Erik Schytt Mannerfelt

• Kleber, Gabrielle E.; Mannerfelt, Erik Schytt; Schloemer, Stefan; Senger, Kim; Magerl, Leonard & Hensgens, Geert [Vis alle 11 forfattere av denne artikkelen] (2026). Subglacial geology and thermal conditions regulate methane emissions from Svalbard glaciers. Nature Communications. 17, s. 1–12. doi: 10.1038/s41467-026-77190-z. Fulltekst i vitenarkiv Vis sammendrag

  Melt rivers from valley glaciers and ice sheets release methane by transporting microbial or geologic methane from beneath glaciers, making it available for atmospheric emission. However, the mechanisms and magnitude of such methane release remain poorly understood due to limited studies. Here, we show how subglacial geology and glacier thermal conditions control methane supersaturation in meltwaters from 19 valley glaciers across central Svalbard. We find that all sampled meltwaters are supersaturated with methane, with peak concentrations up to 425-times atmospheric equilibrium. The carbon isotopic compositions of the methane and the presence of ethane and propane indicate that the methane is largely of thermogenic origin. Ground-penetrating radar surveys show that the extent of temperate ice at the glacier bed plays a critical role in facilitating methane acquisition, particularly in regions underlain by organic-rich, shale-dominated geological formations. This mechanistic insight is relevant for glaciated regions worldwide with organic-rich geology and suggests that accelerated glacier melt may amplify methane mobilization from beneath glaciers.

• Danjou, Loris Cedric; Rinne, Eero & Mannerfelt, Erik Schytt (2026). Svalbard glacier calving front changes from the 1930s to the 1970s from archived satellite and aerial images. The Cryosphere. ISSN 1994-0416. 20(7), s. 4133–4155. doi: 10.5194/tc-20-4133-2026. Fulltekst i vitenarkiv Vis sammendrag

  We obtained calving front positions of 171 Svalbard tidewater glaciers from archived satellite imagery. We used early Landsat images from 1976–1978 as well as declassified intelligence satellite photographs from 1962–1963. To support the analysis of these calving fronts, we also used historical aerial images from 1936–1938. During our study period between 1936–1978, we estimate an average glacier retreat rate of 27.3±3.0myr−1. This corresponds to an average retreat of approximately 1 km for Svalbard tidewater glaciers during this period. By multiplying the retreats by the glaciers’ widths, we estimate the cumulative area loss rate to be 17.0±2.5km2yr−1, which is slightly lower than the estimates found in the existing literature for the periods 1985–2023 and 2000–2020, and consistent with climatic trends from reanalysis data. Looking at individual glaciers, we identify and discuss 15 significant advance events. For four of them, our study provides additional information to current knowledge. We have discovered one undocumented surge– we show evidence that Emmabreen has surged between 1936–1963. We have also narrowed down the time windows of two previously known surges: the surge of Allfarvegen to between 1976–1978 (previously reported to have happened between 1970–1980), and the surge of Stonebreen to be tween 1936–1963 (previously reported between 1936–1971). We also show that Schweigaardbreen and Fonndalsbreen have advanced 400 and 541m, respectively, between 1938–1976. We discuss the potential future uses of our dataset, consisting of georeferenced satellite images used in our study as well as digitized calving fronts, which is freely available for future research.

• Zagel, Bernhard; Yang, Wei; Vargo, Lauren; Usubaliev, Ryskul; Umirzakov, Gulomjon & Tuccella, Paolo [Vis alle 118 forfattere av denne artikkelen] (2026). Global glacier mass change in 2025. Nature Reviews Earth & Environment. 7(4), s. 213–215. doi: 10.1038/s43017-026-00777-z. Fulltekst i vitenarkiv
• Sieglová, Eliska; Mannerfelt, Erik Schytt & Treichler, Désirée (2026). Automatic detection of glacier surges from ICESat-2 altimetry in Svalbard. Journal of Glaciology. ISSN 0022-1430. 72. doi: 10.1017/jog.2026.10136. Fulltekst i vitenarkiv Vis sammendrag

  Glacier surges are dynamic instabilities that dramatically alter glacier flow and geometry. Their triggers remain poorly understood, and improved methods of monitoring to further constrain the phenomenon is therefore important. We present a novel method for detecting glacier surges automatically using surface elevation data from NASAs ICESat-2 laser altimetry satellite. Elevation changes from 20182023 were computed relative to a highresolution reference DEM and analyzed using a hypsometric binning approach. We trained a Random Forest classifier on known surge events in Svalbard to identify spatial elevation change patterns indicative of surging. Our model detected 110 surges, of which 48 were false positives, 20 uncertain cases that may or may not be surges and 42 certain surges confirmed by external validation. Two of these are currently not part of any surge inventory. The classifier achieved an accuracy of 88.4% and highlighted features in the lower glacier region as most predictive. This study demonstrates that sparse altimetry data such as from ICESat-2 can effectively detect glacier surges and offers a promising, scalable approach to monitoring dynamic glacier instabilities.

