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Recent climate dynamics denote patterns and variations in climatic conditions and associated cryospheric changes in the Pamir region, affecting downstream ecosystems and communities. The present investigation describes changes in Baralmos glacier and supraglacial lakes, along with related hazards, using meteorological observations, reanalysis products, and high-resolution satellite imagery from 2002 to 2022. Moreover, observations using Unmanned Aerial Vehicles (UAVs) were conducted between 2020 and 2022 to document recent variations. Reanalysis data suggested that there are no obvious trends in annual air temperature and precipitation except for a significant temperature rise in July (the warmest month) of about 1.34°C/decade (p<0.05) and precipitation decrease in December (p<0.05). During the last two decades of investigation, lake areas expanded from 20500 to 62800 ± 21 m2, representing an approximately threefold increase, leading to increased mudflows in the Surkhob river and causing severe damage to property and infrastructures, most prominently during 2020 and 2022. The UAV data reveal an average decrease of −2.7 ± 0.5 m in surface elevation downstream of Baralmos glacier between 2020 and 2022. This study is vital for implementing more intensive measures of the glacial environment and defining suitable mitigation strategies in the Pamir region. [ABSTRACT FROM AUTHOR]

Climate change is rapidly transforming the coastal margins of Greenland. At the same time, there is increasing recognition that marine‐terminating glaciers provide unique and critical habitats to ice‐associated top predators. We investigated the connection between a top predator occupying glacial fjord systems in Northwest Greenland and the properties of Atlantic‐origin water and marine‐terminating glaciers through a multiyear interdisciplinary project. Using passive acoustic monitoring, we quantified the summer presence and autumn departure of narwhals (Monodon monoceros) at glacier fronts in Melville Bay and modeled what glacier fjord physical attributes are associated with narwhal occurrence. We found that narwhals are present at glacier fronts after Greenland Ice Sheet peak summer runoff and they remain there during the period when the water column is becoming colder and fresher. Narwhals occupied glacier fronts when ocean temperatures ranged from −0.6 to 0.8°C and salinities between 33.2 and 34.0 psu at around 200 m depth and they departed on their southbound migration between October and November. Narwhals' departure was approximately 4 weeks later in 2019 than in 2018, after an extreme 2019 summer heatwave event that also delayed sea ice formation by 2 months. Our study provides further support for the niche conservative narwhal's preference for cold ocean temperatures. These results may inform projections about how future changes will impact narwhal subpopulations, especially those occupying Greenland glacial fjords. [ABSTRACT FROM AUTHOR]

Glaciers and ice sheets are an integral part of Earth's system, advancing and retreating in response to changes in climate. Clues about the past, present and future behaviour of these ice masses are found throughout current and former glaciated landscapes. In this commentary, we outline recent scientific advances from a collection of articles in which geomorphological evidence is used to inform us about the behaviour of glaciers and ice sheets across a range of spatial (landform to continent) and temporal (seasons to millennia) scales. Through a diversity of approaches including field measurements, remote sensing and numerical modelling, these studies build on an extensive background literature to deepen our understanding of how ice flows, how glaciers and ice sheets respond to climate change, and of the processes of ice advance and retreat and the stability of the system. Further integration of knowledge across the fields of geomorphology and glaciology will have tangible benefits for managing the societal and environmental impacts of glacier change and for improved projections of sea‐level rise over the coming decades to centuries. [ABSTRACT FROM AUTHOR]

The critical challenge of ongoing climate warming is resulting in glacier melting globally, a process accompanied by the formation of substantial glacier forelands. This phenomenon emerges as a pivotal area of study, especially in the Tibetan Plateau (TP), known as the Third Pole and the Asian Water Tower. In particular, the rapid retreat of temperate glaciers in the southeastern TP has led to the formation of expansive glacier forelands. These forelands are not merely evidence of climate shifts but are also key areas for transformative carbon dynamics. Moreover, the newly exposed land surface actively adjusts the balance of dissolved organic carbon, especially in meltwater, and influences the release of greenhouse gases from a range of sources including glacial lakes, subglacial sediments, and supraglacial/proglacial rivers. These processes play a crucial role in the dynamics of atmospheric carbon dioxide. Drawing from our intensive and detailed observations over several years, this perspective not only emphasizes the importance of the underexplored impact of glacier forelands on carbon cycles but also opens a window into understanding potential future trajectories in a warming world. [ABSTRACT FROM AUTHOR]

Glaciers and glacial lakes are very sensitive to climate change, and studying their dynamics is important for revealing changes in global climate. In this study, we extracted the boundaries of glaciers and glacial lakes in the Northern Tianshan Mountains based on Landsat TM/ETM+/OLI and Sentinel 2A/2B MSI remote sensing images and analyzed their dynamics and impacts over the past 30 years. The findings indicate that in 2020, the Northern Tianshan region exhibited a total of 3254 glaciers, with an area of 1670.55 km2 and a volume of 95.69 km3. The corresponding numbers, areas, and volumes of glacial lakes were 281, 13.23 km2 and 210.49×106 m3, respectively. Over the past 30 years, glaciers and glacial lakes have exhibited opposite characteristics. The former decreased by 16, 332.64 km2 (−0.60%·a−1) and 18.36 km3 (−0.58%·a−1), respectively, and the latter increased by 56 and 2.48 km2 (0.82%·a−1) and 38.88×106 m3 (0.79%·a−1), respectively. Moreover, different glacier termination types cause differences in the glacier retreat rates. Lake-terminated glaciers retreated faster than land-terminated glaciers, and the type of glacier termination has a greater effect on the retreat rate than the size of the glacial area. [ABSTRACT FROM AUTHOR]

Volcanic debris flows (lahars) are highly destructive volcanic phenomena and present significant challenges in numerical simulation. This manuscript tackles the three fundamental requirements for modelling gravitational flows: determining plausible source configurations; selecting suitable topographic data; and employing appropriate mathematical models to assess the current hazard posed by long-distance lahars at Cotopaxi volcano. After incorporating these elements, we successfully simulated the characteristics of a future 1877- type lahar under current conditions, accounting for glacier size and topography. For the source conditions, or "scenario", we identified 27 equidistant source locations along the lower edge of the current glacier's extent. Each source was assigned a hydrograph based on the weighted volume of water available on Cotopaxi's current glacier. Additionally, we introduced a methodology for quantifying channel width when high-resolution digital elevation models (DEMs) are available. This method enabled us to determine the minimum pixel size required for accurate representation of ravine shapes. While higher resolution DEMs demand robust computational resources and extended computational timeframes, we upscaled Cotopaxi's DEM from 3 m to 15 m to balance accuracy and efficiency, as a 15-m DEM capture over 90% of the topography and reduces computing time significantly. Optimizing DEM selection is crucial, especially when contemplating future ensemble approaches. After employing the dynamic-based model Kestrel, parameterised for large lahars, we obtained predictions closely aligned with field observations, historical flow conditions inferred for the 1877 lahar-event, and results from previous simulation studies. Notably, we observed higher depths and speeds in canyons compared to plains, consistent with historical reports and previous studies. Minor discrepancies in the inundation area, when compared with existing hazard maps, emphasize the importance of understanding flow dynamics and lahar trajectories for effective hazard assessment and mitigation strategies. Furthermore, our results contribute valuable information to current hazard maps and can aid in damage quantification and cost/benefit analyses, particularly when planning the construction of mitigation infrastructure. [ABSTRACT FROM AUTHOR]

Andean glaciers are losing mass rapidly but a centennial‐scale context to those rates is lacking. Here we show the extent of >5,500 glaciers during the Little Ice Age chronozone (LIA; c. 1,400 to c. 1,850) and compute an overall area change of −25% from then to year 2000 at an average rate of −36.5 km2 yr−1 or −0.11% yr−1. Glaciers in the Tropical Andes (Peru, Bolivia) have depleted the most; median −56% of LIA area, and the fastest; median −0.16% yr−1. Up to 10 × acceleration in glacier area loss has occurred in Tropical mountain sub‐regions comparing LIA to 2,000 rates to post‐2000 rates. Regional climate controls inter‐regional variability, whereas local factors affect intra‐region glacier response time. Analyzing glacier area change by river basins and by protected areas leads us to suggest that conservation and environmental management strategies should be re‐visited as proglacial areas expand. Plain Language Summary: Andean glaciers are melting fast but how that rate compares in a longer‐term context is unknown. In this study we mapped the extent of >5,500 glaciers during the Little Ice Age, which was the last major glacial advance culminating about c. 150 years ago. We analyzed the change in glacier size and computed overall area change of −25% from the LIA to year 2000 at a rate of −36.5 km2 per year or −0.11% per year. Glaciers within Peru and Bolivia have shrunk the most by median −56% of LIA area, and the fastest by median −0.16% per year. We discuss that these glaciers are depleting and retreating due to climate change but that response is compounded by glacier size, shape and terminus environment effects. As glaciers melt they reveal proglacial landscapes that tend to be highly unstable, impacting water resources, natural hazards and terrestrial and aquatic ecology. Key Points: Little Ice Age (LIA) chronozone extent of >5,500 glaciers mapped from geomorphological evidenceOverall glacier area change of −25% to year 2000 at a rate of −36.5 km2 yr−1 or −0.11% yr−1Up to 10 × acceleration in glacier area loss for Tropical sub‐regions comparing LIA to 2,000 with post‐2000 rates [ABSTRACT FROM AUTHOR]

