Glacier Retreat Research Articles

Spatiotemporal variations in frost cracking measures in two dimensions: A case study for rock walls in Jotunheimen, southern Norway

The ground thermal regime has a profound impact on geomorphological processes and has been suggested to be particularly important for weathering processes in periglacial environments. Several frost-related damage indices have hitherto been developed to link climate and frost weathering potential in bedrock, although only for individual points or grid cells. Here, we model ground temperature and frost weathering potential in steep rock walls in the Jotunheimen Mountains, southern Norway, along a two-dimensional profile line for the Younger Dryas Stadial-Preboreal transition (c. 11.5 ka), the Holocene Thermal Maximum (c. 7.5 ka), the Little Ice Age (1750), and the 2010s. We use an established heat flow model and frost-cracking index based on the ice segregation theory. A central innovation of our model treatment is the implementation of ensemble simulations using distributions of automatically mapped crack radii in a rock wall, whereas previous frost damage models considered only a single characteristic crack radius. Our results allowed for the identification of sites with enhanced frost weathering. Such sites are typically found between rock walls and retreating glaciers, as well as in areas where snow depth changes abruptly, resulting in large thermal gradients. Hence, frost weathering may be highly active during glacier retreat, enhancing the damage to rock walls during deglaciation by adding to the damage from stress release. The coldest climates of the Younger Dryas Stadial-Preboreal transition and the Little Ice Age were generally most favorable for frost cracking. Such timing compares well with the knowledge about the timing of rockfall accumulations in Norway.

Prokaryotic richness and diversity increased during Holocene glacier retreat and onset of an Antarctic Lake

Knowledge about biodiversity changes during transitions from glacial landscape to lake formation is limited to contemporary studies. Here, we combined analyses of lithology, chronology and geochemistry with sedimentary ancient DNA metabarcoding to assess such transition in maritime Antarctica. We inferred three paleoenvironmental stages covering the Holocene glacier retreat process. From 4900 to 3850 years before the present, we found the lowest prokaryotic richness/diversity, with bacterial taxa indicators associated to soil and terrestrial environments. From 3850 to 2650 years before the present, a higher carbon content, higher Carbon/Nitrogen variability, increased species richness/diversity, and prokaryotic taxa indicators of long-term energy starvation were detected. Finally, from 2650 to 1070 years before the present, we inferred the onset of a genuine lacustrine environment holding stable Carbon/Nitrogen ratios and the highest prokaryotic diversity, with known aquatic bacterial taxa. Our study unveils for the first time the evolution from a glacier-covered to a freshwater lake through a millennial scale.

Tracking rapid and slow ice-dammed lake changes through optical satellites and local knowledge: a case study of Tystigbreen in Norway

Abstract The number of glacial lakes has grown globally concurrently with the retreat of glaciers in the last few decades, increasing the risk of potentially hazardous glacial lake outburst floods (GLOFs) and posing a threat to downstream communities. Norway has several known ice-dammed lakes that produce repeated GLOFs but as we show here, the existing GLOF database is incomplete and needs to be improved through continuous monitoring of glaciers and glacial lakes. This study examines the case of an ice cap in central Norway hosting at least four drainage-prone lakes. We reconstruct the sequence of lake drainage events through a combination of remote sensing, ground-truthing and citizen science while scrutinising the applicability of the PlanetScope imagery vs Sentinel-2 and Landsat-8 OLI products. As opposed to the Landsat imagery that often fails to resolve even the largest glacial lakes of Tystigbreen, both PlanetScope and Sentinel-2 are helpful in identifying previously unrecognised glacial lakes and undocumented drainage events. Our analysis suggests that a fusion of the two satellite products may be beneficial for automated tracking of glacial lake changes. We also demonstrate that local knowledge and systematic involvement of citizens in data collection have a potential to enrich GLOF databases.