• Strozzi, Tazio; Mannerfelt, Erik Schytt; Cartus, Oliver; Santoro, Maurizio; Schellenberger, Thomas & Kääb, Andreas (2026). Glacier surge activity over Svalbard from 1992 to 2025 interpreted using heritage satellite radar missions and Sentinel-1. The Cryosphere. ISSN 1994-0416. 20(3). doi: 10.5194/tc-20-1679-2026. Fulltekst i vitenarkiv Vis sammendrag

  Based on massive processing of heritage radar data from the satellite missions ERS-1/2, JERS-1, ENVISAT ASAR, ALOS PALSAR and Radarsat-2, and in combination with data from the current Sentinel-1 and ALOS-2 PALSAR-2 missions, we compiled a ∼ 30-year time series of radar backscatter over Svalbard. We exploited this data to detect glacier surges by using changes in backscatter as an indicator of increased or decreased surge-related crevassing. In this way, we reconstructed an as consistent as possible time series of surge activity on Svalbard for 1992 to 2025. We recorded 24 surge-type events during the pre Sentinel-1 period 1992–2014 (23 years) and 34 surge-type events during the post Sentinel-1 period 2015–2025 (11 years). This time series shows an approximately threefold increase in surges since 2015, from an average of about one surge per year to more than three surges per year. We show that this increase is unlikely to be explained alone by the better resolution, coverage and quality of the Sentinel-1 data compared to the data from the earlier SAR heritage missions. Simulation results indicate that the observed increase is extremely unlikely to be attributed to random perturbations in surge cyclicity, and instead suggest the influence of an external forcing mechanism. The number of surges during the recent decade seems high, but due to uncertainties in historical records, it remains unclear whether this frequency is exceptional or if earlier decades were unusually quiet. The cause of the observed threefold increase in surge activity also remains uncertain, given our incomplete understanding of surge initiation in relation to climate variability and non-climatic surge controls.

• Lovell, Harold; Benn, Douglas I.; Jiskoot, Hester; Stokes, Chris R.; Flowers, Gwenn E. & Guillet, Gregoire [Vis alle 15 forfattere av denne artikkelen] (2026). Glacier surging and surge-related hazards in a changing climate. Nature Reviews Earth & Environment. doi: 10.1038/s43017-025-00757-9. Fulltekst i vitenarkiv Vis sammendrag

  Glacier surges are ice flow instabilities characterized by periods of acceleration, during which mass is rapidly transferred from high to low elevations and the glacier front often advances. In this Review, we outline global trends in glacier surging and the influence of climate on the distribution and behaviour of surge-type glaciers and surge-related hazards. Glaciers exhibit diverse surging behaviours and typically recur at intervals that range from 5 years to over 100 years, with all surges largely driven by a reduction in basal friction. Most of the ~3,100 surge-type glaciers identified globally are clustered in the Arctic and Subarctic (48.3%) and High Mountain Asia (50.5%), where climate conditions are conducive to the development of surge instabilities, and there is emerging evidence that climate warming is changing surge behaviour. At least 81 surge-type glaciers globally have caused hazards such as ice-dammed glacial lake outburst floods, which can lead to infrastructure damage and loss of life. Future research should acquire spatiotemporally high-resolution remote-sensing data and direct observations of basal processes during all stages of surges, develop numerical models to better capture surge mechanisms and diversity, and project the impact of future climate warming on surge-type glacier behaviour and distribution.

• Harcourt, William D.; Pearce, Danni M; Gajek, Wojciech; Lovell, Harold; Mannerfelt, Erik Schytt & Kääb, Andreas [Vis alle 13 forfattere av denne artikkelen] (2026). Surging glaciers in Svalbard: Observing their distribution, characteristics and evolution. Earth-Science Reviews. ISSN 0012-8252. 275, s. 105410–105410. doi: 10.1016/j.earscirev.2026.105410. Fulltekst i vitenarkiv Vis sammendrag