Climate change is causing widespread melting of land and sea ice in the Arctic, leading to an increase in freshwater input to the ocean. This may have an impact on ocean circulation, marine ecosystems, and biodiversity in the region. Our findings provide new insights into the summer hydrography conditions at proglacial fjord entrances along large parts of the east coast of Greenland. As most freshwater exits the Arctic Ocean through Fram Strait this study focuses on understanding the origin of spatial distribution of temperature and freshwater in the coastal waters in East Greenland. We find that Polar Water and the Atlantic Water variants (Eurasian Basin Atlantic Water/Subpolar Mode Water) dominate coastal waters north and south of Denmark Strait, respectively, and that coastal waters are influenced by advected meltwater from the Arctic Ocean, glacier meltwater and local precipitation. Combining hydrographic observations, water isotope data, and water source fraction analysis, we show that glacier meltwaters can be detected at fjord entrances and down to approximately 200 m. Integrated over the upper 200 m of the water column, glacial meltwater account for approximately 9%, precipitation for around 8% and Polar Water (including sea ice melt) for approximately 83% of the freshwater observed along the East Greenland coast. Below 200 m, Atlantic Water variants dominate the entire coastal section. The freshwater along East Greenland stays close to the coast and we could not detect any glacier meltwater at the slope. Plain Language Summary: The rapid warming of our planet has increased freshwater input to the Arctic Ocean. A major portion of this freshwater is exiting through Fram Strait. Also, meltwater runoff from tundra lands and glaciers connected to the Greenland ice sheet is an increasingly significant freshwater source to fjords. At present, incomplete observations exist regarding the spatial distribution of freshwater and its origin along East Greenland. Here we present results from a compressed survey of the pan‐East Greenland coastal system from the entrance of fjords. We describe the spatial distribution of water masses and source water fractions along East Greenland and their link to proglacial fjords. Key Points: Polar Water and Atlantic Water variants dominate East Greenland coastal waters north and south of Denmark Strait, respectivelyGlacier meltwater cannot be detected at the slope and most Polar Water, meteoric water, and glacier meltwater are confined to the coastAlong the coast, glacial meltwater account for ∼9%, precipitation for ∼8% and Polar Water (including sea ice melt) for ∼83% of the freshwater [ABSTRACT FROM AUTHOR]

This work evaluates glacial dust as a source of sediment, and associated iron (Fe), to the Fe‐limited Gulf of Alaska (GoA). A reanalysis of GoA sediment data, using rare earth elements and thorium as provenance tracers, suggests a flux to the ocean surface of Copper River (AK) glacial dust, and associated Fe, that is comparable to the flux of dust from Asia, at least 1,000 km from the narrow mountain valley glacial dust source area. This work suggests dust from Asia may not be the largest source of Fe to the GoA. Dust models fail to accurately simulate this glacial dust transport because their coarse resolution underestimates wind speeds, and the dust flux. This work suggests that glacial dust fluxes may have been important in the geologic past (e.g., the last glacial maximum) from locations where there was more extensive coverage by glaciers than at present. Plain Language Summary: The growth of phytoplankton, the base of the marine food web, is known to be limited by availability of the micronutrient iron in the Gulf of Alaska. We evaluated the importance of glacial dust in this region as a source of iron, and other trace metals, by using concentrations of the rare earth elements and thorium in particles as tracers of their geographic origin. We analyzed for these elements in glacial dust samples from the Copper River valley (Alaska), the largest source of glacier‐derived dust. Together with previously published concentrations for dust from Asia and volcanic material, we estimated the inputs of each source material to the sediments of the Gulf of Alaska. This information, together with published sediment mass accumulation rates, suggests an important contribution of Alaskan glacial dust and associated iron, to surface waters of the Gulf of Alaska, at least 1,000 km from the source. Dust models fail to accurately simulate this dust transport because their coarse spatial resolution substantially underestimates wind speeds. Glacial dust fluxes may have been important sources of iron in the geologic past (e.g., the Last Glacial Maximum) from New Zealand and South America, when there was more extensive glacial coverage. Key Points: Copper River glacial dust contributes substantially to Gulf of Alaska sediments, and associated iron to surface watersDust models lack sufficient spatial resolution to accurately simulate the winds that drive the flux of glacial dust from narrow valleysGlacial dust‐associated iron may have been important in the geologic past in times and locations with more extensive glacial coverage [ABSTRACT FROM AUTHOR]

Understanding glaciers structural heterogeneity is crucial for assessing their fate. Yet, places where structure changes are strong, such as crevasses fields, are often inaccessible for direct instrumentation. To overcome this limitation, we introduce an innovative technique that transforms seismic sources, here generated by crevasses, into virtual receivers using source‐to‐receiver spatial reciprocity. We demonstrate that phase interference patterns between well‐localized seismic sources can be leveraged to retrieve phase velocity maps using Seismic Michelson Interferometry. The obtained phase velocity exhibits sensitivity to changes in glacier structure, offering insights into the origins of mechanical property changes, with spatial resolution surpassing traditional methods by a factor of five. In particular, we observe sharp variations in phase velocity related to strongly damaged subsurface areas indicating a complex 3‐D medium. Applying this method more systematically and in other contexts will enhance our understanding of the structure of glaciers and other seismogenic environments. Key Points: We transform seismic sources from crevasses into virtual receivers using source‐to‐receiver spatial reciprocityWe derive phase velocity maps in previously inaccessible areas with a resolution five times larger than traditional approachesWe retrieve the influence of glacier geometry and structural heterogeneity on the glacier mechanical properties [ABSTRACT FROM AUTHOR]

Under Arctic warming, near-surface energy transfers have significantly changed, but few studies have focused on energy exchange over Arctic glacier due to limitations in available observations. In this study, the atmospheric energy exchange processes over the Arctic glacier surface were analyzed by using observational data obtained in summer 2019 in comparison with those over the Arctic tundra surface. The energy budget over the glacier greatly differed from that over the tundra, characterized by less net shortwave radiation and downward sensible heat flux, due to the high albedo and icy surface. Most of the incoming solar radiation was injected into the glacier in summer, leading to snow ice melting. During the observation period, strong daily variations in near-surface heat transfer occurred over the Arctic glacier, with the maximum downward and upward heat fluxes occurring on 2 and 6 July 2019, respectively. Further analyses suggested that the maximum downward heat flux is mainly caused by the strong local thermal contrast above the glacier surface, while the maximum upward heat transfer cannot be explained by the classical turbulent heat transfer theory, possibly caused by countergradient heat transfer. Our results indicated that the near-surface energy exchange processes over Arctic glacier may be strongly related to local forcings, but a more in-depth investigation will be needed in the future when more observational data become available. [ABSTRACT FROM AUTHOR]

Cryoconite is a granular structure present on the glaciers and ice sheets found in polar regions including the Himalayas. It is composed of organic and inorganic matter which absorb solar radiations and reduce ice surface albedo, therefore impacting the melting and retreat of glaciers. Though climate warming has a serious impact on Himalayan glaciers, the biodiversity of sub-glacier ecosystems is poorly understood. Moreover, cryoconite holes are unique habitats for psychrophile biodiversity hotspots in the NW Himalayas, but unfortunately, studies on the microbial diversity of such habitats remain elusive. Therefore, the current study was designed to explore the bacterial diversity of the Hamtah Glacier Himalaya using both culturable and non-culturable approaches. The culturable bacterial count ranged from 2.0 × 10³ to 8.8 × 105 colony-forming units (CFUs)/g at the different locations of the glacier. A total of 88 bacterial isolates were isolated using the culturable approach. Based on the 16S ribosomal RNA gene (16S rRNA), the identified species belong to seven genera, namely, Cryobacterium, Duganella, Janthinobacterium, Pseudomonas, Peribacillus, Psychrobacter, and Sphingomonas. In the non-culturable approach, high-throughput sequencing of 16S rRNA genes (using MiSeq) showed unique bacterial community profiles and represented 440 genera belonging to 20 phyla, namely, Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes, Chloroflexi, Acidobacteria, Planctomycetes, Cyanobacteria, Verrucomicrobia, Spirochaetes, Elusimicrobia, Armatimonadetes, Gemmatimonadetes, Deinococcus-Thermus, Nitrospirae, Chlamydiae, Chlorobi, Deferribacteres, Fusobacteria, Lentisphaerae, and others. High relative abundances of Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes were observed in the samples. Phototrophic (Cyanobacteria and Chloroflexi) and nitrifier (Nitrospirae) in bacterial populations indicated sustenance of the micro-ecosystem in the oligotrophic glacier environment. The isolates varied in their phenotypic characteristics, enzyme activities, and antibiotic sensitivity. Furthermore, the fatty acid profiles of bacterial isolates indicate the predominance of branched fatty acids. Iso-, anteiso-, unsaturated and saturated fatty acids together constituted a major proportion of the total fatty acid composition. High cold-adapted enzyme activities such as lipase and cellulase expressed by Cryobacterium arcticum (KY783365) and protease and cellulase activities by Pseudomonas sp. strains (KY783373, KY783377-79, KY783382) provide evidence of the possible applications of these organisms. Additionally, antibiotic tests indicated that most isolates were sensitive to antibiotics. In conclusion, the present study contributed for the first time to bacterial diversity and biopotentials of cryoconites of Hamtah Glacier, Himalayas. Furthermore, the cold-adapted enzymes and polyunsaturated fatty acids (PUFAs)may provide an opportunity for biotechnology in the Himalayas. Inductively coupled plasma mass spectrometry (ICPMS) analyses showed the presence of several elements in cryoconites, providing a clue for the acceleratingmelting and retreating of theHamtah glacier. [ABSTRACT FROM AUTHOR]

