be in precipitation are broadly comparable to those of ⁷Be. However, research on ¹⁰Be in precipitation remains limited, with most studies focusing on mid-latitude regions. In addition, ⁷Be and ¹⁰Be levels in precipitation exhibit pronounced seasonal fluctuations. Discussion The majority of ⁷Be and ¹⁰Be is transferred to the Earth's surface via precipitation. Their concentrations and wet deposition fluxes are strongly influenced by precipitation characteristics, including precipitation type, timing (stage), and magnitude. In general, the correlation between ⁷Be and ¹⁰Be in precipitation is stronger than the correlation between precipitation amounts and their respective production rates or atmospheric transport processes. This is particularly evident for ⁷Be, given its short half-life. The concentrations and deposition fluxes of ⁷Be and ¹⁰Be in precipitation are influenced not only by rainfall, but also by multiple atmospheric processes, including aerosol residence time, Brewer-Dobson circulation, stratosphere-troposphere exchange, and intra-tropospheric transport. These processes further shape the seasonal and latitudinal distributions of ⁷Be and ¹⁰Be concentrations and deposition fluxes in precipitation. Moreover, vegetation cover can significantly modify the amounts of ⁷Be and ¹⁰Be reaching the surface by intercepting and redistributing atmospheric deposition. Conclusions (1) Global observations of ⁷Be and ¹⁰Be in precipitation are predominantly concentrated in mid-latitude regions, while data on ¹⁰Be in precipitation remain particularly limited. (2) There is a lack of data on the spatial and temporal variability of ⁷Be wet deposition within a single rainfall event, which reduces the precision of studies on soil particle dynamics. (3) The influence of vegetation cover on the activity concentration and deposition flux of ⁷Be in precipitation reaching the surface has not been sufficiently discussed, and the effect on ¹⁰Be in precipitation reaching the surface has not yet been reported. Recommendations and perspectives (1) Greater attention should be given to long-term observations and multi-regional studies of ⁷Be and ¹⁰Be in precipitation, particularly the supplementation and systematic analysis of ¹⁰Be precipitation data. (2) Future research should conduct capture analyses of ⁷Be during individual rainfall events across different geographical regions, thereby establishing a basis for investigating soil erosion processes. (3) Systematic studies are needed to quantify the relationships between vegetation types or coverage and the interception and retention of ⁷Be and ¹⁰Be, in order to better constrain the role of vegetation in controlling the distribution of surface radionuclides.]]> 2026/6/30 0:00:00 Background, aim, and scope With the accelerated development of urbanization, O₃ pollution in China is becoming increasingly serious, not only affecting economic and social development, but also posing a serious threat to human physical and mental health. Meteorological factors such as temperature, precipitation and relative humidity are important conditions for O₃ pollution. Hubei Province is located in the middle reaches of the Yangtze River Economic Belt, and in recent years, O₃ pollution has become increasingly serious, especially in the Wuhan urban area, where O₃ concentrations exceed the standard in summer and has become the primary air pollutant. The spatial and temporal variations and influencing factors of air quality in major urban areas of Hubei Province are still unclear. This study focuses on the spatial and temporal evolution of O₃ and concentration forecasting to provide data support and references for understanding urban air quality conditions and developing environmental management. Materials and methods This article analyses the spatial and temporal characteristics of O₃ concentration using a dataset of the maximum daily 8-h average O₃ mass concentration, daily temperature, precipitation, relative humidity, and wind speed from 13 prefecture-level administrative regions in Hubei Province during 2015—2023: Shiyan, Xiangyang, Yichang, Enshi, Suizhou, Jingzhou, Jingmen, Wuhan, Ezhou, Huanggang, Xiaogan, Huangshi, and Xianning. Based on the dynamic time warping (DTW) method, clustering of daily O₃ mass concentration changes was carried out, and various machine learning methods for predicting and evaluating daily O₃ mass concentration are explored. Results From 2015 to 2023, the annual average concentration of O₃ in Hubei Province ranged from 79.30 μg/m³ to 99.79 μg/m³, showing a slight upward trend. Concentrations were higher in spring and summer and lower in autumn and winter. The monthly average concentration ranges from 48.7 μg/m³ to 120.0 μg/m³, with a clear double-peak pattern characterized by extreme values in most areas occurring in June and September, respectively. Before 2020, the average quality concentration of Oon weekends in the central and eastern regions was higher than that on weekdays, resulting in a weekend effect. Based on the dynamic