This study analyzed the spatiotemporal dynamics of the vegetation ecological quality under climate change. Focusing on the vegetation conditions, a vegetation ecological quality index was constructed, expressing as the product of vegetation fraction cover (VFC), net primary productivity (NPP), and geographic coverage area. The results of trend and significance analysis showed that from 2000 to 2023, the VEQI in the Qinling Mountains exhibited a significant improvement, with an average slope of 4.91 gC & centerdot;a-1 and 96.2% of the area showing high stable improvement. Partial correlation analysis revealed that precipitation had a stronger positive influence on VEQI than temperature, with over 98% of the area showing a positive correlation with precipitation, while temperature was positively correlated in 95.0% of the area but negatively correlated in high-altitude mountain zones. Therefore, four climate-driven patterns were identified: precipitation-driven (31.2%), temperature-driven (2.3%), co-driven (54.2%), and climate-stable (12.3%), suggesting that vegetation ecological quality in most regions is co-driven by both temperature and precipitation. Based on the results of trend and significance analysis and climate-driven patterns, the Qinling Mountains were divided into three ecological risk zones: low-risk (36.1%), middle-risk (56.9%), and high-risk (7.0%), with corresponding differentiated control measures proposed.

The Three-River regions, as a crucial water source conservation area in China, plays a crucial role in maintaining the regional hydrological and climatic stability through its extensive highland wetlands.Considering the competitive interaction between soil moisture anomalies and precipitation feedback mechanisms under different environmental conditions, this study conducted control and sensitivity experiments based on the WRF meteorological model, combined with the CTP-HIlow framework and CAPE index, to assess the precipitation response under soil moisture anomaly conditions.The study preliminarily analyzes the impact characteristics and feedback mechanisms of soil moisture anomalies on regional weather, particularly precipitation processes.Specifically, based on transient simplified evaporation experiments and inversion methods, the WRF simulation incorporated hydrological measurement data from multiple soil samples collected within the study area.The results show that the hydraulic properties of wetland soils significantly influence surface thermal properties and energy distribution.The soil hydraulic parameters obtained using the simplified evaporation method significantly improved the model’s simulation of latent heat flux, sensible heat flux, surface temperature, 2-meter air temperature, and 2-meter specific humidity.Soil moisture anomalies have a significant impact on short-term precipitation processes.Under conditions of soil moisture anomalies, both CAPE and CTP values significantly increase, while HIlow values decrease, accompanied by an increase in atmospheric instability and water vapor content, leading to a clear positive feedback response in precipitation.In contrast, under dry anomaly conditions, CAPE and CTP values slightly decrease, while HIlow values increase, accompanied by reduced atmospheric instability and decreased water vapor content, with precipitation showing no clear feedback to soil moisture.The hydraulic characteristics of wetland soils, through regulating surface energy distribution and water vapor flux, significantly affect precipitation processes at both local and regional scales.Especially under soil moisture anomaly conditions, the hydrological regulation effect of wetland soils plays a crucial role in precipitation feedback mechanisms, further highlighting their key position in maintaining regional hydrological and climatic stability.

Dead ice in High Mountain Asia (HMA) varies responsive to dramatic glacier loss, profoundly impacting alpine water cycle patterns. We find significant dead ice increase over this century, additional area exceeds 3,000 km2, with mass 44.3 ± 2.0 ~ 64.1 ± 5.2 Gt. Debris coverage dominates dead ice spatial pattern. Dead ice expansion would significantly alter spatio-temporal patterns of glacier ablation and impact water supply sustainability in World's Water Towers.