This article presents a comparative case study of public valuation of glaciers in Alaska and Norway. The first case examines Alaska's Mendenhall Glacier, which has been central in public debate over the US Forest Service's proposed expansion of the Mendenhall Glacier Recreation Area. The second case centers on Norway's Svartisen glacier, which garnered international attention when the startup company, Svaice, announced its intent to extract glacier ice cubes for cocktail coolers at high-end bars and restaurants. A rhetorical analysis of newspaper coverage relevant to each case reveals that in both debates, instrumental, relational, and intrinsic values are attributed to the respective glaciers, and that government, business, and community actors hold the most power in these conversations. However, nuances within articulations of instrumental value suggest that Norwegian actors strive to balance human and glacier needs, whereas Alaskan actors largely prioritize human needs by constituting the glacier as a utilitarian object. [ABSTRACT FROM AUTHOR]

The study conducted on analysing the characteristics of wastewater composition before and after re-treatment is relevant in the context of environmental protection. The study aims to investigate the characteristics of wastewater before and after re-treatment using a pressure sorption filter. The results of the analysis of quantitative indicators of wastewater revealed that before treatment it was characterised by a wide range of indicators exceeding the normative levels. The greatest excess was observed in the content of suspended solids in sample No. 10, where their concentration reached 1,000 mg/l, which exceeded the normative values by 1.43 times. A pressure sorption filter was installed to improve the quality of treatment. The analysis showed that after its implementation, the wastewater indicators improved significantly: the content of suspended solids decreased by 6.67 times, which indicated the effectiveness of this treatment method. After treatment, the content of pollutants decreased to the levels corresponding to the norms. Economic calculation showed low costs for the installation and operation of the pressure sorption filter, which amounted to 22,570 KGS. It should be concluded that in the end, the results showed that the use of a drip irrigation system was cost-effective to implement because the investment amount of 2,765.2 thousand KGS paid off with additional profit in the period of 1.3 years. The results of the study can be used in practice by hydrologists, hydraulic engineers, resource scientists, environmental engineers, ecologists, ecologists-hydrobiologists, specialists in water management and environmental monitoring, as well as decision-makers in the field of ecology and environmental management to develop and implement measures for the implementation of environmental programmes and projects aimed at improving the environmental situation in the region. [ABSTRACT FROM AUTHOR]

The relationship between rock-slope failure and glacier retreat is complex, and paraglacial failures often lack clearly identified triggers. To better understand the role of glacier retreat in rock-slope failures, we analysed the processes that led to the October 1967 Grewingk landslide in Kachemak Bay State Park on the Kenai Peninsula, Southcentral Alaska. The rock material collapsed onto the glacier toe and into its pro-glacial lake and produced a tsunami wave that swept the outwash plain. On the day of the failure, rainfall and snowmelt were well within normal ranges, and seismic records show no significant shaking. Three years prior to the 1967 failure, the slope withstood the second largest earthquake ever recorded (Great Alaskan earthquake, MW 9.2). We reassessed the volume of the failure by differencing pre- and post-digital terrain models and found a value of 20–24 × 106 m3, which is four times smaller than a previous estimate. The back analysis of the Grewingk landslide is based on remote sensing data and field measurements including aerial satellite image analysis, detailed surveying and understanding of the structural geology, a kinematic analysis, and runout modelling. Our research provides an example of a major paraglacial failure that lacks an obvious trigger and points to several geological factors and changing environmental conditions that likely promote such failures. This study further indicates that the Grewingk landslide, pre-conditioned by the geometry of faults and joints, may have reached a critical stability state due to internal processes and the potential combined effects of seismic activity and glacier retreat prior to the collapse. [ABSTRACT FROM AUTHOR]

Glaciers and snow cover provide freshwater for irrigated agriculture and urban consumption in the Dry Andes. Given the aridity of this environment, sublimation losses are significant, making precise monitoring techniques crucial in estimating glacier changes. Continuous monitoring of glaciers is typically conducted through the use of automatic weather stations (AWS). However, these stations may not capture the full extent of glacier changes, warranting the use of additional monitoring techniques such as close-range remote sensing and satellite imagery. This study utilizes time-lapse photography acquired from 2013 to 2015 to examine the temporal and spatial albedo variations across the Tapado Glacier, along with the surface changes in the debris-covered section. Sequential orthorectified images were used to observe the spatial evolution of ice cliffs and supraglacial ponds as they changed over time. High-resolution displacement measurements were obtained using feature tracking methods on the debris-covered glacier. Additionally, distributed albedo maps were produced by comparing photographic data with point albedo measurements from an AWS. The results indicate decreased albedo values during summer, along with the expansion of supraglacial ponds and ice cliffs in the debris-covered region. The study also proposes a cost-effective remote site monitoring approach using time-lapse photography for continuous observation and data collection. [ABSTRACT FROM AUTHOR]

Glacier inventories serve as critical baseline data for understanding the impacts of climate change on glaciers. The present study maps the outlines of glaciers in the Chandra-Bhaga Basin (western Himalaya) for the years 1993, 2000, 2010, and 2019 using Landsat Thematic Mapper (TM), Enhanced Thematic Mapper (ETM), and Operational Land Imager (OLI) datasets. A total of 251 glaciers, each having an area above 0.5 km2, were identified, which include 216 clean-ice and 35 debris-covered glaciers. Area changes are estimated for three periods: 1993–2000, 2000–2010, and 2010–2019. The total glacierized area was 996 ± 62 km2 in 1993, which decreased to 973 ± 70 km2 in 2019. The mean rate of glacier area loss was higher in the recent decade (2010–2019), at 0.036 km2, compared to previous decades (0.029 km2 in 2000–2010 and 0.025 km2 in 1993–2000). Supraglacial debris cover changes are also mapped over the period of 1993 and 2019. It is found that the supraglacial debris cover increased by 14.12 ± 2.54 km2 (15.2%) during 1993–2019. Extensive field surveys on Chhota Shigri, Panchi II, Patsio, Hamtah, Mulkila, and Yoche Lungpa glaciers were carried out to validate the glacier outlines and supraglacial debris cover estimated using satellite datasets. Controls of various morphological parameters on retreat were also analyzed. It is observed that small, clean ice, south oriented glaciers, and glaciers with proglacial lakes are losing area at faster rates than other glaciers in the basin. [ABSTRACT FROM AUTHOR]

Copyright of Social Anthropology / Anthropologie Sociale is the property of Berghahn Books and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Glaciers are often portrayed as an important water resource in scientific research and public debate. However, the scientific literature calls for caution when presenting this idea. While melting glaciers can increase water insecurity, their contribution to runoff is often minor and other factors like excessive groundwater pumping for irrigation or surface and groundwater contamination pose much greater threats to water availability. As we consider the wide range of environmental impacts due to glacier changes, we must also question the “glacier as water resource” narrative that may unnecessarily contribute to public anxiety. This article is categorized under: Human Water > Water as Imagined and Represented Science of Water > Water and Environmental Change [ABSTRACT FROM AUTHOR]

Copyright of La Granja, de Ciencias de la Vida is the property of Universidad Politecnica Salesiana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Glacial groundwater can mobilize deep-seated methane from beneath glaciers and permafrost in the Arctic, leading to atmospheric emissions of this greenhouse gas. We present a temporal, hydro-chemical dataset of methane- rich groundwater collected during two melt seasons from a high Arctic glacial forefield to explore the seasonal dynamics of methane emissions. We use methane and ion concentrations and the isotopic composition of water and methane to investigate the sources of groundwater and the origin of the methane that the groundwater transports to the surface. Our results suggest two sources of groundwater, one shallow and one deep, which mix, and moderate methane dynamics. During summer, deep methane-rich groundwater is diluted by shallow oxygenated groundwater, leading to some microbial methane oxidation prior to its emergence at the surface. Characterization of the microbial compositions in the groundwater shows that microbial activity is an important seasonal methane sink along this flow-path. In the groundwater pool studied, we found that potential methane emissions were reduced by an average of 29% (±14%) throughout the summer due to microbial oxidation. During winter, deep groundwater remains active while many shallow systems shut down due to freezing, reducing subsurface methane oxidation, and potentially permitting larger methane emissions. Our results suggest that ratios of the different groundwater sources will change in the future as aquifer capacities and recharge volumes increase in a warming climate. [ABSTRACT FROM AUTHOR]

