Search

Glaciers are the ambassadors of climate change. Their worldwide decline has serious impacts on natural hazards, the water cycle, and sea level rise. The monitoring of glaciers documents the increasingly rapid melting, which has culminated in a suite of extreme years—for example, 2023 in North America and the European Alps. Numerical simulations of future glacier change, supported by a large basis of observational data, allow us to understand the enormous changes ahead and prepare us for a world without glaciers. Technical approaches to reduce glacier melting have been developed and are applicable locally—for example, in connection with tourist activities—but they clearly fail at the larger scale. [ABSTRACT FROM AUTHOR]

At least three primary iceberg calving styles have been identified in Greenland: serac collapse, which produces falling icebergs tens of meters in length; slab capsize, which produces rotating icebergs hundreds of meters in length; and tabular rifting, which produces kilometer‐scale icebergs. However, calving styles are mostly undocumented across Greenland. Here, we develop a method to disentangle the sizes of individual calving events and map the dominant calving style at glaciers, using the characteristic properties of step retreats in satellite‐derived terminus positions. At glaciers known to frequently produce calving teleseisms, step retreats greater than 200 m account for >80% ${ >} 80\%$ of net calved length since 2018. In contrast, at glaciers known to calve by serac failure, 200 m step retreats account <20% ${< } 20\%$ of net calving. Thus, terminus change timeseries can offer promising insight into the dominant calving styles at marine‐terminating glaciers. Plain Language Summary: Iceberg calving is ubiquitous at the ocean‐bounded edges of ice sheets. However, not all iceberg calving is the same: at least three distinct mechanisms govern the discharge of solid ice from the Greenland Ice Sheet. We show these are associated with a characteristic range of iceberg sizes. Because calving constitutes a major component of Greenland's continued mass loss, it is important that these distinct mechanisms be understood. We develop a method to identify which calving mechanisms are important at various glaciers. We do so by using satellite observations to estimate the lengths of terminus retreats producing icebergs at individual glaciers. Key Points: Greenland outlet glaciers with different calving styles have different characteristic retreat magnitudes in consecutive satellite imagesAt glaciers which frequently produce calving teleseisms, step retreats in terminus position are dominated by retreats >200 mThe distinct processes underlying different calving styles will likely necessitate several distinct calving laws [ABSTRACT FROM AUTHOR]

Glaciers are an integral part of the high mountain environment and interact with the overlying atmosphere and surrounding terrain in a complex and dynamic manner. The energy exchange between the glacier surface and the overlying atmosphere controls ice melt rates and promotes the formation of a low-level katabatic jet that interacts with other, often thermally driven winds in alpine terrain. Information on the structure of the atmospheric boundary layer over glaciers is crucial for studying the characteristics of the katabatic jet, its broader cooling effect, and its susceptibility to be broken up by strong valley or synoptic winds that promote heat advection from the ice- and snow-free periphery towards the glacier. While the number of ground-based measurements from weather stations and meteorological towers installed on glaciers for boundary layer research has increased in recent years, a lightweight and mobile measurement technique for atmospheric sounding over alpine glaciers has not yet been available. Here we describe a new measurement technique based on a low-cost and open-source fixed-wing UAV, which allows sounding the atmospheric boundary layer over glaciers up to several hundred metres above the surface. Vertical profiles of air temperature, humidity, pressure, wind speed, wind direction and turbulence can be derived from the meteorological and flight recorder data collected by the UAV. The results of a measurement campaign on the Kanderfirn in the Swiss Alps on 16 June 2021 demonstrate the potential of the technique and highlight typical features of the boundary layer above a melting glacier surface. The soundings reveal a persistent low-level katabatic jet, characterised by a pronounced surface-based inversion, relatively dry air, high wind speeds and enhanced turbulence, and a warmer and more humid valley wind aloft. [ABSTRACT FROM AUTHOR]

The Antarctic Ice Sheet (AIS) has been losing ice mass and contributing to global sea level rise (GSLR). Given its mass that is enough to cause ∼58 m of GSLR, accurate estimation of mass balance trend is critical for AIS mass loss monitoring and sea level rise forecasting. Here, we present an improved approach to reconciled solutions of mass balance in AIS and its regions from multiple contributing solutions using the input-out, altimetric, and gravimetric methods. In comparison to previous methods, such as IMBIE 2018, this approach utilizes an adaptive data aggregation window to handle the heterogeneity of the contributing solutions, including the number of solutions, temporal distributions, uncertainties, and estimation techniques. We improved the regression-based method by using a two-step procedure that establishes ensembled solutions within each method (input-output, altimetry, or gravimetry) and then estimates the method-independent reconciled solutions. For the first time, 16 contributing solutions from 8 Chinese institutions are used to estimate the reconciled mass balance of AIS and its regions from 1996 to 2021. Our results show that AIS has lost a total ice mass of ∼3213±253 Gt during the period, an equivalent of ∼8.9±0.7 mm of GSLR. There is a sustained mass loss acceleration since 2006, from 88.1±3.6 Gt yr−1 during 1996–2005 to 130.7±8.4 Gt yr−1 during 2006–2013 and further to 157.0±9.0 Gt yr−1 during 2014–2021. The mass loss signal in the West Antarctica and Antarctic Peninsula is dominant and clearly presented in the reconciled estimation and contributing solutions, regardless of estimation methods used and fluctuation of surface mass balance. Uncertainty and challenges remain in mass balance estimation in East Antarctica. This reconciled estimation approach can be extended and applied for improved mass balance estimation in the Greenland Ice Sheet and mountain glacier regions. [ABSTRACT FROM AUTHOR]

Estimation of the glacier-stored freshwater is important to understand the water security in the Himalayan region. While previous work has studied the western and central Himalayan glaciers, the eastern counterpart received less and more scattered attention. In this study, an attempt is made to quantify the total glacier-stored freshwater in the Brahmaputra basin and later compared with previous global models. Using open-source tools such as COSI-Corr and the Himalayan Glacier Thickness Mapper (HIGTHIM), the surface velocity and thickness of 1075 glaciers (> 1 km2) in the Brahmaputra basin were estimated, resulting in a current ice-volume estimate of 283 × 109 m3. Based on the laminar flow model, the mean ice volume ranges from 8284 to 230,186 m3, with an average of 36,570 m3. Sub-basin-wise evaluations of the total glacier-stored freshwater availability in the basin were also conducted, revealing that the Siang (89.998 × 109 m3, 31.45%) and Lohit (84.371 × 109 m3, 29.49%) sub-basins have significantly larger ice volumes than others. The average mean ice volume for each sub-basin are as follows: Teesta (45,233 m3), Sankosh (45,552 m3), Manas (39,581.7 m3), Subansiri (40,922.4 m3), Kameng (41,241.2 m3), Siang (36,120.5 m3), Dibang (31,792.2 m3), and Lohit (30,340.6 m3). Teesta, Sankosh, and Manas exhibit relatively higher average mean ice volumes than others. In comparison with the global studies, the present study's findings are acceptable with ensemble ice-volume estimates considering an uncertainty of ± 17.35%. Therefore, these results serve as a primary input for assessing the future changes in water resources and hazards related to water in the Brahmaputra basin. [ABSTRACT FROM AUTHOR]

The Vimmerby Moraine is the only significant ice‐marginal moraine on the eastern side of southern Sweden, but no detailed studies exist on its formation during the final deglaciation of the Fennoscandian Ice Sheet. Through ground‐penetrating radar surveys and detailed sediment logging, we provide evidence for an active, oscillating ice margin during the formation of the Vimmerby Moraine, suggesting that the deglaciation of the South Swedish Uplands was, at least in some regions, dynamic. Ground‐penetrating radar surveys enabled imaging of internal sediment and delineation of the bedrock surface. These were complemented by common mid‐point surveys and sediment logging, as well as lithofacies analysis at three exposures in agravel pit. This approach revealed multiple subglacial till units partially separated by intercalated glacifluvial deposits. The glacifluvial sediments exhibit evidence of glaciotectonism, suggesting active overriding by the last ice sheet. Further evidence of an active ice margin is provided by the ground‐penetrating radar profiles collected perpendicular to the moraine crest. These contain a series of northerly dipping reflectors, which we interpret as evidence of repeated basal freeze‐on and melt‐out of sediment slabs during ice margin oscillations, as has been observed at contemporary glacier margins in Iceland, Norway, and the Alps. The data presented here demonstrate that the last Fennoscandian Ice Sheet remained active around the time of the Vimmerby Moraine formation. This work highlights the benefits of including detailed sediment logging and near‐surface geophysical surveys in the interpretation of deglaciation dynamics. [ABSTRACT FROM AUTHOR]