time warping method and elbow method, the daily O₃ mass concentration in Hubei Province was classified into four categories, in which the highest O₃ mass concentration was found in Category Ⅲ, from Wuhan to the southern foot of the Dabie Mountains in northeastern Hubei, where the exceedance rates of the national first- and second-level standards were the highest. The shapley additive explanations (SHAP) values of the main meteorological factors affecting O₃ mass concentration in four different regions were analyzed, and the characteristic variables of O₃ forecasting in typical cities were determined. Comparing the forecasting effects of four machine learning forecasting methods in different areas, the long short-term memory (LSTM) method performed best. Discussion The O₃ mass concentrations in 13 prefecture-level administrative regions in Hubei Province are strongly influenced by season and region. Due to multiple factors such as reduced human activities, the level of O₃ pollution in 2020 decreased compared to that before the pandemic. The average O₃ mass concentrations of 2020 in Hubei Province decreased in spring and summer, with the largest decrease in the summer months, which was attributed to reduced emissions from industrial and mobile sources during the pandemic, including pollutants such as NO₂, SO₂, CO, and VOCs. It is worth noting that in summer, a significantly high O₃ concentration area appeared in the Shiyan and Xiangyang areas of northwestern Hubei, which was mainly affected by mountainous terrain and sinking trans-mountain airflow, resulting in summer temperatures prone to extremes, promoting the generation of local O₃, and further exacerbating O₃ pollution. Similar to areas such as Shanxi and Yunnan, a weekend effect is observed in central-eastern Hubei Province, but an anti-weekend effect is observed after 2020, which may be mainly related to reduced emissions from pollutant sources and changes in human activity pattern. In the summer of 2023, a high O₃ pollution period occurred in several cities in Hubei Province, with serious O₃ pollution in May and August, and the analysis of the effectiveness of four machine learning models for O₃ concentration prediction found that the long short-term memory network was the most effective. This indicates a certain level of forecasting ability, but the parameters still need to be further optimized. Conclusions The concentration of Ois influenced by various meteorological factors such as temperature, precipitation, and wind speed, and the LSTM method has a certain predictive ability for the daily O₃ concentration prediction. Recommendations and perspectives This study reveals the changing pattern of O₃ concentration and its relationship with meteorological factors, and provides a predictive method, which provides a basis for the prevention and control of O₃ in Hubei Province. Meanwhile, these insights provide a scientific foundation for future strategies for reducing air pollution in central Chinese cities.]]> 2026/6/30 0:00:00 Background, aim, and scope At present, the global population is constantly migrating from rural areas to cities, and cities are expanding at an unprecedented speed. Urban expansion has become a common focus of concern for governments and academia. However, current literature mostly focuses on single scale studies of the same region, lacking comprehensive research on the same regional space from a multi-scale perspective. A single scale often masks some important information and cannot balance the overall and local characteristics of the spatial pattern within a region. Therefore, this study chooses the Yellow River Basin as the research area, analyzes the spatiotemporal characteristics of urban expansion in the Yellow River Basin from multiple spatial scales based on impervious surface data, and explores its driving factors, in order to provide theoretical basis and technical support for the coordinated development of cities within the Yellow River Basin and new urbanization. Materials and methods This study adopts multi temporal high-resolution (30 m) global urban boundary data, and explores the spatiotemporal pattern of urban land expansion in the Yellow River Basin from 2000 to 2018 at three scales: provincial, prefectural, and county scales. Focusing on impervious surface dynamics, the research integrates spatial autocorrelation analysis to identify clustering patterns and employs geographic detectors to quantify the socio-economic and infrastructural drivers of this expansion. Results (1) From the spatiotemporal pattern of impervious surface density, expansion speed, and intensity, cities and counties (districts) exhibit similar characteristics. The high value areas of impervious surface density and expansion intensity index are mainly concentrated in downstream areas, with some cities in the middle reaches showing high values. The expansion speed shows a decreasing trend from downstream to upstream. (2) The density, expansion speed, and expansion intensity of impervious surface all