Abstract. Outburst floods from glacial lakes have predominantly occurred during ablation seasons, with few documented cases for frozen lakes during winter. The rarity of winter failures has led to the perception that glacial lakes with frozen surfaces and limited meltwater are generally regarded as safe. Here we report a winter-outburst flood from a frozen proglacial lake in the Central Himalaya on 16 December 2024. Two lateral rockfalls with a total volume of ~4.29 Mm3 broken ~0.35 m thick lake ice below and triggered an “ice tsunami” at the lake terminus, unleashing a partial drainage of the ice-covered lake and triggering a flash flood that travelled roughly 140 km downstream. Although the lake-ice cover had blunted catastrophic overtopping by damping impact energy and wave amplitude, this winter outburst case suggests that the occurrence window for future GLOFs will temporally extend in high mountain areas as paraglacial slope failures increase and lake ice diminishes during winter. This single event therefore reveals a systematic blind spot in current GLOF risk assessments: frozen lakes are not inherently safe. We therefore urge a call to heighten public awareness of this emerging dangerous and future GLOF risk assessments/early-warning systems should incorporate lake-ice condition as one of monitoring parameters under relevant safety protocols.

Glacier response to climate change results in rapid glacier water resource loss. Positive glacial regulatory processes (GRPs) are processes that buffer glacier water resource losses. Nevertheless, these processes are not systematically quantified, which may lead to uncertainty in glacier water resource sustainability assessments. Here, we employ a glacier water balance model to track glacier water resource transport trajectories and quantify contributions of positive GRPs across High Mountain Asia (HMA). The combined impacts of positive GRPs could mitigate 236-255 Gt of HMA glacier water resource loss ( 9

As the global climate warms and mountain glaciers retreat, both the number and size of glacial lakes in High Mountain Asia (HMA) have increased markedly. However, the status, spatial heterogeneity, and formation mechanisms of newly formed glacial lakes remain insufficiently understood. Using glacial lake inventories for 2000 and 2020, we identified newly formed glacial lakes across HMA through spatial and ID-based matching, classified them into formation types based on visual interpretation and geomorphological analysis, and analyzed their spatial distribution and topographic characteristics. A total of 872 newly formed glacial lakes were identified during 2000–2020, most of which were small, with areas of 0.0054–0.23 km2 and a median area of ∼0.01 km2. Glacier-fed lakes and non-glacier-fed lakes accounted for 76.8% and 23.2% of the total, respectively. Glacier-erosion lakes dominated (76.5%), followed by moraine thermokarst lakes (13.3%). Spatially, lake formation was highly heterogeneous, with the largest numbers occurring in the Central Himalaya, Western Himalaya, and Gangdise Mountains, but only a few lakes forming in the Qilian Shan and Eastern Tibetan Mountains. Topographic analysis of 427 lakes with identifiable depressions showed that glacier-erosion lakes and cirque lakes developed in more enclosed and incised basins than moraine thermokarst lakes, as indicated by steeper surrounding slopes and lower Negative Topographic Index (NTI; a metric of lake-basin enclosure and negative-relief morphology) values. Random Forest analysis indicated that surrounding slope, elevation, and NTI jointly contributed to the differentiation of glacier-fed lake types (38.1%, 33.5%, and 28.4%, respectively), whereas surrounding slope dominated differentiation of non-glacier-fed lakes (45.1%). At the subregional scale, lake abundance was more strongly associated with net precipitation change than with warming rate alone. These findings suggest that newly formed glacial lakes in HMA are shaped by the coupled effects of glacier retreat, topographic accommodation, water availability, and local geomorphic conditions, providing a basis for assessing future glacial lake evolution under continued climate change.