Glacial Lake Changes and Risk Assessment in Rongxer Watershed of China–Nepal Economic Corridor

Glacial lake outburst floods (GLOFs) are one of the most severe disasters in alpine regions, releasing a large amount of water and sediment that can cause fatalities and economic loss as well as substantial damage to downstream infrastructures. The risk of GLOFs in the Himalayas is exacerbated by glacier retreat caused by global warming. Critical economic corridors, such as the Rongxer Watershed, are threatened by GLOFs, but the lack of risk assessment specific to the watershed hinders hazard prevention. In this study, we propose a novel model to evaluate the risk of GLOF using a combination of remote sensing observations, GIS, and hydrological models and apply this model to the GLOF risk assessment in the Rongxer Watershed. The results show that (1) the area of glacial lakes in the Rongxer Watershed increased by 31.19% from 11.35 km2 in 1990 to 14.89 km2 in 2020, and (2) 18 lakes were identified as potentially dangerous glacial lakes (PDGLs) that need to be assessed for the GLOF risk, and two of them were categorized as very high risk (Niangzongmajue and Tsho Rolpa). The proposed model was robust in a GLOF risk evaluation by historical GLOFs in the Himalayas. The glacial lake data and GLOF risk assessment model of this study have the potential to be widely used in research on the relationships between glacial lakes and climate change, as well as in disaster mitigation of GLOFs.

Current and future roles of meltwater–groundwater dynamics in a proglacial Alpine outwash plain

Abstract. Glacierized alpine catchments are rapidly evolving due to glacier retreat and consequent geomorphological and ecological changes. As more terrain becomes ice-free, reworking of exposed terrain by the river as well as thawing of the top layer may lead to an increase in surface and subsurface water exchanges, leading to potential changes in water storage and release, which in turn may impact ecological, geomorphological and hydrological processes. In this study, we aim to understand the current and future hydrological functioning of a typical outwash plain in a Swiss Alpine catchment. As with many other fluvial aquifers in alpine environments, this outwash plain is located at the valley bottom, where catchment-wide water and sediment fluxes tend to gather from multiple sources, may store water and provide specific habitats for alpine ecosystems. Their dynamics are however rarely studied in post Little Ice Age proglacial zones. Based on geophysical investigations as well as year-round stream and groundwater observations, we developed a simplified physically based 3D MODFLOW model and performed an optimized automatic calibration using PEST HP. We highlight the strong interactions between the upstream river and the aquifer, with stream infiltration being the dominant process of recharge. Groundwater exfiltration occurs in the lower half of the outwash plain, balancing out the amount of river infiltration at a daily timescale. We show that hillslope contributions from rain and snowmelt have little impact on groundwater levels. We also show that the outwash plain acts as a bedrock-dammed aquifer and can maintain groundwater levels close to the surface during dry periods lasting months, even in the absence of glacier meltwater, but may in turn provide only limited baseflow to the stream. Finally, we explore how new outwash plains may form in the future in this catchment due to glacier recession and discuss from a hydrological perspective which cascading impacts the presence of multiple outwash plains may have. For this case study, we estimate the total dynamic storage of future outwash plains to be about 20 mm, and we demonstrate their limited capacity to provide more stream water than that which they infiltrate upstream, except for very low river flows (<150 to 200 L s−1). Below this limit, they can provide limited baseflow on timescales of weeks, thus maintaining moisture conditions that may be beneficial for proglacial ecosystems. Their role in attenuating floods also appears limited, as less than 0.5 m3 s−1 of river water can be infiltrated. The studied outwash plain appears therefore to play an important role for alpine ecosystems but has a marginal hydrological effect on downstream river discharge.

Glacier retreat and lake outburst floods in the central Himalayan region from 2000 to 2022

Glacier retreat and lake outburst floods in the central Himalayan region from 2000 to 2022

Deep Learning Low-cost Photogrammetry for 4D Short-term Glacier Dynamics Monitoring

