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This paper aims to update our understanding of the carbon cycle in the Himalayas, the most intense collisional orogeny globally, by providing new insight into its impact on Cenozoic climate cooling through the use of isotopic variations in both organic and inorganic carbon and an isotopic mass balance model. Our results from 20 selected hot springs show that the relative contributions of dissolved carbon from the mantle, metamorphic decarbonization, aqueous dissolution, and soil organic matter are approximately 2%, 82%, 6%, and 10%, respectively. Approximately 87% ± 5% of CO2 generated in the deep crust precipitates as calcite, while approximately 5.5% ± 1% of this carbon is converted to biomass through microbial chemosynthesis at depths less than 2 km. Our random forests approach yielded a metamorphic carbon flux from the entire Himalayan orogenic belt of approximately 2.7 ∼ 4.5 × 1012 mol/yr. The minor CO2 released into the atmosphere (2.5 ∼ 4.2 × 1011 mol/yr) is comparable to the carbon consumption driven by Himalayan weathering. This paper provides new insights into deep carbon cycling, notably that approximately 93% of deeply sourced carbon is trapped in the shallow crust, rendering orogenic processes carbon neutral and possibly acting as one of the major triggers of long‐term climate cooling in the Cenozoic. Plain Language Summary: Large‐scale deep metamorphic decarbonization and CO2 release into the atmosphere during continental collision orogenesis worldwide have had significant impacts on Cenozoic global climate change. However, the carbon sources and sinks and the mechanisms underlying their impacts on climate change are not fully understood. This paper reports the chemistry of aqueous solutions, carbon isotopic compositions of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC), and helium and carbon isotopic compositions of free gases from hot springs in southern Tibet. The carbon isotope fractionation model between gas and aqueous solutions revealed that the carbon released from depth underwent six different stages. Based on the random forests machine learning algorithm, we estimated the metamorphic carbon flux across the Himalayan orogenic belt. Furthermore, only a small fraction (7%) of deep carbon is eventually released into the atmosphere, and this volume is the same magnitude as the amount of carbon absorbed by silicate weathering on the Tibetan Plateau. This paper emphasizes that the carbon sequestration process in the upper crust may have resulted in nearly carbon‐neutral geological bodies in the Himalayan orogenic belt, thus playing a critical role in Cenozoic climate cooling. Key Points: Approximately 87% of deeply sourced carbon precipitates as calcite, while approximately 5.5% is sequestered as biomass in the shallow crustThe carbon flux across the Himalayan orogenic belt was estimated by the random forests approachCrustal thickening has attenuated long‐term deep carbon emissions from the Himalayas [ABSTRACT FROM AUTHOR]

Recent climate and environment over the Tibetan Plateau (TP) have undergone significant changes, dominated by variations in the Westerlies and the Indian summer monsoon. However, long‐term shifts in atmospheric circulation during the transitional seasons are still lacking. Here we investigate the modern distribution of Tsuga pollen over the central‐western TP and confirm it as an indicator of variable atmospheric circulation in spring. By combining our Tsuga record from Taro Co with existing records in the Tsuga pollen source area, we suggest that a potential particle transport pathway from the southern slope of the Himalayas to the interior of the plateau appeared in the spring of the late Holocene. Our results show that the springtime atmospheric circulation over the southwestern TP during the early and late Holocene is closely related to the substantial remnants of ice sheets at northern high latitudes and the frequency of El Niño events, respectively. Plain Language Summary: The spring climate over the Tibetan Plateau (TP) is undergoing significant changes that yield profound impacts on environmental changes such as variations in vegetation phenology and alpine treeline. Knowledge of long‐term variations in atmospheric circulation during spring can improve the understanding of current climatic and environmental change and the projection of future variability. In this paper, we use an exotic pollen grain, which can be transported long distances in the air, as an indicator to trace the variability of spring atmospheric circulation over the TP. The results indicate that the spring meridional atmospheric circulation from the southern slope of the TP to its interior has been enhanced in the last four thousand years, which is mainly influenced by the frequency of El Niño events. Key Points: Spring atmospheric circulation change over the southwestern Tibetan Plateau (TP) during Holocene is reconstructedMeridional atmospheric circulation in spring over the southwestern TP is strengthened in the late HoloceneHigh‐(low‐) latitude forcing mainly influence the variations in spring atmospheric circulation during the early (late) Holocene [ABSTRACT FROM AUTHOR]

Conceptual models demonstrate that climate can control the structural evolution of mountain belts and that Pliocene–Quaternary global climate change modulated Himalayan wedge behaviour. A key test of this hypothesis is the timing of foreland accretion. If foreland accretion pre‐dates climate change, then climate is not the primary driver of mountain building. New apatite (U–Th)/He data from NW Himalaya foreland thrust sheets suggest that accretion had occurred by the latest 4 Ma, prior to the Pliocene–Quaternary global climate change. Climate cannot, therefore, be invoked as the principal driver of Himalayan tectonics in the late Cenozoic. Statement of significance: This paper presents 66 new, single grain apatite (U–Th)/He (AHe) dates from the foreland basin that constrain NW Himalayan evolution through the late Cenozoic. We show that accretion of the NW sub‐Himalayan foreland was underway by 4 Ma at the latest, several million years earlier than previous estimates, and was followed by distributed, wedge‐internal deformation by 2 Ma. These and other published data present a consistent pattern and timing of deformation observed over nearly 600 km of the NW sub‐Himalaya. Our new constraints on orogen evolution provide key insights into the relative importance of climate and tectonics in driving orogenic systems. [ABSTRACT FROM AUTHOR]