Structure from motion (SfM) photogrammetry coupled with multiview stereo (MVS) techniques are widely used for generating topographic data for monitoring change in surface elevation. However, study sites on remote glaciers and ice caps often offer suboptimal conditions, including large survey areas, complex topography, changing weather and light conditions, poor contrast over ice and snow, and reduced satellite positioning performance. Here, we provide a review of methodological considerations for conducting aerial photography surveys under challenging field conditions. We generate topographic reconstructions, outlining the entire workflow, from data acquisition to SfM-MVS processing, using case studies focused around two small glaciers in Arctic Canada. We provide recommendations for the selection of photographic and positioning hardware and guidelines for flexible survey design using direct measurements of camera positions, thereby removing the need for ground control points. The focus is on maximising hardware performance despite inherent limitations, with the aim of optimising the quality and quantity of the source data, including image information and control measurements, despite suboptimal conditions. [ABSTRACT FROM AUTHOR]

The Vilcanota is the second-largest snow-capped mountain range in Peru, featuring 380 individual glaciers, each with its own unique characteristics that must be studied independently. However, few studies have been conducted in the Vilcanota range to monitor and track the area and volume changes of the Suyuparina and Quisoquipina glaciers. Notably, there are only a few studies that have approached this issue using LIDAR technology. Our methodology is based on a combination of optical, radar and LIDAR data sources, which allowed for constructing coherent temporal series for the both the perimeter and volume changes of the Suyuparina and Quisoquipina glaciers while accounting for the uncertainty in the perimeter detection procedure. Our results indicated that, from 1990 to 2013, there was a reduction in snow cover of 12,694.35 m2 per year for Quisoquipina and 16,599.2 m2 per year for Suyuparina. This represents a loss of 12.18% for Quisoquipina and 22.45% for Suyuparina. From 2006 to 2013, the volume of the Quisoquipina glacier decreased from 11.73 km3 in 2006 to 11.04 km3 in 2010, while the Suyuparina glacier decreased from 6.26 km3 to 5.93 km3. Likewise, when analyzing the correlation between glacier area and precipitation, a moderate inverse correlation (R = −0.52, p < 0.05) was found for Quisoquipina. In contrast, the correlation for Suyuparina was low and nonsignificant, showing inconsistency in the effect of precipitation. Additionally, the correlation between the snow cover area and the annual mean air temperature (R = −0.34, p > 0.05) and annual minimum air temperature (R = −0.36, p > 0.05) was low, inverse, and not significant for Quisoquipina. Meanwhile, snow cover on Suyuparina had a low nonsignificant correlation (R = −0.31, p > 0.05) with the annual maximum air temperature, indicating a minimal influence of the measured climatic variables near this glacier on its retreat. In general, it was possible to establish a reduction in both the area and volume of the Suyuparina and Quisoquipina glaciers based on freely accessible remote sensing data. [ABSTRACT FROM AUTHOR]

Glacier meltwater is an indispensable water supply for billions of people living in the catchments of major Asian rivers. However, the role of glaciers on river runoff regulation is seldom investigated due to the lack of annual glacier mass balance observation. In this study, we employed an albedo-based model with a daily land surface albedo dataset to derive the annual glacier mass balance over the Tuotuo River Basin (TRB). During 2000–2022, an annual glacier mass balance range of −0.89 ± 0.08 to 0.11 ± 0.11 m w.e. was estimated. By comparing with river runoff records from the hydrometric station, the contribution of glacier mass change to river runoff was calculated to be 0.00–31.14% for the studied period, with a mean value of 9.97%. Moreover, we found that the mean contribution in drought years is 20.07%, which is approximately five times that in wet years (4.30%) and twice that in average years (9.49%). Therefore, our results verify that mountain glaciers act as a significant buffer against drought in the TRB, at least during the 2000–2022 period. [ABSTRACT FROM AUTHOR]

In recent decades, glaciers in the Amundsen Sea Embayment in West Antarctica have made the largest contribution to mass loss from the entire Antarctic Ice Sheet. Glacier retreat and acceleration have led to concerns about the stability of the region and the effects of future climate change. Coastal thinning and near-synchronous increases in ice flux across neighbouring glaciers suggest that ocean-driven melting is one of the main drivers of mass imbalance. However, the response of individual glaciers to changes in ocean conditions varies according to their local geometry. One of the largest and fastest-flowing of these glaciers, Pine Island Glacier (PIG), underwent a retreat from a subglacial ridge in the 1940s following a period of unusually warm conditions. Despite subsequent cooler periods, the glacier failed to recover back to the ridge and continued retreating to its present-day position. Here, we use the ice-flow model Úa to investigate the sensitivity of this retreat to changes in basal melting. We show that a short period of increased basal melt was sufficient to force the glacier from its stable position on the ridge and undergo an irreversible retreat to the next topographic high. Once high melting begins upstream of the ridge, only near-zero melt rates can stop the retreat, indicating a possible hysteresis in the system. Our results suggest that unstable and irreversible responses to warm anomalies are possible and can lead to substantial changes in ice flux over relatively short periods of only a few decades. [ABSTRACT FROM AUTHOR]

The Earth exhibits an equatorial flattening specified by the ellipticity and the east longitude (or orientation) of the equatorial major axis, which is uniquely determined by the degree 2 and order 2 gravitational coefficients, C22 and S22. The 31-year SLR (satellite laser ranging) and 22-year GRACE/GRACE-FO (gravity recovery and climate experiment) data are analyzed to study the climate-related secular and 5.7 years to decadal variations in C22 and S22, in turn, the drift and decadal variation in the Earth's equatorial ellipticity and orientation of the principal axis of the least moment of inertia. The effects of the surface floating mass changes (including atmosphere, ocean and surface water redistribution and the melting of the mountain and polar glaciers) and the interior fluid convective (Earth's core flows) were evaluated. Results reveal that the equatorial ellipticity of the Earth is linearly increasing along with a remarkable decadal variation and the Earth's equator is flattening by ~ 0.16 mm/yr. [ABSTRACT FROM AUTHOR]

Here we present the first Lateglacial and Holocene glacial history from Rotsunddalen, northern Troms and western Finnmark county, northern Norway, based on both relative and numerical moraine dating using Schmidt hammer, soil chronosequencing and terrestrial cosmogenic nuclide dating. We combine these chronological data with a regional map of the glacial geomorphology to hypothesize key events in the glacial history from around 14 ka to present. Our reconstruction shows that, following deglaciation of the main ice sheet across central Troms and Finnmark, mountain glaciers were terminating on land, close to the coast, between around 12.1 and 10.6 ka. Continued recession of the main Fennoscandian Ice Sheet margin towards the SE led to the isolation of several large plateau icefields and outlet glaciers that generated moraines at around 10.2–9.2 ka, which we ascribe to the Erdalen Event, and 8.4–8.2 ka, which is broadly contemporaneous with the 8.2 ka cold event. Although the latter corresponds with the Scandinavian Finse Event, very few moraines have been dated to this time and we therefore view it as a tentative hypothesis for future work to test. During the Holocene Thermal Maximum (~6.6 to 6.3 ka) most (if not all) glaciers in the region disappeared, but then regrew during the Neoglaciation and produced large moraines dated to around 4.7 ka that lie a few hundred metres distal to the prominent Little Ice Age moraines (previously dated to AD 1810s–1870s). Given the limitations of our dating approach, the preservation of moraines dated to this period in northern Norway also warrants further investigation. We also highlight that terrestrial cosmogenic nuclide dating of the moraines is not consistent with other dating approaches and the widely established deglaciation history of the region, probably owing to cosmogenic inheritance and insufficient glacial erosion. [ABSTRACT FROM AUTHOR]

Copyright of German International Journal of Modern Science / Deutsche Internationale Zeitschrift für Zeitgenössische Wissenschaft is the property of Artmedia24 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.)