AbstractShort-term monitoring of alpine glaciers is crucial to understand their response to climate change. This paper presents a low-cost multi-camera system tailored for 4D glacier monitoring using deep learning stereo-photogrammetry. Our approach integrates multi-temporal 3D reconstruction from stereo cameras and surface velocity estimation from a monoscopic camera through digital image correlation. To address the challenges posed by wide camera baselines in complex environments, we have integrated state-of-the-art deep learning feature matching algorithms into ICEpy4D, a Python toolkit designed for 4D monitoring (https://github.com/franioli/icepy4d). In a pilot study conducted on the debris-covered Belvedere Glacier (Italian Alps), our stereoscopic setup, with a camera base–height ratio close to one, captured daily images from May to November 2022. Our approach utilized SuperPoint and SuperGlue for feature matching, resulting in a daily 3D reconstruction of the glacier terminus, as traditional SIFT-like feature matching fails in this scenario. Using dense point clouds with decimetric accuracy, we estimated daily ice volume loss and glacier retreat at the terminus. The total ice volume loss was $$63\,000\,\text{m}$$ 63 000 m $${}^{3}$$ 3 and the retreat was $$17.8\,\text{m}$$ 17.8 m . Surface kinematics revealed three times higher surface velocity during the warm season (May–September) than in the fall (September–November). Daily analyses revealed a significant short-term correlation between air temperature, glacier surface velocity and ice ablation, providing insight into the glacier’s response to external forces. The low cost and ease of deployment of the proposed system facilitates replication at other sites for short-term monitoring of glacier dynamics.

Oceanographic Variability in Cumberland Bay, South Georgia, and Its Implications for Glacier Retreat

AbstractSouth Georgia is a heavily glaciated sub‐Antarctic island in the Southern Ocean. Cumberland Bay is the largest fjord on the island, split into two arms, each with a large marine‐terminating glacier at the head. Although these glaciers have shown markedly different retreat rates over the past century, the underlying drivers of such differential retreat are not yet understood. This study uses observations and a new high‐resolution oceanographic model to characterize oceanographic variability in Cumberland Bay and to explore its influence on glacier retreat. While observations indicate a strong seasonal cycle in temperature and salinity, they reveal no clear hydrographic differences that could explain the differential glacier retreat. Model simulations suggest the subglacial outflow plume dynamics and fjord circulation are sensitive to the bathymetry adjacent to the glacier, though this does not provide persuasive reasoning for the asymmetric glacier retreat. The addition of a postulated shallow inner sill in one fjord arm, however, significantly changes the water properties in the resultant inner basin by blocking the intrusion of colder, higher salinity waters at depth. This increase in temperature could significantly increase submarine melting, which is proposed as a possible contribution to the different rates of glacier retreat observed in the two fjord arms. This study represents the first detailed description of the oceanographic variability of a sub‐Antarctic island fjord, highlighting the sensitivity of fjord oceanography to bathymetry. Notably, in fjords systems where temperature decreases with depth, the presence of a shallow sill has the potential to accelerate glacier retreat.

Fluctuaciones recientes del glaciar Alerce (1953-2020), Andes de Patagonia norte

In recent decades, glacier retreat has been observed in all the world’s mountain ranges. Over the last 20 years, glaciers in the Andes have lost mass at one of the highest rates on record. Particularly, glaciers in the northern Patagonian Andes show the highest rate of loss of all the Andean regions for the last decade. Detailed records of long-term variations in glacier extent are crucial to put current climate change into context and quantify its impact on mountain areas. In the present study, a reconstruction of the extension (length and area) of the Alerce glacier (41.15° S-71.81° W) for the last 70 years was carried out. By means of historical documents and satellite images (Landsat and Pléiades), detailed maps of glacier fluctuations were generated for the period 1953-2020. Four methodologies were evaluated to measure the front position: i) central flow line; ii) curvilinear box; iii) multiline; and iv) variable box. The magnitude of the front position variations depends on the methodology applied. The method that best addresses glacier front variations over the period analyzed is the variable box method. Between 1953 and 2020, the Alerce glacier lost 35% of its area (1.1±0.1 km2) and 67% of its total length (1.49±0.04 km). It is possible to distinguish periods with different rates of retreat. A stage of slight retreat (-11.3±0.5 ma-1) between 1953 and 1976, followed by a period of stability (-6.7±0.5 ma-1) between 1977 and 1983, then a strong retreat (-58.7±0.5 ma-1) between 1984 and 1999, followed by another period of stability (-5.4±0.5 ma-1) between 2000 and 2009 and, finally, another retreat (-8.7±0.5 ma-1) between 2010 and 2020. The retreat rates for the Alerce glacier mimic those observed in other glaciers in the region, possibly representing a regional climatic signal.