The high‐mountain system, a storehouse of major waterways that support important ecosystem services to about 1.5 billion people in the Himalaya, is facing unprecedented challenges due to climate change during the 21st century. Intensified floods, accelerating glacial retreat, rapid permafrost degradation, and prolonged droughts are altering the natural hydrological balances and generating unpredictable spatial and temporal distributions of water availability. Anthropogenic activities are adding further pressure onto Himalayan waterways. The fundamental question of waterway management in this region is therefore how this hydro‐meteorological transformation, caused by climate change and anthropogenic perturbations, can be tackled to find avenues for sustainability. This requires a framework that can diagnose threats at a range of spatial and temporal scales and provide recommendations for strong adaptive measures for sustainable future waterways. This focus paper assesses the current literature base to bring together our understanding of how recent climatic changes have threatened waterways in the Asian Himalayas, how society has been responding to rapidly changing waterway conditions, and what adaptive options are available for the region. The study finds that Himalayan waterways are crucial in protecting nature and society. The implementation of integrated waterways management measures, the rapid advancement of waterway infrastructure technologies, and the improved governance of waterways are more critical than ever. This article is categorized under:Engineering Water > Sustainable Engineering of Water [ABSTRACT FROM AUTHOR]

Globally, treelines form a transition zone between tree‐dominated forest downslope and treeless alpine vegetation upslope. Treelines represent the highest boundary of "tree" life form in high‐elevation mountains and at high latitudes. Recently, treelines have been shifting upslope in response to climate warming, so it has become important to understand global tree diversity and treeline distributions. However, to the best of our knowledge, no global database on tree flora of treelines exists, which limits our capacity to undertake macroecological analyses. Here, for the first time, we present a global data set on the trees of the treeline ecotone, supported by an online ToTE database. We synthesized the database from 1202 studies published over the last 60 years (1962 to 2022) following the Preferred Reporting Items in Systematic Reviews and Meta‐Analysis (PRISMA) protocol. We classified the tree species in the database into three categories: treeline tree (TL) species, near to treeline (NTL) tree species, and tree species with an upper montane range limit (TUMR). The ToTE Version‐1 presents a total of 208 tree taxa, including 189 species, five subspecies, and 14 varieties, belonging to 54 genera and 26 families distributed across 34 mountain regions worldwide that either grow exactly at the treeline or have a range limit below the treeline. Of the total taxa, 155, 14, and 39 belong to TL, NTL, and TUMR, respectively. Genera such as Abies, Picea, Pinus, Larix, and Juniperus are more represented in the treeline tree category. On the other hand, Acer, Prunus, Populus, and Quercus have more representatives in the near to treeline category, whereas Erica, Nothofagus, and Polylepis contribute more tree species with an upper montane range limit. Furthermore, families such as Rosaceae and Pinaceae include trees that occur both at the treeline and with an upper montane range limit, whereas Sapindaceae includes trees that occur exclusively near to treeline. Our database also includes information on the global distribution patterns of treeline tree species richness across mountains and biomes. The mountains with the highest number of tree species are the Andes (39) followed by the Himalaya (37). Close to 67% of tree species show restricted distributions in different mountains, with the highest endemism in the Andes and the Himalaya. In terms of tree species distribution, Pinus sylvestris was widespread, with a distribution across nine mountain regions, followed by Picea glauca and Fagus sylvatica, both distributed across five mountain regions. In terms of species' distribution across biomes, the temperate biome harbors the highest treeline tree species richness (152 species), which may reflect the fact that the majority of studies are available from the temperate regions of the world. The remaining 56 species are distributed within five other biomes, with the least in dry tropical and subarctic (four species each). Furthermore, currently 40 treeline tree species fall under different International Union for Conservation of Nature threat categories. We anticipate that our database will help advance research on macroecological, biogeographic, evolutionary, climate‐change, and conservation aspects of the treeline on a global scale. The data are released under a Creative Commons Attribution 4.0 international license. Please cite this data paper when the data are reused. [ABSTRACT FROM AUTHOR]

The interaction of recent orographic uplift and climate heterogeneity acted as a key role in the East Himalaya‐Hengduan Mountains (EHHM) has been reported in many studies. However, how exactly the interaction promotes clade diversification remains poorly understood. In this study, we both used the chloroplast trnT‐trnF region and 11 nuclear microsatellite loci to investigate the phylogeographic structure and population dynamics of Hippophae gyantsensis and estimate what role geological barriers or ecological factors play in the spatial genetic structure. The results showed that this species had a strong east–west phylogeographic structure, with several mixed populations identified from microsatellite data in central location. The intraspecies divergence time was estimated to be about 3.59 Ma, corresponding well with the recent uplift of the Tibetan Plateau. Between the two lineages, there was significant climatic differentiation without geographic barriers. High consistency between lineage divergence, climatic heterogeneity, and Qingzang Movement demonstrated that climatic heterogeneity but not geographic isolation drives the divergence of H. gyantsensis, and the recent regional uplift of the QTP, as the Himalayas, creates heterogeneous climates by affecting the flow of the Indian monsoon. The east group of H. gyantsensis experienced population expansion c. 0.12 Ma, closely associated with the last interglacial interval. Subsequently, a genetic admixture event between east and west groups happened at 26.90 ka, a period corresponding to the warm inter‐glaciation again. These findings highlight the importance of the Quaternary climatic fluctuations in the recent evolutionary history of H. gyantsensis. Our study will improve the understanding of the history and mechanisms of biodiversity accumulation in the EHHM region. [ABSTRACT FROM AUTHOR]

