Glaciers are critical freshwater reservoirs in the Central Andes. Although supraglacial debris covers over 40% of the glacierised area in the Atlantic basins, the long-term surface evolution of debris-covered glaciers remains poorly constrained. In this study, we quantify glacier surface evolution over four decades (1985–2024) for 229 debris-covered glaciers across five major Atlantic basins in the Central Andes. Using ANDESMAG, a Python-based decision-tree algorithm employing spectral thresholds, we analysed more than 60 000 Landsat and Sentinel-2 image tiles in Google Earth Engine. Overall, debris-covered area increased by $20\pm11$% and debris-emergence elevation rose by $122\pm99$ m, while snowline altitude at the end of summer increased by $181\pm91$ m and snow-cover ratio declined by $9\pm11$%. Most of these changes occurred after 2009, during the Central Andes Megadrought, and correlated more strongly with declining precipitation than with rising air temperature. Our open-access workflow, which achieves a classification accuracy of 94%, provides the first annual regional assessment of debris-covered glacier surface evolution in the Central Andes of Argentina. Our results highlight the vulnerability of debris-covered glaciers to ongoing climate change and offer a transferable tool applicable to glacierised mountain regions worldwide.

Glaciers actively store and release meltwater with significant impacts on glacier flow velocity and downstream environments. The evolution of this drainage system is a key component in understanding glacier dynamics. In temperate alpine glaciers, the change of the subglacial drainage network from distributed to channelised is theoretically known, but lacks empirical documentation. As subglacial channels are extremely difficult to access, it is important to test innovative methods for locating them. Here, we use surface seismic monitoring, which enables us to identify the location of multiple subglacial channels below Glacier d’Otemma, Valais, Switzerland. We calculate time delays between pairs of seismic sensors and backtrack source locations. Using matched field processing and beamforming analysis, we obtain spatial and temporal patterns of seismic noise produced by the glacier. This allows us to interpret a possible evolution of the subglacial drainage network from a distributed to an efficient one and locate three distinct subglacial channels in close proximity.

We use all 27 years of airborne laser altimetry from the University of Alaska Fairbanks to quantify changes in surface elevation across 205 large glaciers that together represent 56% of the glacier area in Alaska and adjacent Canada, including 71% of the ice cover in Alaska’s National Parks. We reprocessed lidar point clouds into a homogenized publicly available 2.5 m digital elevation model (DEM) archive, implemented a new double-differencing approach to incorporate partially overlapping surveys and derived elevation change in 10 m elevation bins to assess glacier-wide mass balance for all surveyed epochs on each glacier. The resulting mean balance rate for all measured glaciers shows statistically significant acceleration of mass loss, ranging from $-0.83 \pm{0.13} \,\, \text{m}\,\, \text{w.e.}\ \text{a}^{-1}$ before 2008 to $-1.16 \pm{0.08} \,\, \text{m}\,\, \text{w.e.}\ \text{a}^{-1}$ thereafter. Extrapolating measured thinning rates from the latter period (2008–22) to unsurveyed glaciers suggests that Alaskan National Parks are losing 33.74 $\text{Gt a}^{-1}$ of ice, approximately one third of all estimated losses in the region. We use case studies of several prominent glaciers to show how this sustained acceleration of mass loss, which is consistent with recent global assessments, is having direct impacts on visitors, land managers, ecosystems and geohazards in the National Parks.

Despite advances in global glacier modeling, notable uncertainties remain in part due to model overparameterization. We develop a novel Bayesian inference framework to calibrate the Python Glacier Evolution Model (PyGEM) against spatially distributed surface elevation change data. The utility of this framework is demonstrated using a 1994–2021 airborne laser altimetry record for 185 glaciers in Alaska, which altogether represent over half of the region’s glacier area. Calibration against these data reduces parameter uncertainty by 5–18% and lowers the mean absolute error in hindcast surface elevation change by 0.18 m a−1 (15% compared to prior models). Model projections for these 185 glaciers estimate mass loss ranging from 43 $ \pm $ 17% to 67 $ \pm $ 27% depending on the emissions scenario. The projections highlight considerable subregional variability ranging from a median glacier mass loss of 57–99% by the end of the century for Lake Clark, Denali, Kenai Fjords, and Glacier Bay national parks, compared to 28–51% lost for Wrangell–St. Elias National Park and Preserve. As additional spatially distributed elevation change datasets become available in Alaska and elsewhere, the framework presented here is well suited to further refine model calibration and improve projections, while remaining flexible to incorporate additional glacier change observations as they become available.