The article examines the heightened political and environmental turbulence of this year.

In recent years, photographs and visualisations of glacier retreat have become emblematic images of climate change and its ecological consequences. This paper presents glacier photography as a subtype of environmental photography. I argue that photographs and photographic projects that focus on glacial retreat are best conceived not only as strategies for proving climate change or as visual rhetoric for social transformation, but also as a practice that potentially plays an integral role in dealing and coping with human-induced environmental loss. To this end, I draw on praxeological accounts in theory of photography and philosophy of art as well as some exemplary photographic projects to develop a framework to analyse glacier photography. With the help of this praxeological framework, multiple orientations in glacier photography are identified: epistemic, aesthetic, emotional and evocative, social, ethical, and political orientations. All these photographic orientations, I argue, point in their own way to the process and consequences of glacial disappearance and loss. The framework presented innovatively brings together scholarship on climate change visualisation, imagery and art, the theory of photography, and philosophical aesthetics. [ABSTRACT FROM AUTHOR]

Managing and living with geohazards is especially challenging in mountain landscapes and requires an understanding of catchment‐scale sediment dynamics and internal system functioning. While sediment budgeting is a valuable framework, challenges remain including partitioning sediment yield by source and grain size and addressing scale issues. This study advances our understanding of bed material dynamics in glacierized mountain catchments by applying a range of complementary techniques to measure sediment transfers in the Fitzsimmons Creek watershed. First, we measured the historical bed material yield using field surveys and historical air photo analysis, revealing an average specific sediment yield of 210 Mg km−2 yr−1, that varied by a factor of 17 over the 76‐year record. Hydro‐meteorological and historical analyses suggest that gravel extraction had the largest impact over the past three decades, while an extreme landslide and flood event produced the highest recorded sediment yield. Second, we constructed a detailed sediment budget along the river system using high‐resolution, multi‐temporal lidar and geomorphic mapping data. Sediment source partitioning indicates that landslide, active channel, and floodplain sources each contributed about one‐third of the total sediment supply. Net degradation occurred along the valley bottom upstream of the fan‐delta, resulting in steadily increasing downstream sediment yield. This trend is punctuated by chronic landsliding near the outlet, driven by postglacial incision through glaciogenic sediments at a hanging valley step. Contemporary glacial and proglacial sources were not measured directly but surprisingly contributed minimally. These findings provide insight into the sediment dynamics of glacierized mountain catchments and their potential controls. Plain Language Summary: Managing and living with geohazards in mountain landscapes can be quite challenging. To manage these risks effectively, it's crucial to understand how sediment moves through these landscapes and how they change over time. Sediment budgeting, which describes how much sediment is added to, stored in, or removed from the landscape, can be used as a practical management tool. In this study, we aimed to refine our understanding of sediment movement in mountain landscapes with glaciers using the Fitzsimmons Creek watershed as an example. To do this, we first looked at how much sediment had accumulated in the river delta over the past 76 years and found that the amount varied by up to 17 times. Gravel removal and a very large landslide and flood event had the most control on the amount of sediment reaching the delta. Next, we used detailed elevation data and field surveys to look at the spatial patterns of erosion, deposition, and transport. Interestingly, we found that landslides, the riverbed, and floodplains each contributed about one‐third of the sediment, while very little sediment came from glaciers. This research provides valuable insights into sediment dynamics in glacierized mountain areas and helps inform better management strategies. Key Points: The 76‐year bed material yield record varied by up to a factor of 17, primarily in response to an extreme event and gravel extractionSediment source partitioning suggests that landslide, active channel, and floodplain sources each contribute one third of the total yieldGlacial landscape configuration was important, while contemporary glacial and proglacial sources supplied little sediment [ABSTRACT FROM AUTHOR]

Sediment erosion, transport, and deposition by glaciers and ice sheets play crucial roles in shaping landscapes, provide important nutrients to downstream ecosystems, and preserve key indicators of past climate conditions in the geologic record. While previous work has quantified sediment fluxes from subglacial meltwater, we also observe sediment entrained within basal ice, transported by the flow of the glacier itself. However, the formation and evolution of these debris‐rich ice layers remains poorly understood and rarely represented in landscape evolution models. Here, we identify a characteristic sequence of basal ice layers at Mendenhall Glacier, Alaska. We develop a numerical model of frozen fringe and regelation processes that describes the co‐evolution of this sequence and explore the sensitivity of the model to key properties of the subglacial sedimentary system, using the Instructed Glacier Model to parameterize ice dynamics. Then, we run numerical simulations over the spatial extent of Mendenhall Glacier, showing that the sediment transport model can predict the observed basal ice stratigraphy at the glacier's terminus. From the model results, we estimate basal ice layers transport between 23,300 m3 ${\mathrm{m}}^{3}$a−1 ${\mathrm{a}}^{-1}$ and 39,800 m3 ${\mathrm{m}}^{3}$a−1 ${\mathrm{a}}^{-1}$ of sediment, mostly entrained in the lowermost ice layers nearest to the bed, maximized by high effective pressures and slow, convergent flow fields. Overall, our results highlight the role of basal sediment entrainment in delivering eroded material to the glacier terminus and indicate that this process should not be ignored in broader models of landscape evolution. Plain Language Summary: Glaciers shape landscapes by eroding mountain ranges and moving the eroded sediment downstream to the lakes, fjords, and other ecosystems near the terminus. To quantify this supply of sediment, and thus understand the evolution of high alpine landscapes, we often use numerical models to simulate the processes of erosion and transport. Previous work has focused on the role of meltwater channels underneath glaciers to transport sediment, analogous to how rivers move sediment across much of Earth's surface, but we also know from field observations that a portion of the underlying sediment is picked up and incorporated into the ice itself. Here, we develop a new model to simulate where and how sediment is incorporated into ice beneath the glacier, and how those debris‐rich ice layers are modified as the glacier flows downstream. We use this model to predict the total amount of sediment reaching a glacier's snout, as well as the spatial distribution and thickness of the debris‐rich ice. Our results show that the amount of sediment transported in glacier ice likely represents a significant component of the total amount of sediment eroded or transported by the glacier, and thus should not be ignored in broader models of landscape evolution. Key Points: We develop a model of sediment entrainment beneath an alpine glacier to predict sediment fluxes and basal ice stratigraphy at the terminusThe model explains the co‐occurrence of solid, debris‐rich ice layers and overlying dispersed basal ice facies observed at glacier marginsAt a case study, we find sediment can be entrained up to 5 m in basal ice, maximized at high effective pressure and slow, convergent flow [ABSTRACT FROM AUTHOR]

This study investigates the glacial lake outburst flood (GLOF) hazards in the Tsambagarav mountain range in Western Mongolia, focusing on the Khukhnuruu Valley and its interconnected proglacial lakes. Over the last 30 years, significant glacier retreats, driven by rising temperatures and changing precipitation patterns, have led to the formation and expansion of several proglacial lakes. Fieldwork combined with satellite data and meteorological analysis was used to assess the dynamics of glacier and lake area changes, with particular focus on the flood events of July 2021. The research reveals a substantial reduction in glacier area, particularly in the Khukhnuruu E complex, where glacier area decreased by 19.3%. The study highlights the influence of increasing temperatures and summer precipitation, which have accelerated ice melt, contributing to the expansion and eventual breaching of lakes. Additionally, lake area changes were influenced by the steepness of the terrain, with steeper slopes exacerbating peak discharge during floods. Of the studied seven lakes (Lake 1 to Lake 7), Lake 1 experienced the most dramatic reduction, with a decrease in area by 73.51% and volume by 84.84%, followed by Lake 7. This study underscores the region's vulnerability to climate-induced hazards and stresses the need for a comprehensive early warning system and disaster preparedness measures to mitigate future risks. [ABSTRACT FROM AUTHOR]