exhibit spatial positive autocorrelation at different scales, and their spatial clustering states at different scales share common characteristics: high-high clustering areas are mainly distributed in downstream areas, while low-low clustering areas are mainly distributed in the middle and upper reaches, and the high value "island" phenomenon in the middle and upper reaches and the low value "basin" phenomenon in the downstream areas always exist; low-high clustering areas and high-low clustering areas are mostly concentrated around high-high clustering areas and low-low clustering areas. (3) The factors that affect urban expansion in the Yellow River Basin are multifaceted, and the dual effects of population and economy basically determine the pattern of urban spatial expansion. Discussion The difference in spatial agglomeration status of urban expansion indicators at different scales lies in the fact that high-high clustering areas at the city scale are concentrated in the lower reaches of the Yellow River Basin, while high-high clustering areas at the county scale are sporadically distributed in the middle reaches in addition to the downstream areas. In addition, low value clustering areas at the county level have also appeared within the high value clustering areas at the city level, indicating localized and dispersed characteristics at the micro level. Furthermore, from the results of interaction detection, the impact of any two driving factors on urban expansion in the Yellow River Basin is greater than that of a single driving factor alone. Among them, the cross influence of economy and transportation has the most obvious enhancing effect on urban expansion, which is mainly achieved by driving the flow of factors such as funds, labor, and resources. Conclusions (1) There is a certain spatial correspondence between the degree of urban expansion and the level of economic development at different scales. Regions with relatively high levels of economic development have a relatively large degree of urban expansion; regions with relatively low levels of economic development also have relatively small levels of urban expansion. (2) At the county and city scales, urban expansion exhibits a phenomenon of fragmentation, indicating that the imbalance in the process of urban expansion in the Yellow River Basin is still relatively serious. Recommendations and perspectives In practice, we should fully utilize the common and individual characteristics of urban expansion and agglomeration in the Yellow River Basin, construct a multi-scale collaborative development mechanism in the Yellow River Basin, properly handle the "siphon effect", make full use of national spatial planning methods to reasonably guide the rational layout of large, medium, and small cities, establish a precise identification and exit mechanism for inefficient land use, and ultimately form a new spatial pattern of land development and protection characterized by complementary regional advantages and a reasonable division of functions. At the same time, it is necessary to comprehensively apply multiple policy tools, find multiple policy driving points, and promote the rational expansion of urban land through comprehensive policy measures.]]> 2026/6/30 0:00:00 Background, aim, and scope Soil salinization is one of the most severe environmental challenges globally, significantly constraining the efficient utilization of agricultural land and contributing to persistently low crop productivity. Saline-alkali soils are extensively distributed across arid and semi-arid regions, as well as coastal zones, on all continents. Excessive salt accumulation adversely alters the physical and chemical properties of soil, degrading soil structure, impairing water and air permeability, and diminishing the soil's capacity to supply water and nutrients. These changes deteriorate the crop growth environment, severely affecting seed germination, plant establishment, and development, ultimately leading to reduced agricultural yields. Consequently, there is an urgent need to develop highly effective, economical, and environmentally sustainable soil conditioners designed to alleviate salinity stress, enhance crop productivity, and restore the ecological functions of saline-alkali lands. This article provides a systematic review of research progress on the application of biochar and humic acid in the amelioration of saline-alkali soils and the regulation of plant growth under salt stress. This review aims to establish a scientific basis for enhancing the productivity of saline-alkali lands. Materials and methods It begins by outlining the global distribution, formation mechanisms, and conventional remediation strategies for saline-alkali soils. Subsequently, it describes the fundamental physicochemical properties of biochar and humic acid, compares their individual and combined effects on soil improvement, and focuses on elucidating their synergistic mechanisms and comprehensive impacts on soil properties and crop performance. Results