The Canadian Arctic Archipelago constitutes a primary source of contemporary sea-level rise from glaciers and ice caps, yet glacier-scale, multi-decadal records on Baffin and Bylot Islands remain limited. This study reconstructs long-term elevation and volume change for seven glaciers, six in Auyuittuq National Park and one in Sirmilik National Park, using 1958/59 imagery from the Canadian National Air Photo Library. Historical digital elevation models were reconstructed using TanDEM-X for vertical ground control and PlanetScope imagery for horizontal ground control, with ArcticDEM supporting final co-registration and on-ice elevation-change analysis. Uncertainty was quantified from stable-terrain residuals, with normalized median absolute deviation values of $2.08$–$4.07$ m. Specific geodetic mass balances for the Auyuittuq glaciers ranged from $-0.22$ to $-0.35$ m w.e. a$^{-1}$ for 1959–2021/22, while Fountain Glacier averaged $-0.35$ m w.e. a$^{-1}$ for 1958–2022. Cumulative ice-volume change totalled $-4.76 \times 10^{9}$ m$^{3}$, equivalent to $-4.05 \pm 0.29$ Gt. Auyuittuq glaciers shortened by $7$–$16\%$ and lost $9$–$28\%$ of their area. Spatial variability reflects glacier hypsometry, with lower-elevation glacier areas showing greater sensitivity to atmospheric warming. These results provide new glacier-scale geodetic mass-balance estimates for the Canadian Arctic Archipelago based on archival photogrammetry, although density assumptions that omit firn evolution require further refinement when estimating mass change.

Although most Greenland glaciers have undergone thinning and frontal retreat in recent decades, the tidewater glacier Eqalorutsit Kangilliit Sermiat in South Greenland departs from this regional pattern. This outlet glacier has advanced its terminus by almost 2 km since the mid-20th century and thickened persistently with ever-increasing rates, in contrast to neighbouring glaciers. Actively pushed lateral moraines with vegetation and absent trimlines provide visible evidence in the landscape. This study investigates potential explanations of the glacier’s anomalous behaviour, emphasizing surface mass balance (SMB) and reduced frontal ablation. A negative SMB trend and the relatively short modelled frontal response time to abrupt climatic changes rule out SMB as an explanation for the glacier’s behaviour. Oceanic forcing is also considered unlikely due to warm Atlantic water reaching the terminus. Sedimentary processes such as morainal bank shoving or sediment erosion and redeposition potentially reduce frontal ablation or provide buttressing, but evidence is lacking due to limited bathymetric data near the terminus. However, the observed thickening, slowdown and advance is consistent with the modelled response to an advancing terminus on a retrograde bed slope, highlighting the complex interaction between bed shape, calving dynamics and ice flow as key controlling factors.

Observing glacier mass changes is essential for understanding and projecting the impacts of climate change on sea-level rise, water resources and natural hazards, as well as providing data for developing, calibrating and validating glacier evolution models. The principal methods used to measure glacier mass changes — glaciological, geodetic (surface elevation differencing) and gravimetric — differ in the spatial and temporal scales at which they are most effectively applied. Here, we review these methods in the context of challenges that arise when comparing published mass-balance estimates. Compatibility can be hampered by (1) inconsistent reporting and lack of relevant information; (2) discrepancies in which mass-balance components are included; (3) differences in the time span analyzed; and (4) variations in the spatial domain of the reported mass balance. We provide recommendations for more rigorous and comprehensive reporting of mass-balance estimates to improve comparability and synthesis of reported glacier mass changes, and we emphasize open data and code sharing to enable full reproducibility and future reinterpretation. Our recommendations apply equally to both glacier and ice-sheet mass-balance reporting, and they are generally valid for mass balances simulated by numerical models.