Study region: China-Pakistan Karakoram Highway (KKH) and its surroundings. Study focus: Glaciers along the China-Pakistan International Karakoram Highway (KKH) exhibit relative stable or mass gain, a phenomenon termed "Karakoram Anomaly", contrasting with widespread global glacier retreat. However, rising ice velocities and advancing termini are triggering more frequent glacier hazards, threatening infrastructure and communities. Despite these risks, a comprehensive assessment of their impacts on highway safety remains lacking. Here, we present a comprehensive assessment of potential ice avalanches (PIAs) and potential surging glaciers (PSGs) along the KKH over the past two decades, by combining machine learning techniques and statistical methods. New hydrological insights for the region: We identified 344 PSGs and 1001 PIAs in 533 glaciers, primarily in the Karakoram and northeastern Pamir. These hazards pose catastrophic risks to 17 basins, directly affecting 25% basins, 68% local residents, 14 bridges, 154 attaching sites, and 130 km critical highway segments. SHapley Additive exPlanations (SHAP) analysis reveals that terrain conditions, such as elevation, slope, and aspect, control PIAs, while climate warming significantly intensifies PSGs. It is projected to transit to a warming-wetting trend, signaling the weakening or even the end of the Karakoram Anomaly and leading to more frequent and severe glacier hazards. These findings highlight accelerating glacier instability under climate change and provide critical evidence for disaster prevention/mitigation strategies and infrastructure resilience in this region.

Glacierized-catchment runoff (GR) across High Mountain Asia (HMA) is approaching peak water, but the timing is not uniform. Glacier size, elevation, and regional climate push that threshold to different points in time, with direct implications for downstream water security. We used OGGM v1.6.1, forced by bias-corrected GSWP3-W5E5 historical data and an ensemble of 13 CMIP6 GCMs under four SSP scenarios, to simulate glacier mass balance, dynamics, and glacierized-catchment runoff across 17 major HMA basins from 1940 to 2100. By 2100, HMA-wide glacier mass declines by 70.7 ± 9.6%, relative to 2000 levels, and total GR falls by 10 ± 6.5% between the early (2001–2020) and late (2081–2100) century periods. Small, low-elevation glaciers have already passed peak runoff in many basins, some before 2020, and are losing volume rapidly. Large, high-elevation glaciers continue buffering downstream flows well into the late 21st century, with basin-wide peaks as late as 2058 in Tarim and 2064 in the Amu Darya, and individual large high-elevation glacier classes peaking as late as 2083 in Tarim under high-emission scenarios. We identify three distinct peak-GR regimes: early, transitional, and delayed, driven by the size and elevation composition of glacier classes within each basin, rather than average glacier behavior. Basin-averaged projections may obscure important class-specific runoff transitions, underscoring the need for class-resolved, basin-specific water resource planning across HMA

The Qinghai-Tibet Plateau (QTP) is a global biodiversity hotspot where Quaternary climatic oscillations profoundly shaped the evolution of endemic alpine flora. Understanding how genetic diversity and structure in these species responded to past climate change is crucial for deciphering regional evolutionary mechanisms. Using chloroplast and nuclear genome data of 958 samples from 48 populations, we evaluated the genetic diversity and population structure of Primula sikkimensis. We then investigated the lineage differentiation and dynamics of species by combining an Approximate Bayesian Computation procedure and species distribution modeling. Our study indicates that P. sikkimensis maintained separate glacial refugia in the Hengduan Mountains and eastern Himalayas during the Last Glacial Maximum (LGM). Our results suggest that postglacial range expansions onto the inner QTP plateau were accompanied by gene flow arising from both intraspecific secondary contact between previously isolated populations and interspecific hybridization events, which collectively enhanced genetic diversity and adaptive capacity in plateau populations. Our findings underscore the critical role of postglacial population dynamics and gene flow in shaping genetic diversity and adaptive potential of alpine endemics like P. sikkimensis, highlighting evolutionary responses to Quaternary climate change on the QTP.