ABSTRACT Glaciers host a variety of cold‐adapted taxa, many of which have not yet been described. Interactions among glacier organisms are even less clear. Understanding ecological interactions is crucial to unravelling the functioning of glacier ecosystems, particularly in light of current glacier retreat. Through a review of the existing literature, we aim to provide a first overview of the biodiversity, primary production, trophic networks, and matter flow of a glacier ecosystem. We use the Forni Glacier (Central Italian Alps) – one of the best studied alpine glaciers in the world – as a model system for our literature review and integrate additional original data. We reveal the importance of allochthonous organic matter inputs, of Cyanobacteria and eukaryotic green algae in primary production, and the key role of springtails (Vertagopus glacialis) on the glacier surface in sustaining populations of two apex terrestrial predators: Nebria castanea (Coleoptera: Carabidae) and Pardosa saturatior (Araneae: Lycosidae). The cryophilic tardigrade Cryobiotus klebelsbergi is the apex consumer in cryoconite holes. This short food web highlights the fragility of nodes represented by invertebrates, contrasting with structured microbial communities in all glacier habitats. Although further research is necessary to quantify the ecological interactions of glacier organisms, this review summarises and integrates existing knowledge about the ecological processes on alpine glaciers and supports the importance of glacier‐adapted organisms in providing ecosystem services. [ABSTRACT FROM AUTHOR]

As part of the southern Cascades, Mt. Hood is the tallest and most glacierized peak in Oregon, USA. Despite alpine glaciers being one the clearest indicators of human-caused climate change, the 21st century behavior of glaciers on Mt. Hood has not been directly documented at the ground level. Here we directly measure changes in the extents of Mt. Hood's glaciers from 2003 to 2023 and find dramatic retreat of all glaciers, with one glacier ceasing to flow (joining another glacier that ceased flowing before 2003) and another three glaciers retreating towards this status. By 2023, Mt. Hood glaciers had lost ∼17 % of their 2015–2016 area and ∼39 % of their 1981 area. The rate of area loss from 2015–2016 to 2023 (∼2.10 % yr -1) was ∼2.6 times faster than the rate from 1981 to 2015–2016 (∼0.81 % yr -1). The seven largest glaciers on the volcano lost ∼25 % of their area between 2000 and 2023. Comparison to historic records of glacier area back to 1907 shows that this 21st century retreat is unprecedented relative to the previous century. The rate of area loss over the last 23 years (∼1.07 % yr -1) was ∼1.9 times faster than the fastest rate documented in the last century from 1907 to 1946 (∼0.56 % yr -1) and ∼3.5 times faster than the 20th century average (∼0.31 % yr -1). This unprecedented rate of retreat corresponds to regional summer warmth reaching 1.7–1.8 °C (2013–2023 average) relative to the early 1900s, but not with regional changes in winter precipitation. We conclude that Mt. Hood's glaciers are retreating in response to a warming climate and that this recession has accelerated in the 21st century. [ABSTRACT FROM AUTHOR]

The article "Molecular phylogeography of Hipposideros pratti in China" discusses the genetic diversity and population dynamics of the bat species Hipposideros pratti in China. The study found that H. pratti has low genetic diversity and is divided into two clades, the central-western clade and the eastern clade. The research did not detect a clear east-to-west dispersal route, and the eastern clade spread outward from one population to another while the central-western clade spread gradually. The study also highlighted the importance of preserving bat populations and the need for in situ conservation measures. [Extracted from the article]

Copyright of Nachhaltigkeitsrecht is the property of Verlag Oesterreich GmbH 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.)

Mountains have a critical role in freshwater supply for downstream populations. As the climate changes, groundwater stored in mountains may help buffer the impacts to declining water resources caused by decreased snowpack and glacier recession. However, given the scarcity of groundwater observation wells in mountain regions, it remains unclear how mountain groundwater is being impacted by climate change across ecoregions. This study quantifies temporal trends in mountain groundwater levels and explores how various climatic, physiographic and anthropogenic factors affect these trends. We compiled data from 171 public groundwater observation wells within mountain regions across Canada and the United States, for which at least 20 years of monthly data is available. The Mann‐Kendall test for monotonic trend revealed that 54% of these wells have statistically significant temporal trends (p < 0.05) over the period of record, of which 69% were negative and therefore indicating overall declining groundwater storage. Wells in the western mountain ranges showed stronger trends (both positive and negative) than the eastern mountain ranges, and higher elevation wells showed fewer negative trends than the low elevation (<400 m asl) wells (p < 0.05). Correlation, Kruskal‐Wallis tests, stepwise multiple linear regression and random forest regression were used to identify factors controlling groundwater trends. Statistical analysis revealed that lower‐elevation mountain regions with higher average annual temperatures and lower average annual precipitation have the greatest declines in groundwater storage under climate change. Trends in temperature and precipitation, and ecoregion were also important predictors on groundwater level trends, highlighting geographic differences in how mountain wells are responding to climate change. Furthermore, sedimentary bedrock aquifers showed markedly more negative trends than crystalline bedrock aquifers. The findings demonstrate that the impact of climate change on mountain water resources extends to the subsurface, with important implications for global water resources. [ABSTRACT FROM AUTHOR]

Despite their extensive global presence and the importance of variations in their speed as an essential climate variable, only about a dozen global time series document long-term changes in the velocity of rock glaciers – large tongue-shaped flows of frozen mountain debris. By analysing historical aerial photographs, we reconstruct here 16 new time series, a type of data that has not previously existed for the North American continent. We observe substantial accelerations, as much as 2–3 fold, in the surface displacement rates of rock glaciers across the mountains of the western contiguous United States over the past six to seven decades, most consistent with strongly increasing air temperatures in that region. Variations between individual time series suggest that different local and internal conditions of the frozen debris bodies modulate this overall climate response. Our observations indicate fundamental long-term environmental changes associated with frozen ground in the study region. The study reconstructs 16 new time series for rock glacier flow in North America, marking the first for the continent. Analysis shows 2-3 fold accelerations in surface velocities over the past 60-70 years, linked to rising air temperatures. [ABSTRACT FROM AUTHOR]

Lake-terminating glaciers are among the most severely retreating glacier types in high mountain areas. However, the characteristic of being covered by glacial lakes after retreat makes it hard to estimate their actual ice loss in recent years, as does the contribution of different parts in ice loss, which leads to significant obstacles not only in evaluating solid water resources but understanding inter-relationships between glacial ice and glacial lakes. This study presents a detailed investigation of Jiongpu Co, one of the biggest glacial lakes in the Tibetan Plateau, including its bathymetry and area evolution. The ice loss in the last two decades was analyzed using a multisource DEM dataset. The main results showed that from 1976 to 2021, Jiongpu Co had expanded from 1.19 ± 0.09 km2 to 5.34 ± 0.07 km2. The volume of Jiongpu Co showed a surprising increment from 0.09 ± 0.004 Gt to 0.66 ± 0.03 Gt from 1976 to 2021, leading to a subaqueous equivalent ice loss of 0.32 ± 0.01 Gt water from 2000 to 2020 and resulting in an underestimated ice loss of 0.06 Gt, 19% compared with previous evaluations. The total ice loss of the Jiongpu glacier was 1.52 ± 0.37 Gt from 2000 to 2020, and more than 1/3 ice loss was related to lake expansion (0.32 ± 0.01 Gt underwater, 0.19 ± 0.02 Gt above water). This study makes a further contribution to the understanding of ice loss in the complicated system of lake-terminating glaciers. [ABSTRACT FROM AUTHOR]