A systematic evaluation of domestic and international studies on the application of biochar and humic acid in saline-alkali soil remediation reveals that the use of either amendment alone can improve soil structure and hydraulic properties, enhance aggregate stability, and promote desalination and dealkalization processes. Both amendments also increase soil enzyme activity and nutrient cycling efficiency. Notably, the combined application of biochar and humic acid demonstrates significant synergistic effects: the porous structure and high adsorption capacity of biochar provide a stable matrix for humic acid, reducing its leaching loss; in turn, humic acid forms localized acidic microenvironments on biochar surfaces, enhancing its solubility and facilitating nutrient release. This synergistic interaction alleviates salt stress during seed germination and mitigates the toxic effects of salt ions on plant tissues, thereby effectively improving the quality of saline-alkali soils. Discussion Despite the considerable potential of biochar and humic acid for soil improvement, several limitations persist. First, commercially produced biochar often contains elevated levels of alkali metals and soluble salts; long-term or high-rate application may exacerbate soil salinization, raising concerns regarding its predictability and scientific applicability across different types of saline-alkali soils. Second, humic acid exhibits limited stability and is susceptible to microbial degradation; excessive application may lead to the formation of hydrogels that reduce soil hydraulic conductivity and impede salt leaching, potentially worsening salinization. Third, while the combined use of biochar and humic acid offers complementary benefits and enhanced remediation efficacy— accelerating soil recovery and representing a more promising sustainable improvement strategy— the optimal application rates, ratios, and operational protocols remain to be established. Systematic evaluations are therefore required to determine the practical viability of this composite remediation approach for large-scale restoration of saline-alkali lands. Conclusions The combined application of biochar and humic acid effectively improves soil structure, reduces soluble salt content, enhances nutrient availability and microbial abundance, mitigates salt-induced inhibition of seed germination and plant growth, and ultimately increases agricultural productivity in saline-alkali soils. Recommendations and perspectives The ameliorative effects of biochar and humic acid depend not only on their intrinsic properties but also on external factors such as soil texture, climatic conditions, and irrigation water quality. Current research on their mechanisms of action and ecological effects requires strengthened fundamental investigations to explore the applicability of biochar and humic acid across different climatic zones and soil types. Such efforts will enable the precise optimization of their application efficiency within targeted soil improvement strategies.]]> 2026/6/30 0:00:00 Background, aim, and scope Engineering construction contributes to nearly one-third of China's total carbon emissions, making carbon reduction and emission control in this sector a critical challenge. In this context, green infrastructure development has become an important goal for the construction industry. As a key component of infrastructure construction, slope protection engineering also has environmental impacts that cannot be ignored. This study aims to establish a comprehensive evaluation system for loess slope protection engineering by integrating four dimensions: low-carbon performance, safety, economy, and aesthetics. By comprehensively evaluating and comparing different slope protection schemes, this study provides a decision-making basis for engineering selection, promotes the application of low-carbon technologies in loess slope protection, and supports the sustainable development of this field. Materials and methods The comprehensive evaluation system developed in this study combines an improved Analytic Hierarchy Process (AHP) with the fuzzy comprehensive evaluation method to determine indicator weights and comprehensive scores. The system consists of four primary indicators: low-carbon performance, safety, economy, and aesthetics. Each primary indicator is further divided into secondary indicators based on the principles of measurability, representativeness, independence, and completeness. The low-carbon indicator includes carbon emissions, carbon sequestration, and carbon-neutralization period. The safety indicator includes structural characteristics, single-stage slope height, and anti-scour capacity. The economy indicator includes project cost, service life, and construction duration. The aesthetics indicator includes plant diversity and vegetation coverage. Nine commonly used slope protection schemes were selected for evaluation: concrete retaining wall, facing wall, anti-slide pile, stone slope protection, geocell-assisted