1.5. Rapid Changes in the Arctic and their Interactions with the Global Climate Systems: Observations, Driving Forces, and Social Consequences

26 March 2025 | 13:30 - 15:30 (MDT) - Part 1

Room:  Glen Miller Ballroom - UMC 208

27 March 2025 | 10:30 - 12:00 (MDT) - Part 2

Room:  UMC Second Floor 247

Open Session - HYBRID

Organisers:  Xiangdong Zhang (North Carolina State University, USA); Elana Wilson Rowe (Norwegian Institute of International Affairs, Norway); Archana Dayal (Aberystwyth University, UK); Seong-Joong Kim (Korean Polar Research Institute, Republic of Korea); Céline Rodrigues (Universidade Nova de Lisboa, Portugal)

Session Description:

Rapid changes have occurred across the Arctic climate system, driving it to a new state. Outstanding examples include amplified warming at a rate faster than anywhere over the globe, largely increased ocean temperatures at the surface and in the deeper layers, drastic sea ice decrease in both extent and thickness throughout the year, accelerating Greenland Ice Sheet melt, intensifying hydrological cycle, thawing of permafrost, increase in methane release, and more frequent occurrence of extreme events. All of these changes have been projected to continue in the future. Along with these changes, interactions across the climate components within the Arctic and between the Arctic and lower latitudes have strengthened. Positive feedbacks between the Arctic climate components can be triggered or enhanced to accelerate the Arctic changes. The changed Arctic can alter global atmospheric and oceanic circulations to increase heat energy transport into the Arctic, adding an additional driving force. On the other hand, the altered atmospheric and oceanic circulations influence the climate and weather outside the Arctic, causing extreme events. All of these changes and events have significantly impact daily life, infrastructure, and broader socio-economic activities.

This session will present new research progresses on the topic and serve as a venue to promote an engagement of the Arctic and global communities into the ICARP IV research priority planning. The presentations and discussions will also provide input to the Research Priority Team 1 activities for the identification and recommendation of research priorities, which make foundational contributions to all other research priority teams.

Oral Presentations - Part 1 on 26 March: 

• unfold_moreArctic sea ice evolution in recent climate assessments and updates: A brief overview — Sebastian Gerland

  Sebastian Gerland ¹; Walter N. Meier ^{2
  1} Norwegian Polar Institute; ² National Snow and Ice Data Center, CIRES/University of Colorado

  Format: Oral in-person

  Abstract:

  Climate assessments focusing mainly or partially on polar climate, Arctic climate and Arctic sea ice, are issued and updated regularly. Choices what is shown on Arctic sea ice varies, depending on assessment type. Here we give a brief overview on climate-related assessments featuring Arctic sea ice. Among short-timescale updates with days to months intervals, the NSIDC, University of Bremen, and the Norwegian Meteorological Institute show the development of Arctic sea ice extent, some including regional scales. NSIDC discusses monthly changes, and, using online tools, developments can be compared with previous years. Annual updates of the sea ice situation in the Arctic are given in a section of the NOAA Arctic Report Card, issued each December, which also includes an assessment of the ice thickness development. Another publication that includes a view on sea ice in a year is the WMO State of the Global Climate report. Assessments appearing less often than annually are the AMAP climate updates and the IPCC assessment reports, both results of longer writing processes, lasting several years. All mentioned updates or assessments include presentations of Arctic sea ice extent or area, based on satellite data, obtained since 1979. More detailed assessments address also changes of sea ice thickness, age, and drift speed. Some information can only be found in detail in the rather extensive IPCC and AMAP assessments, such as changes in snow cover, future projections, context within historic and paleo time scales, effects for ecosystem and society, and attribution of Arctic sea ice changes.

• unfold_moreSeasonality and scenario dependence of rapid Arctic sea ice loss events in CMIP6 simulations — Annelies Sticker

  Annelies Sticker ¹; Francois Massonnet ¹; Thierry Fichefet ¹; Alexandra Jahn ^{2
  1} Earth and Life Institute, Earth and Climate UCLouvain, Louvain-la-Neuve, Belgium; ² Department of Atmospheric and Oceanic Sciences and INSTAAR, University of Colorado Boulder

  Format: Oral in-person

  Abstract:

  The decline in summer Arctic sea ice extent that has been underway for several decades is set to continue until summer Arctic sea ice disappears completely by the middle of the century, according to the latest climate projections. Based on observations and these climate model projections, the rate at which sea ice is retreating is not linear: the decrease in the Arctic sea ice cover is marked by periods of abrupt sea ice decline. Specifically, it has been suggested that these rapid ice loss events (RILEs) will become a frequent phenomenon in the coming decades. The causes of such events remain poorly understood and we are still unable to reliably predict their evolution. Furthermore, investigations are needed to gain a better understanding of the possible impacts of Arctic RILEs. The rate and manner of sea ice decline affect the ability of ecosystems and societies to adapt to these rapid changes. It is critical to improve the understanding of the conditions favoring rapid losses of Arctic sea ice. Therefore, we conduct an inventory of these events using the latest available climate projections from the CMIP6 database. While RILE occurrence persists year-round in model simulations, differences in timing and persistence occur between winter/spring and summer/fall. Our study stresses the importance of improving prediction for summer months, given projections of a seasonally ice-free Arctic, potentially accelerated by RILEs in the near future. Additionally, the probability of RILEs in winter and spring underscores the importance of emission reductions.

• unfold_moreFrom flakes to floes: snow in the changing Arctic sea-ice system — Melinda Webster

  Melinda Webster ^{1
  1} University of Washington

  Format: Oral in-person

  Abstract:

  Snow is the most reflective, and also the most insulative, natural material on Earth. As a consequence, it is an integral component of the sea ice and Earth’s climate systems. For Arctic sea ice, snow’s high albedo greatly reduces solar absorption, which mitigates sea ice melt and ocean warming in summer, whereas snow's insulating properties in winter inhibit sea ice growth and atmospheric warming. Knowing when and where snow is present on sea ice is therefore of great importance for understanding the functioning of the Arctic and global climate systems. In this work, we highlight recent advances in observing snow on Arctic sea ice, present the 1954-2024 trend in snow depth from newly merged observations, reveal key atmospheric-oceanic drivers of snow depth variability and associated albedo effects, and end with Earth system model projections of the snow-ice system under different climate scenarios. Drawing on these results and community input, we conclude with priority knowledge gaps on the Arctic snow-ice system and recommendations for addressing them. These recommendations include stronger coordination across the observational, remote sensing, and modeling communities, collecting process-oriented observations for model diagnostics and understanding coupled feedbacks, and improving remote sensing capabilities of large-scale monitoring of snow on sea ice for interdisciplinary and societal applications.

• unfold_moreAn assessment of the role of Arctic sea-ice loss in Arctic amplification — Eui-Seok Chung

  Eui-Seok Chung ¹; Seong-Joong Kim ¹; Kyung-Ja Ha ²; Sun-Seon Lee ^{3
  1} Korea Polar Research Institute; ² Pusan National University; ³ IBS Center for Climate Physics

  Format: Oral in-person

  Abstract:

  The near-surface warming response to greenhouse gas forcing is greatest in the Arctic in both observations and model simulations. This phenomenon, commonly referred to as Arctic amplification, is simulated even without surface albedo feedback, which implies that Arctic sea-ice loss may not play a major role in Arctic amplification. However, previous studies showed that longwave feedback processes and/or poleward energy transport, suggested as a primary process responsible for Arctic amplification, might not be independent of Arctic sea-ice loss and related radiative flux changes. Hence, it is unclear whether the characteristics of Arctic amplification can be fully explained by longwave feedback processes and/or enhanced poleward energy transport without Arctic sea-ice loss. In this study, by analyzing a range of model simulations, we show that Arctic sea ice is an indispensable component of the current Arctic amplification regime, although it may not be a trigger of Arctic amplification. Our results imply that the characteristics of Arctic amplification might change considerably in a much warmer future climate.