Can inter-annual climate variability alone explain the glacier retreat since the Little Ice Age in the Hailuogou catchment, southeastern Tibetan Plateau?

Inter-annual climate variability has the potential to induce hundred-to-thousand meters of glacier length change, comparable to the glacier retreats from their Little Ice Age (LIA) positions (Roe and O'Neal, 2009). Distinguishing the roles of inter-annual climate variability and climate change in glacier changes can help us read the true climate signal from the history of glacial activity and provide a basis for detailed attribution of currently observed glacier retreats. Here, we used ArcGIS tools to reconstruct the LIA glacier in the Hailuogou catchment on the southeastern Tibetan Plateau (TP) and calculated the corresponding glacier equilibrium-line altitude (ELA). Based on the LIA ELA, we inferred the climate change supporting the LIA glaciers in the region. Further, we quantified the impact of inter-annual climate variability on the Hailuogou Glacier change using a three-stage linear model. During the LIA, the area of the Hailuogou Glacier was 42.64 km2 and its volume was 3.73 × 109 m3. The LIA ELA was 5068 m above sea level (a.s.l.), lowering by 213 m relatively to the present. The LIA summer temperature was estimated to be ∼1.31–2.21 °C colder than the present with the LIA precipitation constraint being 90–100% of the modern precipitation. Forced by the inter-annual variabilities in summer temperature and annual precipitation, the Hailuogou Glacier has a possible maximum negative excursion of 459 m, which can only explain 19.3% of the actual retreat since the LIA. According to the probability density function (PDF) of the modeled length anomalies, the likelihood is <1% for the actual glacier retreat completely due to the inter-annual climate variability. We therefore argued that the inter-annual climate variability alone cannot explain the glacier retreat since the LIA in the Hailuogou catchment. Further, glacier geometry and topography might be the main factors determining the strength of the response of the Hailuogou Glacier to inter-annual climate variability.

The importance of species addition 'versus' replacement varies over succession in plant communities after glacier retreat.

The mechanisms underlying plant succession remain highly debated. Due to the local scope of most studies, we lack a global quantification of the relative importance of species addition 'versus' replacement. We assessed the role of these processes in the variation (β-diversity) of plant communities colonizing the forelands of 46 retreating glaciers worldwide, using both environmental DNA and traditional surveys. Our findings indicate that addition and replacement concur in determining community changes in deglaciated sites, but their relative importance varied over time. Taxa addition dominated immediately after glacier retreat, as expected in harsh environments, while replacement became more important for late-successional communities. These changes were aligned with total β-diversity changes, which were more pronounced between early-successional communities than between late-successional communities (>50 yr since glacier retreat). Despite the complexity of community assembly during plant succession, the observed global pattern suggests a generalized shift from the dominance of facilitation and/or stochastic processes in early-successional communities to a predominance of competition later on.

The Impact of Climate Change on Glacier Retreat

Purpose: The main objective of this study was to explore the impact of climate change on glacier retreat.&#x0D; Methodology: The study adopted a desktop research methodology. Desk research refers to secondary data or that which can be collected without fieldwork. Desk research is basically involved in collecting data from existing resources hence it is often considered a low cost technique as compared to field research, as the main cost is involved in executive’s time, telephone charges and directories. Thus, the study relied on already published studies, reports and statistics. This secondary data was easily accessed through the online journals and library.&#x0D; Findings: The findings revealed that there exists a contextual and methodological gap relating to the impact of climate change on glacier retreat. Preliminary empirical review revealed that glacier retreat, driven by rising global temperatures and greenhouse gas emissions, poses significant threats to our environment, water resources, ecosystems, and communities. The studies emphasize glaciers' role as sensitive indicators of climate change and the urgent need for further research to understand regional variations and develop adaptation strategies. To address these challenges, international collaboration and sustainable solutions are essential to slow glacier retreat, mitigate impacts, and preserve these vital natural resources for the future.&#x0D; Unique Contribution to Theory, Practice and Policy: The Theory of Anthropogenic Climate Change, Theory of Glacier Response to Temperature Change and Theory of Glacial Mass Balance may be used to anchor future studies on glacier retreat. The study recommends a three-fold approach to address the impact of climate change on glacier retreat: first, urgent global efforts to reduce greenhouse gas emissions and mitigate climate change; second, the development of adaptive strategies for vulnerable communities, focusing on water resource diversification and sustainable agricultural practices; and third, the continuous monitoring and research of glacier dynamics to enhance our understanding and inform localized strategies for glacier-dependent regions.