Climate warming exacerbates the degradation of the mountain cryosphere, including glacier retreat, permafrost degradation, and snow cover reduction. These changes dramatically alter the local and downstream hydrological regime, posing significant threats to basin-scale water resource management and sustainable development. However, this issue is still not adequately addressed, particularly in mountainous catchments. We developed an integrated cryospheric–hydrologic model, the FLEX-Cryo model, to comprehensively consider glaciers, snow cover, and frozen soil and their dynamic impacts on hydrological processes. Taking the mountainous Hulu catchment located in the upper Heihe River of China as a case study, we utilized the state-of-the-art climate change projection data under two scenarios (SSP2-4.5 and SSP5-8.5) 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 under the medium-emission scenario (SSP2-4.5) and high-emission scenario (SSP5-8.5), by the end of the 21st century, the glacier will completely melt out around the years 2051 and 2045, respectively. 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 d. The freeze onset of seasonally frozen soil is expected to be delayed by 10 and 22 d, while the thaw onset of permafrost is likely to advance by 19 and 32 d. Moreover, the maximum freeze depth of seasonally 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, catchment total runoff exhibits a decreasing trend, and the tipping point of glacier runoff occurs approximately between 2019 and 2021. Permafrost degradation will likely reduce the duration of low runoff in the early thawing season; the discontinuous baseflow recession gradually transitions into linear recessions, and the baseflow increases. 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]

Glaciers, distinct from the Greenland and Antarctic ice sheets, play a crucial role in Earth's climate system by affecting global sea levels, freshwater availability, nutrient and energy budgets and regional climate patterns. Accurate measurements of glacier mass changes are needed to understand and project glacier evolution and its related impacts on the climate system. Two distinct methods allow to measure glacier mass changes at high spatial resolution. Remotely sensed surface elevation data provides volume change estimates over large glacierized regions for multi-annual to decadal time periods. Field glaciological measurements provide annually to seasonally resolved information on glacier mass change for a small sample of the world's glaciers. By combining the two methods we provide annual time series of individual glacier mass changes and related uncertainties spanning the hydrological years from 1976 to 2023. The per-glacier time series can then be seamlessly integrated into annually resolved global regular grids of glacier mass changes at user-specified spatial resolution. Our results undergo a leave-one-out cross-validation confirming uncertainty estimates at the glacier level to be in the conservative side. Our dataset provides a new baseline for future glacier change modelling assessments and their impact on the world's energy, water, and sea-level budget. The present annual mass change time-series for the individual glaciers and the derived global gridded annual mass change product at a spatial resolution of 0.5° latitude and longitude will be made available from the WGMS webpage. During the review process, the dataset is temporarily available from URL: https://user.geo.uzh.ch/idussa/Dussaillant_etal_ESSD_data/. [ABSTRACT FROM AUTHOR]

Radio-echo sounding is a standard technique for imaging the englacial stratigraphy of glaciers and ice sheets. In most cases, internal reflection horizons (IRHs) represent former glacier surfaces, comprise information about past accumulation and ice deformation, and enable the linking of ice core chronologies. IRHs in the lower third of the ice column are often difficult to detect or coherently trace. In the polar ice sheets, progress in IRH detection has been made by using multistatic, phase-coherent radars, enabling focused synthetic aperture radar (SAR) processing. However, these radar systems are often not suitable for deployment on mountain glaciers. We present a proof-of-concept study for a lightweight, phase-coherent and ground-based radar system, based on the phase-sensitive radio-echo sounder (pRES). To improve the detectability of IRHs we additionally adapted a layer-optimized SAR processing scheme to this setup. We showcase the system capability at Colle Gnifetti, Switzerland and Italy, where specular reflections are now apparent down to the base of the glacier. Compared to previously deployed impulse radar systems, with the mobile pRES the age of the oldest continuously traceable IRH could be increased from 78±12 to 288±35 a. Corresponding reflection mechanisms for this glacier are linked to stratified acidic impurities which in the upper part were deposited at a higher rate due to increased industrial activity in the area. Possible improvements to the system are discussed. If successfully implemented, these may provide a new way to map the deep internal structure of Colle Gnifetti and other mountain glaciers more extensively in future deployments. [ABSTRACT FROM AUTHOR]

This paper concerns a numerical stabilization method for free-surface ice flow called the free-surface stabilization algorithm (FSSA). In the current study, the FSSA is implemented into the numerical ice-flow software Elmer/Ice and tested on synthetic two-dimensional (2D) glaciers, as well as on the real-world glacier of Midtre Lovénbreen, Svalbard. For the synthetic 2D cases it is found that the FSSA method increases the largest stable time-step size at least by a factor of 5 for the case of a gently sloping ice surface (∼ 3°) and by at least a factor of 2 for cases of moderately to steeply inclined surfaces (∼ 6° to 12°) on a fine mesh. Compared with other means of stabilization, the FSSA is the only one in this study that increases largest stable time-step sizes when used alone. Furthermore, the FSSA method increases the overall accuracy for all surface slopes. The largest stable time-step size is found to be smallest for the case of a low sloping surface, despite having overall smaller velocities. For an Arctic-type glacier, Midtre Lovénbreen, the FSSA method doubles the largest stable time-step size; however, the accuracy is in this case slightly lowered in the deeper parts of the glacier, while it increases near edges. The implication is that the non-FSSA method might be more accurate at predicting glacier thinning, while the FSSA method is more suitable for predicting future glacier extent. A possible application of the larger time-step sizes allowed for by the FSSA is for spin-up simulations, where relatively fast-changing climate data can be incorporated on short timescales, while the slow-changing velocity field is updated over larger timescales. [ABSTRACT FROM AUTHOR]

The article discusses the role of scientists as prophets in the context of Christian and Islamic eco-theology. It highlights the importance of heeding prophetic warnings about the future of the planet and the need for urgent action to prevent disaster. The article also explores the historical reluctance of theologians to engage with scientific prophecies and the changing attitudes towards scientific knowledge. It emphasizes the interconnectedness of ecological sustainability and social justice, and calls for collaboration between Muslims and Christians to envision a just and sustainable world. The article concludes with a prayer for the restoration and care of the Earth. [Extracted from the article]

Tropical glaciers have retreated over recent decades, but whether the magnitude of this retreat exceeds the bounds of Holocene fluctuations is unclear. We measured cosmogenic beryllium-10 and carbon-14 concentrations in recently exposed bedrock at the margin of four glaciers spanning the tropical Andes to reconstruct their past extents relative to today. Nuclide concentrations are near zero in almost all samples, suggesting that these locations were never exposed during the Holocene. Our data imply that many glaciers in the tropics are probably now smaller than they have been in at least 11,700 years, making the tropics the first large region where this milestone has been documented. [ABSTRACT FROM AUTHOR]

The Western Himalayan Region (WHR) is under constant threat from Land Use and Land Cover Change (LULCC) brought on by various socioeconomic activities such as urbanization, agricultural expansion, and population growth. Detailed research into the scope of these changes is necessary to comprehend the challenges they represent. This study aimed at (1) examining and quantifying spatiotemporal patterns of LULCC from 1975 to 2015, (2) mapping the hotspots of forest loss, and (3) modelling future LULCC for the year 2055 using medium spatial resolution multispectral satellite imagery (MSS, TM, LISS-I, LISS-III, AWiFS), field data, visual interpretation and logistic regression model in the WHR. Logistic regression integrated various drivers of LULCC, including climatic, topographic, and socio-economic factors and past LULCC trends to forecast potential LULC in the WHR by 2055. The results highlight an outrageous 184% increase in regional urbanization. Expansion of urban and cropland (12%) led to deforestation which reduced the area of natural habitats, specifically forests (−11%), water bodies (−8%) and scrubland (−6%). A significant rise in barren land by 30% was noted, while there was a decrease of 20% in glacier/snow melt. The future projection for 2055 anticipates continuing current trends, emphasizing an intensified urban expansion of 63% and an approximate 9% reduction in overall forest coverage. The accuracy of the predicted 2015 LULC map was assessed using ROC/AUC (Receiver Operating Characteristic/Area under Curve) which was found to be 0.79. [ABSTRACT FROM AUTHOR]