• unfold_moreIdentifying Energy Balance Drivers and Feedbacks of Greenland Ice Sheet Surface Melt Using Causal Inference — Ziqi Yin

  Ziqi Yin ¹; Aneesh Subramanian ¹; Rajashree Datta ²; Adam Herrington ³; Danni Du ⁴; Sahara Ali ⁵; Jianwu Wang ^{6
  1} University of Colorado, Boulder; ² Delft University of Technology; ³ National Center for Atmospheric Research; ⁴ Princeton University; ⁵ University of North Texas; ⁶ University of Maryland Baltimore County

  Format: Oral in-person

  Abstract:

  The mass loss from the Greenland Ice Sheet (GrIS) has accelerated during the past decades, with surface mass balance (SMB) decrease becoming the dominant contributor due to enhanced surface melt. SMB directly results from the complex interactions and feedbacks between the ice sheet and the atmosphere across different time scales. The relevant processes could be nonlinear, and their exact causal dependencies cannot be detected in conventional correlative approaches. Causal inference can extract underlying physically plausible networks from these interactions and allow us to focus on fewer highly relevant dependencies, thus delivering better interpretability. In this study, we investigate causal links among the key processes that contribute to the summer surface melt of the GrIS across different time scales with causal inference. First, the causal discovery method PCMCI+ is applied to the outputs of historical CESM2 simulations. Significant energy balance drivers and related feedbacks to surface melt during summer will be identified with quantified strength and time lag. The resulting causal graph is evaluated by comparing to the graphs derived from high-resolution regional climate model and firn model outputs. Then we apply the same method to identify the causal dependencies in the outputs of CESM2 simulations under a future warming scenario, and the potential changes of the melt regime under global warming are estimated.

• unfold_moreMethanogenic activity in debris piles on the surface of a High Arctic glacier — Archana Dayal

  Archana Dayal ^{1
  1} Postdoctoral researcher, Aberystwyth University, UK

  Format: Oral in-person

  Abstract:

  With the ongoing recession of glaciers, debris entrained within glaciers is being advected to the surface, potentially hosting methanogenic microbial communities. To test this hypothesis, fieldwork was conducted on Foxfonna glacier in Svalbard (High Arctic) over a three-month period from June to August 2023. Eight surveys were performed to measure methane (CH₄) and carbon dioxide (CO₂) fluxes from conical and flat debris piles situated on the glacier surface across three sites. On-site monitoring of methane and carbon dioxide was conducted using a Los Gatos analyzer and a 20-litre chamber. Preliminary data processing involved pre-processing raw CH₄ and CO₂ measurements and developing optimized regression models for the entire dataset. Additionally, incubation experiments were conducted to understand the pathways of methanogenesis within the microbial community. Debris samples were incubated under anoxic conditions, amended with acetate, and maintained at field temperatures. Significant concentrations of methane were also found on glaciers in Ny-Ålesund, suggesting that this is likely a widespread phenomenon. The novelty of this study lies in the first documentation of surface methanogenesis on a glacier surface. The findings underscore the importance of considering microbial activity in glacial debris when assessing the impact of glacier retreat on global methane budgets, as such processes and fluxes have been previously unaccounted for.

• unfold_moreDynamics of the Beaufort Gyre Freshwater Content Trends — Subrahmanyam Bulusu

  Subrahmanyam Bulusu ^{1
  1} University of South Carolina, USA

  Format: Oral in-person

  Abstract:

  Freshwater has changed more frequently in the Arctic Ocean in recent years due to differing rates of sources and exports especially within the BG. Depending on the gyre’s characteristics such as its strength and vertical movement, changes the increase or decreasing amount of freshwater added. In the last few decades, the BG has experienced anomalous freshening followed by its stabilization between 2007-2008. We will use available satellite derived salinity data from NASA's Soil Moisture Active Passive (SMAP), ESA's Soil Moisture and Ocean Salinity (SMOS), and recently launched NASA's Surface Water and Ocean Topography Mission (SWOT) altimetry data. Due to the lack of in situ and satellite observations in the BG, we use the Ocean Reanalysis System version 5 (ORAS5) to compare with in situ and satellite data. This study focuses on the years in which the BG retained more fresh water than averaged over the 1989-2023 period. This period follows years when the gyre is thought to have stabilized or slowed down its freshwater accumulation. By observing the air-sea interactions and the subsurface characteristics, we can identify features connected to abnormal freshening and understand the BG better. This study examines the dynamics of the BG between 1989 and 2023, especially in the anomalously fresher years of 2011, 2016, 2017, and 2018, in which the BG’s suggested stabilization. This study provides insight into the important dynamics linked to anomalous freshening within the BG during recent years with broader implications for the potential buildup or release of freshwater to adjacent seas.  

• unfold_moreUnderstanding the Beaufort Gyre’s Role in Modulating Flow through Bering Strait — Annika Margevich

  Annika Margevich ¹; Mary-Louise Timmermans ²; Seth Danielson ^{3
  1} Yale University; ² Department of Earth and Planetary Sciences, Yale University; ³ College of Fisheries and Ocean Sciences, University of Alaska Fairbanks

  Format: Oral in-person

  Abstract:

  The flow through Bering Strait, connecting the Pacific Ocean to the Arctic Ocean, has been increasing by ~ 0.01 Sv/yr over the last three decades, where local processes and remote processes have been explored as potential drivers of this increase in transport. We analyze monthly satellite-derived Dynamic Ocean Topography (DOT) data, wind reanalysis, and sea ice data to show that changes in wind and sea ice concentration are not leading to significant changes in local surface stresses that would enhance northward geostrophic transport through Bering Strait. This suggests that remote processes are playing a more prominent role in driving the increased transport through Bering Strait. The strength and position of the Beaufort Gyre, an anticyclonic circulation system north of Canada, has also changed over the last few decades. We explore how changes in the Beaufort Gyre may modulate flow through Bering Strait using an analytical model. We examine the frontal boundary over the Chukchi region where fresher surface waters stored in the Beaufort Gyre meet the denser Pacific inflow over bottom topography that transitions from a shelf into a sloping bottom. We find that changes in the position of the front with respect to the shelf break influence the strength of the cross-isobath flow, which is a possible mechanism for halocline ventilation, and, therefore, a possible pathway for Pacific inflow to the interior Arctic Ocean. These changes in cross-isobath flow suggest that the Beaufort Gyre is subducting increased volumes of Pacific Water which requires increased volume transport through Bering Strait.

 

Oral Presentations - Part 2 on 27 March: 

• unfold_moreScenario Building for Communicating Future Ecological Extreme Events — James Overland

  James Overland ¹; Elizabeth Siddon ²; John Walsh ³; Muyin Wang ^{1,4
  1} NOAA Pacific Marine Environmental Laboratory; ² NOAA Alaska Fisheries Science Center; ³ Univeristy of Alaska Fairbanks; ⁴ University of Washington

  Format: Oral in-person

  Abstract:

  The greater Arctic is subject to an increasing number of an unprecedented extreme events. These include rapid/sudden sea-ice loss, heatwaves, wildfires, Greenland ice-sheet melt, storms, heavy rainfall/floods, and ecosystem movement and reorganization. We propose that an increased frequency of extreme events over the next decades, considering the interaction of internal variability with continued global warming. For example, the northern Bering Sea is undergoing major changes from shifts in storm tracks, increasing temperatures, extreme minimum sea-ice extent in 2018 and 2019, through an ecosystem reorganization due to changing food webs and predatory fish moving northward, to negative impacts on communities’ economic and subsistence food resources. After 2021 there was a return to more typical weather and sea-ice conditions. Societal implications of climate change assessment have multi-sectors: transportation, infrastructure, public health, food security, and livelihoods. Through scenario building one identifies critical future impacts and apply a sense of how these factors have interacted in the past using modeling and the limited data and might interact in the future. For the northern Bering Sea, we prioritize future changes in species composition that impact fisheries, harmful algal blooms, and increased severity of storms with coastal erosion. Arctic communities should prepare for such extreme intermittent events. We hypothesize that radically low sea ice will have a frequency of one to three 2018-like low sea-ice events per decade, based on a historical meteorological analysis and ensemble climate model projections. We expect multi-year impacts following single year physical extremes. Data collection is needed every year.