Helm Glacier is a World Glacier Monitoring Service reference glacier and is one of three glaciers in Western Canada with a mass balance record which exceeds 40 years. An ice-penetrating radar survey reveals a mean and maximum ice thickness of 13.0 and $37.2\,\mathrm{m}$, respectively. We combine ice thickness data and altimetric data from repeat LiDAR surveys to project ice disappearance. We use simple extrapolation and a multivariate linear regression to predict surface elevation change based on incoming shortwave radiation, end-of-winter snow depth, positive degree days, slope and aspect. Both approaches project the disappearance of Helm Glacier by 2035. We estimate that Helm Glacier has a current mass balance sensitivity to temperature of ${\mathrm C}_{\mathrm T}=-0.58\,{\mathrm m\boldsymbol\,\mathrm w.\mathrm e.\boldsymbol\,\mathrm a}^{-1}\,^\circ\,\mathrm C^{-1}$, which is slightly less negative than the balance sensitivity of ${\mathrm C}_{\mathrm T}=-0.64\,{\mathrm m\boldsymbol\,\mathrm w.\mathrm e.\boldsymbol\,\mathrm a}^{-1}\,^\circ\,\mathrm C^{-1}$ derived from the in situ balance record. Helm Glacier is more than 4$\rm{^\circ}C$ out of balance with current climate conditions [2014–24].

NASA’s ICESat-2 mission was launched in 2018, carrying a photon-counting laser altimeter, with a primary objective of measuring height changes across Earth’s surface. ICESat-2 has provided measurements of ice surface height between 88º N and S, repeated four times per year, with high vertical accuracy and along-track spatial resolution. Its accuracy and coverage has enabled near-complete recovery of height changes across the ice sheets, capturing subtle changes in the interior, and rapid changes along the dynamic margins with steep slopes and the floating peripheral ice shelves. The ICESat-2 Science Team has developed a suite of algorithms that produce along-track and gridded land ice height products at various levels of processing, all freely available at the National Snow and Ice Data Center. Here, we describe three higher-level land-ice data products derived from ATL06 and their underlying algorithms: along-track height change (ATL11), digital elevation model (ATL14) and gridded surface height change (ATL15). We demonstrate the suitability of each data product for studying different ice sheet regions. We then show height changes for Greenland and Antarctica from ATL15 during the first 6 years of the ICESat-2 mission (October 2018–December 2024), illustrating how ICESat-2 measurements can distinguish the multi-year trends from seasonal fluctuations.

Disappearing glaciers are observed worldwide, but a reliable counting is only available for some regions. This is due to several issues, ranging from inconsistent glacier identification to different criteria applied to decide whether or not a glacier has disappeared. The public perception of a glacier being lost usually has a focus on specific, often well-known glaciers, with a related media attention. In contrast, hundreds of glaciers might disappear in other regions over the same period without any notice. When they are not widely known, this silent disappearance can also happen to scientifically valuable glaciers. For example, the loss of benchmark glaciers with decades of mass balance measurements is also a loss of important information about climate variability in remote high-mountain regions. This study gives an overview of the challenges and different criteria used to determine if a glacier has disappeared and presents recommendations for a proper counting and change assessment.

Land-to-lake glacier terminus transition can alter glacier dynamics and enhance mass loss. However, the magnitude and timing of dynamic changes during this transition remain poorly constrained, especially in hyperhumid regions such as western Patagonia. We analyze this process at four glaciers by acquired bathymetry data combined with multi-temporal remote-sensing observations to track lake development and glacier retreat. Although each glacier shows distinct patterns, three glaciers underwent marked periods of rapid retreat associated with the onset of buoyant conditions at the termini, while the fourth glacier appears to be entering this stage. Results indicate that during rapid retreat, subaqueous ice loss contributed to 8–40% of total mass loss, underscoring its relevance for glacier mass balance. Based on land-lake contact and dynamics behavior, we propose reclassifying Exploradores Glacier from land- to lake-terminating. The analysis is constrained by the limited spatial coverage of bathymetric surveys, particularly at Grosse and Exploradores Glaciers. Nevertheless, the findings underline the importance of improving bed models and buoyant condition analysis to anticipate glacier changes. Many Patagonian glaciers are expected to evolve into lake-terminating systems, making updated inventories and inclusion of subaqueous mass loss critical for hazard assessment and projections of future ice loss.