Research in Antarctica is of great importance for understanding the Earth's climate system and the processes that drive it. This study evaluated the spatial distribution of glacial sediment properties on the Bellingshausen Dome or Collins Ice Cap (King George Island, Antarctica). The particle-size distribution, pH H2O, total organic carbon (TOC), mobile forms of ammonium nitrogen (N–NH4), potassium (K2O), and phosphorus (P2O5) were measured and then spatially modelled using regression kriging (RK) and ordinary kriging (OK) approaches. The terrain attributes (elevation, aspect, slope) derived from a digital elevation model with 10-m spatial resolution and distance from a coast were used as explanatory variables. Multiple linear regression models were fitted to describe the relationships between the covariates and properties. The performance of the models was evaluated by the mean absolute error (MAE), root mean square error (RMSE), coefficient of determination (R2), and Nash–Sutcliffe efficiency coefficient (NSE) indices. Overall, model performance statistics showed that RK models performed better than OK and the spatial patterns of some properties were closely related to the character of the glacier topography. Thus, the application of the RK method in combination with auxiliary environmental covariates improved the accuracy of spatial prediction. [ABSTRACT FROM AUTHOR]

The near‐surface boundary layer can mediate the response of mountain glaciers to external climate, cooling the overlying air and promoting a density‐driven glacier wind. The fundamental processes are conceptually well understood, though the magnitudes of cooling and presence of glacier winds are poorly quantified in space and time, increasing the forcing uncertainty for melt models. We utilize a new data set of on‐glacier meteorological measurements on three neighboring glaciers in the Swiss Alps to explore their distinct response to regional climate under the extreme 2022 summer. We find that synoptic wind origins and local terrain modifications, not only glacier size, play an important role in the ability of a glacier to cool the near‐surface air. Warm air intrusions from valley or synoptically‐driven winds onto the glacier can occur between ∼19% and 64% of the time and contribute between 3% and 81% of the total sensible heat flux to the surface during warm afternoon hours, depending on the fetch of the glacier flowline and its susceptibility to boundary layer erosion. In the context of extreme summer warmth, indicative of future conditions, the boundary layer cooling (up to 6.5°C cooler than its surroundings) and resultant katabatic wind flow are highly heterogeneous between the study glaciers, highlighting the complex and likely non‐linear response of glaciers to an uncertain future. Plain Language Summary: The presence of a 0°C ice surface cools the near‐surface air and generates a unique micro‐climate that complicates a glaciers response to future warming. Using a new data series on three glaciers during an extreme summer of 2022, we explore how variable this cooling is in space and time and investigate the factors that can control it. We focus largely on the role of valley and synoptic winds that are found to affect glaciers of varying size and orientation differently, influencing the amount of heat transfer to the ice surface that glaciers receive from outside its own micro‐climate. Moreover, we find that the presence of glacier winds can act to enhance or reduce overall heat transfer to the glacier, depending on the wind strength and degree of boundary layer disruption. We highlight the complexities that are ignored in simpler melt modeling frameworks and demonstrate how, especially under extreme summer heat, indicative of future conditions, static parameters to relate glacier melt to temperature are likely to be inappropriate. Key Points: Glacier size and alignment with valley/synoptic wind gradients control the magnitude of near‐surface coolingValley/synoptic winds can occur between 19% and 64% of the time and contribute between 3% and 81% of total sensible heat to the ice surfaceLocalized cooling and turbulence in the boundary layer increase the complexity and non‐linearity of glacier response to climate [ABSTRACT FROM AUTHOR]

Numerical modeling of ice sheet motion and hence projections of global sea level rise require information about the evolving subglacial environment, which unfortunately remains largely unknown due to its difficulty of access. Here we advance such subglacial observations by reporting multi‐year observations of seismic tremor likely associated with glacier sliding at Helheim Glacier. This association is confirmed by correlation analysis between tremor power and multiple environmental forcings on different timescales. Variations of the observed tremor power indicate that different factors affect glacial sliding on different timescales. Effective pressure may control glacial sliding on long (seasonal/annual) timescales, while tidal forcing modulates the sliding rate and tremor power on short (hourly/daily) timescales. Polarization results suggest that the tremor source comes from an upstream subglacial ridge. This observation provides insights on how different factors should be included in ice sheet modeling and how their timescales of variability play an essential role. Plain Language Summary: The Greenland Ice Sheet has lost ice increasingly in the past few decades, contributing significantly to global sea level rise. However, large uncertainties remain in computer simulations of such ice mass loss and hence sea level rise. This uncertainly is mainly attributed to the lack of information on what is happening at the bottom of the ice sheet and how that affects ice sheet movement. For example, how much water is there and whether it is in isolated pockets or is well distributed as a thin sheet can have an important effect on ice movement. In this paper, we observe small ground motions that are generated during glacier movement at a marine‐terminating glacier in Greenland. By analyzing the energy variation of the small ground motions over multiple years as well as observing the reasons that cause the variations, we learn that subglacial water pressure may control ice flow speeds on a seasonal/annual scale, and that ocean tides can change ice flow on an hourly/daily scale. This observation provides important constraints for computer simulations of future sea level rise in terms of the impacting factors and their respective timescales. Key Points: Multi‐year seismic records reveal glacial slip and tremor variability at Helheim GlacierTremor correlates with high effective pressure at tidal timescales, opposite to the expectation at longer timescalesThe tremor source points to an upstream subglacial ridge [ABSTRACT FROM AUTHOR]

The paper considers Sr, Nd, and Pb isotope data obtained for two cores of bottom sediments taken in the Oga and Tsivolki bays of Severny Island of the Novaya Zemlya archipelago. The studied sequence of sediments from Oga Bay has accumulated over the last thousand years. The 87Sr/86Sr ratio decreases from top to bottom down the section from 0.72225 to 0.71995, the value of εNd varies from –6.1 to –5.5. The Pb isotopic composition varies within narrow limits: the 206Pb/204Pb ratio from 19.107 to 19.139, the 207Pb/204Pb ratio from 15.632 to 15.635, and the 208Pb/204Pb ratio from 38.568 to 38.635. A rapid decrease in the 87Sr/86Sr ratio at a relatively stable neodymium and lead isotope composition indicates a change in the source of the clastic material. This can be explained by the fact that the material of the destruction of Permian clay shales, and then Devonian–Silurian sedimentary carbonates, first entered the area of glacier abrasion and further, respectively, into the sedimentation zone. The sediment column from Tsivolki Bay was formed over a little more than 10 000 years. Based on the Sr, Nd, and Pb isotope ratios, these bottom sediments are divided into lower and upper parts: before and after 150 cm (or ~3500 years). In the lower part of the column, the 87Sr/86Sr ratio increases from 0.72055 to 0.72580, the value of εNd remains approximately the same and varies around –8.2. In the upper part, the 87Sr/86Sr ratio drops to 0.72049 in the near-surface layer; at the same time, the value of εNd increases to –6.4. At the boundary of these two units, the 206Pb/204Pb ratio abruptly changes from about 18.0 in the lower part to 19.3 in the upper part and 208Pb/204Pb from about 36.5 in the lower part to 38.7 in the upper part of the section. The change in the Sr, Nd, and Pb isotope characteristics is likely a reflection of changes in the composition of the rocks in the area where the basin was removed, which is now being eroded by the glacier. Comparison with modern sources supplying clastic material to the Kara Sea showed that the material is supplied to the Oga and Tsivolki bays only from Novaya Zemlya. [ABSTRACT FROM AUTHOR]

The northwestern part of the Indian ocean is Arabian sea. It is formed roughly around 50 million years ago. Since last few decades climate along the Indian Ocean and particularly on Arabian Sea is changing very fast. The excessive heat and energy warm the ocean and change the temperature of the ocean and cause effects like rising sea level rise, increasing ocean temperature, algal blooming, ocean acidification, rain pattern, migration in fishes, salt water intrusion on land, decline in fishes. The sea level rise has direct relationship with climate change which leads to the rising in temperature which result in melting of glaciers, snow and ice caps this add up into sea water level. Right now, sea level rise by 1-8th inches per year. The excessive heat and energy warms the ocean, leads to change in temperature. Because of rapid increase in human population equivalent of a third of human waste carbon dioxide mixed in ocean water. The increasing of carbon dioxide emissions from fossil fuel combustion have led to an exponential increase in the net amount of CO2 being dissolved in the ocean Over the past 200 years, the increase of carbon dioxide in ocean water reduces the ocean pH level. Sea temperature has increased by 1.20°C to 1.40°C. Higher temperatures combined to increased storm water runoff of nutrients can results in conditions favorable for algal bloom and growth of harmful algae and cyanobacteria in salt and brackish water. Sea surface temperature (SST) one of the reasons for coral bleaching which effect marine organisms. As the temperature rises it leads to the coral to expel the algae (Zooxanthellae) living in their tissue causing coral to completely white by which corals are more prone to being dead. Approximately 30% of the anthropogenic CO2 emission has been absorbed by the oceans. Due to acidification water becomes acidic, and shells bearing organisms and plankton gets break down, which secrets calcium carbonate coatings. Acidification effect to shells as it becomes more corrosive and reduce the formation of shells in Arabian ocean. 0.015 units per 1!, pH get disturb by temperature on Arabian sea. Ocean Acidification results in Deteriorate the minerals which produced by oysters, clams, lobsters, shrimps, shells and skeleton. Ultimately it gets in food web harming all type of organisms. As the tides go higher the sea water goes towards land. Water resources near to sea can faces the risks from saltwater intrusion. Loss of fresh water, vegetation and saline mudflats are caused due to saltwater intrusion. Due to saltwater intrusion crocodile breeding grounds get destructed. Upstream movement of brackish or saline water that cause concentration of salt and other seawater derived ions to increase. These changes having important and widely applicable effects in affecting marine ecosystem, coastal communities and regional weather pattern. [ABSTRACT FROM AUTHOR]