  Glacier surges are episodes of significantly increased ice flow due to ice-dynamical feedbacks, and are often repeated in a quasi-periodical manner. Ice mass is redistributed during a surge, which leads to surface lowering at high elevation as ice is transferred down-glacier and thickening nearer the terminus. In this paper, we review different approaches for monitoring and detecting glacier surges in Svalbard, one of the most prominent global clusters of surge-type glaciers. Current surge detection is mainly based upon tracking the speed of glaciers over time, measuring elevation and frontal changes, and more recently automatically detecting surface changes such as increased crevassing. Thermal and hydrological changes near the glacier bed drive surge dynamics and can be measured using geophysical sensors such as ground-penetrating radar (GPR) and seismometers. When glaciers surge, they often produce diagnostic landforms in subglacial and proglacial environments, allowing historical surging to be identified even if surges have not been directly observed. Through this review, we have compiled an updated database of surge-type glaciers in Svalbard and find that 36% of glaciers display surge-type behaviour, which accounts for 75% of the total glacier area on Svalbard. Only 10% of all glaciers have been directly observed to surge, yet account for 48% of the total glacier area on Svalbard. Svalbard surge-type glaciers have gentler slopes, are generally longer, and extend across a larger elevation range compared to non surge-type glaciers across the archipelago. We find that the behaviour of surge-type glaciers is variable and more closely resembles a continuum from glaciers that do not surge to those which redistribute mass in a single event of strongly enhanced ice flux. We can describe the variability in surge behaviour using the concept of enthalpy and a six-stage surge model that characterises the build-up of energy at the glacier bed driven initially by thermal change and then ice acceleration which is prompted by changes in subglacial hydrology. Observations of glacier surges have improved significantly with routine mapping from satellites such as Sentinel-1, Sentinel-2 and the Landsat satellite series. Furthermore, an increasing number of geophysical measurements is enabling an improved understanding of subglacial processes before, during and after a surge, which is crucial for improving models of surge behaviour. As our observations of surges continue to improve, we expect to uncover new elements and details of surge behaviour, reaffirming the need to rethink the binary classification of glaciers as either ‘surge-type’ or ‘not surge-type’ in Svalbard and across the world.

• Hamm, Alexandra; Mannerfelt, Erik Schytt; Mohammed, Aaron A.; Painter, Scott L.; Coon, Ethan T. & Frampton, Andrew (2025). Model-based analysis of solute transport and potential carbon mineralization in the active layer of a hillslope underlain by permafrost with seasonal variability and climate change. The Cryosphere. ISSN 1994-0416. 19(9), s. 3693–3724. doi: 10.5194/tc-19-3693-2025. Fulltekst i vitenarkiv Vis sammendrag

  Permafrost carbon, stored in frozen organic matter across vast Arctic and sub-Arctic regions, represents a substantial and increasingly vulnerable carbon reservoir. As global temperatures rise, the accelerated thawing of permafrost releases greenhouse gases, exacerbating climate change. However, freshly thawed permafrost carbon may also experience lateral transport by groundwater flow to surface water recipients such as rivers and lakes, increasing the terrestrial-to-aquatic transfer of permafrost carbon. Mobilization and subsurface transport mechanisms are poorly understood and not accounted for in global climate models, leading to high uncertainties in the predictions of the permafrost carbon feedback. Here, we focus on a hillslope in Endalen Valley, Svalbard, as a representative example of a high-Arctic hillslope underlain by continuous permafrost. We analyze solute transport in the form of a non-reactive tracer representing dissolved organic carbon (DOC) using a physics-based numerical model with the objective to study governing cryotic and hydrodynamic transport mechanisms relevant for warming permafrost regions. We first analyze transport times for DOC pools at different locations within the active layer under present-day climatic conditions and proceed to study susceptibility for deeper ancient carbon release in the upper permafrost due to thaw under different warming scenarios. Results suggest that DOC in the active layer near the permafrost table experiences rapid lateral transport upon thaw due to saturated conditions and lateral flow, while DOC close to the ground surface experiences slower transport due to flow in unsaturated soil. Deeper permafrost carbon release exhibits vastly different transport behaviors depending on warming and thaw rate. Gradual warming leads to small fractions of DOC being mobilized every year, while the majority moves vertically through percolation and cryosuction. Abrupt thaw resulting from a single very warm year leads to faster lateral transport times, similar to active layer DOC released in saturated conditions. Lastly, we analyze the potential susceptibility of DOC to mineralization to CO2 prior to export due to soil moisture and temperature conditions. We find that high liquid saturation during transport coincides with very low mineralization rates and potentially inhibits mineralization into CO2 before export. Overall, the results highlight the importance of subsurface hydrologic and thermal conditions for the retention and lateral export of permafrost carbon by subsurface flow.