• unfold_moreArctic atmospheric rivers: historical trends and impact on wintertime Arctic warm extremes — Hailong Wang

  Hailong Wang ¹; Weiming Ma ¹; Yiling Huo ^{1
  1} Pacific Northwest National Laboratory

  Format: Oral in-person

  Abstract:

  Atmospheric rivers (ARs), long and narrow corridors of intense moisture transport in the atmosphere, are responsible for most of the poleward atmospheric moisture transport over mid-latitudes, suggesting their potential contribution to the Arctic warming. Arctic ARs can also trigger a wide range of weather extremes. Based on hourly reanalysis dataset, wintertime high-Arctic warm extremes are analyzed for 1980-2021. The atmospheric blocking patterns over the northern Eurasia are found to be a key ingredient in driving these events, as they can effectively deflect the eastward propagating cyclones poleward, facilitating intense moisture and heat intrusions into the high Arctic. Arctic ARs are further identified as the direct driver for most of these historical Arctic warm extreme events. Using reanalysis data and CMIP6 large ensemble simulations, we show that the observed Arctic AR frequency has increased twice as much over the Atlantic sector than the Pacific sector. In contrast, the Arctic AR trends in CMIP6 models, mostly externally forced, are spatially more uniform. This discrepancy between the observed and the CMIP6 simulated trends can be explained by the phase shift of the Interdecadal Pacific Oscillation (IPO) and Atlantic Multidecadal Oscillation (AMO) in recent decades. More specifically, the observed negative phase shift of IPO and positive phase shift of AMO both favor the increase of ARs over the Atlantic sector and the reduction over the Pacific sector. We will also present how the Arctic regionally refined meshes in Energy Exascale Earth System Model (E3SM) impact the model performance in simulating historical Arctic ARs.

• unfold_moreThe IPWP as a Capacitor for Autumn Sea Ice Loss in the northeastern Canada — Shiyuan Zhong

  Shiyuan Zhong ¹, Timo Vihma Shuoyi Ding ¹, Cuijuan Sui ¹, and Bo Sun ^{1
  1} Polar Research Institute of China

  Format: Oral virtual

  Abstract:

  The Indo-Pacific warm pool (IPWP) has been warming due largely to increasing greenhouse gas emissions, but its impact on Arctic sea ice loss </a>remains unclear. Our study analyzed long-term data and historical simulations from 49 CMIP6 models, finding a significant negative correlation between the IPWP strength and sea ice concentration in the broader Arctic region, encompassing the Hudson Bay, Baffin Bay and Labrador Sea in boreal autumn (October-December). Our results suggest that IPWP warming statistically accounts for 45% of sea ice loss observed in this region. We introduce the "Arctic capacitor effect of the IPWP" a novel concept that expounds upon the distant connection between greenhouse gas emissions and Arctic sea ice loss. Specifically, as greenhouse gases elevate temperatures in the IPWP, a planetary wavetrain is initiated, traversing towards the Arctic and thereby influencing the strength of the Arctic vortex. This intricate interplay ultimately triggers sea ice retreat. The validity of this concept is bolstered by controlled numerical experiments employing the Community Atmosphere Model Version 5 (CAM5). Our findings highlight the crucial role of tropical oceans in the broader context of global climate change, emphasizing the necessity of accounting for their impact on polar climate.

• unfold_moreRegional climate model simulations of the low-level jets at the Tiksi observatory (Laptev Sea, Siberia) and evaluation using SODAR observations — Guenther Heinemann

  Guenther Heinemann ¹; Clemens Druee ^{1
  1} University of Trier

  Format: Oral in-person

  Abstract:

  Low-level jets (LLJs) are important features in the Arctic climate system. The forecast of LLJs in polar regions is highly relevant for logistic operations, particularly for aircrafts, as well as for wind energy and air pollution transport. In the present paper, LLJs are investigated during 2014/15 at the Tiksi observatory in the Laptev Sea region. Besides the routine synoptic observations, data from a meteorological tower, and SODAR (Sound Detection And Ranging) data were available from October 2014 to September 2015. The SODAR yields vertical profiles of the wind speed and wind direction. These measurements are used to evaluate simulations performed with the regional climate model CCLM with 5 km resolution. Simulations are used establish an increased understanding of the formation and a climatology of LLJs.

  CCLM simulations agree well with near-surface and SODAR observations and represent the LLJ structures very well. Due to limitations of the SODAR, a full picture of the atmospheric boundary layer structure and LLJ events could be obtained only with the model data. The simulations show that LLJs at Tiksi occur in about 70% of all profiles. When only LLJs in the range of the SODAR and with wind speeds of less than 10m/s are considered, only about 20% of all profiles show LLJs, which is the same amount as found in the SODAR profiles. LLJs with at least 3h duration are simulated for the same days as the observations in about 80% of all cases.

• unfold_moreArctic Cyclones and Its Driving Role in the Rapidly Changing Arctic Climate System — Xiangdong Zhang

  Xiangdong Zhang ¹; Han Tang ¹; Jing Zhang ²; Erika Roesler ³; Benjamin Hillman ³; Wilbert Weijer ⁴; Milena Veneziani ^{4
  1} North Carolina State University; ² North Carolina Agricultural and Technical State University; ³ Sandia National Laboratories; ⁴ Los Alamos National Laboratory

  Format: Oral in-person

  Abstract:

  In conjunction with the amplified Arctic warming and drastically retreating sea ice, extremely intense cyclones have been more frequently observed throughout the year in the Arctic. These cyclone systems have also, in turn, enhanced air-sea-ice interactions, leading to transient warming and sea ice loss events and cumulatively contributing to the long-term Arctic climate changes. We conduct systematic analysis of Arctic cyclone activity from its climatic variability and changes to process-level studies on selected rare extreme cases using both reanalysis datasets and model simulations. The results indicate that Arctic cyclone activity, measured by an energy-based, integrative index, has intensified during last seven decades, which is supported by the CMIP6 model historical simulations. The underlying physical mechanisms are increased surface baroclinicity due to sea ice retreat and warmed open ocean, as well as the strengthened downward influence of the stratospheric vortex. When examining specific intense cyclone cases, it is found that intense summer cyclone can induce Ekman upwelling, transporting subsurface warm water to the upper ocean, and increase upper ocean mixing. As a consequence, summer sea ice melt accelerates. During winter, intense cyclones can trigger blowing snow, moisten the atmospheric boundary layer, and form low level clouds, favoring surface warming and sustaining polynya. Further analysis also suggests that higher model spatial resolution captures more numerous cyclones, which is important for understanding the finer-scale interactive processes between cyclones and the underlying sea ice and ocean.