Flood and landslide hazards frequently overlap spatially, thereby increasing population exposure worldwide. However, global assessments quantifying flood–landslide multi-hazard population exposure and disentangling the relative roles of climate and population change remain limited. Here, we develop a global framework integrating multi-source remote sensing datasets, machine learning-based susceptibility models validated with both non-spatial and spatial cross-validation, and a multi-hazard risk matrix to delineate high-risk areas under historical and future climate scenarios (SSP1–2.6, SSP2–4.5, SSP5–8.5). Population exposure is quantified within these areas at 10 km resolution, revealing pronounced national-scale concentration, with China and India together accounting for more than 40% of the population residing within high and extremely high risk areas. Baseline exposure, representing inherited population distributions and historical hazard configurations, constitutes the largest share of total future population exposure, illustrating the enduring structural determinants of risk. Relative contribution analysis further reveals pronounced scenario-dependent variability in the drivers of future exposure growth. Population change dominates exposure increases under the intermediate-emission pathway, whereas climatic and demographic contributions become comparatively more balanced under both low- and high-emission scenarios. Joint effects remain limited overall, but become increasingly evident within stricter high-risk areas. These results highlight the scenario-dependent interplay between climatic and demographic drivers and demonstrate the importance of baseline population structures in shaping future exposure. Collectively, this framework provides a systematic basis for evaluating the drivers and uncertainties of global flood–landslide exposure, informing targeted adaptation strategies and multi-hazard risk management under global change.

Soil organic carbon (SOC) decomposition underpins soil-atmosphere carbon exchange and is regulated by climate change-mediated variations in soil redox conditions. Periodic anoxia, commonly occurring following precipitation, soil flooding, and erosion events, is assumed to preserve SOC. Yet, water saturation may also increase SOC decomposition relative to unsaturated conditions, and contradictory findings among previous studies remain unexplained. Here, using incubation experiments on 20 soils collected across a 24° latitude gradient in China, we show that 70% of the soils showed a higher or similar anoxic decomposition rate of SOC compared to the oxic treatment, indicating fast SOC loss under relatively short anoxia. Methane production was far lower than CO2 due to the presence of alternative terminal electron acceptors (TEAs). Variation in alternative TEAs and microbial community shows that fast anoxic decomposition was primarily driven by iron (Fe) reduction, which accounted for up to 90% of anoxic CO2 production. Meanwhile, positive relationships among water-extractable organic carbon (OC), hydrochloric acid-extractable ferrous Fe, relative abundance of Fe-reducing prokaryotes, and the SOC decomposition rate suggest the release of readily metabolized substrates following Fe reduction. This release provided substrates for anoxic metabolism and potentially led to the loss of OC protected by Fe (Fe-bound OC; a slow-cycling OC pool under oxic conditions). Mass balance calculation confirms that Fe-bound OC loss was mostly similar to elevated anoxic SOC decomposition in magnitude, and random forest modeling indicates that soils rich in reducible Fe, SOC, and Fe-reducing prokaryotes most likely experience elevated SOC decomposition under periodic anoxia. Overall, our findings demonstrate that fast anoxic decomposition of SOC is a potentially important pathway that may stimulate SOC loss under climate change-mediated intense hydrologic regimes, particularly for soils rich in reducible Fe and SOC.

AimsThe landscape of sand-covered hilly areas has been reshaped by afforestation in these areas. Dynamic changes in soil moisture and nutrients in forests after afforestation have become evident. However, clear studies have not focused on whether rainfall interception in these plantations affects soil concentration or concentration.MethodsThis largely limits the development of effective management techniques for plantations and hinders the optimal utilization and management of water resources. In this study, an investigation was conducted on the plant community structure, rainfall interception characteristics, and soil organic carbon (SOC) and total nitrogen (N) concentrations or concentrations of three different plantations in the sand-covered hilly area of the Kuye River Basin. Grassland (Gl) was taken as the control.ResultsThe critical throughfall values for C. korshinskii (Ck), S. Cheilophila (Sc) and P. sylvestris (Ps) were 0.28, 1.78 and 2.04 mm, respectively. Corresponding stemflow critical values measured were 2.93, 1.08, and 3.30 mm, respectively. Ps exhibited the highest interception capacity, which was attributable to its dense canopy and layered branch architecture. Sc ranked second due to its larger leaf area, while Ck showed the lowest interception because of wide branch angles and smaller leaf area. Post-rainfall ground-level soil moisture and litter deposition are regulated by vegetation canopy structure in a direct way. SOC and N concentrations are subsequently controlled by these ground-level parameters. SOC concentration under Ps was 1.54 compared to that under Gl, while N concentration was 1.50 times higher, respectively.ConclusionsThus, Ps demonstrates optimal effectiveness for improving soil quality in sandy hill restoration areas and merits continued implementation in this region.