• Nanni, Ugo; Bouchayer, Coline Lili Mathy; Åkesson, Henning; Lefeuvre, Pierre-Marie; Mannerfelt, Erik Schytt & Köhler, Andreas [Vis alle 12 forfattere av denne artikkelen] (2025). Observed positive feedback between surface ablation and crevasse formation drives glacier acceleration and potential surge. Nature Communications. 16(1). doi: 10.1038/s41467-025-66349-9. Fulltekst i vitenarkiv Vis sammendrag

  Sudden glacier acceleration and instability, e.g. surges, strongly influence glacier ice loss. However, lack of in-situ observations of the involved processes hampers our ability to understand, quantify and model such a role. We present an analysis of the initiation of a surge (Kongsvegen glacier, Svalbard), focusing on the interplay between climatic and glacier-specific drivers. We integrate two decades of in-situ observations (GNSS, borehole and surface seismometers) with runoff simulations, and remotely sensed surface-elevation changes. We show that initial glacier thinning led to localized acceleration and crevassing. Then, we show that stronger surface melt enabled meltwater to reach the glacier bed. This input promotes high basal water pressure and glacier sliding, and in turn further surface crevassing. Our observations suggest that this positive feedback leads to the expansion of the initially localized instability. Our findings highlight mechanisms that could trigger glacier instabilities under a warming atmosphere beyond the High Arctic.

• Mannerfelt, Erik Schytt; Schellenberger, Thomas & Kääb, Andreas (2025). Tracking glacier surge evolution using interferometric SAR coherence-examples from Svalbard. Journal of Glaciology. ISSN 0022-1430. 71. doi: 10.1017/jog.2025.27. Fulltekst i vitenarkiv Vis sammendrag

  We present a practically simple methodology for tracking glacier surge onset and evolution using interferometric synthetic aperture radar (InSAR) coherence. Detecting surges early and monitoring their build-up is interesting for a multitude of scientific and safety-related aspects. We show that InSAR coherence maps allow the detection of surge-related instability on Svalbard many years before being detectable by, for instance, feature tracking or crevasse detection. Furthermore, we present derived data for two types of surges; down- and up-glacier propagating, with interestingly consistent surge propagation and post-surge relaxation rates. The method works well on Svalbard glaciers, and the data and core principle suggest a global applicability.

• Mannerfelt, Erik Schytt; Hodson, Andrew; Håkansson, Lena & Lovell, Harold (2024). Dynamic LIA advances hastened the demise of small valley glaciers in central Svalbard. Arctic Science. ISSN 2368-7460. 10(4), s. 815–833. doi: 10.1139/as-2024-0024. Fulltekst i vitenarkiv Vis sammendrag

  Most small land-terminating glaciers in Svalbard have experienced large recession since the Little Ice Age (LIA) and today are thin, cold, and largely inactive. This likely contrasts to their LIA conditions, but the observational record from that time is sparse. We investigate the evolution of five small glaciers in central Nordenskiöld Land, Svalbard, from the LIA to 2019. Photogrammetric reconstructions and ground penetrating radar are used to reconstruct their geometric changes since 1936, and historical observation, photographs, and geomorphological mapping extend this history to before the 1900s. Our results show that from 1936 to 2019, the study glaciers on average lost 49.6% of their area and 77.4% ± 7.7% of their volume, with the greatest volume loss at Scott Turnerbreen of 91% ± 5%. Four out of these five glaciers strongly indicate a history of surge-like advances near the end of the LIA within one or two decades, and the rate of subsequent mass loss seems connected to their previous dynamics. This apparent switch to high activity during a period of rapid climatic change, could have implications for our understanding of past and future glacier evolution; climate change and highly dynamic glacier responses may be more connected than previously thought.

• Pirk, Norbert; Aalstad, Kristoffer; Mannerfelt, Erik Schytt; Clayer, Francois; Wit, Heleen de & Christiansen, Casper Tai [Vis alle 9 forfattere av denne artikkelen] (2024). Disaggregating the Carbon Exchange of Degrading Permafrost Peatlands Using Bayesian Deep Learning. Geophysical Research Letters. ISSN 0094-8276. 51(10). doi: 10.1029/2024GL109283. Fulltekst i vitenarkiv Vis sammendrag

  Extensive regions in the permafrost zone are projected to become climatically unsuitable to sustain permafrost peatlands over the next century, suggesting transformations in these landscapes that can leave large amounts of permafrost carbon vulnerable to post-thaw decomposition. We present 3 years of eddy covariance measurements of CH4 and CO2 fluxes from the degrading permafrost peatland Iškoras in Northern Norway, which we disaggregate into separate fluxes of palsa, pond, and fen areas using information provided by the dynamic flux footprint in a novel ensemble-based Bayesian deep neural network framework. The 3-year mean CO2-equivalent flux is estimated to be 106 gCO2 m−2 yr−1 for palsas, 1,780 gCO2 m−2 yr−1 for ponds, and −31 gCO2 m−2 yr−1 for fens, indicating that possible palsa degradation to thermokarst ponds would strengthen the local greenhouse gas forcing by a factor of about 17, while transformation into fens would slightly reduce the current local greenhouse gas forcing.