• unfold_morePolar-to-midlatitude teleconnections in a warmer world: Statistical relationships from large ensembles — Carley Iles

  Carley Iles ¹; Bjørn Samset ¹; Marianne Lund ^{1
  1} CICERO Center for International Climate Research

  Format: Oral virtual

  Abstract:

  How are polar-to-midlatitude teleconnections represented in recent large ensembles of climate model simulations? And how do they evolve with global warming? Using the rich information on internal variability available from large ensembles, we investigate the relationship between sea ice amount and atmospheric circulation for both Arctic and Antarctic sea ice variability, in CESM2 and ACCESS-ESM1-5. We find that sea level pressure (SLP) and temperature teleconnections depend on the region in which Arctic sea ice decreases, for instance with low Barents-Kara sea ice in January being associated with a positive North Atlantic Oscillation SLP pattern and high pressure over Northern Eurasia. These patterns persist with increased levels of global warming, until around 3 or 4°C when they start to evolve in some cases, as sea ice starts to disappear. Surface air temperatures increase near the region of sea ice retreat with varying patterns of remote cooling elsewhere. For some regions, the SLP teleconnections persist in a weakened state for subsequent months (lag +1), whilst for others they evolve, e.g. into a negative Arctic Oscillation response for Barents-Kara sea ice reduction. However, the lagged responses differ in the two models examined. SLP responses to Antarctic sea ice are model dependent, but feature a negative SAM pattern in ACCESS-ESM1-5. In CESM2, we find a less zonally symmetric pattern which also consists of high pressure over the pole in Autumn and Winter.

 

Poster Presentations (during Poster Exhibit and Session on Wednesday 26 March):

• unfold_moreAssessing urbanization trends and surface heat island dynamics in selected Arctic cities — Liliia Hebryn Baidy

  Liliia Hebryn Baidy ¹; Gareth Rees ^{1
  1} Scott Polar Research Institute, University of Cambridge

  Format: Poster in-person

  Poster number: #47

  Abstract:

  The rising global temperatures and uncontrolled heat waves, largely driven by human activities over the past fifty years, are particularly pronounced in the Arctic a phenomenon known as Arctic amplification. Urbanization in Arctic settlements intensifies the Urban Heat Island (UHI) effect, where cities generate and retain more heat than rural areas. This has significant environmental and societal implications, including increased greenhouse gas emissions and threats to ecosystems. Our research analyses and compares the spatiotemporal distribution of surface urban heat islands (SUHI) in selected Arctic cities: Tromsø (Norway), Kiruna (Sweden), and Rovaniemi (Finland). We leverage multi-spectral remote sensing data from Landsat, MODIS, and Planet Scope satellites to investigate land surface temperature (LST) trends across diverse land use/land cover (LULC) types over four decades (1984-2024) to determine whether urbanization has influenced regional temperature increases. Additionally, incorporating climate data from the CRU TS dataset reveals broader air temperature trends, providing further insight into climate change. We aim to enhance LST analysis by improving the spatial resolution of maps, using high-resolution imagery to better delineate landscapes. Integrating digital elevation models will also improve temperature accuracy. These findings are critical for understanding the environmental impacts of urban expansion in climate-sensitive Arctic zones. Examining the interaction between urban growth and ecosystems will provide valuable data to inform climate adaptation strategies for Arctic cities. This research highlights the utility of remote sensing for environmental monitoring and urban planning in regions facing rapid climate and anthropogenic changes.

• unfold_moreBlue rings in juniper wood as ecological indicators of post-volcanic cooling events recorded in Arctic shrubs — Magdalena Opała-Owczarek

  Magdalena Opała-Owczarek ¹; Ulf Buntgen ²; Piotr Owczarek ^{3
  1} University of Silesia; ² University of Cambridge; ³ University of Wrocław

  Format: Poster in-person

  Poster number: #261

  Abstract:

  Climate reconstructions in the Arctic are largely based on ice-core records; non-glaciated areas are less well represented. Arctic dendrochronology can fill the gaps between short meteorology series and proxies with lower time resolution, such as ice cores and lake sediment. Studies of the dynamics of plant annual rings can answer questions about how tundra ecosystems may have been altered by climate change over the past few centuries. Owing to their limited age, they are not suitable for reconstructing the climate of the past. Here, for the first time, we compile a continuous time series from 1526 to 2023, the longest dendrochronological record for the Arctic. The new dendrochronological record reflects the temperature conditions of the Greenlandic and Icelandic terrestrial ecosystem during the last half millennium and shows the warming and cooling phases since the Little Ice Age in the non-glaciated areas. The very difficult cross-dating was further verified by using less lignified cell walls, known as blue rings, as time markers first time observed in Greenland and Iceland. The highest frequency of BR structures was recorded in the years when the Laki (1783-1784) and Tambora (1815) eruptions occurred. We highlight the beneficial aspect of using the BRs feature as an added value for dendroecology - as an indicator of summer cooling, but also as pointer years to improve cross-dating, often challenging in the case of juniper wood.

  The research was funded by a Polish National Science Centre project no. UMO-2019/35/D/ST10/03137.

• unfold_morePermafrost Pathways: Connecting science, people, and policy to advance understanding of the local to global impacts of permafrost thaw and develop just and equitable responses — Brendan Rogers

  Brendan Rogers ¹; Susan Natali ¹; John Holdren ²; Kyle Arndt ¹; Valeria Briones ¹; Chu-Chun Chang ¹; Patrcia Cochran ³; Jackie Dean ¹; Greg Fiske ¹; et al.
  ¹ Woodwell Climate Research Center; ² Harvard University, Belfer Center for Science and International Affairs; ³ Alaska Native Science Commission

  Format: Poster in-person

  Poster number: #67

  Abstract:

  The permafrost region is warming between two and four times the global rate, with temperatures already greater than 2°C above preindustrial levels. Rapid warming is intensifying wildfires and thawing permafrost, both of which are transforming northern ecosystems and creating hazardous conditions that are forcing arctic communities to make difficult and urgent adaptation decisions. These changes can also impact global climate through carbon feedbacks, and thus there is an urgent need to reduce the uncertainties that observational and modeling gaps create in understanding the current and future state of permafrost feedbacks. Despite this need, most climate policy planning does not even reflect current scientific understanding of future emissions from a warming Arctic.

  Here we present our objectives, progress to date, and opportunities for collaboration as part of the Permafrost Pathways project. Our multi-disciplinary approach includes strategic expansion of carbon flux monitoring sites across the permafrost zone; remote sensing of landscape disturbances associated with permafrost thaw; development of a model-data assimilation system to project permafrost carbon-climate feedbacks; informing fire management for carbon protection and Indigenous sovereignty; modeling and remote sensing at spatial and temporal scales relevant for adaptation planning; supporting Arctic climate resilience including through the co-creation of just and equitable, Indigenous-led adaptation plans that respect tribal sovereignty; and fostering partnerships with local leaders and national policymakers to incorporate permafrost thaw and emissions into climate adaptation and mitigation policy.

• unfold_moreArctic Winter Heatwaves: An Ever Increasing Phenomenon Challenging the Arctic Environment and Local Communities — Andrea Spolaor

  Andrea Spolaor ¹; Roberto Salzano ²; Elena Barbaro ³; Catherine Larose ⁴; Alfonso Saiz-Lopez ⁵; Feiyue Wang ⁶; Ward van Pelt ⁷; Federico Scoto ³; Roberta Pirazzini ⁸; et al.
  ¹ Istituto di Scienze Polari - Consiglio Nazionale delle Ricerche (ISP-CNR); ² Institute of Atmospheric Pollution Research - National Research Council; ³ Institute of Polar Sciences - National Research Council; ⁴ Centre national de la recherche scientifique; ⁵ Consejo Superior de Investigaciones Científicas; ⁶ University of Manitoba; ⁷ University of Uppsala; ⁸ Finnish Metereological institute

  Format: Poster in-person

  Poster number: #50

  Abstract:

  Rising temperatures are leading to an increase in the frequency of extreme events, when anomalous temperature and rain precipitation occur. Winter heatwaves, sometimes characterized by persistent warm and humid air masses, result in prolonged periods of unusually high temperatures and are often associated with "rain-on-snow" (ROS) events. These phenomena present a significant challenge to the Arctic ecosystem and its inhabitants, impacting environmental, ecological, and socioeconomic aspects. Despite their sporadic nature, winter heatwaves affect both coastal and inland areas of the Arctic, influencing the cryosphere and snow-free terrestrial ecosystems. They alter the snow-albedo feedback, accelerate the hydrological cycle, activate snow and ice microbial communities, increase heat transfer to permafrost, and cause the early remobilization of contaminants deposited during winter. Furthermore, they modify atmospheric dynamics and composition, creating complex interactions within the Arctic climate system. Understanding the effects of these extreme events throughout the snow accumulation and melting periods is crucial for assessing their impact on the winter Arctic environment. Research priorities include the definition of different Arctic Winter Extreme events and associate them to their impact on the Cryosphere. This challenge implies standardization and harmonization of datasets and algorithms aimed at enhancing climate models. Additional effort is required for integrating the knowledge about the source and composition of air masses, about the precipitation phase changes, and their impact on cryosphere dynamics, hydrology, and biogeochemical cycles. Knowledge co-production with Indigenous communities, is the key strategy developing effective adaptation strategies and mitigating the consequences of these extreme events.