Ignition delay times (IDTs) of ammonia(NH3)/butan-1-ol mixtures with NH3/butan-1-ol mole ratios of 100/0, 95/5, 90/10 and 70/30 were measured behind reflected shock waves in a shock tube over a range of experimental conditions: temperature range of 1100 - 2000 K, pressures of 0.14 and 0.5 MPa, equivalence ratios of 0.5, 1.0 and 2.0. A new NH3/butan-1-ol reaction mechanism, capable of predicting the experimental results reliably, was developed. Chemical kinetic analyses were performed with the model. It is demonstrated that increasing the content of butan-1-ol in the reaction system results in a non-linear trend of shortening on the IDTs of mixtures, adding 5 % molar fraction of butan-1-ol results in shortening rates of over 70 %. As the butan-1-ol blending ratio increases from 5 % to 30 %, the discrepancy in IDT of the mixture between equivalence ratios of 0.5 and 1.0 diminishes while it remains more pronounced between equivalence ratios of 1.0 and 2.0. The presence of butan-1-ol does not change the oxidation pathways of the NH3 mixture. R72(NH3 + M = NH2 + H + M) and R75(NH2 + HO2 = NH3 + O-2) are key reactions to activate chain reactions of the NH3 mixture during the initial reaction stage, for a temperature of 1500 K, a pressure of 0.14 MPa, and an equivalence ratio of 1.0. Reactive radicals produced through the process of butan-1-ol oxidation result in a significant increase in the initial dehydrogenation consumption rate of NH3, by a factor of 5 similar to 6 powers of ten, accelerating chain reactions.

Glacio-hydrological models have been increasingly utilized to evaluate hydrological responses to climate change in glacierized regions, particularly at the catchment and basin scales. However, comprehensive global assessments remain inadequate. This review investigates the fundamental processes and structures of glacio-hydrological models, summarizes their applications, and discusses the prevailing challenges and outlooks of glacio-hydrological modelling worldwide. Previous findings indicate that simple empirical algorithms, including the degree-day model and volume-area scale, are widely employed in existing glacio-hydrological models, whereas physical-based algorithms, such as energy balance and glacier dynamics, remain limited, but are imperative for future model development. Various glacio-hydrological models have been implemented to investigate the glacio-hydrological responses to climate change worldwide, with a growing research focus from the Alps to High Mountain Asia (HMA). Concurrently, the spatial scales of these studies have exhibited a noticeable transition from catchment-wise towards basin-wise in the Alps and North America, and from basin-wise towards regional-wise in the Tibetan Plateau. Moreover, global glacier meltwater is projected to reach a tipping point by the mid-21st century, varying in regions, glaciated areas, volumes, and warming rates. Consequently, regulation effect and hydrological regime in glacierized regions will experience changes that affect water-related hazards, risk adaptations, and downstream livelihoods, such as agricultural irrigation. Furthermore, there are significant uncertainties and inconsistences regarding glacier runoff contributions, streamflow regime changes, peak water timings, and associated impacts, primarily owing to variations in driving forces and model complexities, including spatio-temporal resolutions, model structures, parameterizations and calibration schemes. Existing glacio-hydrological models also suffer from inconsistent definitions of glacier runoff and a lack of high-quality and quantity-rich forcing datasets. Overall, there is an urgent need to refine and develop models that provide comprehensive and robust descriptions of glacier- and snow-related hydrological processes while leveraging data-driven models and multi-source datasets. This review is expected to provide scientific insights into policymaking and sustainable resource management of pivotal glacier-dependent ecosystems.

High Mountain Asia stands out as the global epicentre of cryospheric risk, and is possible to provide a model for global resilience in a rapidly warming world. Typesetting of author information: set at the end of the article. use the same type as that of the Perspective articles.