• Kleber, Gabrielle Emma; Hodson, Andrew; Magerl, Leonard; Mannerfelt, Erik Schytt; Bradbury, Harold J. & Zhu, Yizhu [Vis alle 8 forfattere av denne artikkelen] (2023). Groundwater springs formed during glacial retreat are a large source of methane in the high Arctic. Nature Geoscience. ISSN 1752-0894. 16, s. 597–604. doi: 10.1038/s41561-023-01210-6. Fulltekst i vitenarkiv Vis sammendrag

  Permafrost and glaciers in the high Arctic form an impermeable ‘cryospheric cap’ that traps a large reservoir of subsurface methane, preventing it from reaching the atmosphere. Cryospheric vulnerability to climate warming is making releases of this methane possible. On Svalbard, where air temperatures are rising more than two times faster than the average for the Arctic, glaciers are retreating and leaving behind exposed forefields that enable rapid methane escape. Here we document how methane-rich groundwater springs have formed in recently revealed forefields of 78 land-terminating glaciers across central Svalbard, bringing deep-seated methane gas to the surface. Waters collected from these springs during February–May of 2021 and 2022 are supersaturated with methane up to 600,000 times greater than atmospheric equilibration. Spatial sampling reveals a geological dependency on the extent of methane supersaturation, with isotopic evidence of a thermogenic source. We estimate annual methane emissions from proglacial groundwaters to be up to 2.31 kt across the Svalbard archipelago. Further investigations into marine-terminating glaciers indicate future methane emission sources as these glaciers transition into fully land-based systems. Our findings reveal that climate-driven glacial retreat facilitates widespread release of methane, a positive feedback loop that is probably prevalent across other regions of the rapidly warming Arctic

• Kääb, Andreas; Bazilova, Varvara; Leclercq, Paul & Mannerfelt, Erik Schytt (2023). Global clustering of recent glacier surges from radar backscatter data, 2017-2022. Journal of Glaciology. ISSN 0022-1430. 69(277), s. 1515–1523. doi: 10.1017/jog.2023.35. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Using global Sentinel-1 radar backscatter data, we systematically map the locations of glaciers with surge-type activity during 2017–22. Patterns of pronounced increases or decreases in the strongest backscatter between two winter seasons often indicate large changes in glacier crevassing, which we treat here as a sign of surge-type activity. Validations against velocity time series, terminus advances and crevassing found in optical satellite images confirm the robustness of this approach. We find 115 surge-type events globally between 2017 and 2022, around 100 of which on glaciers already know as surge-type. Our data reveal a pronounced spatial clustering in three regions, (i) Karakoram, Pamirs and Western Kunlun Shan (~50 surges), (ii) Svalbard (~25) and (iii) Yukon/Alaska (~9), with only a few other scattered surges elsewhere. This spatial clustering is significantly more pronounced than the overall global clustering of known surge-type glaciers. The 2017–22 clustering may point to climatic forcing of surge initiation.

• Holmlund, Erik Schytt (2020). Aldegondabreen glacier change since 1910 from structure-from-motion photogrammetry of archived terrestrial and aerial photographs: Utility of a historic archive to obtain century-scale Svalbard glacier mass losses. Journal of Glaciology. ISSN 0022-1430. doi: 10.1017/jog.2020.89. Fulltekst i vitenarkiv
• Kirchner, Nina; Noormets, Riko; Kuttenkeuler, Jakob; Erstorp, Elias Strandell; Holmlund, Erik Schytt & Rosqvist, Gunhild Ninis [Vis alle 9 forfattere av denne artikkelen] (2019). High-resolution bathymetric mapping reveals subaqueous glacial landforms in the Arctic alpine lake Tarfala, Sweden. Journal of Quaternary Science. ISSN 0267-8179. 34(6), s. 452–462. doi: 10.1002/jqs.3112. Fulltekst i vitenarkiv
• Holmlund, Erik Schytt & Holmlund, Per (2019). Constraining 135 years of mass balance with historic structure-from-motion photogrammetry on Storglaciaren, Sweden. Geografiska Annaler: Series A, Physical Geography. ISSN 0435-3676. 101(3), s. 195–210. doi: 10.1080/04353676.2019.1588543. Fulltekst i vitenarkiv
• Hodson, Andrew J.; Nowak, Aga; Redeker, Kelly Robert; Holmlund, Erik Schytt; Christiansen, Hanne H & Turchyn, Alexandra V. (2019). Seasonal Dynamics of Methane and Carbon Dioxide Evasion From an Open System Pingo: Lagoon Pingo, Svalbard. Frontiers in Earth Science. 7(Art. 30). doi: 10.3389/feart.2019.00030. Fulltekst i vitenarkiv Vis sammendrag