Picturing finitude: Photography of mountain glaciers as a multiple practice of dealing with environmental loss

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.

Cross-domain interactions confer stability to benthic biofilms in proglacial streams

Cross-domain interactions are an integral part of the success of biofilms in natural environments but remain poorly understood. Here, we describe cross-domain interactions in stream biofilms draining proglacial floodplains in the Swiss Alps. These streams, as a consequence of the retreat of glaciers, are characterised by multiple environmental gradients and perturbations (e.g., changes in channel geomorphology, discharge) that depend on the time since deglaciation. We evaluate co-occurrence of bacteria and eukaryotic communities along streams and show that key community members have disproportionate effects on the stability of community networks. The topology of the networks, here quantified as the arrangement of the constituent nodes formed by specific taxa, was independent of stream type and their apparent environmental stability. However, network stability against fragmentation was higher in the streams draining proglacial terrain that was more recently deglaciated. We find that bacteria, eukaryotic photoautotrophs, and fungi are central to the stability of these networks, which fragment upon the removal of both pro- and eukaryotic taxa. Key taxa are not always abundant, suggesting an underlying functional component to their contributions. Thus, we show that there is a key role played by individual taxa in determining microbial community stability of glacier-fed streams.

Impact of shallow sills on circulation regimes and submarine melting in glacial fjords

Abstract. The increased melting and rapid retreat of marine-terminating glaciers is a key contributor to sea-level rise. In glacial fjords with shallow sills common in Patagonia, Alaska, and other systems, these bathymetric features can act as a first-order control on the dynamics. However, our understanding of how this shallow bathymetry interacts with the subglacial discharge from the glacier and impacts the fjord circulation, water properties, and rates of submarine melting is limited. To address this gap, we conduct idealized numerical simulations using a coupled plume–ocean fjord model spanning a wide range of initial ocean conditions, sill depths, and subglacial discharge. A previously documented circulation regime leads to strong mixing and vertical transport over the sill, where up to ∼ 70 % of the colder water from the upper-layer outflow is refluxed into the deeper layer, cooling the incoming warm oceanic water by as much as 1 ∘C and reducing the stratification near the glacier front. When the initial stratification is relatively strong or the subglacial discharge is relatively weak, an additional unsteady circulation regime arises where the freshwater flow can become trapped below the sill depth for weeks to months, creating an effective cooling mechanism for the deep water. We also find that submarine melting often increases when a shallow sill is added to a glacial fjord due to the reduction of stratification – which increases submarine melting – dominating over the cooling effect as the oceanic inflow is modified by the presence of the sill. These results underscore that shallow-silled fjords can have distinct dynamics that strongly modulate oceanic properties and the melting rates of marine-terminating glaciers.

Antarctic benthic species distribution models and compositional analysis in a coastal ecosystem under glacier retreat

Antarctic benthic species distribution models and compositional analysis in a coastal ecosystem under glacier retreat

Maps of Quaternary sediments and features in Austria and neighbouring countries at the scales of 1:500 000 and 1:1 500 000