• unfold_moreChemical, biogeochemical, and physical drivers of the coupled polar atmosphere and climate: a planning workshop for the 5th International Polar Year 2032-33 - Synthesis and outcomes — Markus Frey

  Markus Frey ¹; Hélène Angot ²; Stefanie Arndt ³; Steve Arnold ⁴; Petra Heil ⁵; Kathy Law ⁶; Lisa Miller ⁷; Georgia Sotiropoulou ⁸; Nadja Steiner ⁹; Letizia Tedesco
  ¹ British Antarctic Survey UKRI-NERC; ² Institute of Environmental Geosciences (IGE), Université Grenoble Alpes; ³ Alfred Wegener Institut; ⁴ Institute for Climate & Atmospheric Science, University of Leeds; ⁵ Australian Antarctic Division; ⁶ Laboratoire Atmosphères et Observations Spatiales (LATMOS) - CNRS; ⁷ Institute of Ocean Sciences, Fisheries and Oceans Canada (DFO); ⁸ University of Athens; ⁹ Institute of Ocean Sciences, Fisheries and Ocean Canada (DFO); ¹⁰ Finnish Environment Institute (SYKE)

  Format: Poster in-person

  Poster number: #106

  Abstract:

  The international initiatives CATCH, PACES, BEPSII, ASPeCt and QUiesCENT held a joint workshop in November 2024 bringing together scientists and stakeholders with an interest in atmosphere-ice-ocean research focussing on chemical, biogeochemical and physical processes in the Arctic and Antarctic and links to climate change. Also considered were cold regions which are seasonally or permanently covered by snow and ice, notably the Third Pole. Keynotes on selected topics were used to create awareness of the inter-disciplinary nature and coupled system view needed to address IPY5 research challenges. Presentations on current and planned international (pre-)IPY5 initiatives were followed by brainstorming sessions to identify ‘big picture’ science questions, research priorities and implementation pathways for research activities in field, laboratory and modelling before and during the 5th International Polar Year (IPY) 2032-2033. A workshop synthesis in form of a white paper will be used to shape IPY5 funding calls, underpin grant applications, and influence the planning of polar research cruises, field campaigns and new long-term measurement capabilities. Here we present a summary of the workshop and steps forward, including outlines of potential IPY5 research programmes focused on the coupled polar atmosphere and climate.

• unfold_moreIce-ocean interplay in the central Canadian Arctic Archipelago area during the final deglacial-Holocene transition — Mingwei Shi

  Mingwei Shi ¹; Xiaotong Xiao ²; Ruediger Stein ³; Johanna Hingst ⁴; Wenshen Xiao ⁵; Duanping Shi ⁶; Kirsten Fahl ⁷; Simone Kasemann ⁸; Meixun Zhao ^{9
  1} Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, China, Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China; ² Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, China, Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, China; ³ Faculty of Geosciences and Center for Marine Environmental Sciences, University of Bremen, Germany, Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China; ⁴ Faculty of Geosciences and Center for Marine Environmental Sciences,University of Bremen, Germany; ⁵ State Key Laboratory of Marine Geology, Tongji University, Shanghai, China; ⁶ State Key Laboratory of Marine Geology, Tongji University, Shanghai, China; ⁷ Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany; ⁸ Faculty of Geoscience and Centre for Marine Environmental Science, University of Bremen, Germany; ⁹ Frontiers Science Center for Deep Ocean Multispheres and Earth System, and Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, China, Laoshan Laboratory, Qingdao, China

  Format: Poster in-person

  Poster number: #142

  Abstract:

  The ice sheet reconstruction during the last glacial-interglacial transition provides valuable insights into the rapid global climate changes in future warming scenario. The Canadian Arctic Archipelago (CAA) experienced a rapid ice sheet retreat during the late stage of the last deglaciation, and eventually reconnected the Arctic-Atlantic passages. However, considerable uncertainty remains regarding the dynamics, processes and controlling mechanisms of ice sheet-sea ice-ocean interplays during the crucial final deglacial-Holocene transition. Here we present well-dated and high-resolution records (including sedimentological, geochemical and radiogenic isotopic data) from the central CAA reflecting the rapid fluctuations in ice sheet-ocean interactions during the final deglaciation-Holocene transition.</a> Our results suggest the centennial variability of ice sheet/sea-ice/open water productivity during the final stage of deglaciation (~11.2-10.4 ka BP), followed by the amelioration from perennial sea-ice cover (~10.4-10.0 ka BP) to seasonal sea-ice cover (~10.0-8.8 ka BP). Two events of ice sheet decay at the final stage of the last deglaciation were identified by abrupt changes in ice-rafted debris deposition and the marine productivity. We suggest that the oscillated penetration of warm Atlantic water contributed to ice sheet instability and further promoted the deglacial process, before the inflow of Arctic surface water became the dominant factor shaping the sea surface characteristics after the final ice sheets disintegration. Our findings underline the influence of rapid climate change on ice sheet and sea-ice variabilities during the final stage of the deglaciation, and highlight the potential influence of ocean currents/water masses on the ice sheet melting process.

• unfold_moreExtreme events in arctic terrestrial ecosystems: rapid events changing rapidly — Gareth Phoenix

  Gareth Phoenix ^{1
  1} University of Sheffield

  Format: Poster in-person

  Poster number: #87

  Abstract:

  Arctic ecosystems are experiencing extreme climatic, biotic and physical disturbance events that can cause substantial loss of plant biomass and productivity, sometimes at scales of > 1000 km2. These “browning events” are key contributors to the spatial and temporal complexity of Arctic greening and vegetation dynamics. Here the main extreme browning events in Arctic ecosystems are compared, including their impacts and rates of recovery, and likely future changes in frequency and distribution. Commonalities in impacts across these highly contrasting event types are also considered.

  While extreme browning events can cause high levels of plant damage (up to 100% mortality), ecosystems also have substantial capacity for recovery, with biomass largely re-established within five years for many events. Furthermore, despite the substantial loss of leaf area of dominant species, compensatory mechanisms such as increased productivity of undamaged subordinate species lessen the impacts on carbon sequestration. The common responses apply most to climatic and biotic events, but much less so for physical events including fire and abrupt permafrost thaw, due to the greater removal of vegetation. Some events also provide conditions for greater productivity (greening) in the longer-term. Projected changes in the causes of browning events currently suggest many types of event will become more frequent, with events of tundra fire and abrupt permafrost thaw expected to be the greatest contributors to future browning. Overall, browning events may have increasingly important consequences for biodiversity and feedback to climate.