  The processes associated with the release of CH4 and CO2 from sub-permafrost groundwaters are considered through a year-long monitoring investigation at a terrestrial seepage site in West Spitsbergen. The site is an open system pingo thought to be associated with the uplift of a former sea-floor pockmark in response to marked isostatic recovery of the coastline following local ice sheet loss over the last 10,000 years. We find that locally significant emissions of CH4 and (less so) CO2 to the atmosphere result from a seepage <1 L s−1 that occurs all year. Hydrological and meteorological conditions strongly regulate the emissions, resulting in periodic outbursts of gas-rich fluids following ice fracture events in winter, and significant dilution of the fluids in early summer by meltwater. Evasion of both gases from a pond that forms during the 100 days summer (45.6 ± 10.0 gCH4-C m−2 and 768 ± 211 gCO2-C m−2) constitute between roughly 20 and 40% of the total annual emissions (223 gCH4-C m−2 a−1 and 2,040 gCO2-C m−2 a−1). Seasonal maximum dissolved CH4 concentrations (up to 14.5 mg L−1 CH4) are observed in the fluids that accumulate beneath the winter ice layer. However, seasonal maximum dissolved CO2 levels (up to 233 mg L−1) occur during late summer. Differences between the δ13C-CH4 composition of the winter samples [average 58.2 ± 8.01‰ (s.d.)] and the late summer samples [average 66.9 ± 5.75‰ (s.d.)] suggest minor oxidation during temporary storage beneath the winter ice lid, although a seasonal change in the methane source could also be responsible. However, this isotopic composition is strongly indicative of predominantly biogenic methane production in the marine sediments that lie beneath the thin coastal permafrost layer. Small hotpots of methane emission from sub-permafrost groundwater seepages therefore deserve careful monitoring for an understanding of seasonal methane emissions from permafrost landscapes.

Se alle arbeider i NVA

• David, Harcourt, William; Pearce, Danni M; Wojciech, Gajek,; Harold, Lovell,; Mannerfelt, Erik Schytt & Kääb, Andreas [Vis alle 10 forfattere av denne artikkelen] (2025). Svalbard Surge Database 2024 (RGI2000-v7.0-G-07). doi: 10.5281/zenodo.15240754. Fulltekst i vitenarkiv Vis sammendrag

  We have developed a new database of surge-type glaciers in Svalbard by combining existing compilations and reviewing studies examining their dynamics. Our database is based upon the Global Land and Ice Measurements from Space (GLIMS) database (König et al. 2014), which is now incorporated into RGI 7.0 (RGI 7.0 Consortium 2023) and consists of 1,583 glaciers in Svalbard. Therefore, the first five fields come from the RGI 7.0 database: rgi_id: Glacier ID from RGI database. glims_id: Glacier ID from GLIMS database. cenlon: Longitude of glacier centre point. cenlat: Latitude of glacier centre point. glac_name: Name of glacier. Our compilation of existing Svalbard-wide glacier surge databases is sourced from several studies: Lefauconnier and Hagen (1991) [LH1991]; Hagen et al. (1993) [H1993]; Sevestre and Benn (2015) [SB2015]; Farnsworth et al. (2016) [F2016]; Kääb et al. (2023) [KA2023]; and Koch et al. (2023) [KO2023]. The compilation of LH1991 only covers eastern Svalbard and is focused on marine-terminating glaciers but is included as it contains several important details on surge characteristics. H1993 is the original database of glaciers across Svalbard and similarly contains details of historical surges. The current RGI 7.0 database defines the “surge status” of each glacier according to Sevestre and Benn (2015): no evidence of surging (0); possible surge (1), probably surge (2), and observed surge (3). Where the SB2015 database does not have corresponding evidence from one of the other compilations, we determine the glaciers surge status to be ‘undefined’ and do not include it in the S_All field. The F2016 compilation was manually translated into the RGI 7.0 database. The glacier names described in F2016 often referred to tributaries which are now combined into single glacier catchments (e.g., Nuddbreen / Strongbreen), hence we manually combined these entries. The recent compilations from KA2023 and KO2023 were manually transcribed from tables in PDF files. The subsequent eight fields document each compilation: SB2015: Surge database from Sevestre and Benn (2015). [0-3] F2016: Surge database from Farnsworth et al. (2016). [0-1] H1993: Surge database from Hagen et al. (1993). [0-1] LH1991: Surge database from Lefauconnier and Hagen (1991). [0-1] KA2023: Surge observations from Kääb et al. (2023). This data set is based on manual surge identification in annual Sentinel-1 interferometric wide-swath (IW) satellite radar backscatter differences between 2017 and 2022 (Kääb et al. 2023). This has been updated in this database (version 3) by mapping more recent surges from winter-to-winter differences 2022-2023, 2023-2024, and 2024-2025 using new IW data. Before 2017, no Sentinel-1 IW data are available over Svalbard, and we use 2015-2016 and 2016-2017 extended wide-swath data (EW) instead, acknowledging that these coarser data (compared to IW) might lead to less detailed surge identification, or overlooking of surges of small glaciers or surges accompanied by only limited backscatter changes. Based on these additional data, we are also able to update some surge information contained in the original KA2023, for instance concerning surge start and end years, and by adding the last year of strongly enhanced backscatter (before backscatter reduction). The new 2015-2025 backscatter-derived surge inventory over Svalbard contains now 40 surging glaciers (the 2017-2022 KA2023 contained 26 surging glaciers). [0-1] KO2023: Surge observations from Koch et al. (2023). [0-1] Other: Surge observations from other literature sources. [0-1] S_Direct: All surges that have been directly observed. [0-1] S_Indirect: All surges that have been indirectly observed e.g. from palaeo-glaciological analysis. [0-1] S_All: All surges that have been either directly observed or inferred from the palaeo-glaciological record. [0-1] Contemporary and palaeo-glaciological evidence of surges is generally limited to the period ~1850–present, which broadly corresponds to the end of the LIA through to the modern-day. Where multiple surges have been recorded, we separate these using “;” in the database, and use “n/a” where the details of the surge have not been recorded. Surges have been classified as a binary 0 (not surge-type) or 1 (surge-type), with the exception of the Sevestre and Benn (2015) database as described above. The subsequent eight fields document (if known) the following characteristics for each glacier in Svalbard: S_Onset: Surge Onset (Year) S_Term: Surge Termination (Year) S_Act_Vel: Max Active-Phase Velocity (m/d) S_Qui_Vel: Mean Quiescence Velocity (m/d) S_Term_Ch: Terminus Change (m) Here, we use 'n/a' for glaciers with no evidence of surging, whilst 'Not observed' is used where we have not observed any of the above characteristics for a glacier with evidence of surging. The final column contains references to where surges have been reported. Included in this version is also a version of the RGI for Svalvard with the new database included.  