This paper presents a map of terrestrial glacial geomorphology of eleven surge-type and nonsurge- type glacier forefields in southwest and west Spitsbergen, Svalbard. Glacier forefields were mapped using a combination of field surveys and the use of an uncrewed airborne vehicle in September 2022 and satellite imagery captured in 2020, with mapping performed in ArcGIS Pro at a 1:5000 scale. Maps were constructed for glaciers in Van Kuelenfjorden and Van Mijenfjorden (southwest Spitsbergen), and in Isfjorden, Billefjorden a fjord branch of Isfjorden and St. Jonsfjorden (west Spitsbergen), to obtain a breadth of glacier types and features representative of glacial landsystems on Svalbard. The detailed landform inventory was divided into: (i) ice marginal, (ii) subglacial, (iii) glaciofluvial and glaciolacustrine, (iv) supraglacial and (v) other non-glacial and contemporary features. These detailed maps provide a geomorphological insight into the past and present characteristics of glaciers on Svalbard. [ABSTRACT FROM AUTHOR]

A 54-year-long series of continuous instrumental measurements of mass balance and its main components has already been accumulated at the Djankuat Glacier, which is representative of the Caucasus and the most studied glacier in Russia. The anomalies of these indicators in 2017/2018–2020/2021 were evaluated against an analysis of meteorological reasons that predetermined them. Each of the four balance years under consideration represents a particular anomaly of varying severity. As for conditions of mass income, three years saw accumulation higher than average, and in one year (2018/2019) it approached the norm. As for summer ablation conditions, similarly, in one season (2019) the melting differed from the average only slightly, but in the other three it was much higher. Consequently, in one year (2020/2021) the state of the glacier was close to normal, in another (2017/2018) the budget situation was much more favorable for Djankuat, and in the other two the final losses significantly exceeded the average annual mass loss rate. At the same time, in 2019/2020, an absolute record of ablation since the beginning of monitoring in 1967/1968 was recorded (4360 mm w.e.). Nevertheless, although negative mass balance values continue to be recorded annually, signs of an inevitable slowdown in the rate of glacier degradation in the Caucasus have appeared in the last 4-year-long period: the continued growth of winter snow accumulation overlaps the ongoing intensification of summer melting. The growth of debris cover in terms of area and thickness also affects this mass loss slowdown to some extent. This inhibits ablation, exerting a heat-insulating effect. Because of this, the congruence of mass balance parameters vs. altitude curves is distorted. Also, a tendency toward increasing annual glacier mass turnover was revealed for the last half-century. This fact gradually increases the energy of glaciation and indirectly indicates a weakening of continentality in the climate of the Caucasian highlands. [ABSTRACT FROM AUTHOR]

To further elucidate the Late Pleistocene glacial history of mid-elevation mountainous regions in Central Europe, 10Be cosmic-ray exposure (CRE) dating was applied to moraines in the Zastler Tal Valley in the Southern Black Forest. Periods of glacier recession from moraines in this valley began no later than 16 ka, 15 ka, and 13 ka. CRE ages of moraines in this and other parts of the Southern Black Forest cluster around 17–16 ka and 15–14 ka, thus suggesting a common forcing of glacier recession. Equilibrium-line altitudes (ELAs) during moraine formation were calculated for precipitation reconstruction. Observed spatial discrepancies in ELAs at ca. 15–14 ka are explained best by the size of snow-contributing areas. The reconstructed annual precipitation at the ELA for ca. 16 ka and ca. 15 ka is affected by large uncertainties, representing a wide range from ~50% to ~150% of present-day values. Due to various factors, such as drifting snow, the lower bounds of the estimates appear most realistic, thus concurring with the common hypothesis of less precipitation during the last glacial termination than today in Central Europe. Further research is needed before ELAs of small ice masses can be employed for precise precipitation estimates. [ABSTRACT FROM AUTHOR]

Climate warming exacerbates the degradation of the mountain cryosphere, including glacier retreat, reduction in snow cover area, and permafrost degradation. These changes dramatically alter the local and downstream hydrological regime, posing significant threats to basin-scale water resource management and sustainable development. However, there is still a lack of systematic research that evaluates the variation of cryospheric elements in mountainous catchments and their impacts on future hydrology and water resources. In this study, we developed an integrated cryospheric-hydrologic model, referred to as the FLEX-Cryo model. This model comprehensively considers glaciers, snow cover, frozen soil, and their dynamic impacts on hydrological processes in the mountainous Hulu catchment located in the Upper Heihe river of China. We utilized the state-of-the-art climate change projection data from the sixth phase of the Coupled Model Intercomparison Project (CMIP6) to simulate the future changes in the mountainous cryosphere and their impacts on hydrology. Our findings showed that the two glaciers in the Hulu catchment will completely melt out around the years 2045-2051. By the end of the 21st century, the annual maximum snow water equivalent is projected to decrease by 41.4% and 46.0%, while the duration of snow cover will be reduced by approximately 45 and 70 days. The freeze onset of seasonal frozen soil is expected to be delayed by 10 and 22 days, while the thaw onset of permafrost is likely to advance by 19 and 32 days. Moreover, the maximum freeze depth of seasonal frozen soil is projected to decrease by 5.2 and 10.9 cm per decade, and the depth of the active layer will increase by 8.2 and 15.5 cm per decade. Regarding hydrology, runoff exhibits a decreasing trend until the complete melt-out of glaciers, resulting in a total runoff decrease of 15.6% and 18.1%. Subsequently, total runoff shows an increasing trend, primarily due to an increase in precipitation. Permafrost degradation causes the duration of low runoff in the early thawing season to decrease, and the discontinuous baseflow recession gradually transitions into linear recessions, leading to an increase in baseflow. Our results highlight the significant changes expected in the mountainous cryosphere and hydrology in the future. These findings enhance our understanding of cold-region hydrological processes and have the potential to assist local and downstream water resource management in addressing the challenges posed by climate change. [ABSTRACT FROM AUTHOR]

Unmanned aerial systems have a wide range of uses in studying the impacts of climate change over several fields. Recently, its combination with a ground-penetrating radar (GPR) technology has been demonstrated to be highly effective for surveying glaciers, especially in difficult and inaccessible terrains like Antarctica. In this context, this study focused on exploring the potential of using an unmanned aerial vehicle (UAV)-GPR to measure the depth of glaciers on Horseshoe Island, West Antarctica. The data were collected during the seventh Turkish Antarctic Expedition (TAE-VII) in February and March 2023, within the scope of the international project titled "Glacier monitoring and 3D modeling in Horseshoe Island Antarctica based on UAV-GPR observations", carried out by the bilateral cooperation of İstanbul Technical University and the Bulgarian Academy of Sciences. In order to determine the depth of the glacier, this investigation utilized both terrestrial GPR and UAV-GPR data. The UAV-GPR depth was determined as 9 cm root mean square error as a consequence of comparison with terrestrial GPR results. Furthermore, it was demonstrated that measurements performed with the UAV were completed approximately 25 times faster than those conducted with the terrestrial GPR, demonstrating a significant efficiency benefit. As a result, it can be concluded that using the airborne GPR approach offers a beneficial and effective way to undertake surveys of glaciers quickly and affordably with promising accuracy. [ABSTRACT FROM AUTHOR]

This article considers the characteristics of two systems of the supraglacial runoff of the polar glacier: a hydro-network of streams and a porous layer of melting crust. Field methods have revealed fundamental differences between these systems in the drainage area and the features of the meltwater movement and runoff regime. Calculation of the supraglacial runoff has shown its maximum level in the hydro-network during the peak of snowmelt in July, while the runoff in the melting crust becomes predominant in the second half of summer (in August). [ABSTRACT FROM AUTHOR]

Small glaciers of the Polar Urals are at the limits of their existence. Their state and changes serve as an important natural indicator of modern climatic changes. In 2019 and 2021, we performed ground-based radar studies of one of these glaciers, the IGAN Glacier, to measure ice thickness and snow cover. We used Picor-Led (1600 MHz), and VIRL-7 (20 MHz) GPRs. According to these data, the glacier has an average thickness of 49 m, maximum 113 m. The glacier has a polythermal structure: a cold ice layer with an average thickness of 12 m (maximum 43 m), overlaps the temperate ice with an average thickness of 37 m (maximum 114 m in the upper part of the glacier). The volume of ice contained in the glacier (in its studied part) is 14.3 × 106 m3, of which 10.89 × 106 m3 is temperate ice and 3.44 × 106 m3 is cold ice. For comparison: according to the radar data of 1968, the total ice thickness then reached 150 m in the central part, and the thickness of the upper layer of cold ice was 40–50 m. Radar snow measurement survey allowed us to plot the distribution of seasonal snow thickness over the glacier surface in 2019 and 2021, where a general spatial pattern of snow thickness increase from 2 m on the glacier terminus to 8 m and more towards the back wall of the cirque which is due to the significant influence of avalanche nourishment and wind transport. Over the last decade, the glacier has lost about 3.2 × 106 m3 of ice, and if the rate of loss continues, it may disappear in 40–50 years. However, this process may have a non-linear character, as it involves not only climatic factors, but also local terrain features, on the one hand contributing to a high accumulation of snow, on the other hand – to the formation of a glacial lake during glacier retreat, which may intensify ablation. [ABSTRACT FROM AUTHOR]