Chironomids of the genus Diamesa (Meigen, 1835, Diptera: Chironomidae) inhabit cold, oxygen-rich running waters. We have investigated the presence of Diamesa and other freshwater macroinvertebrates at 22 stream sampling sites in 3 European high mountain regions (the Central Pyrenees, the Ötztal Alps, and the Tatra Mountains) to establish suitable temperature conditions for Diamesa dominance. It has been generally accepted that their high abundance was linked to the presence of glaciers; however, we have shown that in the Tatra Mountains, where there are no glaciers, the conditions for the dominance of Diamesa species are created due to permanent snowfields, the geographical orientation of the valley and shading by the surrounding high peaks. The historical connection of Diamesa to glaciers was investigated from the paleolimnological records of subfossil chironomid assemblages from the Bohemian Forest, where glaciers disappeared before or during the Late Glacial period. As expected, water temperature seems to be the main driver of Diamesa distribution, and we determined that the relative abundance of Diamesa species was significantly higher at the sites with a mean July water temperature below 6.5 °C. The Diamesa -dominated stream communities seems to be endangered due to ongoing climate warming and this assumption is supported by our paleolimnological results from the Bohemian Forest lakes, where Diamesa has disappeared due to warming of lake inflows at the beginning of the Holocene. These findings strengthen the former suggestions that some Diamesa species could be used as an indicator for tracking recent environmental changes in vulnerable ecosystems of cold mountain streams. [ABSTRACT FROM AUTHOR]

Copyright of Arid Land Geography is the property of Chinese Academy of Sciences, Xinjiang Institute of Ecology & Geography 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.)

Proglacial forefields commonly include highly dynamic fluvial systems associated with the fundamental instability between topography, flow hydraulics and sediment transport. However, there is limited knowledge of how these systems respond to changing subglacial hydrology and sediment supply. We investigated this relationship using the first continuous field‐collected data sets for both suspended and bedload sediment export and proglacial river dynamics for an Alpine glacier forefield, the Glacier d'Otemma, Switzerland. The results show a strong sensitivity of fluvial morphodynamics to the balance between sediment transport capacity and supply. When subglacial bedload export rates exceeded fluvial transport capacity, we found bar construction leading to net forefield aggradation and surficial coarsening, especially on bar heads. This intensified braiding buffered the downstream transport of coarse sediment. When subglacial bedload export rates were lower than transport capacity, incision occurred, with reduced braiding intensity, net erosion and important amounts of bedload leaving the proglacial system. We found a net fining of surficial deposits except for very isolated coarsening patterns on bar heads. Thus, proglacial forefield morphodynamics are strongly conditioned by subglacial hydrology and sediment supply, but this conditioning is also influenced by the response of the forefield itself. Proglacial forefields have an important influence on the longitudinal connectivity of sediment flux in regions sensitive to climate change, such as recently deglaciated high mountain areas. The linkages we report between subglacial processes and river morphodynamics are critical for understanding the development of embryonic forefield ecosystems. Plain Language Summary: This study focuses on Alpine proglacial forefields, braided fluvial streams flowing in deglaciated terrains, and their geomorphic response to both sediment and water exported from retreating glaciers. This is achieved using the first continuous field‐collected data sets combining sediment flux quantifications at the glacier terminus and downstream changes of the river over time collected in the Glacier d'Otemma forefield (Switzerland). Results show that the fluvial landscape in recently deglaciated terrains changes rapidly, influenced by the balance between the amount of sediment being transported from under the glacier and the river's capacity to carry it. When the released amount of sediment matches the river's capacity, the deposition of coarser material dominates and the stream becomes more complex with increasing braiding intensity. However, when the river carries more sediment than supplied by the glacier, flow becomes more confined into fewer channels, promoting the erosion of previously deposited material, particularly for the coarser sediment fractions. The study emphasizes how both the river configuration and the landscape near a melting glacier depend on whether the river itself can transport the quantities of sediment delivered by the glacier. This balance can affect the downstream sediment flux from glaciered catchments and the development of ecosystems following climate change‐induced glacier retreat. Key Points: First study combining continuous subglacial sediment export rates and proglacial forefield geomorphic change at the melt season scaleStrong sensitivity of proglacial forefield morphodynamics to subglacial bedload export rates and fluvial transport capacityBar construction processes filter the downstream transport of bedload particles buffering the longitudinal connectivity of sediment flux [ABSTRACT FROM AUTHOR]

Basal shear stress on hard‐bedded glaciers results from normal stress against bed roughness, which depends on basal water pressure and cavity size. These quantities are related in a steady state but are expected to behave differently under rapid changes in water input, which may lead to a transient frictional response not captured by existing friction laws. Here, we investigate transient friction using Global Positioning System vertical displacement and horizontal velocity observations, basal water pressure measurements, and cavitation model predictions during rain‐induced speed‐up events at Glacier d'Argentière, French Alps. We observe up to a threefold increase in horizontal surface velocity, spatially migrating at rates consistent with subglacial flow drainage, and associated with surface uplift and increased water pressure. We show that frictional changes are mainly driven by changes in water pressure at nearly constant cavity size. We propose a generalized friction law capable of capturing observations in both the transient and steady‐state regimes. Plain Language Summary: Changes in water input at the bed of glaciers greatly modify their sliding speed by changing subglacial water pressure. High water pressure, induced by extreme meltwater input, is thought to increase cavity size, a process known as cavitation, which reduces direct contact and increases basal sliding speed. Our Global Positioning System observations indicate that the existing cavitation law, which is based on multidecadal sliding velocities of an alpine glacier, fails at capturing short‐lived, rain‐induced speed‐ups. This is because cavities have insufficient time to adjust their size in response to water pressure changes. Here, we propose a generic friction law that satisfyingly captures observations by incorporating a direct dependency of basal friction on water pressure. Key Points: With Global Positioning System we observe rain‐induced glacier speed‐up events associated with surface uplift and down‐glacier migrationObservations and modeling show that water pressure rather than cavity size mainly controls changes in basal friction during these eventsWe propose a generalized version of the "regularized" Coulomb friction law, adapted to transient friction under rapid water pressure variations [ABSTRACT FROM AUTHOR]

The ice phenomena are an inherent component of rivers in temperate, continental, and polar climate zones. Evident progress in global warming leads to a decrease in snow cover on land and ice phenomena in water bodies, disrupting the stability of the hydrological cycle and aquatic ecosystems. Although common observations indicate the disappearance of ice phenomena in rivers over recent decades, detailed quantitative research is lacking in many regions, especially in the temperate zone. In this paper, ice phenomena were analyzed on the rivers of southern Poland, located in the upland and mountain areas of the country, as no such studies have been conducted so far. The temporal changes in the annual number of days with ice (NDI) phenomena were studied in locations where ice phenomena were observed every year for at least 30 years between 1951 and 2021. Using straightforward but commonly accepted procedures, such as the Mann-Kendall test, statistically significant decreasing trends in the annual NDI were revealed for the majority of gauging stations. The Theil-Sen (TS) slope mean values were -1.66 (ranging from -3.72 to -0.56), -1.41 (from -3.22 to -0.29), and -1.33 (from -2.85 to -0.29) for the datasets representing the periods 1992–2020, 1987–2020, and 1982–2020, respectively. The results for the annual NDI were additionally presented within the context of meteorological characteristics such as annual and winter (Nov-Apr) air temperature, precipitation, and water temperature. Correlation and regression analyses revealed that the main factor triggering the decrease in NDI is the increase in the average winter air temperature. An increase in temperature by 1°C results in a decrease in NDI by up to twenty days. If these negative trends continue, ice phenomena may disappear completely from southern Polish rivers within few decades. [ABSTRACT FROM AUTHOR]