• Kleber, Gabrielle Emma; Hodson, Andrew; Magerl, Leonard; Mannerfelt, Erik Schytt & Turchyn, Alexandra (2025). Methane emissions driven by glacier retreat. Fulltekst i vitenarkiv
• Kleber, Gabrielle Emma; Mannerfelt, Erik Schytt; Schloemer, Stefan; Hensgens, Geert; Enzenhofer, Ursula & Magerl, Leonard [Vis alle 10 forfattere av denne artikkelen] (2025). Assessing the roles of geology and glacier thermal regime on subglacial methane release. Fulltekst i vitenarkiv Vis sammendrag

  Rapidly rising air temperatures in the Arctic have cascading effects due to the temperature sensitivity of high latitude environments. Glacier melt and permafrost thaw initiate feedback loops that can lead to increased natural emissions of methane, a powerful greenhouse gas, thus amplifying the warming trend. The anoxic environment of a glacier bed facilitates the microbial production of methane from buried organic carbon. Additionally, thermogenic methane from geologic reservoirs can migrate to the subglacial environment through fractures in the bedrock. Increased meltwater production during glacier retreat may enhance the release of this methane that has accumulated at the glacier bed. While measurements are scarce, methane emissions driven by glacial meltwaters are expected to be widespread and largely undocumented throughout the Arctic. We undertook an extensive field study to establish the pervasiveness of these emissions in glacier catchments on Svalbard and to determine the factors, such as geology and glacier thermal regime, that may govern the magnitude of emissions. Covering a range of geological settings and landterminating glacier sizes, we measured aqueous methane concentrations and the stable carbon isotopic composition of methane in transects along the lengths of 19 glacial rivers across central Spitsbergen. In addition, we used ground penetrating radar to assess the thermal regime of the glaciers. Our measurements confirm that proglacial rivers are super-saturated with methane across the entire central Spitsbergen region and that the methane is largely of geologic origin. We extrapolate our measurements to roughly estimate a total seasonal methane flux from glacial rivers across Svalbard. Our findings are also used to identify the factors that control the extent of methane supersaturation in glacier meltwaters, which will help pinpoint other glaciated regions of the world that may be hotspots for methane release

• Kleber, Gabrielle Emma; Mannerfelt, Erik Schytt; Schloemer, Stefan; Hensgens, Geert; Magerl, Leonard & Hollander, Jamie [Vis alle 8 forfattere av denne artikkelen] (2025). Field studies of glacial methane seeps on Svalbard. Fulltekst i vitenarkiv Vis sammendrag