• unfold_moreMercury Dynamics in Different Permafrost Systems: Insights from Fieldwork in the Canadian Subarctic and Greenland — Beatriz Malcata Martins

  Beatriz Malcata Martins ¹; Holger Hintelmann ²; Martin Pilote ³; Diogo Folhas ⁴; Rodrigo Dias ⁵; João Canário ⁶; Torben R. Christensen ^{7
  1} Centro de Química Estrutural, Institute of Molecular Sciences and Department of Chemical Engineering, Instituto Superior Técnico, Center for Northern Studies (CEN), Université Laval; ² Water Quality Centre, Trent University; ³ Environment and Climate Change Canada, Aquatic Contaminants Research Division; ⁴ Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, Center for Northern Studies (CEN), Université Laval; ⁵ Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico; ⁶ Centro de Química Estrutural, Institute of Molecular Sciences, Instituto Superior Técnico, Center for Northern Studies (CEN), Université Laval; ⁷ Department of Ecoscience, Aarhus University, Water, Energy and Environmental Engineering Research Unit, Oulu University

  Format: Poster in-person

  Poster number: #251

  Abstract:

  The Arctic and Subarctic contain vast permafrost areas that can store several contaminants, including mercury (Hg). These regions are categorized based on permafrost coverage: continuous (90-100%), discontinuous (50-90%), sporadic (10-50%), and isolated (<10%). As permafrost thaws, it releases stored Hg into the ecosystems. Furthermore, thawing creates thermokarst lakes, where Hg can be transformed into methylmercury (MMHg). MMHg is bioavailable and can enter aquatic food webs. This process threatens local ecosystems, as MMHg bioaccumulates in fish and other organisms, potentially affecting wildlife and human populations that rely on these ecosystems for food. Climate change accelerates permafrost thaw, amplifying Hg release in these regions.
  In this study, thermokarst lakes were sampled across three permafrost regions: sporadic permafrost in Kuujjuarapik (Canada), discontinuous permafrost in Kangiqsualujjuaq (Canada), and continuous permafrost in Zackenberg (Greenland). Sediment samples were collected from two lakes per site in the summers of 2022-2023. Total Hg and MMHg concentrations were analyzed and incubation experiments using isotope enriched Hg were conducted to measure methylation rates. Kangiqsualujjuaq lakes exhibited the highest THg concentrations (40–84 ng/g), while Zackenberg had the lowest (12–20 ng/g). Despite having lower THg, the lake with the highest concentration of MMHg (2 ng/g) was sampled in Zackenberg, which suggests a high microbial activity or high availability of inorganic Hg. In fact, this lake methylated 13% of added Hg within 6 hours, which is the highest methylation potential observed in this study. Important factors influencing the methylation potential might be related to permafrost coverage and age of the lake.

• unfold_morePerspective from ArCS II ocean research program for the next stage — Eiji Watanabe 

  Eiji Watanabe ^{1
  1} JAMSTEC

  Format: Poster in-person

  Poster number: #73

  Abstract:

  The second phase of the Arctic Challenge for Sustainability (ArCS II) project was launched in June 2020 and will end in March 2025. The Ocean Research Program of this project was engaged in research on Arctic marine environments and production of corresponding public datasets. Sub-program 1 was established to clarify ocean heat/freshwater transport and biogeochemical cycles in seasonal and multi-year sea ice zones. Sub-program 2 focused on assessment of the vulnerability and resilience of marine ecosystems in response to rapid sea ice retreat. Sub-program 3 examined air–sea interactions related to sea ice and waves. The expected outcomes included refinement of Earth System Models, advancement of ecosystem-based fishery management, and development of safer maritime navigation. My presentation compiles the major findings from this programs, together with brief summaries on the research cruises, sea ice field campaigns, and modeling experiments conducted through various international collaborations. The ArCS II research programs are categorized into discrete fields of the atmosphere, ocean, cryosphere, and land, although cross-program collaborations are encouraged. Based on such situations, the third phase of this project (ArCS III) promoting more integrated analyses of the water and carbon cycles will also be briefly introduced. The scientific achievements of our research activities hopefully support deeper understanding of the effects of climate change and provide information for socioeconomic benefit.

• unfold_moreKey Risks from permafrost thaw – a comparative, trans- and interdisciplinary risk assessment — Susanna Gartler

  Susanna Gartler ¹; Johanna Scheer ²; Alexandra Meyer ^{1
  1} University of Vienna, Austrian Polar Research Institute; ² Umea University

  Format: Poster in-person

  Poster number: #86

  Abstract:

  Permafrost degradation has global climate implications and affects local livelihoods. This study presents an inter- and transdisciplinary analysis of permafrost thaw risks in Arctic coastal areas. Permafrost thaw impacts on socio-ecological systems remain understudied, in the Arctic, which is undergoing rapid societal changes amidst geopolitical tensions. This necessitates understanding permafrost thaw implications for its communities. Our goal is to contribute to climate-related hazard assessments, vulnerability, resilience, and adaptation research in the Arctic. The "Nunataryuk" project, conducted a six-year study (2019-2023) across sites in Svalbard, Greenland, Canada, and Yakutiya. We employed a mixed-methods approach, involving local experts and diverse (Indigenous) populations. Our research employs a comparative, multidisciplinary synthesis to analyze permafrost thaw risks, drawing from diverse disciplines and Indigenous knowledge. We define risk holistically, rooted in stakeholder perceptions, encompassing physical processes, hazards, and socio-ecological consequences. Risks are dynamic, influenced by socio-economic, political, and environmental contexts. Our risk analysis identified five key hazards in relation to permafrost thaw: 1) infrastructure failure, 2) mobility and supply disruption, 3) water quality decline, 4) food security challenges, and 5) increased exposure to diseases and contaminants. These hazards impact ecosystems, societies, economies, governance, and community wellbeing. Complex interconnections between these hazards are illustrated in a comprehensive risk graphic, which includes possible adaptation actions. Permafrost thaw significantly affects Arctic coastal communities. Our transdisciplinary approach provides insights into key risks and adaptation practices offering a framework for future research and emphasizing the need for proactive measures in the face of uncertainties.

• unfold_moreMicroplastic emergency and the associated plastisphere in freshwater habitats of the Arctic — Maurizio Azzaro

  Angelina Lo Giudice ¹; Maurizio Azzaro ^{1
  1} Institute of Polar Sciences, National Research Council of Italy (CNR-ISP), Messina, Italy

  Format: Poster in-person

  Poster number: #186

  Abstract:

  Microplastic pollution is of great environmental concern. Microplastics have been found all over the Earth, which is indicative for the important threat they constitute. Yet, while the ocean is object of major interest, the data available in the literature about microplastic pollution in the freshwaters, including those of the Earth’s poles, are limited to few reports, questioning the transport patterns through which microplastics reach these remote areas. Microplastics can indeed be ingested by animals and can physically damage their digestive tracts, as well as escalate the trophic levels down to indigenous people. Microplastics can also alter microbial community biodiversity and functions by serving as surfaces onto which microbes (including pathogens) can grow and develop (plastisphere), and can ehance icemelting when trapped in glaciers. Plastic-attached microbes could be also capable of degrading plastic polymers, thus altering the buoyancy of polymers and the toxicity of plastics. In turn, the ability to degrade plastics by cold-adapted microorganisms could lead to an environmental-friendly solution in mitigating plastic pollution in cold environments. In this context, an international in-person trans-disciplinary workshop, held in Messina (Italy) and involving about 30 scientists, was endorsed by the International Arctic Science Committee (IASC) and received funding by the Italian Arctic Research Program (PRA) for its organization. The workshop allowed gaining relevant information to take actions in thwarting plastic pollution in Arctic freshwaters (e.g., snow, glaciers, lakes and rivers), along with a focus on the plastisphere. Here, the outcomes of the workshop shared with ICARP IV for implementation are reported.