The article presents the results of studying specific organomineral formations—cryoconite sediments—samples of which were taken on the surface of the Witte Glacier (Medvezhiy Bay, Novaya Zemlya) on cruise 76 of the R/V Akademik Mstislav Keldysh. The specific activities of 137Cs, 241Am, 207Bi, 210Pb, and 7Be were measured in 14 samples. Analysis of the materials suggests that cryoconite contains radioactive contamination deposited in the glacier in the period from September 1957 to December 1962 as a result of atmospheric nuclear explosions at the Sukhoy Nos test site, located 100 km from the glacier. Extremely high Bi, Ag, Sb, Mo, Pb, Sn contents and a strong correlation with anthropogenic radionuclides may indicate the technogenic emission of these elements during the destructive impact of nuclear explosions on bedrock, the metallogenic specialization of which corresponds to rich polymetallic mineralization. [ABSTRACT FROM AUTHOR]

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The Greenland Ice Sheet is losing mass at an accelerating pace, increasing its contribution to the freshwater input into the Nordic Seas and the subpolar North Atlantic. It has been proposed that this increased freshwater may impact the Atlantic Meridional Overturning Circulation by affecting the stratification of the convective regions of the North Atlantic and Nordic Seas. Observations of the transformation and pathways of meltwater from the Greenland Ice Sheet on the continental shelf and in the gyre interior, however, are lacking. Here, we report on noble gas derived observations of submarine meltwater distribution and transports in the East and West Greenland Current Systems of southern Greenland and around Cape Farewell. In southeast Greenland, submarine meltwater is concentrated in the East Greenland Coastal Current core with maximum concentrations of 0.8%, thus significantly diluted relative to fjord observations. It is found in water with density ranges from 1,024 to 1027.2 kg m−3 and salinity from 30.6 to 34, which extends as deep as 250 m and as far offshore as 60 km on the Greenland shelf. Submarine meltwater transport on the shelf averages 5.0 ± 1.6 mSv which, if representative of the mean annual transport, represents 60%–80% of the total solid ice discharge from East Greenland and suggests relatively little offshore export of meltwater east and upstream of Cape Farewell. The location of the meltwater transport maximum shifts toward the shelfbreak around Cape Farewell, positioning the meltwater for offshore flux in regions of known cross‐shelf exchange along the West Greenland coast. Plain Language Summary: The Greenland Ice Sheet is losing a lot of ice very quickly and this is causing more lightweight freshwater to flow into the North Atlantic Ocean. This extra freshwater could possibly influence the way that the surface and interior of the ocean interact, impacting global ocean currents. We do not have enough information about how the ice that is melting from Greenland is affecting the ocean, in part because we do not have many tools to observe where the meltwater goes. In this work, we made measurements with the best tools available to follow the ice melted from marine terminating glaciers as it travels around Greenland. We were able to make some of the most comprehensive direct measurements of the oceanic pathways of glacial meltwater in coastal Greenland. We found that the freshwater from Greenlandic glacier's submarine melted ice is not very concentrated when it gets to the ocean, but it does go deep and, at first, not too far away from the shore. The Greenland meltwater stays close to shore along the east coast up to Cape Farewell. However, meltwater moves farther from shore after that and may mix out into the open ocean from there. Key Points: Direct measurements of the pathways and fluxes of glacial meltwater in coastal GreenlandLittle offshore export of meltwater east and upstream of Cape FarewellMeltwater moves offshore toward shelfbreak around Cape Farewell [ABSTRACT FROM AUTHOR]

Due to high altitudes, Central Asian alpine lakes can serve as indicators of localized climate change. This article monitored the water volume time series trends of the ungauged alpine Lake Karakul, which is typical because of the abundance of glaciers in the basin, from 1990 to 2020 via multiple source remote sensing data. The "Global-Local" multi-scale lake extraction method is used to delineate the boundary of Lake Karakul. Consistency analysis was performed on the altimetry data of CryoSat-2, ICESat-1 and ICESat-2, assuming that the lake surface was flat; a threshold value was set to remove gross error, and then 3σ was used to remove the surface elevation anomaly. Based on the pyramid volume model, the lake area and surface elevation information were used to reconstruct the water volume time series of Lake Karakul. The influencing factors of water volume temporal variation were discussed. The results show that Lake Karakul has been on an expansionary trend in recent years: The lake area increased from 394.9 km2 in 1988 to 411.4 km2 in 2020; the rate of increase is 0.74 m/year. The surface elevation increased from 3886.6 m in 2003 to 3888.6 m in 2020; the rate of increase is 0.11 km2/year. The lake water volume accumulated was 0.817 km3 in 2003–2020, with an accumulation rate of 0.059 km3/year. The Lake Karakul basin is developing towards dry heat, with a cumulative temperature variation rate of +0.38 °C/year; the average rate of variation in annual cumulative precipitation is −3.37 mm/year; the average evapotranspiration in the watershed is on a fluctuating increasing trend, with a rate of variation of +0.43 mm/year; glaciers in the lake basin have a retreating trend, with an average annual rate of variation of −0.22 km2/year from 1992 to 2020. Lake Karakul is more sensitive to temperature variations, and the runoff from retreating glaciers in the basin is an important contribution to the expansion of Lake Karakul. [ABSTRACT FROM AUTHOR]

The composition of runoff in the basins located in the arid region of Northwest China is complex. How to better simulate and analyze the hydrological process and runoff situation of the basin through hydrological models is the key to the effective management of the regional water resources. This study focused on the Qarqan River Basin in Xinjiang, which is a typical river originating from glaciers and crucial for maintaining the oasis ecology in the downstream Tarim River. Based on the original SWAT model, a SWAT-Gla model containing a new glacier module was constructed according to the characteristics of the basin. After simulating, parameter calibration, and verification of the models, it was found that during the calibration period (1975–2009) and verification period (2010–2019), the R2, NSE, and PBIAS results of the SWAT-Gla model were much better than the original SWAT model. Moreover, SWAT-Gla could also simulate the runoff much better, especially in the peak and recession parts of the hydrograph compared with the original SWAT model. It was found that SWAT-Gla could better describe the runoff process in the basin where glacier recharge was the main component of runoff. Further, the analysis revealed that over the past 50 years, glacier and snowmelt water contributed to approximately 80% of the total basin recharge, which predominantly occurred from March to September. The volume of glacier meltwater exhibited a strong correlation with temperature, with both demonstrating an upward trend. The simulation found that in terms of groundwater, the groundwater recharge in the Qarqan River was relatively stable, stabilizing at 13% over the past 30 years, and groundwater recharge was mainly distributed in spring and summer, accounting for about 95% in total. Overall, we observed an increasing trend in the replenishment of glacial meltwater in both the surface runoff and groundwater in the basin. Therefore, it is essential to pay more attention to the future changes in water resources in the basin to ensure the sustainable development of water resources. [ABSTRACT FROM AUTHOR]

Context: Syntheses of vegetation responses over the last century are rare for the Alps, and limited in chronological and taxonomical resolution. We propose that pollen records from glaciers can be used to fill this gap. Objectives: Our aim is to evaluate the reliability of glacier pollen records as historical archives of biodiversity to obtain plant diversity data and landscape changes. In detail, we aim at reconstructing taxa and vegetation trends in central sector of the Italian Alps over the last century integrating pollen-inferred vegetation trends with drifts in spatially explicit land-cover. Methods: Our study area is the Lombardy region (Italy). We performed pollen analyses of Adamello glacier cores, and reconstructed trends of single taxa and main vegetation types since the 1950s. Pollen-inferred vegetation trends were calculated using pollen indicators obtained from a database of vegetation-plot observations. The reliability of these trends is evaluated by comparison with spatially explicit tendencies reconstructed with a time-series of land-cover maps. Results: Pollen records well represent the natural vegetation types as the temperate and the riverine forests, and the anthropic vegetation as crops and alien species. From the 1980s a thermophilisation took place, and warm-demanding native and alien species expanded. The contraction of cultivated land since the 1970s, and the decline of the riverine forest appear driven by socio-economic factors. Conclusions: We conclude that pollen-inferred vegetation trends from glaciers can be used to obtain large scale biodiversity information. This is relevant also for areas where biodiversity data are scarce but needed for landscape management planning. [ABSTRACT FROM AUTHOR]