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Chir pine (Pinus roxburghii, Sarg.) forests are dominant in the Indian Himalayan region and act as a huge carbon (C) sink. However, measuring the C sink in soil is complex and time‐intensive, and therefore the present study attempts to estimate the soil organic carbon (SOC) through a remote sensing (RS) approach. We estimated SOC stock of chir pine forests along an altitudinal gradient at three soil depths (0–30, 30–60 and 60–100 cm) in the Garhwal Himalaya, Uttarakhand. Fourteen forest stands at four altitudes, viz., <1000 m above sea level (m asl), 1001–1400 m asl, 1401–1800 m asl and >1801 m asl were surveyed and served for data collection. A model for predicting SOC was developed through stepwise regression analysis based on vegetation information and altitude as independent variables with the field data on SOC. For vegetation information, we used the normalized difference vegetation index (NDVI) measured through remote sensing (RS). The mean SOC stock up to 100 cm depth was increased with increasing altitude and were in the order of 69.66 ± 19.86, 85.27 ± 17.53, 95.68 ± 7.90 and 148.41 ± 71.39 million g ha−1 (million gram per hectare) for <1000, 1001–1400, 1401–1800 and >1801 m_asl, respectively. The result showed that NDVI was a good predictor for SOC estimation. The model predicted SOC stock between 57 and 152 million g ha−1 with a mean of 93 million g ha−1, which was close to the SOCs from field inventory. Therefore, RS could be used to precisely map the SOC stock in the chir pine forests of the Himalayas through NDVI and provide information to policymakers for forest management. [ABSTRACT FROM AUTHOR]

Speleothems are widely used terrestrial archives for the reconstruction of regional paleoclimatic conditions using mainly stable oxygen isotopes. However, the isotopic signals are quite vulnerable to post‐depositional recrystallization, and in the absence of detailed petrographic characterization, the validity of the isotopic dataset remains elusive. The present study is an attempt to bridge the gap between speleothem physical and geochemical proxies, their interrelationship and applicability, to reconstruct the regional climatic conditions in the northwestern Himalayas. We have identified different zones of depleted/enriched oxygen isotopes linked with the enhanced/decreased regional rainfall with strong/weak Indian summer monsoon. Prograding growth laminae and distinct columnar crystalline texture in calcite are associated with depleted oxygen isotopes. This suggests ample water availability and a higher drip rate in the cave, and further approves the wetter regional climate. Whereas, retractional growth laminae with dark micrite and microspar point towards slower drip rate and high evaporation associated with decreased rainfall. The presence of microspar in the studied stalagmite may indicate possible diagenetic alteration. However, oxygen isotopes data is unable to detect these small‐scale changes. Nevertheless, a coherency exists between isotopes and petrographic proxies for regional climate variability on a larger scale, and diagenesis in the studied sample possibly occurred during the early stage of precipitation. Therefore, isotopic studies coupled with detailed petrography can better ascribe paleoclimate conditions, and minimize the chances of erroneous interpretation because of diagenetic alterations of carbonate. [ABSTRACT FROM AUTHOR]

The Hindu Kush Himalaya region in Nepal is considered hydrologically vulnerable and fragile, and is likely to face adverse impacts due to climate change. Many rivers originate in this region, which are the lifeline for the millions of riparian people. The Marsyangdi river basin is the hub of hydroelectric power generation. The main objective of this study is to assess the impact of climate change in water availability by using the Soil and Water Assessment Tool (SWAT) model. Future climate projections were derived from three regional climate models (RCMs), namely ACCESS1‐CCAM (ACCESS) CNRM‐CM5‐CCAM (CNRM), and MPI‐ESM‐LR‐CSIRO‐CCAM under two representative concentration pathways, RCP 4.5 and RCP 8.5. These projections were bias‐corrected against the observed historical data, and simulation of impact was assessed using the SWAT model. This study reveals an increase in maximum temperature by 1.4°C by the 2040s (2031–50) and 2.6°C by the 2070s (2061–80) and in minimum temperature by 1.8 and 2.9°C by the 2040s and 2070s, respectively. The future projected rainfall shows a declining trend in all the models. The maximum increase in annual rainfall in the CNRM model is about 31.1% for RCP 8.5 during the 2040s and the MPI RCP 8.5 model show a minimum reduction of about 19.6% in the 2070s. In all three models the average annual rainfall is expected to increase by 10.2 and 10.7% by the 2040s and 2070s respectively. The reduction in streamflow in 2031–2050 is maximally about 19% in the CNRM RCP 8.5 and minimally about 6.3% in the MPI RCP 8.5. For the period 2061–2080, the CNRM RCP 8.5 shows a maximum decrease in streamflow of about 18.9% and the MPI RCP 8.5 shows a minimum reduction in streamflow of about 2.6%. This study will give significant insight to the planners for sustainable and integrated management of water resources and for the operation and design of hydropower projects in the basin. [ABSTRACT FROM AUTHOR]

