29 March 2026 | 13:15 - 15:00 CEST / UTC+2
Open Session - HYBRID
Room: Jeppe Vontilius Auditorium
Session Description:
This session highlights the changing Arctic cryosphere, including glaciers, permafrost, snow and sea ice. It considers how cryospheric change affects sea level, ecosystems and communities, and how observations and modelling help assess current trends and future risks.
Keynote: Prof. Hanne H. Christiansen
Oral presentations:
Name: Nishchal Baniya (EVEREST SUSTAINABILITY FOUNDATION)
Title of presentation: Sustained Glacier Mass Loss and Hydrological Shift in the Nepal
Abstract text: The Hindu Kush Himalaya (HKH), the Third Pole, faces systemic cryospheric collapse due to regional warming of 0.28°C per decade (derived from ground station networks and RCM reanalysis). This study assesses integrated cryospheric change within Nepal's major glaciated river basins. Multi-decadal geodetic mass balance analysis (using the DEM-of-Difference technique on satellite-derived DEMs) confirms unprecedented acceleration: glaciers melted 65% faster during 2011–2020 than the previous decade. This sustained loss results in mean specific mass balance deficits of approximately -0.65 m w.e. per year across the region. Hydro-climatic risks are intensifying: the HKH Snow Update 2025 reports seasonal snow persistence as 23.6% below normal (a 23-year low, based on satellite products and glacio-hydrological modeling), critically threatening late-season river flows for agriculture and hydropower. The rapid proliferation of unstable glacial lakes poses an acute Glacial Lake Outburst Flood (GLOF) threat. A catastrophic example occurred in July 2025 in the Bhotekoshi Basin, where a GLOF (from a supraglacial lake that peaked at 638,000 m2 in size) caused extensive infrastructural damage. This single event led to financial losses exceeding Rs 5 billion and halted approximately 600 MW of hydropower generation across 10 critical projects. These scientifically documented, accelerating changes mandate urgent policy integration, climate finance mobilization, and structural mitigation strategies for regional resilience.
Name: Valentina Ekimova (University of Virginia)
Title of presentation: Urban Effects on Snow Retention and Melt in Utqiaġvik from Satellite Observations
Abstract text: Thawing permafrost across the Arctic is reshaping landscapes and increasing risks for communities. Snow strongly controls how fast and where this thaw progresses, because its low thermal conductivity and high albedo regulate heat exchange between air and ground. In Arctic towns, snow conditions are highly variable and difficult to monitor, and standardized methods for mapping snow depth and albedo at community scales remain limited. We address this gap using high-resolution Sentinel-2 imagery and field observations from Utqiaġvik, Alaska, to track seasonal snow dynamics and assess how infrastructure and snow management modify snow cover.We derive snow cover from the Normalized Difference Snow Index (NDSI), albedo using the broadband conversion of Liang et al. (2001), and snow depth from NDSI-based models implemented in ArcGIS Pro. Satellite-based snow depth is calibrated and evaluated with depth measurements and Snow Water Equivalent collected in April and May 2025 using Snowmetrics instruments. To quantify urban effects, we group results by building density using kernel density estimation.Using satellite imagery, we observed clear seasonal patterns in the study area. From April to June 2023, starting from nearly complete snow cover, more than 60 percent of the snow was lost, accompanied by a major decline in albedo. Areas with higher building density showed shallower snow and faster melt, while open tundra retained thicker, brighter snow for longer. Ground data confirmed that high-density zones lost about 22 percent more snow cover than lower-density areas over the same period. Local snow management practices, such as fencing and snow piling, created patches of persistent snow that modified ground insulation and influenced permafrost conditions.This study demonstrates a transferable remote sensing framework for urban Arctic environments, improving permafrost model inputs and supporting community-scale understanding of snow, infrastructure, and climate interactions.