• unfold_moreVerification of high-resolution satellite-derived data by dendrochronological ground-based research - a new approach in the study of Arctic dwarf shrubs — Piotr Owczarek

  Piotr Owczarek ¹; Magdalena Opała-Owczarek ²; Jacek Ślopek ³; Mohit Phulara ⁴; Ewa Łupikasza ⁵; Wojciech Szymański ⁶; Michał Węgrzyn ⁷; Bartosz Korabiewski ^{8
  1} University of Wroclaw, Institute of Geography and Regional Development, Pl. Uniwersytecki 1, 50-137 Wroclaw; ² Institute of Earth Sciences, University of Silesia in Katowice; ³ Institute of Geography and Regional Development, University of Wroclaw; ⁴ Institute of Earth Sciences, University of Silesia in Katowice; ⁵ Institute of Earth Sciences, University of Silesia in Katowice; ⁶ Institute of Geography and Spatial Management, Jagiellonian University; ⁷ Institute of Geography and Spatial Management, Jagiellonian University; ⁸ Institute of Geography and Regional Development, University of Wroclaw

  Format: Poster in-person

  Poster number: #150

  Abstract:

  There is a lack of comprehensive and complementary studies in which satellite-derived data is verified by dendrochronological ground-based research. This is a key gap in the knowledge of the greening and browning of Arctic tundra. Therefore, detailed ground-based analyses, in conjunction with satellite-derived research, are crucial for the proper understanding of trends in plant productivity. The objective of this research is to examine the consistency, or potential for over- or underestimation, between NDVI data and tundra productivity as derived from direct dendrochronological research. The research area is located in Svalbard in four test plots. 10 detailed morphologically diverse research sites were selected in each plot to sample Salix polaris and Dryas octopetala. The dendrochronological analysis was compared with data from Sentinel-2 obtained for the period 2010 - 2022.The results show that the relationship between the growth-ring width of dwarf shrubs and the value of NDVI is not obvious. The values of the year-to-year index in relation to the dendrochronological measurements are underestimated or overestimated. This suggests that many factors influence NDVI, including regional hydrometeorological conditions and local conditions down to a microtopographic scale. For instance, mosses, which dominate the vegetation at high latitudes, affect NDVI measurements to various extents depending on their moisture content. This may significantly influence satellite measurements and often affects the incorrect interpretation of vegetation indices.

  Acknowledgments: The research was founded by a Polish National Science Centre project no. UMO-2021/41/B/ST10/03381

• unfold_moreFrontiers in storm surge and wave climate: exploring Alaska’s changing coastal hazards — Tyler Miesse

  Tyler Miesse ¹; Rafael Bendo ¹; Andre de Lima ¹; Celso Ferreira ¹; Thomas Ravens ^{2
  1} George Mason University; ² University of Alaska Anchorage

  Format: Poster in-person

  Poster number: #219

  Abstract:

  The Arctic region is experiencing significant changes due to climate change, most notably the decline in sea ice, which affects ocean dynamics and intensifies coastal hazards. This study utilizes numerical models to simulate interactions between the ocean, land, sea ice, and atmosphere, focusing on the period from 1979 to 2023. Using the coupled Advanced CIRCulation (ADCIRC) and Simulating WAves Nearshore (SWAN) models, we simulate the flooding and waves generated by extratropical and arctic polar cyclones in the Arctic. Data from the European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA5), including sea ice concentration and atmospheric forcing were utilized to support these simulations, which investigate annual conditions in the Alaskan Arctic. Our research identifies trends in cyclones that place Alaskan coastal communities at risk of moderate and major flood stages. This analysis enables us to assess the potential risks based on the main characteristics of cyclones affecting Alaska. Additionally, these results generate a 44-year database of storm surges and significant wave heights in Alaska. The findings offer critical insights into the frequency and intensity of coastal inundation, revealing the flood exposure of coastal communities in Western and Northern Alaska. Thus, our work enhances our understanding of coastal vulnerabilities on mitigation strategies in response to ongoing climatic changes.

• unfold_moreSpatiotemporal Variability of Carbon Fluxes in Response to Climatic Factors at a Tussock Tundra Site near Council, Alaska — Kelcy Kent

  Kelcy Kent ¹; Kyle Arndt ²; Marco Montemayor ³; Patrick Murphy ²; Dani Trangmoe ²; Anna Virkkala ²; Sigrid Denegel ⁴; Margaret Torn ⁴; Susan Natali ^{2
  1} Woodwell Climate Research Center & University of Virginia; ² Woodwell Climate Research Center; ³ UC Santa Cruz; ⁴ Lawrence Berkeley National Lab

  Format: Poster in-person

  Poster number: #332

  Abstract:

  The top three meters of Arctic permafrost harbors roughly two times the amount of carbon found in the atmosphere, making permafrost soils a vital global carbon stock. Arctic ecosystems, however, experience outsized consequences from climate warming, evidenced by large-scale shifts in ecosystem characteristics and alterations in biogeochemical processes and fluxes. Warming soils result in permafrost thaw and subsequent remobilization of organic material and nutrients from historically frozen soils, leading to increased microbial activity and increased potential for carbon loss. Whether various regions of the Arctic will remain carbon sinks or evolve into carbon sources – and how much C may be released from Arctic warming – is still poorly understood. In this study, we aim to track C fluxes using eddy covariance tower (EC) flux data (2017 – 2022) and experimental micro-warming soil chamber data (2017 – 2019) from an NGEE-Arctic (Next Generation Ecosystem Experiment) tussock tundra site near Council, Alaska (Ameriflux site US-NGC). By tracking changes in CO2 and CH4 fluxes (dominant forms of greenhouse gasses) in relation to meteorological and environmental parameters (such as air and soil temperature, soil moisture, and radiation) among different landscape positions (upland, lowland, slope) within the Council site watershed, we can glean insight into spatiotemporal variations in C fluxes across a landscape and how similar Arctic ecosystem C budgets may be changing with Arctic warming.

• unfold_moreOngoing development of the subseasonal-to-seasonal prediction system based on a coupled global climate model (KPOPS-Earth) — Joo-Hong Kim

  Joo-Hong Kim ¹; Sang-Yoon Jun ¹; Yonghan Choi ¹; Young-Chan Noh ¹; Yoo-Geun Ham ²; Sang-Moo Lee ²; Hyo-Jong Song ³; Eui-Seok Chung ¹; Seong-Joong Kim ¹; et al.
  ¹ Korea Polar Research Institute; ² Seoul National University; ³ Myongji University

  Format: Poster in-person

  Poster number: #545

  Abstract:

  Subseasonal-to-seasonal (S2S) prediction is essential for decision-making in sectors like disaster preparedness, agriculture, water management, energy, health, and the economy. Organizations wirldwide are working to enhance S2S predictability by reducing model errors and improving initial conditions for the atmosphere, ocean, land, and sea ice. KOPRI aims to develop a global climate model-based prediction system, called KPOPS-Earth, to forecast large-scale extreme events on S2S timescales. This effort is driven by research linking Arctic warming, sea ice decline, and extreme events across the Arctic and mid-latitudes. KPOPS-Earth is based on the NCAR CESM2 model and integrates a coupled data assimilation system for the atmosphere, sea ice, and ocean. By the end of 2025, KPOPS-Earth will generate initial fields and perform test forecasts, including historical reforecasts. Ocean assimilation uses a deep learning-based method, while sea ice and atmospheric assimilation use ensemble Kalman filters via NCAR's DART system. These individual assimilation components generate a coupled initial field through weakly coupled assimilation. Model error assessment is being conducted for the Arctic through a combination of Arctic observations to understand surface temperature changes due to ocean-boundary layer-cloud interactions. Climate feedback analysis tools are also used to evaluate the model's performance in simulating Arctic and mid-latitude extreme events, specifically assessing the contributions of different feedback components. By evaluating model errors related to extreme events, we aim to identify improvement targets and clarify the connection between Arctic changes and extreme events. Ultimately, KPOPS-Earth will serve as a valuable validation and prediction tool on S2S timescales.