Climate change and land use change jointly are the largest drivers of population declines, range contraction and extinction for many species across the globe. Wide‐ranging and large‐bodied species are especially vulnerable to habitat loss and fragmentation due to their typically low population densities, reflecting their need for extensive and connected habitats. We used the multi‐scale Random Forests machine learning algorithm to identify factors driving the habitat selection and future changes in habitat of Himalayan brown bear, an iconic wide‐ranging and large‐bodied species of high conservation interest, across a range of spatial scales. Habitat selection of brown bears was scale‐dependent, with most variables selected at broad scales. Climatic variables such as maximum temperature of coldest month, minimum temperature of warmest month and the potential evapotranspiration of wettest quarter strongly influenced habitat selection of brown bears. Future projections indicate a strong difference between the high and low emission scenarios. Alarmingly, our model suggests that high emission scenarios, with or without land use change, may result in a decline of brown bear habitat of >90% by the end of the century. In contrast, low emission scenarios are projected to reduce brown bear habitat by <23%, with much of the species range shifting to higher elevations. This study provides an integrative understanding of scale‐dependent variables in brown bear habitat selection, providing critical information for prioritizing areas for habitat management and conservation. Most importantly, our future projections imply that traditional conservation efforts, such as in situ conservation, will not be sufficient to protect the species without climate change mitigation. The incorporation of climate change mitigation and adaptation in conservation strategies will be one of the most pressing priorities in biodiversity conservation in this region. [ABSTRACT FROM AUTHOR]

Aim: The Tibetan Plateau (TP) hosts many endemic species, but questions regarding when and from where these species originated have not been comprehensively answered. Here, we provide a synthesis of the biogeographical history of terrestrial vertebrates endemic to the TP and investigate the potential drivers of their spatio‐temporal origins. Location: Tibetan Plateau and its surrounding regions. Time period: Cenozoic. Major taxa studied: Terrestrial vertebrates. Methods: We used dispersal–extinction–cladogenesis models based on time‐calibrated phylogenies to reconstruct the ancestral ranges of 174 endemic TP species and compiled the ancestral ranges and age estimates of their dispersal events. We generated a possibility map of source areas for endemic TP species by counting the incidence of non‐TP sister clades in 110 km × 110 km grid cells. We used generalized linear mixed models to assess the relative importance of historical processes and environmental factors in explaining the geographical variations in the source areas. We created subsets based on four vertebrate classes to test whether the dispersal events varied spatially and temporally among taxonomic groups. Results: We found that the endemic species colonized the TP as early as 55 Ma, and that the main colonization phase started to increase around 15 Ma and peaked after 6 Ma. The major source areas of endemic TP species include the Hengduan Mountains, the Himalayas, and Central Asia. Elevation difference had the strongest effect on the source areas, followed by geographical distance. The spatio‐temporal origins of species endemic to the TP and the potential drivers showed significant differences among vertebrate classes. Main conclusions: Our study supports the hypothesis that endemic TP species originated from various zoogeographical regions at different times and highlights the important roles of the TP uplift and past climatic changes for determining the spatio‐temporal origins of endemic TP species. [ABSTRACT FROM AUTHOR]

Climate change and habitat degradation are amongst the two greatest threats to biodiversity. Together, they can interact to imperil species. However, how climate change and land‐use change jointly affect the demographic vital rates that underpin population viability remains unknown. Here, using long‐term data on birds from the increasingly degraded and rapidly warming Himalayas, we show that survival trends over time are linked to species' elevational ranges in primary, but not in selectively logged forest. In primary forest, populations at their cold‐edge elevational range limit show increases in survival rates over time, whereas those at their warm‐edge elevational range limit suffer survival declines. This pattern is consistent with species tracking favorable climatic conditions over time, leading to improved demographic outcomes at progressively higher elevations with climate change, which in turn lead to upslope range shifts. In logged forest, however, survival rates remain relatively constant over time. This suggests that, in response to climate change in the long term, individuals of the same species can maintain demographic vital rates in higher‐elevation primary forest, but not in logged forest. This is the first demonstration of how two of the most disruptive anthropogenic influences on biodiversity interact to threaten survivorship in natural populations. Ignoring interactions between climate change and land‐use change can potentially undermine accurate forecasting of the future of species in an increasingly warm and degraded world. Importantly, large tracts of well‐protected primary forests across Earth's tropical elevational gradients may be essential to enable tropical montane species to persist in the face of climate change. [ABSTRACT FROM AUTHOR]