Several studies have analyzed the ice margin behavior of the Quelccaya Ice Cap (QIC), Earth's largest tropical ice cap, through the Holocene. However, continuous integration of new information to produce a more cohesive history of the QIC is necessary. Here, the radiocarbon dates of 33 rooted plant specimens collected in situ along the western ice margin between 2002 and 2018 reveal the timing of its past extent as it advanced during the mid‐Holocene. The most recent evaluation of collected specimens indicates that the QIC margin advanced ∼350 m down the Challpacocha Valley between 7.1 and 4.5 ka BP. Past studies of documented ice extent on the western side of the QIC based on a variety of techniques are compiled to create a more comprehensive history of the QIC's behavior throughout the Holocene. Records of documented ice extent, as well as other proxy records, indicate a climate transition ∼5–7 ka BP that created the proper environmental conditions for the expansion of the QIC. Evidence from nearby valleys indicates that the QIC behaved similarly to the documented ice extent in the Challpacocha Valley in response to Holocene climatic fluctuations. The ability to collect the plant specimens and recent analysis of satellite imagery reveals rapid retreat rates of the western outlet glaciers from 1985 to 2020, leaving the western margin of the QIC at its smallest extent since the mid‐Holocene. Plain Language Summary: The area around the Quelccaya Ice Cap (QIC) is unique as wetland plant samples have been found preserved in their growth positions, buried by past advancing ice, whereas the ice typically removes vegetation and soil in its advance down a valley. Using the 14C dates of these plants, we map a 350‐m advance of the ice margin between 7.1 and 4.5 ka BP. Combined with a variety of previous studies involving different methods and records from ice and lacustrine sediment cores, a larger picture of the QIC's behavior comes into view. A largely accepted global climate shift between ∼7 and 5 ka BP occurred in tandem with the QIC's advance. Although the QIC has fluctuated before, at no time has the western margin receded to the current extent since the mid‐Holocene. This is indicated by the exposure of the plants and current margin retreat rates calculated from satellite imagery (1985–2020). Key Points: Mid‐Holocene advance of the Quelccaya Ice Cap (QIC) is documented using 14C dating of in situ vegetation exposed during the recent retreatPlant ages of ∼4.5 to ∼7.1 ka BP provide evidence of a mid‐Holocene climate transition and the QIC ice‐margin expansionAnalysis of satellite imagery from 1985 to 2020 documents a recent rapid retreat (∼20 m/yr) of the QIC margin [ABSTRACT FROM AUTHOR]

Biospheric particulate organic carbon (POCbio) burial and rock petrogenic particulate organic carbon (POCpetro) oxidation are opposing long‐term controls on the global carbon cycle, sequestering and releasing carbon, respectively. Here, we examine how watershed glacierization impacts the POC source by assessing the concentration and isotopic composition (δ13C and Δ14C) of POC exported from four watersheds with 0%–49% glacier coverage across a melt season in Southeast Alaska. We used two mixing models (age‐weight percent and dual carbon isotope) to calculate concentrations of POCbio and POCpetro within the bulk POC pool. The fraction POCpetro contribution was highest in the heavily glacierized watershed (age‐weight percent: 0.39 ± 0.05; dual isotope: 0.42 (0.37–0.47)), demonstrating a glacial source of POCpetro to fjords. POCpetro was mobilized via glacier melt and subglacial flow, while POCbio was largely flushed from the non‐glacierized landscape by rain. Flow normalized POCbio concentrations exceeded POCpetro concentrations for all streams, but surprisingly were highest in the heavily glacierized watershed (mean: 0.70 mgL−1; range 0.16–1.41 mgL−1), suggesting that glacier rivers can contribute substantial POCbio to coastal waters. Further, the most heavily glacierized watershed had the highest sediment concentration (207 mgL−1; 7–708 mgL−1), and thus may facilitate long‐term POCbio protection via sediment burial in glacier‐dominated fjords. Our results suggest that continuing glacial retreat will decrease POC concentrations and increase POCbio:POCpetro exported from currently glacierized watersheds. Glacier retreat may thus decrease carbon storage in marine sediments and provide a positive feedback mechanism to climate change that is sensitive to future changes in POCpetro oxidation. Plain Language Summary: Particulate organic carbon (POC) in rivers can come from bedrock and the biosphere. When POC produced by vegetation and soils gets buried in fjords, it can be stored for hundreds of thousands of years. In contrast, when bedrock erodes and rock organic carbon reacts with oxygen, carbon previously stored long term can enter the atmosphere as carbon dioxide. Thus, understanding the balance between these two sources of POC and their fates can help predict future carbon cycling. Here, we study POC in glacial rivers, where bedrock erosion produces rock derived POC and where soil and forests produce biospheric POC. We show how much POC comes from each source across the glacial melt season in four rivers in Southeast Alaska whose watershed range in percent glacier coverage from 0% to 49%. The watershed with the largest glacier coverage produces the most rock‐derived POC, providing evidence of the glacial source of rock‐derived carbon that can occur in Southeast Alaskan fjords. However, the most glacial watershed also carries the highest concentration of POC from the biosphere and the most sediment, suggesting that glacier rivers play an outsized role in carrying both rock‐ and plant‐derived carbon to fjords where its burial can help mitigate climate change. Key Points: Carbon isotope data show a petrogenic source contributed to glacier river particulate organic carbon (POC) entering Southeast Alaska fjordsGlacier erosion and melt increased the river petrogenic POC:biospheric POC ratio, while non‐glacial runoff lowered the ratioHeavily glacierized rivers can have high biospheric POC and sediment concentrations, implying high carbon burial potential in fjord sediments [ABSTRACT FROM AUTHOR]

Worldwide, there are great challenges for meteorological monitoring and glacier ablation monitoring in high-altitude mountain areas. It is often difficult to capture fine-scale climate and glacial changes in high-altitude mountainous areas due to the harsh natural environment and the extreme lack of observational sites. Based on high-altitude meteorological stations erected on the eastern shore of Aqikkule Lake (AQK) and at the terminus of Shenshechuan Glacier (SSG), as well as on mass balance data from SSG, the characteristics and correlation of temperature, solar radiation, relative humidity, precipitation, wind speed and direction of the two regions, and the mass balance in the ablation area of SSG from 30 May 2022 to 18 May 2023 were analyzed, and the average melting depth of SSG was simulated. The results indicate the following: (1) The average annual temperature of AQK and the terminus of SSG is −3.7 °C and −7.7 °C, respectively, and the vertical lapse rate of temperature in the summer half of the year is greater than that in the winter half of the year. Precipitation timing has a great influence on daily temperature differences. (2) Precipitation in both places is concentrated in summer; the glaciers in this area are of the summer recharge type, and precipitation has a significant reducing effect on the solar incident radiation and increases the relative humidity in this region. (3) AQK and SSG both have local circulation development, in the area of AQK all year round due to the lake effect, while the terminus of SSG only has the development of valley winds in the summer, being controlled in the winter by the westerly wind belt. (4) The average mass balance value of the ablation area of SSG was −1786 mm as measured by the range poles method. The average annual ablation depth of SSG simulated by using the empirical formula was 587–597 mm, which is not large compared with other glacier areas in the Tibetan Plateau, and it has the characteristics of typical continental-type glaciers. [ABSTRACT FROM AUTHOR]

The centennial response of land‐terminating glaciers in Greenland to climate change is largely unknown. Yet, such information is important to understand ongoing changes and for projecting the future evolution of Arctic subpolar glaciers, meltwater runoff, and sediment fluxes. This paper analyses the topography, geomorphology, and sedimentology of prominent moraine ridges and the proglacial areas of ice cap outlet glaciers on the Qaanaaq peninsula (Piulip Nunaa). We determine geometric changes of glaciers since the neoglacial maximum; the Little Ice Age (LIA), and we compare glacier behaviour during the LIA with that of the present day. There has been very little change in the rate of volume loss of each outlet glacier since the LIA compared with the rate between 2000 and 2019. However, the percentage of each glacier that is likely composed of cold‐based ice has increased since the LIA, typically by 20%. The LIA moraines comprise subrounded, striated, and faceted clasts that evidence subglacial transport, and outwash plains, flutes, kames, and eskers that evidence subglacial motion and meltwater within temperate ice. Contrastingly, contemporary ice margins and their convex ice surfaces comprise pronounced primary foliation, ephemeral supraglacial drainage, sediment drapes from thrust plane fractures, and an absence of open crevasses and moulins. These calculations and observations together lead us to interpret that these outlet glaciers have transitioned towards an increasingly cold‐based thermal regime despite a warming regional climate. Thermal regime transitions control glacier dynamics and therefore should be incorporated into glacier evolution models, especially where polythermal glaciers prevail and where climate is changing rapidly. [ABSTRACT FROM AUTHOR]

Interferometric Synthetic Aperture Radar (InSAR) remote sensing generally lacks deformation sensitivity in the along-track direction. In this proposed approach, across-track observations from conventional InSAR, using both ascending and descending passes, were superimposed with the along-track movement derived from multi-aperture InSAR (MAI) to determine the full three-dimensional (3-D) velocity of the Siachen Glacier in the Karakoram range of the Himalayas. The along-track velocity signal is essential for estimating the movement component in the north/south direction, which is needed for a complete delineation of 3-D deformation. The velocity observed was improved using the MAI technique in comparison to the conventional ascending/descending 3-D velocity estimation approach, and substantial differences were noticed between these two methods, particularly in the lower part of the glacier, which is moving almost in an along-track (north/south) direction. Glacier velocity varied from 0.3 md−1 in the accumulation zone to 0.60 md−1 in the terminus zone of the Siachen Glacier using this newly proposed approach. This study presents a 3-D velocity estimation without any preconceived assumptions regarding the flow conditions of glaciers and without any azimuth ambiguity. [ABSTRACT FROM AUTHOR]