grass slope protection, vegetated wrapped reinforced retaining wall, honeycomb grid grass slope protection, mortar-stone skeleton grass slope protection, and planting bag slope protection. Expert scoring and membership matrix construction were used to determine the comprehensive scores and evaluation grades of each scheme. Results The results show that the weights of low-carbon performance, safety, economy, and aesthetics are 0.180, 0.585, 0.180, and 0.055, respectively. The vegetated wrapped reinforced retaining wall achieved the highest comprehensive score of 92.35 and was classified as a Grade Ⅰ scheme, indicating its superior performance in low-carbon performance, safety, economy, and aesthetics. Geocell-assisted grass slope protection and mortar-stone skeleton grass slope protection obtained scores of 84.45 and 80.84, respectively, and were classified as Grade Ⅱ schemes. Other schemes, including planting bag slope protection, honeycomb grid grass slope protection, anti-slide pile, concrete retaining wall, stone slope protection, and facing wall, obtained scores ranging from 67.73 to 77.74, with evaluation grades ranging from Grade Ⅲ to Grade Ⅳ. Discussion Ecological slope protection schemes replace high-carbon concrete and stone materials with low-carbon geosynthetics and vegetation, thereby significantly reducing carbon emissions during material production, transportation, and construction. At the same time, vegetation and soil provide continuous carbon sequestration, effectively shortening the carbon-neutralization period and contributing to excellent low-carbon performance. The vegetated wrapped reinforced retaining wall combines the structural stability of reinforced retaining walls with the ecological benefits of vegetation, resulting in good performance in terms of safety, economy, and landscape compatibility. In contrast, traditional protection schemes mainly rely on high-strength rigid structures. Although these schemes can provide high safety, they usually involve high carbon emissions, high costs, and poor landscape compatibility, leading to lower comprehensive performance. Existing studies have mostly focused on single-dimensional evaluations, such as safety, economy, or carbon emission accounting, and few have integrated low-carbon performance into a multi-objective evaluation framework. Some studies have analyzed carbon emissions in slope protection projects, but they rarely combine carbon emissions, carbon sequestration, and the carbon-neutralization period. Methodologically, conventional AHP is often limited by consistency testing and strong subjectivity, whereas the improved AHP adopted in this study enhances objectivity and credibility. In terms of engineering applicability, most previous studies are not specifically oriented toward loess areas, while the evaluation system proposed in this study is closely linked to the geological characteristics of loess slopes and is therefore more applicable to loess slope protection engineering. The innovations of this study are as follows. First, a four-dimensional comprehensive evaluation system of "low carbon-safety-economy-aesthetics" is constructed for loess slope protection engineering, overcoming the limitations of single-index evaluation. Second, the improved AHP is combined with fuzzy comprehensive evaluation to achieve quantitative and standardized comprehensive assessment. Third, the carbon-neutralization period is introduced to reflect the dynamic balance between carbon emissions and carbon sequestration, which is more consistent with the goals of carbon peaking and carbon neutrality. Conclusions A low-carbon comprehensive evaluation system including four primary indicators and eleven secondary indicators was developed for loess slope protection engineering. The improved AHP and fuzzy comprehensive evaluation method were used to achieve scientific weighting and quantitative assessment. The evaluation of nine slope protection schemes shows that ecological protection schemes perform significantly better than traditional rigid protection schemes. Among them, the vegetated wrapped reinforced retaining wall is identified as the optimal scheme, with a score of 92.35 and a Grade Ⅰ classification. The proposed evaluation system and method can support the scientific selection of loess slope protection schemes and promote the low-carbon and sustainable development of infrastructure construction. Recommendations and perspectives To further enhance the practical applicability of the comprehensive evaluation system, future research should expand the scope of evaluation indicators and refine the evaluation methods. Additional environmental and social factors, such as biodiversity conservation and community impacts, could be incorporated to provide a more holistic assessment of slope protection measures. Moreover, the integration of advanced technologies, such as big data and machine learning, may improve the accuracy and efficiency of the evaluation process.]]> 2026/6/30 0:00:00 2026/6/30 9:13:41