Natural disasters in High Mountain Asia (HMA) are largely induced by precipitation and temperatures extremes. Precipitation extremes will change due to global warming, but these low frequency events are difficult to analyse using (short) observed time series. In this study, we analysed large 2000 year ensembles of present day climate and of a 2 and 3°C warmer world produced with the EC‐Earth model. We performed a regional assessment of climate indicators related to temperature and precipitation (positive degree days, accumulated precipitation, [pre‐ and post‐] monsoon precipitation), their sensitivity to temperature change and the change in return periods of extreme temperature and precipitation in a 2 and 3°C warmer climate. In general, the 2°C warmer world shows a homogeneous response of changes in climate indicators and return periods, while distinct differences between regions are present in a 3°C warmer world and changes no longer follow a general trend. This non‐linear effect can indicate the presence of a tipping point in the climate system. The most affected regions are located in monsoon‐dominated regions, where precipitation amounts, positive degree days, extreme temperature, extreme precipitation and compound events are projected to increase the most. Largest changes in climate indicators are found in East Himalaya, followed by the Hindu Kush and West and Central Himalaya regions. Western regions will experience drier summers and wetter winters, while monsoon dominated regions drier winters and wetter summers and northern regions a wetter climate year round. We also found that precipitation increases in HMA in a 3°C warmer world are substantially larger (13%) compared to the global average (5.9%). Additionally, the increase in weather extremes will exacerbate natural hazards with large possible impacts for mountain communities. The results of this study could provide important guidance for formulating climate change adaptation strategies in HMA. [ABSTRACT FROM AUTHOR]

The Himalayas and Tibetan Plateau, identified as the Third Pole (TP), is a unique region because of its insertion into global environmental and climatic changes. Deposition of atmospheric nitrate in this region is one of the most important sources of reactive nitrogen to glacial‐hydrologic system and ecosystems. The isotopic composition of atmospherically deposited nitrate preserved in ice bodies plays a central role in delineating environmental and climatic changes, present, and past. Here, we provide an overview of the complete isotopic compositions (δ15N, δ18O, and Δ17O) of nitrate in aerosol, snow, ice, and water samples (n = 46) collected across the Southern, Southeastern, Central, and Northern TP to constrain complex nitrogen cycles of the atmosphere, cryosphere, hydrosphere, and, potentially, the biosphere. A large variability of snow nitrate isotopic compositions is observed across the TP at different spatial scales (from a single glacier to the entire plateau), likely due to the complex landscape and relevant physical and chemical processes across the TP. Large nitrate Δ17O values are observed in water samples collected from the Mt. Everest region, highlighting the considerable fraction (up to 45%) of atmospheric nitrate to the nitrate load in this Himalayan hydrologic system. Our work reveals the complex chemical, depositional, and postdepositional processes over the TP that are greater than previously thought and identifies further comprehensive investigations, which entail using nitrate isotopic compositions as an identifier for nitrate source apportionment in various ecosystems and understanding past atmospheric and climatic conditions in this region. Key Points: Complete isotopic compositions of nitrate in aerosol, snow, ice, and water samples collected across the Tibetan Plateau were measuredNitrate isotopic compositions in the cryosphere over the Tibetan Plateau is spatially highly heterogeneousContribution of atmospheric nitrates to the hydrologic system is high at Himalayas [ABSTRACT FROM AUTHOR]

Aim: The spatial patterns of tree populations reflect multiple ecological processes. However, little is known on whether these patterns mediate responses to climate in marginal tree populations such as those forming alpine tree lines. We examined the influence of tree‐to‐tree interactions on the responsiveness of tree lines to climate warming. Location: Central Himalayas. Taxon: Betula utilis; Abies spectabilis. Methods: We analysed a network of 17 tree line sites located across the central Himalayas, encompassing a wide longitudinal gradient characterized by increasing precipitation eastwards. We quantified the changes in density and the spatial patterns of three 50‐year age classes of the two main tree species found at the tree line (Betula utilis and Abies spectabilis), and related them to reconstructed shifts in tree line elevation. Results: Younger trees showed clustering near the tree line, while older trees tended to show random spatial distribution. Clustering decreased as climate conditions ameliorated, that is, in the wetter eastern sites. Lower rate of tree line elevation change was observed at the sites with higher clustering intensity. Main Conclusions: Our study indicates that tree aggregation weakens tree line responsiveness to climate warming, and thus warming‐induced drought stress tends to lower tree line shift rates by enhancing clustering. It also highlights the complexity and contingency of site‐dependent tree line responses to climate. Hence, to advance our understanding of tree line processes, we should consider both direct and indirect influences of relevant biotic (tree‐to‐tree interactions) and abiotic (climate) drivers of tree line dynamics. [ABSTRACT FROM AUTHOR]

In the Himalayas, water is seen by some as intricately linked to humans and produced through ethical actions. Its materiality, as a lack or excess of rain or snow, as healthy or receding ice, as destructive hail or flash flood, is a reflection of humans' moral attitude and an outcome of a process of reciprocity that links humans to nonhumans, the land, and divine beings. This perspective departs from the conception of water seen through development projects and from studies about climate change, which tend to objectify water through an epistemology that isolates nature from culture. Water as the materiality of ethics is examined by drawing on cases from Ladakh and Zanskar in the Himalayas and by reviewing studies from other parts of the Himalayas. In particular, water as the materiality of ethics is analyzed through three perspectives: how water is produced as people interact with a sacred geography, how snowy peaks are produced as objects of morality through affective attachment and encounters, and how water is produced as part of multispecies assemblages. A review of an ontology of water defined by reciprocity is important considering the significant changes currently taking place in the Himalayas and which are brought about by climate change and state production through large‐scale development projects. It can enrich our understanding of their implications for the cultural life of the often marginalized peoples of the Himalayas and contribute to narratives about the Anthropocene. This article is categorized under:Human Water > Water as Imagined and RepresentedHuman Water > Rights to Water [ABSTRACT FROM AUTHOR]