Name: Joost van Genuchten (The Arctic University of Norway - Centre for Ice, Cryosphere, Carbon and Climate)
Title of presentation: Methane dynamics of proglacial lakes in Greenland
Abstract text:Methane, a potent greenhouse gas, is increasingly recognised to be emitted from newly deglaciated environments, particularly in the Arctic. Yet due to data scarcity, these sources remain underrepresented in global methane budgets. Deglaciation leads to the expansion of proglacial terrains, driving the formation of an increasing number of proglacial lakes worldwide, especially in Greenland. Small to medium sized glacial lakes, formed by glacial processes, typically contain organic-poor minerogenic sediments and exhibit relatively low diffusive and ebullitive methane emissions compared to other types of Arctic lakes. However, recent evidence from southwest Greenland suggests glacier-fed lakes (GFL) may produce disproportionally high methane ebullition fluxes compared to glacial lakes that are hydrologically disconnected from glacial meltwater (non-GFL). It is hypothesized that glacially derived sediments and meltwaters influence the biogeochemistry of proglacial lake environments, altering methane production dynamics. We sampled 18 proglacial lakes in the ice-marginal terrain of southwest and southeast Greenland. Our methodological approach included lake sediment coring, geo- and hydro-chemical analyses, gas measurements, and phylogenetic microbial analyses. Preliminary results indicate that GFL and non-GFL can sustain similar methane concentration profiles within lake sediments and water. In addition, methane depth profiles and geochemistry reveal distinct layers and active production zones, highlighting complex methane dynamics. Further analyses focus on identifying carbon sources and environmental factors that control methane production. As the number of proglacial lakes is increasing, there is a growing need to understand methane emissions from these systems. This research aims to identify key drivers of methane production, reduce uncertainties in global budgets, and improve predictions of the potential significance of methane emissions from proglacial lakes as deglaciation continues.
Name: Ahra Mo (Korea Polar Research Institute)
Title of presentation: Arctic and Subarctic Pteropods as Indicators of Ocean Acidification Stress
Abstract text: The Subarctic and Arctic oceans represent some of the most sensitive areas to ongoing ocean acidification, making shelled pteropods valuable sentinels of environmental change. In 2017, we collected Limacina helicina and accompanying seawater samples across these regions to explore how shell characteristics respond to varying carbonate conditions. Our observations showed pronounced regional differences in body size, with Arctic individuals reaching nearly twice the size of those found in the Subarctic. Analyses further revealed that both the developmental stage of the organisms and the degree of aragonite undersaturation play key roles in determining shell density. Even under comparable aragonite saturation states, shell density consistently declined as individuals advanced through their life stages. These results highlight the need to better understand how multiple stressors interact across ontogeny and emphasize the importance of life-stage–specific responses when evaluating the vulnerability of pteropods to ocean acidification.
Name: Thomas Erni (National Physical Laboratory)
Title of presentation: Quantifying Uncertainty in Sea Ice Thickness: A Metrological Approach
Abstract text: Sea ice is an essential climate variable that plays a crucial role in climate regulation of polar regions. It reflects incoming solar radiation and provides a stable platform for the formation of snow, which in turn offers a habitat for animals to live due to the snow’s low thermal conductivity. Satellite altimetry is the main method used for evaluating sea ice thickness, as it offers high temporal and spatial coverage. Sea ice measurements obtained from satellite altimetry are challenging to validate since there are limited non-satellite measurements available for comparison. The comparison between satellite and non-satellite datasets is also complicated by differences between the measurands of the different datasets (freeboard, thickness, draft), scaling issues, spatial and temporal representativeness, and by the motion of sea ice. Here, we present work to develop a rigorous metrological understanding of the uncertainties associated with both satellite and non-satellite sea ice thickness measurements. The uncertainties have been summarised and documented within uncertainty tree diagrams, and we have developed sea ice uncertainty propagation software. The software evaluates the associated total combined uncertainty on sea ice thickness using both Monte-Carlo (MC) and Law of Propagation of Uncertainties (LPU) methods. This presentation describes the differences between MC and LPU methods, the dominant sources of uncertainty in the sea ice equation and any other related effects. The uncertainty analysis work will be described in the context of projects that validate satellite datasets including those of CryoSat-2, Sentinel 3 and CRISTAL. (Projects: St3TART/St3TART-FO, CRISTAL IN-PROVA, Met4EO, QA4EO, SIN’XS). We will also show how the metrological approach to uncertainties benefits the scientific studies of the ArcFresh project, which is investigating the closure of the Arctic Ocean freshwater flux budget.