Abstract Today’s landscape and morphology of Austria is markedly affected by erosional and sedimentary processes active during the Quaternary. Particularly, large glaciers have shaped the landscape of the Eastern Alps. The presented maps at the scales of 1:500 000 and 1:1 500 000 aim to visualise areas, where deposition or erosion in different stages of the Quaternary prevailed. The maps (free download available) were generated with ArcGIS software using available map sheets at larger scales (1:50 000, 1:200 000). No additional field work has been conducted. The most obvious observation is that an extensive cover of Quaternary sediments predominantly occurs in the northern Alpine foreland, especially outside of Austria. The maps show that large glacier tongues of the Middle to Late Pleistocene glaciations (Günz, Mindel, Riss and Würm) existed in the northern and southeastern alpine foreland. In the east, hardly any signs of glacial coverage are visible due to later fluvial cannibalisation of features partly deposited in narrow valleys. Bordering terminal moraines, extensive, terraced fluvial deposits occur within and around the Alps showing that river courses partly changed during the Pleistocene. Aeolian sediments often accompany these sediments, but also cover huge areas in the Vienna and Tulln Basin and the Little Hungarian plain. The distribution of large rockslide events shows that they mainly formed in glacially covered areas as a result of rock destabilisation after glacier retreat. Additionally, the map shows that the alpine foreland is subject of inhomogeneous uplift since the Neogene. For example, between Salzburg and Munich, wide areas are covered by Pleistocene deposits, whereas to the west of Munich and in Upper Austria, recent rivers incised deeper into Neogene sediments.

APPLICATION OF SATELLITE DATA FOR MONITORING THE RETREAT OF MOUNTAIN GLACIER MORTERATSCH, SWISS ALPS, OVER A PERIOD OF 51 YEARS

The presented study aims to apply a method for monitoring the retreat of mountain glacier in Alpine region of Swiss Alps, which consists of using optical satellite imagery and their spectral capabilities to observe snow and ice objects on earth surface. Satellite imagery with its big legacy archive dating back to 1972 for Landsat imagery, can be of big help to track and monitor the alpine glaciers retreat for long periods and serve as a database for modelling and predicting the glaciers retreat in the future. By combining different satellite data processing approaches, results have been obtained on the spatial distribution and dynamics of the Morteratsch Glacier over a period of 51 years. The focus of the study is to track the changes that have occurred along the positions of the ice front (terminus) in glacier’s ablation zone to obtain information about glacier’s dynamics during the study period.

Extinctions in the Rise; A Study on the Pandemic in the Pacific

The paper examines the Anthropogenic climate change is a key cause of biodiversity loss. The Galapagos Islands are a global hotspot for environmental change. The unique and endemic biodiversity of the Galapagos is at risk. The Galapagos Islands are located near the equator where temperature is likely to change above the global average level. Due to climate change, the island is in the verge of extinction. The island faces serious environmental threats such as a rise in sea level, increased retreat of glaciers, decrease in annual runoff and increased vulnerability to floods and droughts. Many species can’t migrate or adapt in response to changing climate conditions making them particularly vulnerable. Climate fiction explores the impacts of climate change on the environment, society, and individuals. Climate fiction is an immediate action. Climate fiction not only has the potential to represent the aftereffects of climate change, but also the capacity to provide a space in which to address the Anthropocene’s emotional, ethical, and practical concerns. Due to climate change, there is an increase in extreme weather patterns. The results of the review are important aspects of understanding the far-reaching implications of climate change on the islands. Methods of qualitative research were used in this study. The results of the qualitative study were acquired from a range of secondary sources, including press reports, scholarly journal articles, and previous theses. An overview of the causes of the negative environmental effects on the island was provided using a discourse analysis method, along with a few case studies that were taken from news reports and journals. When the islands become an exploiting hub rather than an exploring place it is where the problem arises. The study's most essential finding is that climate fiction is more than simply a discussion; it is a necessity. To conclude it is better to maintain the existing ecology than to prevent it from destruction if it is too late. The repercussions of climate change have already begun, but current attempts can mitigate the effects to a certain amount rather than preventing the planet from apocalypse. It further paves the way to blue humanities, deep ecology and many other aspects.

The Geography of Risks of Breakthrough of Glacial Lakes and Valleys

Against the background of climate warming, various natural events are frequent. One of them is floods, which occur when drowned lakes that are damaged by many factors break through. Such events are common during the advance and retreat of glaciers. The resulting dammed lakes differ from each other in their strength, duration, character and other properties. The result of floods has mostly a negative impact on the surrounding area in the glacier valley. There are examples of both processes in Georgia, and their results are always negative, so their study and some kind of systematization is necessary to properly manage the expected natural event to avoid the catastrophic consequences of overflowing floods. &#x0D;