The Zugspitzplatt represents a key high-alpine reference landscape in German geography. Located below the Zugspitze, Germany’s highest peak, it still hosts some of the country’s small remaining glacier ice reserves. Owing to its long history of scientific observation, high accessibility, and pronounced sensitivity to climatic change, the Zugspitzplatt has acquired emblematic significance as a national reference site for alpine geomorphological and glaciological research. The observation of the Schneeferner glaciers follows a long-standing tradition of glacier monitoring in this region. As of 2022, one of the two glaciers has completely disappeared, and the remaining one is critically endangered. Here, we present geodetic mass balances since 1892 based on historical maps and own surveys. Measurements of ice thicknesses allow the determination of absolute ice masses and their change. From 52 megatons of ice in 1892, less than one megaton was left in 2023 and its disappearance is inevitable. While this deglaciation will have negligible effects on humankind, it represents a potent visual and emotional indicator of climate change. Given the presence of a touristic hotspot and an environmental research station, the Zugspitzplatt has the potential to serve as a focal point for climate education.

Glacial lakes are increasing in number and size worldwide, posing growing risks for outburst floods. Norway’s last glacial lake inventory used semi-automatic mapping on Sentinel-2 imagery from 2018–19. In this study, we test a more automated and reproducible workflow for updating glacial lake extents in Norway using Sentinel-2 and Sentinel-1 satellite imagery and a Random Forest classifier. Here, glacial lakes are defined as water bodies within 200 m of glaciers larger than 0.1 km2 with a minimum lake size of 400 m2. A 10th-percentile Sentinel-2 summer composite from 2023–24 mitigated snow and cloud cover, while Sentinel-1 ascending-descending difference composites reduced shadow misclassification without relying on DEMs. Validation across six glacier regions shows high detection reliability (F1-score: 0.81) as well as high delineation accuracy (median deviation <6.5 m). However, manual correction remains necessary, especially in steep terrain. We identified 1382 glacial lakes in 2023–24, covering 124 km2—a substantial increase relative to 2018–19. Excluding regulated lakes and adjusting for methodological differences, we estimate a 9–22% lake area increase over the past five years, mainly driven by glacier retreat. The workflow is efficient and reproducible, but regional threshold adaptation and retraining are required for transfer to other regions.

An alpine glacier below Sunlight Peak in northwest Wyoming was first photographically documented in 1893, near the end of the Little Ice Age and during the time of industrialization. Since then, evolving technologies have been applied to observe this glacier and nearby discontinuous permafrost for studies spanning Earth, environmental, and planetary sciences. Surveys in the 21st century indicate negative mass balance coinciding with rising average air temperature. This paper reviews the geological and geophysical data on record for the Sunlight Glacier system, presents new results from a 2023 fieldwork campaign combined with remote sensing analysis and comments on likely scenarios of future evolution for this individual body of ice within a broader alpine cryosphere feeding the watersheds of western North America.

The archaeology of glaciers and ice patches has developed as a distinct new field in response to climate change and the melting of mountain ice. Thousands of artefacts and biological materials, dating back up to 10 000 years are being released from melting ice patches and retreating glaciers, offering unique insight into past human activities in cold environments. This paper examines the historical development of glacial archaeology, the preservation or loss of archaeological material from snow and ice, and the methodological challenges in locating and recovering such finds. Key finds and sites from North America, the Alps and Norway are presented. The emerging history demonstrates that high mountain areas were used more intensively in the past than previously assumed, including during winter. The paper argues that closer collaboration between glacial archaeology, glaciology and palaeoclimate research would be highly beneficial, particularly through joint investigations of the ice at glacial archaeological sites.