The highly glacierized eastern part of the Tibetan Plateau is the key source region for seven major rivers: Yangtze, Yellow, Lancang-Mekong, Nu-Salween, Irrawaddy, Ganges, and Brahmaputra rivers. These rivers are vital freshwater resources for more than one billion people downstream for their daily life, irrigation, industrial use, and hydropower. However, the glaciers have been receding during the last decades and are projected to further decline which will profoundly impact the water availability of these larger river systems. Although few studies have investigated glacier mass changes in these river basins since the 1970s, they are site and temporal specific and limited by data availability. Hence, knowledge of glacier mass changes is especially lacking for years prior to 2000. We therefore applied digital elevation models (DEMs) derived from large scale topographic maps based on aerial photogrammetry from the 1970s and 1980s and compared them to the Shuttle Radar Topography Mission (SRTM) DEM to provide a complete picture of mass change of glaciers in the region. The mass changes are presented on individual glacier bases with a resolution of 30 m and are also aggregated into gridded formats at resolutions of 0.1° and 0.5°. Our database consists of 13117 glaciers with a total area of ~21695 km2. The annual mean mass loss of glaciers is -0.30 ± 0.12 m w.e. in the whole region. This is larger than the previous site-specific findings, the surface thinning increases on average from west to east along the Himalayas-Hengduan mountains with the largest thinning in the Irrawaddy basin. Comparisons between the topographic map-based DEMs and DEMs generated based on Hexagon KH-9 metric camera data for parts in the Himalayas demonstrate that our dataset provides a robust estimation of glacier mass changes. However, the uncertainty is high in high altitudes due to the saturation of aerial photos over low contrast areas like snow surface on a steep terrain. The dataset is well suited for supporting more detailed climatical and hydrological analyses and is available at https://doi.org/10.11888/Cryos.tpdc.301236 (Liu et al., 2024). [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]

Quantitative understanding of the land water loading is a prerequisite to the construction of reliable tectonic deformation velocity field in the Tibetan Plateau (TP). Here, for the first time, we image the three‐dimensional crustal loading deformation velocity field of each land water component in the TP. Our results reveal that the loading signal strength of the six land water components ranks from largest to smallest as groundwater, glacier, lake, soil water, permafrost, and snow, with the maximum vertical velocity close to ±1.60 mm/yr and the maximum horizontal velocity exceeding 0.40 mm/yr. All land water components can achieve a strong enough vertical loading velocity exceeding the present‐day Global Positioning System (GPS) velocity at some sites. But for horizontal loading, apparent impacts are only from glacier, lake and groundwater, however, are very limited, with the absolute ratio of loading velocity to GPS velocity being smaller than 5% at almost all the sites. Plain Language Summary: The crustal kinematic characteristics and uplift mechanism of the Tibetan Plateau (TP) have been widely studied based on the three‐dimensional deformation velocity field from Global Positioning System (GPS) measurements. However, except for tectonic signal, the land water loading effect is also involved in GPS observation and may lead to the biased tectonic interpretation of GPS deformation velocity field. In this study, we construct a set of three‐dimensional crustal loading deformation velocity fields for the TP based on the state‐of‐the‐art multi‐component land water mass change fields constrained by multi‐source data spanning ∼20 years. Results reveal that the loading signal strength of the six land water components ranks from largest to smallest as groundwater, glacier, lake, soil water, permafrost, and snow. We find that all land water components can achieve a strong enough vertical loading velocity exceeding the present‐day GPS vertical velocity at some sites, but show very limited horizontal loading. Our results could provide loading correction reference for the construction of high‐accuracy TP tectonic deformation velocity field. Key Points: We image the three‐dimensional crustal deformation velocity fields of the Tibetan Plateau due to multi‐component land water loadingEvident loading is from groundwater, glacier, and lake, with the maximum vertical and horizontal velocities exceeding ±1.0 mm/yr and 0.2 mm/yr, respectivelyAll land water components can achieve a vertical loading velocity exceeding the Global Positioning System velocity at some sites, but show very limited horizontal loading [ABSTRACT FROM AUTHOR]

Climate contrasts across drainage divides, such as orographic precipitation, are ubiquitous in mountain ranges, and as a result, mountain topography is often asymmetric. During glacial periods, these climate gradients can generate asymmetric glaciation, which may modify topographic asymmetry and drive divide migration during glacial‐interglacial cycles. Here we quantify topographic asymmetry caused by asymmetric glaciation and its sensitivity to different climate scenarios. Using an analytical model of a steady‐state glacial profile, we find that the degree of topographic asymmetry is primarily controlled by differences in the equilibrium line altitude across the divide. Our results show that glacial erosion can respond to the same climate asymmetry differently than fluvial erosion. When there are precipitation differences across the divide, glacial erosion produces greater topographic asymmetry than fluvial erosion, all else equal. These findings suggest that glaciations may promote drainage reorganization and landscape transience in intermittently glaciated mountain ranges. Plain Language Summary: In mountainous regions, the amount of rain, snow, and ice that falls and builds up often varies from one side of a mountain to the other. Over thousands to millions of years, these variations can make the length and steepness of the mountain sides differ, too. When glaciers form during ice ages, they can make this asymmetry in the topography even more pronounced. Our study looks at how glaciers affect the landscape and how glaciers and landscapes change in different climate conditions. Using a computer model, we discovered that the landscape becomes even more asymmetric when it is shaped by glaciers compared to when it is shaped by rivers. Our findings suggest that glaciers can cause landscapes to constantly change between ice ages. Key Points: We quantify topographic asymmetry caused by asymmetric glaciationGlacial erosion causes greater topographic asymmetry than fluvial erosion all else equalGlacial‐interglacial cycles can cause divide migration [ABSTRACT FROM AUTHOR]

The southeastern Qinghai-Xizang Plateau has significant topographical variations, active tectonic movements and developed glaciers and permafrost. A variety of geotechnical disasters occur frequently in this region. In order to study the distribution characteristics and movement patterns of geotechnical hazards in this region, the Degin section of the Lancang River was selected as the research area. Based on the data form ALOS-2 satellite of one track and Sentinel-1A satellite of three tracks, large-scale geotechnical hazards investigation in the study area were conducted using Stacking-InSAR technology, while time-series monitoring of typical debris flow source areas was carried out using DS-InSAR technology. Singular spectrum analysis (SSA) was employed to extract the periodic characteristics of deformation. The results show that there are a total of 670 deformation areas in the study area, most of which are rock glaciers located on the mountain tops of high elevations, and 27 landslides are distributed within a 5 km- distance from the Lancang River; the deformation time series of the selected typical debris flow source area from 2017 to 2022 shows a linear trend; both precipitation and temperature are correlated with the periodic deformation of the rock glacier from this source area. [ABSTRACT FROM AUTHOR]

The recession of Alpine glaciers causes an increase in the extent of proglacial areas and leads to changes in the water discharge and sediment balance (morphodynamics and sediment transport). Although the processes occurring in proglacial areas are relevant not only from a scientific point of view but also for the purpose of climate change adaptation, there is a lack of work on the continuous monitoring and multitemporal characterization of these areas. This study offers a multidisciplinary approach that merges the contributions of different scientific disciplines, such as hydrology, geophysics, geomatics, and water engineering, to characterize the Rutor Glacier and its proglacial area. Since 2020, we have surveyed the glacier and its proglacial area using both uncrewed and crewed aerial surveys (https://doi.org/10.5281/zenodo.8089499 , ; https://doi.org/10.5281/zenodo.10100968 , ; https://doi.org/10.5281/zenodo.10074530 , ; https://doi.org/10.5281/zenodo.10101236 , ; https://doi.org/10.5281/zenodo.7713146 ,). We have determined the bathymetry of the most downstream proglacial lake and the thickness of the sediments deposited on its bottom (https://doi.org/10.5281/zenodo.7682072 ,). The water depth at four different locations within the hydrographic network of the proglacial area (https://doi.org/10.5281/zenodo.7697100 ,) and the bedload at the glacier snout (https://doi.org/10.5281/zenodo.7708800 ,) have also been continuously monitored. The synergy of our approach enables the characterization, monitoring, and understanding of a set of complex and interconnected processes occurring in a proglacial area. [ABSTRACT FROM AUTHOR]