  Rapidly rising air temperatures in the Arctic have cascading effects due to the temperature sensitivity of high latitude environments. Glacier melt and permafrost thaw initiate feedback loops that can lead to increased natural emissions of methane, thus amplifying the warming trend. A substantial lack of understanding exists around the temperature-dependent mechanisms of methane release in the Arctic, largely due to the difficulty of accessing these remote regions and the consequent scarcity of measurements. Through spatial and temporal field studies, the GlaciGas project is expanding our understanding of Arctic methane emissions in glacial environments, both onshore and offshore. Throughout the summers of 2023 and 2024, we measured methane concentrations in transects along the melt rivers of 19 Svalbard glaciers. We found methane to be supersaturated in all rivers, up to 425 times greater than the atmospheric equilibrium concentration, indicating that these rivers flush a substantial amount of methane from the glacier bed and act as a net source of methane to the atmosphere. Our findings will help determine the factors that govern subglacial methane release in the terrestrial environment. To understand the dynamics of methane release in the marine environment, we conducted monthly surveys of methane in fjord waters at the margin of a tidewater glacier. Our findings from February-September 2024 show consistently methane-supersaturated surface waters, likely due to methane-rich groundwater seeps at the sea floor. With the use of acoustics and ROVs in 2025, we aim to identify the mechanisms of this release.

• Schuler, Thomas; Nanni, Ugo; Bouchayer, Coline Lili Mathy; Åkesson, Henning; Lefeuvre, Pierre-Marie & Mannerfelt, Erik Schytt [Vis alle 9 forfattere av denne artikkelen] (2024). Observed weakening of glacier ice-bed interface caused by climatic and hydro-mechanical feedbacks: towards glacier-wide acceleration? Fulltekst i vitenarkiv Vis sammendrag

  Stronger and more widespread surface melt may alter the flow of glaciers and ice sheets and trigger instability. However, observational deficiencies hamper our ability to better understand and thus predict such responses. We deployed surface and borehole seismometers along the centerline of a High Arctic glacier in Svalbard. The records span over six years and are analyzed in relation to the measured increase of surface velocity. We complement our seismic analysis (icequakes and seismic noise) with long-term measurements of glacier-surface velocity, surface-elevation changes, and runoff modeling. Since 2000, we observe glacier thinning and steepening, coinciding with acceleration of up to 1000%. In response, new crevasses have opened and provide access pathways for surface melt water to the base of the glacier, affecting the ice-bed coupling. This mechanism represents a positive hydro-mechanical feedback that fuels further acceleration and crevassing. This feedback may have wider implications for triggering of glacier-wide instabilities, increasing short-term sea-level rise and local hazards. Beyond the Arctic, we suggest that, under a warming atmosphere, glaciers may transition from stable to unstable flow through such a mechanism.

• Kleber, Gabrielle Emma; Hodson, Andrew; Magerl, Jasper Leonard & Mannerfelt, Erik Schytt (2023). Enhanced methane emissions due to glacial retreat in the high Arctic. Fulltekst i vitenarkiv
• Mannerfelt, Erik Schytt (2026). Glacier Surge Dynamics in a Warming Arctic. Universitetet i Oslo. Fulltekst i vitenarkiv Vis sammendrag

  Glaciers are iconic climate indicators, and affect sea-level rise and local downstream environments, as they presently lose mass globally at an accelerated pace. There is still a large uncertainty in the dynamic and geometrical responses of many glaciers to climate change, being difficult to model and predict in detail. Frictional instabilities, such as glacier surges, speed up momentary mass loss, create hazards, and their complexities reveal fundamental gaps in our knowledge of basal friction. Understanding them further requires more data on where, when and how surges and other members of the spectrum of instabilities develop. This thesis is the summation of multi-method approaches to surge detection and characterization that have previously been difficult at regional and global scales. The main projects surround interferometric synthetic aperture radar and high-resolution elevation change estimation to quantify surge propagation and active phase dynamics, and ground-penetrating radar to reveal thermal characteristics that may drive the behavior. Most of the work surrounds the archipelago of Svalbard, as a rapidly warming Arctic representative, but secondary projects take the thesis to a pan-Arctic and global scope. The results paint a new picture on the effects of climate change, as Svalbard has experienced a threefold increase in recent surging, despite an often seen inability to regain reservoir mass. This raises questions on the possibility of regional populations of unrecoverable surges, where these events may add a substantial negative bias to future mass prognoses. The wide variability of unstable behavior that is observed in Svalbard and elsewhere support the perspective of seeing surges as just one member of a wider instability spectrum. Future improvements, of which many are outlined in this thesis, in observation and modeling may therefore yield further insight in how frictional instabilities may relate to climate change at all temporal and spatial scales.

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