Chemical weathering of silicate rocks on continents is thought to have played an important role in the evolution of past atmospheric carbon dioxide over geologic timescales. However, the detailed links between continental weathering and climate change over shorter timescales, and their potential impact on sediment records deposited in the ocean, remain poorly understood. Here, we present clay mineralogy and strontium‐neodymium isotopic data for marine sediment records from the Northern Indian Ocean, with the aim of investigating the weathering response of large Himalayan river basins to orbital and millennial climate forcing. We show that past glaciated episodes of the late Quaternary corresponded to periods of increased physical erosion, associated with the preferential export of illite and chlorite assemblages from the Himalayan highlands having relatively radiogenic Sr isotopic signatures. In contrast, the warm periods of enhanced monsoon rainfall coincided with the transport of intensively weathered smectite‐dominated soils derived from the floodplains, characterized by lower 87Sr/86Sr signatures. This finding suggests that the short‐term climatic variability over late Quaternary timescales was accompanied by concomitant changes between high mountain‐ versus floodplain‐dominated weathering regimes, with possible impact on the nature of weathered rocks and, as a consequence, on the carbon cycle. Key Points: Orbital‐millennial clay records in Northern Indian Ocean of past 190 and 80 kyr are reportedClimate change results in a shift from mountain‐ to floodplain‐dominated weathering regimesPossible impact of climate‐driven weathering regimes in mountainous watersheds on carbon cycle [ABSTRACT FROM AUTHOR]

Cenozoic atmospheric circulation, climatic changes, sedimentation and weathering over the Indian sub‐continent were mainly influenced by the northward drift of the Indian Plate, the shrinking Paratethys, India‐Asia collision and the rise of the Himalayas. This study is aimed at exploring the fluvial sedimentary record of the north‐west part of the Himalayan Foreland Basin to interpret weathering and pedogenesis during early Oligocene to Mid‐Miocene time. Palaeopedological investigation of a 3.1 km thick succession from Kangra sub‐basin of the Himalayan Foreland Basin shows that the lower 2 km part of the succession is characterized by the red (10R hue) and the upper 1.1 km part of the succession by the yellow (2.5Y hue) palaeosols with varying intensity of weathering and pedogenesis. The association of sedimentary rocks and pedogenic expression in palaeosols indicate four (Type‐A to Type‐D) pedofacies in the entire Oligocene–Miocene succession. The pedofacies are defined by a decrease in the intensity of palaeopedogenic development from strongly‐developed palaeopedofeatures in Type‐A, moderately‐developed palaeopedofeatures in Type‐B, weakly‐developed palaeopedofeatures in Type‐C and to the only incipient stage of palaeopedogenesis in Type‐D pedofacies. The palaeolatitudinal shift during the convergence of the Indian Plate played a major role in weathering and palaeopedogenesis with the inception of seasonality during the early Oligocene, which is demonstrated by the formation of the red palaeosols with pedogenic CaCO3 and vertic features in tropical conditions. The transition to yellow palaeosols at about 20 Ma is marked by increased humidity, rapid aggradation, pronounced uplift and enhanced erosion of the hinterland. These yellow palaeosols are characterized by the abundance of weakly‐developed Bw and Bss horizons, pure clay pedofeatures and absence of any pedogenic CaCO3 during short pedogenic intervals in subtropical conditions. [ABSTRACT FROM AUTHOR]

High‐elevation forests are experiencing high rates of warming, in combination with CO2 rise and (sometimes) drying trends. In these montane systems, the effects of environmental changes on tree growth are also modified by elevation itself, thus complicating our ability to predict effects of future climate change. Tree‐ring analysis along an elevation gradient allows quantifying effects of gradual and annual environmental changes. Here, we study long‐term physiological (ratio of internal to ambient CO2, i.e., Ci/Ca and intrinsic water‐use efficiency, iWUE) and growth responses (tree‐ring width) of Himalayan fir (Abies spectabilis) trees in response to warming, drying, and CO2 rise. Our study was conducted along elevational gradients in a dry and a wet region in the central Himalaya. We combined dendrochronology and stable carbon isotopes (δ13C) to quantify long‐term trends in Ci/Ca ratio and iWUE (δ13C‐derived), growth (mixed‐effects models), and evaluate climate sensitivity (correlations). We found that iWUE increased over time at all elevations, with stronger increase in the dry region. Climate–growth relations showed growth‐limiting effects of spring moisture (dry region) and summer temperature (wet region), and negative effects of temperature (dry region). We found negative growth trends at lower elevations (dry and wet regions), suggesting that continental‐scale warming and regional drying reduced tree growth. This interpretation is supported by δ13C‐derived long‐term physiological responses, which are consistent with responses to reduced moisture and increased vapor pressure deficit. At high elevations (wet region), we found positive growth trends, suggesting that warming has favored tree growth in regions where temperature most strongly limits growth. At lower elevations (dry and wet regions), the positive effects of CO2 rise did not mitigate the negative effects of warming and drying on tree growth. Our results raise concerns on the productivity of Himalayan fir forests at low and middle (<3,300 m) elevations as climate change progresses. [ABSTRACT FROM AUTHOR]