Study region: Western Nyainqentanglha Mountains, Tibetan Plateau Study focus: Rock glaciers, as distinctive debris landforms prevalent in high mountain regions, are a crucial component of the regional frozen water reservoir system. However, the up-to-date distribution and hydrological significance of rock glaciers have received comparatively less attention, primarily due to considerable challenges in inventorying. Here we focus on the automated identification of rock glaciers in the semi-aird Western Nyainqentanglha Mountains using machine learning algorithms and Sentinel data, and then perform the first systematic quantification of the water volume equivalent (WVEQ) of these rock glaciers to assess their hydrological contribution to the region. New hydrolgical insights for the region: A total of 1068 rock glaciers are mapped across the region, covering an area of approximately 140.2 km2 and spanning an elevation range from 4536 to 6000 m. For these rock glaciers, the total WVEQ is estimated to be 2.33 km3, and the regional rock glacier-to-glacier WVEQ ratio is 1:13. This first-order approximation of the WVEQ provides substantial evidence that rock glaciers serve as a critical component of the regional water supply system at decadal and longer timescales. Given the increasing climate-driven imbalance of frozen water reservoirs, our findings highlight the importance of incorporating the water storage potential of rock glaciers into predictions of water availability and sustainable development strategies in the semi-arid Western Nyainqentanglha Mountains.

Accurate snow cover data are critical for understanding the Earth’s climate system, and exploring hydrological processes and regional water resource management over High Mountain Asia (HMA). However, satellite-based remote sensing observations of snow cover have inevitable data gaps originating from cloud cover, sensor, orbital limitations and other factors. Here an effective cloud-gap-filled (CGF) method was developed to fully fill the data gaps in Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference snow index (NDSI) product. The CGF method combines the respective strengths of the cubic spline interpolation method and the spatio-temporal weighted method for generating the CGF Terra-Aqua MODIS NDSI product over HMA from 2000 to 2021. Based on the validation results of in situ snow-depth observations, the CGF NDSI product achieves a high range overall accuracy (OA) of 93.54–98.08%, a low range underestimation error (MU) of 0.15–3.49% and an acceptable range overestimation error (MO) of 0.84–5.77%. Based on the validation results of high-resolution Landsat images, this product achieves the OA of 88.52–92.40%, the omission error (OE) of 1.42–10.28% and the commission error (CE) of 5.97–17.58%. The CGF MODIS NDSI product can provide scientific support for eco-environment sustainable management in the high mountain region.

Maritime glaciers in the southeastern Tibetan Plateau (TP) have experienced important changes in mass and dynamics over the past decades, challenging the regional water supply and glacier-related hazards. However, knowledge about long-term variations in the surface velocity and mass balance of maritime glaciers remains incomplete due to the lack of representative observations in the southeastern TP. In this study, offset tracking is employed to measure spatiotemporal variation in the surface velocity of the Hailuogou Glacier (HLG) in Mount Gongga of the southeastern TP using Sentinel-1A imagery, while the time series of the HLG mass balance is reconstructed since 1950 by a physically based energy–mass balance model. Our satellite-based results find that HLG surface velocity shows significant spatial heterogeneity with a double-peak pattern along the flow line, and sustained slowdown below the icefall zone has been observed during the past nearly 40 years, although the icefall zone and the area above it have become relatively active. Our modeling indicates a persistent increase in mass loss over the last seven decades with an average rate of −0.58 m water equivalent (w.e.) year−1, which has accelerated in the past two decades. Sustained slowdown on the glacier is concomitant with pronounced negative mass balance, thereby enhancing glacier wastage in recent decades. The long-term trend in HLG mass loss is mainly driven by an increase in positive air temperature that decreases surface albedo and solid precipitation ratio and increases longwave incoming radiation, besides the influence of supraglacial debris cover. Large-scale atmospheric circulation patterns in the Eurasian region provide important implications for regional-to-local climate variability, unsustainably intensifying the trend of the negative mass balance of the HLG in the southeastern TP in the past two decades.