The glacial and torrential basin of Taconnaz (Mont-Blanc massif, France) dominates the Chamonix valley. It is one of the major paths for snow avalanches in the Alps, often triggered by serac falls from the Taconnaz glacier. On 24 November 2018, the basin's multi-risk nature was further accentuated by a new type of hazard with a rockfall triggered at c. 2700 m a.s.l. It travelled down over a distance of 1.85 km and stopped 165 m away from the construction site of a micro-hydroelectric power station. We studied the triggering conditions at the permafrost lower limit, the effects of the supra-glacial path on the flow patterns, and the fate of the scar and the deposit on torrential activity. By comparing a pre-event Structure from Motion model with a post-event LiDAR model, we estimated the volume of the scar to be 42,900 m3 (±5%). A numerical model was employed to simulate the rapid runout. It revealed the complexity of the flow, attributed to the sequestration of a part of the deposit in crevasses, the incorporation of a significant volume of ice resulting in a transition from a dry granular flow to a mud-like flow, and the presence of numerous deposit zones. Subsequent monitoring of the area after the event allowed for the documentation of the scar's evolution, including a landslide, as well as the progressive degradation and evacuation of the deposit by the torrent without producing debris flow. The study of the triggering factors indicated glacial retreat as the probable main cause, assisted by the melting of ice lenses left by the permafrost disappearance. Finally, we present replicable methods for managing risks at the site following the event. This event improves the understanding of cascading processes that increasingly impact Alpine areas in the context of climate change. [ABSTRACT FROM AUTHOR]

This study provides the first comprehensive account of the glaciation of the Yankti Kuti valley of the upper Kali Ganga catchment of the Kumaon Himalaya, Uttarakhand. Employing multi-year satellite images from 1990 to 2021, the study investigated the loss of glacial area, ice volume, snout recession, and the changes in the equilibrium line altitude (ELA) in the Yankti Kuti Valley. The investigation showed an overall reduction of ~ 21 km2 (~ 21%) of the total glacier area of the basin. The basin witnesses an ice volume loss of ~ 23% and ~ 41 m upward shifting of the equilibrium line altitude (ELA) between 1990 and 2021. The retreat rate of the four studied glaciers shows ranges from ~ 18 to 41 m/year. The glaciers in the valley are melting at a significant rate due to global warming, giving rise to the increasing number of pro-glacial lakes in the study area from 04 in 1990 to 10 in 2021 and making them vulnerable to glacial lake outburst floods (GLOFs) in the future. The study, therefore, calls for continued glacier monitoring in the upper Kali Ganga catchment in order to assess the future response of the Himalayan cryosphere and to make robust quantitative assessments about the sustainable mitigation and adaptation strategies in the lower valleys. [ABSTRACT FROM AUTHOR]

Shifting precipitation patterns, a warming climate, changing snow dynamics and retreating glaciers are occurring simultaneously in glacierized mountain headwaters. To predict future hydrological behavior in an exemplar glacierized basin, a spatially distributed, physically based cold regions process hydrological model including on and off‐glacier process representations was applied to the Peyto Glacier Research Basin in the Canadian Rockies. The model was forced with bias‐corrected outputs from a high‐resolution Weather and Research Forecasting (WRF‐PGW) atmospheric simulation for 2000–2015, and under pseudo‐global warming for 2085–2100 under a business‐as‐usual climate change scenario. The simulations show that the end‐of‐century increase in precipitation nearly compensates for the decreased ice melt associated with almost complete deglaciation, resulting in a decrease in annual streamflow of 7%. However, the timing of streamflow advances drastically, with peak flow shifting from July to June, and August streamflow dropping by 68%. To examine the sensitivity of future hydrology to possible future drainage basin biophysical attributes, the end‐of‐century simulations were run under a range of initial conditions and parameters and showed the highest sensitivity to initial ice volume and surface water storage capacity. This comprehensive examination suggests that hydrological compensation between declining icemelt and increasing rainfall and snowmelt runoff as well as between deglaciation and increasing basin depressional storage capacity play important roles in determining future streamflow in a rapidly deglaciating high‐mountain environment. Conversely, afforestation and soil development had relatively smaller impacts on future hydrology. Plain Language Summary: We studied how water flow in mountain basins will change due to climate change, glacier retreat, and landscape evolution. Specifically, we focused on the Peyto Glacier Research Basin in the Canadian Rockies. By the end of the century, the Peyto Glacier is expected to nearly disappear, reducing the amount of meltwater reaching the stream. However, precipitation is predicted to increase, resulting in an overall 7% decrease in annual streamflow. The timing of streamflow will also shift significantly, with peak flow moving from July to June, and late summer flow dropping by 68%. There is uncertainty about how the basin will look once the glacier is gone. What will replace the glacier ice? Will vegetation grow? Will the proglacial lake expand? To explore different scenarios, we conducted additional simulations. We found that late summer streamflow was highly influenced by how much glacier ice remained by the end of the century. On the other hand, the variability in streamflow was more sensitive to surface water storage, such as the development of ponds and lakes in the deglaciated area. Soil development and vegetation growth had a much smaller impact on future streamflow. Key Points: Predicted streamflow volume is highly sensitive to glacier cover, but streamflow variability is more sensitive to water storage capacityIncreases in future precipitation will nearly compensate for deglaciation impacts on streamflow volume in the Peyto Glacier Research BasinFuture streamflow will be dominated by snowmelt and rainfall, modulated by depressional storage and will occur much earlier in the year [ABSTRACT FROM AUTHOR]

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Glacier recession is creating new water bodies in proglacial forelands worldwide, including Antarctica. Yet, it is unknown how microbial communities of recently formed "young" waterbodies (originating decades to a few centuries ago) compare with established "old" counterparts (millennia ago). Here, we compared benthic microbial communities of different lake types on James Ross Island, Antarctic Peninsula, using 16S rDNA metabarcoding and light microscopy to explore bacterial and diatom communities, respectively. We found that the older lakes host significantly more diverse bacterial and diatom communities compared to the young ones. To identify potential mechanisms for these differences, linear models and dbRDA analyses suggested combinations of water temperature, pH, and conductivity to be the most important factors for diversity and community structuring, while differences in geomorphological and hydrological stability, though more difficult to quantify, are likely also influential. These results, along with an indicator species analysis, suggest that physical and chemical constraints associated with individual lakes histories are likely more influential to the assembly of the benthic microbial communities than lake age alone. Collectively, these results improve our understanding of microbial community drivers in Antarctic freshwaters, and help predict how the microbial landscape may shift with future habitat creation within a changing environment. [ABSTRACT FROM AUTHOR]

The speed‐up of glaciers following ice shelf collapse can accelerate ice mass loss dramatically. Investigating the deformation of landfast sea ice enables studying its resistive (buttressing) stresses and mechanisms driving ice collapse. Here, we apply offset tracking to Sentinel‐1A/B synthetic aperture radar data to obtain a 2014–2022 time‐series of horizontal velocity and strain rate fields of landfast ice filling the embayment formerly covered by the Larsen B Ice Shelf, Antarctic Peninsula until 2002. The landfast ice disintegrated in 2022, and we find that it was precipitated by a few large opening rifts. Grounded glaciers did not accelerate instantaneously after the collapse, which implies little buttressing effect from landfast ice, a conclusion also supported by the near‐zero correlation between glacier velocity and landfast ice area. Our observations suggest that buttressing stresses are unlikely to be recovered by landfast sea ice over sub‐decadal timescales following the collapse of an ice shelf. Plain Language Summary: The Antarctic Ice Sheet is a potentially major contributor to sea‐level rise due to glaciers' dynamic response to changing oceanic and atmospheric conditions. Its floating extensions, ice shelves, play a critical role in stabilizing the ice sheet by resisting the flow of glaciers that feed into them. However, ice shelves can collapse rapidly. In 2002, a Rhode Island‐sized section of the Larsen B Ice Shelf disintegrated, causing adjacent glaciers to speed up. In 2011, landfast sea ice replaced the ice shelf in the Larsen B embayment, but it broke up in 2022. We use remote sensing data to investigate why the landfast ice collapsed and whether it resisted glacier flow as the ice shelf did. We show that opening rifts may be responsible for ice disintegration. We find no detectable buttressing effect from the landfast ice because glaciers did not speed up after removing landfast ice, and seasonal change of landfast ice extent did not affect the grounded glacier velocities. It may be because landfast ice is thinner and easier to deform than the ice shelf. Our observations suggest a possible precursor to ice collapse and highlight the limited role that landfast ice plays in slowing down ice mass loss. Key Points: We produce time‐dependent velocity and strain rate fields over Larsen B landfast sea ice from 2014 to 2022Opening rifts within the landfast sea ice may contribute to its disintegration in 2022Landfast sea ice provides no apparent buttressing to the upstream grounded glaciers [ABSTRACT FROM AUTHOR]