Mahseer (Tor) fish species are critical components of locally adapted freshwater food webs across the Indian Himalayan biodiversity hotspot; however, multiple human stressors compounded by climate change have significantly depleted their populations over recent decades.Mahseer species are now considered locally vulnerable or endangered in many regions. Hydropower projects in particular have fragmented populations, impairing genetic exchange, obstructing migratory paths, and changing the structure and functioning of riverine habitats, especially of formerly fast‐flowing rivers.Worryingly, a literature survey and group discussions reveal that the increasing spread of non‐native fish species further compounds threats to mahseer and overall freshwater ecology. A better understanding of the current distribution, habitat requirement, and dispersal of non‐native fish is therefore essential to manage the growing threats to mahseer in the Indian Himalayan region. [ABSTRACT FROM AUTHOR]

Aim: Climate change has increased the risk of biological invasions, particularly by increasing the climatically suitable regions for invasive alien species. The distribution of many native and invasive species has been predicted to change under future climate. We performed species distribution modelling of invasive alien plants (IAPs) to identify hotspots under current and future climate scenarios in Nepal, a country ranked among the most vulnerable countries to biological invasions and climate change in the world. Location: Nepal. Methods: We predicted climatically suitable niches of 24 out of the total 26 reported IAPs in Nepal under current and future climate (2050 for RCP 6.0) using an ensemble of species distribution models. We also conducted hotspot analysis to highlight the geographic hotspots for IAPs in different climatic zones, land cover, ecoregions, physiography and federal states. Results: Under future climate, climatically suitable regions for 75% of IAPs will expand in contrast to a contraction of the climatically suitable regions for the remaining 25% of the IAPs. A high proportion of the modelled suitable niches of IAPs occurred on agricultural lands followed by forests. In aggregation, both extent and intensity (invasion hotspots) of the climatically suitable regions for IAPs will increase in Nepal under future climate scenarios. The invasion hotspots will expand towards the high‐elevation mountainous regions. In these regions, land use is rapidly transforming due to the development of infrastructure and expansion of tourism and trade. Main conclusions: Negative impacts on livelihood, biodiversity and ecosystem services, as well as economic loss caused by IAPs in the future, may be amplified if preventive and control measures are not immediately initiated. Therefore, the management of IAPs in Nepal should account for the vulnerability of climate change‐induced biological invasions into new areas, primarily in the mountains. [ABSTRACT FROM AUTHOR]

ABSTRACT: This study investigated a detailed picture of some statistical properties of winter rainfall on monthly and seasonal basis over the Western Himalaya (WH) using rain gauge station data during 1902–2005. Results showed a significant shift in the rainfall and rainy‐day pattern during 1960–1970 in most of the stations over the WH. State‐wise analysis indicated that Himachal Pradesh has received more rainfall (50%) and rainy day (∼57%) compared to the state of Uttarakhand. Station data revealed that past winter rainfall has changed in a periodic manner with averaged periodicity (epoch) of 20 years in which 1920–1940 was characterized by excess rainfall period while 1970–1990 was depicted as deficient rainfall period. Most of the rain gauge stations showed declining trends of rainfall and rainy days while the intensity of rainfall indicated increasing trends during the 1902–2005 period. Regional‐averaged winter rainfall and rainy day have shown a significant declining trend during 1902–2005. It was found that the rainfall trends are mainly arising due to internal variability although short‐term trends (signal) override the internal variability (noise) in some cases. Among five goodness‐of‐fit distribution, the generalized extreme value (GEV) has emerged as the best fit for the majority of the station locations. Estimated monthly assured rainfall at 75% probability level revealed a range of 100–150 mm, which will be useful for agricultural activities over WH region. The impact of topography on rainfall and rainy day indicated increasing trends up to a certain elevation (∼1356 m), thereafter they showed decreasing trends that has been described through a second‐order polynomial fit. [ABSTRACT FROM AUTHOR]

Seed traits are related to several ecological attributes of a plant species, including its distribution. While the storage physiology of desiccation-sensitive seeds has drawn considerable attention, their ecology has remained sidelined, particularly how the strong seasonality of precipitation in monsoonal climate affects their temporal and spatial distribution. We compiled data on seed mass, seed desiccation behavior, seed shedding, and germination periodicity in relation to monsoon and altitude for 198 native tree species of Indian Himalayas and adjoining plains to find out (1) the adaptive significance of seed mass and seed desiccation behavior in relation to monsoon and (2) the pattern of change in seed mass in relation to altitude, habitat moisture, and succession. The tree species fall into three categories with respect to seed shedding and germination periodicities: (1) species in which both seed shedding and germination are synchronized with monsoon, referred to as monsoon-synchronized ( MS, 46 species); (2) species in which seed germination is synchronized with monsoon, but seeds are shed several months before monsoon, referred to as partially monsoon-synchronized ( PMS, 112 species); and (3) species in which both shedding and germination occur outside of monsoon months, referred to as monsoon-desynchronized ( MD, 39 species). The seed mass of MS species (1,718 mg/seed) was greater than that of PMS (627 mg/seed) and MD (1,144 mg/seed). Of the 40 species with desiccation-sensitive seeds, 45% belong to the MS category, almost similar (approx. 47%) to woody plants with desiccation-sensitive seeds in evergreen rain forests. Seed mass differed significantly as per seed desiccation behavior and successional stage. No relationship of seed mass was found with altitude alone and on the basis of seed desiccation behavior. However, seed mass trend along the altitude differed among monsoon synchronization strategies. Based on our findings, we conclude that in the predicted climate change (warming and uncertain precipitation pattern) scenario, a delay or prolonged break-spell of monsoon may adversely affect the regeneration ecology of desiccation-sensitive seed-bearing species dominant over large forest areas of monsoonal climate. [ABSTRACT FROM AUTHOR]