We have been conducting mass-balance monitoring on Aldegondabreen since the early 21st century. Over the most recent five year period (2019/20–2023/24), the glacier has experienced its most negative mass balance, averaging −2.0 m w.e. a−1. This dramatic loss is linked to rising air temperatures, with several of the warmest years on record for the Arctic land occurring during this interval. In 2024, for the first time, the critical threshold of 1.5°C above pre-industrial levels was exceeded globally, and this resulted in the lowest annual balance observed since the beginning of our monitoring program (−2.48 m w.e. a−1). Archival evidence indicates that such intense melting is unprecedented since at least 1911, which marked the end of the Little Ice Age in the region. As of 2025, the glacier’s mean ice thickness has been estimated at 39 m (33 m w.e.) meaning that the loss of 10 m w.e. in just the last five years is an enormous change.

The Tropical Andes stand out as one of the mountain regions most affected by global warming. Here, we present a synthesis of recent glacier evolution in the Cordillera Blanca, based on the glaciers that have been monitored with in situ glaciological measurements over the past decades. In particular, we describe the evolution of the Glacier Yanamarey, a reference glacier in the Peruvian Andes in the World Glacier Monitoring Service database. This glacier is currently on the verge of vanishing—similar to several other glaciers in the Cordillera Blanca. Finally, we address the current state of glacier monitoring in the region and the main challenges to ensure the continuity and sustainability of these monitoring programs.

Patagonia and Tierra del Fuego (Austral Andes) are the most glacierised regions in the Southern Hemisphere, where glaciers have experienced significant mass changes in recent decades. Understanding glacier–climate–water interactions is crucial for addressing future climate challenges. Open-access data play a key role in advancing geoscience research, improving models and assessing the impacts of hazards and sea-level rise impacts. Here, we present QFuego-Patagonia, a free glacier-related GIS dataset and web portal covering Patagonia and Tierra del Fuego, which provides essential geospatial information across four scientific topics: Glaciology, Atmosphere, Terrain Models, and Glacial Geology and Geomorphology. This initiative aims to foster interdisciplinary research and collaboration, synthesise current knowledge and establish an advanced glacier data repository that will be continuously updated as new data and insights become available.

Sequential photographic records of glacier termini go back to the mid-20th century, revealing climate-driven retreat. More recently, time-lapse imagery has enabled detailed analysis of glacier dynamics, including calving. Here, we use long-term, high-frequency (15 min) time-lapse images from May–October 2016 to manually investigate calving activity at Hansbreen, a marine-terminating glacier in Hornsund Fjord, Svalbard. We explore the spatio-temporal variability in calving frequency and styles along the glacier terminus and its relationship to environmental drivers. Average calving frequency was found to be 30 events d−1, and peaking at 60 d−1. The calving activity aligns well with air and ocean temperature at a seasonal scales, while some peaks in calving correspond to increased modeled meltwater runoff and rainfall. These links are inconsistent and reflect high complexity. Calving at Hansbreen varies greatly in time and across five delineated terminus zones. In two of the zones, over 60% of waterline events occur during ebb tide; these segments also experience regular ice cave formation. However, further efforts are needed to explore the high-frequency evolution of terminus morphology and its link to calving. Our dataset can also be used to train automated algorithms for calving detection from time-lapse imagery.

This study presents the first nationwide assessment of vanished glaciers in Switzerland. By comparing the Swiss Glacier Inventories SGI1973 and SGI2016, we identify 1019 vanished glaciers, representing more than 40% of all glaciers inventoried in 1973 and accounting for 13% (47±3 km²) of total glacier area loss. Glacier disappearance was most widespread along the main Alpine divide, in regions with relatively low peak elevations. Most vanished glaciers were very small (<0.10 km2) and steep, south- or east-facing glaciers more often vanished with respect to the initial glacier distribution. In the 2300–2550 m elevation band, vanished glaciers contributed over 30% of total area loss. Regionally, the Rhine basin hosts the largest number of vanished glaciers (423), while the Po (39%) and Danube (55%) basins have the highest share of glaciers disappearing with respect to the initial number. These findings underscore the relevance of systematically including vanished glaciers in change assessments. With a new inventory underway and two extreme melt years in 2022 and 2023, this study provides a benchmark for tracking continued glacier extinction in the Swiss Alps.