Many glaciers on the Antarctic Peninsula have retreated and accelerated in recent decades. Here we show that there has been a widespread, quasi-synchronous, and sustained increase in grounding line discharge from glaciers on the west coast of the Antarctic Peninsula since 2018. Overall, the west Antarctic Peninsula discharge trends increased by over a factor of 3, from 50 Mtyr-2 during 2017 to 2020 up to 160 Mtyr-2 in the years following, leading to a 7.4 % increase in grounding line discharge since 2017. The acceleration in discharge was concentrated at glaciers connected to deep, cross-shelf troughs hosting warm-ocean waters, and the acceleration occurred during a period of anomalously high subsurface water temperatures on the continental shelf. Given that many of the affected glaciers have retreated over the past several decades in response to ocean warming, thereby highlighting their sensitivity to ocean forcing, we argue that the recent period of anomalously warm water was likely a key driver of the observed acceleration. However, the acceleration also occurred during a time of anomalously high atmospheric temperatures and glacier surface runoff, which could have contributed to speed-up by directly increasing basal water pressure and, by invigorating near-glacier ocean circulation, increasing submarine melt rates. The spatial pattern of glacier acceleration therefore provides an indication of glaciers that are exposed to warm-ocean water at depth and/or have active surface-to-bed hydrological connections; however, many stages in the chain of events leading to glacier acceleration, and how that response is affected by glacier-specific factors, remain insufficiently understood. Both atmospheric and ocean temperatures in this region and its surroundings are likely to increase further in the coming decades; therefore, there is a pressing need to improve our understanding of recent changes in Antarctic Peninsula glacier dynamics in response atmospheric and oceanic changes in order to improve projections of their behaviour over the coming century. [ABSTRACT FROM AUTHOR]

Ongoing climate change threatens the biodiversity of glacier‐fed river ecosystems worldwide through shifts in water availability and timing, temperature, chemistry, and channel stability. However, tropical glacier‐fed rivers have received little attention compared to those in temperate and Arctic biomes, despite their unique biodiversity potentially responding differently due to additional stress from higher altitude locations thus lower oxygen availability, diurnal freeze–thaw cycles, and annual monsoon rainfall disturbances. This study quantified aquatic biodiversity responses to decreasing glacier cover in the Cordillera Blanca range of the Peruvian Andes. Ten rivers were studied along a gradient of decreasing glacier cover in the Parón, Huaytapallana, and Llanganuco basins, with a specific focus on macroinvertebrates and physicochemical parameters in both the dry and wet seasons. We found higher temperatures, more stable and lower turbidity rivers as glacier cover decreased, which were related significantly to higher local diversity and lower β‐diversity. Analysis of similarity revealed significant differences in the macroinvertebrate community among rivers with high, medium, or low glacier cover, illustrating turnover from specialists to generalists as glacial influence decreased. Redundancy analysis demonstrated that there were more species found to prefer stable beds and water temperatures in medium and low glacier cover in a catchment rivers. However, certain taxa in groups such as Paraheptagyia, Orthocladiinae, Anomalocosmoecus, and Limonia may be adapted to high glacial influence habitats and at risk of glacier retreat. Although species composition was different to other biomes, the Cordillera Blanca rivers showed similar benthic macroinvertebrate biodiversity responses to glacier retreat, supporting the hypothesis that climate change will have predictable effects on aquatic biodiversity in mountain ranges worldwide. [ABSTRACT FROM AUTHOR]

Glaciers are present in many large river basins, and due to climate change, they are undergoing considerable changes in terms of area, volume, magnitude and seasonality of runoff. Although the spatial extent of glaciers is very limited in most large river basins, their role in hydrology can be substantial because glaciers store large amounts of water at varying timescales. Large-scale hydrological models are an important tool to assess climate change impacts on water resources in large river basins worldwide. Nevertheless, glaciers remain poorly represented in large-scale hydrological models. Here we present a coupling between the large-scale glacier model Open Global Glacier Model (OGGM) v1.5.3 and the large-scale hydrological model Community Water Model (CWatM) V1.08. We evaluated the improved glacier representation in the coupled model against the baseline hydrological model for four selected river basins at 5 arcmin resolution and globally at 30 arcmin resolution, focusing on future discharge projections under low- and high-emission scenarios. We find that increases in future discharge are attenuated, whereas decreases are exacerbated when glaciers are represented explicitly in the large-scale hydrological model simulations. This is explained by a projected decrease in glacier-sourced runoff in almost all basins. Calibration can compensate for lacking glacier representation in large-scale hydrological models in the past. Nevertheless, only an improved glacier representation can prevent underestimating future discharge changes, even far downstream at the outlets of large glacierized river basins. Therefore, incorporating a glacier representation into large-scale hydrological models is important for climate change impact studies, particularly when focusing on summer months or extreme years. The uncertainties in glacier-sourced runoff associated with inaccurate precipitation inputs require the continued attention and collaboration of glacier and hydrological modelling communities. [ABSTRACT FROM AUTHOR]

Globally, glaciers and icefields contribute significantly to sea level rise. Here we show that ice loss from Juneau Icefield, a plateau icefield in Alaska, accelerated after 2005 AD. Rates of area shrinkage were 5 times faster from 2015–2019 than from 1979–1990. Glacier volume loss remained fairly consistent (0.65–1.01 km3 a−1) from 1770–1979 AD, rising to 3.08–3.72 km3 a−1 from 1979–2010, and then doubling after 2010 AD, reaching 5.91 ± 0.80 km3 a−1 (2010–2020). Thinning has become pervasive across the icefield plateau since 2005, accompanied by glacier recession and fragmentation. Rising equilibrium line altitudes and increasing ablation across the plateau has driven a series of hypsometrically controlled melt-accelerating feedbacks and resulted in the observed acceleration in mass loss. As glacier thinning on the plateau continues, a mass balance-elevation feedback is likely to inhibit future glacier regrowth, potentially pushing glaciers beyond a dynamic tipping point. The glaciers of Juneau Icefield, Alaska are reconstructed from 1770 to 2020 AD. Ice loss has accelerated dramatically, with a number of positive feedbacks now happening that accelerate ice loss and inhibit future stabilisation and regrowth. [ABSTRACT FROM AUTHOR]

Estimating permafrost distribution in high‐mountain areas is challenging. In these situations, rock glaciers, provide valuable insights into permafrost distribution and are often used as proxies for identifying permafrost occurrence. Integrating various climatological and topographical conditioning factors with rock glaciers enables inferring the distribution of permafrost in these environments. This study utilized three machine learning models such as random forest (RF), support vector (SVM), and artificial neural network (ANN), and one statistical model, namely, the frequency ratio (FR), to assess the permafrost probability over the northern Kargil region of Indian Himalayas. Among 198 rock glaciers identified through high‐resolution images from Google Earth, 70% are used as training dataset, rest 30% as testing dataset. The study considered eight factors: slope, aspect, elevation, curvature, mean annual land surface temperature (MA‐LST), mean annual normalized difference snow index (MA‐NDSI), mean annual normalized difference water index (MA‐NDWI), and lithology for mapping. Furthermore, the SHapley Additive exPlanations (SHAP) test assessed the variable importance for model performance. The results revealed that the RF model performs best for permafrost probability mapping, followed by the SVM, FR, and ANN models. The study also found that 11% of the total geographic area has a high and very high probability of permafrost occurrence. [ABSTRACT FROM AUTHOR]

Land surface temperature (LST) is one of the most important variables in the physical processes of surface energy and water balance. The temporal behavior of LST was analyzed between the latitudes 32°00′ S and 34°24′ S (Valparaíso and Metropolitana regions of Chile) for three summer months (December, January, and February) in the 2000–2017 period, using the Terra MODIS image information and applying the Mann–Kendall test. The results show an increase in LST in the study area, particularly in the Andes mountain range in January (5240 km2), which mainly comprises areas devoid of vegetation and eternal snow and glaciers, and are zones that act as water reserves for the capital city of Santiago. Similarly, vegetated areas such as forests, grasslands, and shrublands also show increasing trends in LST but over smaller surfaces. Because this study is regional, it is recommended to improve the spatial and temporal resolutions of the images to obtain conclusions on more local scales. [ABSTRACT FROM AUTHOR]