ABSTRACT The spatial climatic characteristics of the Himalayas are complex and a challenge for regional climate models ( RCMs). There is no doubt that some form of correction before any application of RCM simulations is a must. In recent years, simple bias correction techniques have been overshadowed by more popular and complex bias correction techniques. In this study an attempt is made to compare the performance of a simple and of a comparatively complex correction technique for hydrological analysis at a monthly resolution in the Kaligandaki River Basin of Nepal. The research workflow consists of bias correction of temperature and precipitation using a simple technique (linear scaling) and a comparatively complex one (quantile mapping). The performance at monthly resolution is evaluated against observed meteorological data while a combined evaluation is made via hydrological model response analysis. The wetter and colder RCM estimates were significantly improved after bias correction. The hydrological modelling response also shows the importance of the bias correction of the RCMs. However, no significant difference was observed between the outputs of linear scaling and quantile mapping which exhibited almost identical performances. Hence, this study has a novel conclusion that a simple method, such as linear scaling, is sufficient for hydrological analysis at monthly resolution. [ABSTRACT FROM AUTHOR]

ABSTRACT The Chinese Himalayas ( CH) is highly sensitive to global climate change. The analyses of monthly mean air temperature and monthly precipitation data during the 1971-2007 from 24 meteorological stations show a significant increase of 0.31 °C per decade or about 1.15 °C for annual mean air temperature over the entire region. The temperature rise occurs primarily during the period of 1991-2007, up to 0.73 °C per decade. Climate warming is characterized by all-year temperature increase in particular during winters with the maximum value of 0.38 °C per decade during the 1971-2007, up to 1.24 °C per decade during 1991-2007. Distributions of annual temperature trends show significant south-to-north, low-to-high and east-to-west warming trends to increase with the latitude and elevation while to decrease with the longitude in the CH, respectively. Annual precipitation increases, but not significantly during the 1971-2007. Seasonal precipitation has no significant trend during the same period, either. Spatial discrepancy of the variations in precipitation is particularly great. It is evident that the climate was significantly warming and drying in the western CH over the past 37 years. [ABSTRACT FROM AUTHOR]

The interplay of orographic uplift and climatic changes in the Himalaya- Hengduan Mountains region ( HHM) have had a key role in speciation and population demography. To gain further insight into these processes, we investigated their effects on Taxus wallichiana by combining molecular phylogeography and species distribution modeling., Molecular data were obtained from 43 populations of T. wallichiana. Nineteen climatic variables were analyzed alongside genetic discontinuities. Species distribution modeling was carried out to predict potential past distribution ranges., Two distinct lineages were identified, which diverged c. 4.2 (2.0-6.5) million years ago (Ma), a timescale that corresponds well with the recent uplift of the Qinghai-Tibet Plateau and subsequent climatic changes of the region. Correlations with climatic variables also suggest that ecological factors may have further reinforced the separation of the two lineages. Both lineages experienced population expansion during the last glaciation., The high genetic divergence, long-term isolation and ecological differentiation suggest a scenario of cryptic speciation in T. wallichiana associated with geological and climatic changes in the HHM. Our findings also challenge the notion of general population 'contraction' during the last glaciation in the HHM. [ABSTRACT FROM AUTHOR]

The article reports on research conducted by Xing Ma and team on Kejie watershed to assess the impact of climatic change and land cover on the hydrological process in the Himalaya Mountains. Researchers used the Soil Water Assessment Tool (SWAT) and found that global climate change increases the temperature and variation of precipitation in the area. They found that it also modifies both the supply and demand of water.

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Through the late Quaternary, the global climate system ranged from full glacial to temperate interglacial conditions. On a smaller spatial scale, regional climates of the late Quaternary exhibited fluctuations that were at times asynchronous to these global changes. For example, glacier expansion in the Himalayas during the mid- Holocene appears to be at odds with the notion of increased global temperature. A clear understanding of the dynamical processes governing regional climate is therefore essential to the correct interpretation of proxy climate data. We summarize results from numerical simulations of the Last Glacial Maximum (LGM) and the mid-Holocene, and focus on the multiple processes that control regional climate of the Himalaya and surrounding areas, with emphasis on monsoon dynamics and variability. It is shown that changes in the south Asian monsoon (caused by fluctuations in Earth's orbital parameters, by tropical Pacific Ocean temperatures, or by exposure of the Sunda shelf) alter the hydrological balance in regions bordering the Tibetan Plateau, a balance for which there are extensive continental proxy records. Numerical results correlate with the expansion/contraction cycles of deserts near the Chinese Loess Plateau. In addition, the LGM monsoon exhibits significant snow accumulation in the eastern Himalaya, whereas the mid-Holocene monsoon exhibits increased accumulation in the northwestern Himalaya. Simulated changes are therefore in accord with field data and demonstrate that numerical simulations can be a useful tool in the interpretation of regional proxy data, particularly when those data are asynchronous to global records. [ABSTRACT FROM AUTHOR]