• unfold_moreRapid summer Russian Arctic sea-ice loss enhances the risk of recent Eastern Siberian wildfires — Binhe Luo

  Binhe Luo ¹; Dehai Luo ²; Cunde Xiao ¹; Aiguo Dai ^{3
  1} Beijing Normal University; ² Institute of Atmospheric Physics, Chinese Academy of Sciences; ³ State University of New York

  Format: Poster in-person

  Poster number: #352

  Abstract:

  In recent decades boreal wildfires have occurred frequently over eastern Siberia, leading to increased emissions of carbon dioxide and pollutants. However, it is unclear what factors have contributed to recent increases in these wildfires. Here, using the data we show that background eastern Siberian Arctic warming (BAW) related to summer Russian Arctic sea-ice decline accounts for ~79% of the increase in summer vapor pressure deficit (VPD) that controls wildfires over eastern Siberia over 2004-2021 with the remaining ~21% related to internal atmospheric variability associated with changes in Siberian blocking events. We further demonstrate that Siberian blocking events are occurring at higher latitudes, are more persistent and have larger zonal scales and slower decay due to smaller meridional potential vorticity gradients caused by stronger BAW under lower sea-ice. These changes lead to more persistent, widespread and intense high-latitude warming and VPD, thus contributing to recent increases in eastern Siberian high-latitude wildfires.

• unfold_moreEffects of assimilating additional radiosonde observations in the Arctic on weather forecasts — Yonghan Choi

  YONGHAN CHOI ¹; JOO-HONG KIM ¹; SANG-YOON JUN ¹; TAEJIN CHOI ¹; XIANGDONG ZHANG ^{2
  1} Korea Polar Research Institute; ² North Carolina State University

  Format: Poster in-person

  Poster number: #527

  Abstract:

  The number of conventional observations (e.g., radiosonde) over the Arctic is comparatively fewer than that in the midlatitudes, which leads to limited weather predictability in the Arctic. The Korea Polar Research Institute (KOPRI) has contributed to enhancing Arctic observations through ship-borne radiosonde observations using ice breaking research vessel (IBRV) Araon, and station-based radiosonde observations at Ny-Alesund in collaboration with international research colleagues. Observing system experiments (OSEs) were conducted using a regional model, the Weather Research and Forecasting (WRF) model and its data assimilation (DA) system, WRF Data Assimilation (WRFDA) system to investigate effects of assimilating KOPRI’s additional radiosonde observations on weather forecasts over the Arctic.

   The overall assimilation effects of the extra observational data on the analyses and forecasts over the Arctic are positive. The DA effects on the analyses are the most substantial in the temperature in the mid/lower troposphere. The assimilation effects spread to the wind in the upper troposphere for early forecasts. The DA effects of the additional radiosonde observations have year-to-year variability, and this variability is closely related to relative locations of radiosonde observations and synoptic conditions (e.g., cyclone activity). The upper-level potential vorticity has played an important role in improving later forecasts, especially when Arctic cyclones are developed. Suggestions for future observing strategies and observation network design in the Arctic will be presented based on OSE results.

• unfold_moreContribution of seasonal source waters to changing Arctic ecohydrology — Hotaek Park

  Hotaek Park ¹; Tetsuya Hiyama ^{2
  1} JAMSTEC; ² Nagoya University

  Format: Poster in-person

  Poster number: #459

  Abstract:

  The warming climate in the Arctic terrestrial regions resulted in earlier snowmelt in spring, larger rainfall in the summer season, and deeper active layer thickness. The changes were linked to the direction of higher summer evapotranspiration and alternation of seasonal hydrograph with increasing river discharge. However, very few studies have provided quantitative assessments for changes in the seasonal hydrological processes, including contributions of the seasonal source waters (i.e., snow, rain, and ground ice water) to the changes. For assessing the changes, a land surface model, coupled a tracer scheme tracking along the flow route of individual source waters in the hydrological processes was applied to the pan-Arctic scale for the past five decades. The simulations represented that the contribution of the summer season-sourced rain water to evapotranspiration and river discharge was significantly increased during the study period. In addition, the summer rain water was connected to the peak river discharge and evapotranspiration in spring of the next year, suggesting a soil-water memory effect that the autumnal rainfall, stored as frozen soil water during the winter season and activated at the next spring season with soil thawing. The permafrost degradation-associated ground ice meltwater showed a weak relationship with river discharge. This model study provides a possibility to distinguish quantitatively the changes in the Arctic ecohydrological processes, resulted from the future climate warming.

• unfold_moreAdvancing Earth observation research through NASA’s multi-scale coordinated campaign: Science highlights and gaps remaining from the Arctic-Boreal Vulnerability Experiment (ABoVE) — Scott Goetz

  Scott Goetz ¹; Charles Miller ²; Peter Griffith ³; Elizabeth Hoy ⁴; Libby Larson ^{3
  1} Northern Arizona University; ² NASA Jet Propulsion Lab; ³ NASA/SSAI; ⁴ NASA/GST, Inc.

  Format: Poster in-person

  Poster number: #415

  Abstract:

  NASA’s Arctic Boreal Vulnerability Experiment (ABoVE) is a coordinated, multi-disciplinary research effort addressing ecosystem changes taking place in biomes of the Arctic and boreal region. This decade-long campaign has an international science team with over 150 projects and 1000 participants. Although the geographic focus of the field campaigns centers on northwestern North America (Alaska and western Canada), ABoVE research is ultimately designed to address scaling from field measurements, to multi-sensor airborne data acquisitions, to satellite remote sensing, and finally to terrestrial biosphere models. As such, ABoVE has pan-Arctic and pan-boreal implications and applications. This presentation will highlight top-level science results from a decade of ABoVE research and discuss key knowledge gaps that remain. ABoVE has advanced our understanding of the Earth system, particularly in terms of documenting and capturing in models how climate change and associated disturbances are altering terrestrial ecosystems, and how those ecosystem changes are in turn influencing climate. However, key knowledge gaps remain which reveal critical research areas for understanding of the interactions and feedbacks between the climate system and changes in the spatial and temporal environmental drivers. Addressing these gaps will also improve our ability to capture these dynamics in prognostic models.

• unfold_moreImpact of Arctic sea ice loss on the Arctic hydrological cycle — Ed Blockley

  Ed Blockley ^{1
  1} Met Office, FitzRoy Road, Exeter

  Format: Poster in-person

  Poster number: #439

  Abstract:

  Sea ice is an important component of the climate system and plays an important role in the Arctic environment. Loss of reflective sea ice and snow surfaces is key driver of Arctic amplification. Arctic sea ice also creates a natural barrier between the ocean and atmosphere limiting the exchange of heat and moisture. In particular surface evaporation from the Arctic Ocean is limited by the presence of sea ice.

  Water vapor in the Arctic can be attributed to local evaporation and transport from mid-latitudes. Here we investigate the response of Arctic water vapor to declining sea ice in a climate model, using an idealized warming scenario in which the Arctic becomes ice free year-round.

  We show the loss of sea ice leads to a step-change in the uptake and seasonal cycle of atmospheric water vapor in the Arctic. The greatest impact is in the Arctic winter when local evaporation dominates over the transport of water vapor from midlatitude regions. We also show changes in the vertical structure of the near-surface atmosphere and cloud types, with a transition from stable to turbulent regimes in autumn and winter.

• unfold_moreRapid response of Svalbard glaciers to ocean warming — Geir Moholdt

  Geir Moholdt ^{1
  1} Norwegian Polar Institute

  Format: Poster in-person

  Poster number: #453

  Abstract:

  About one third of the glacier area of the Arctic drains towards ocean-terminating fronts that ablate by calving and melting above and below the waterline. This frontal ablation is a significant but poorly quantified part of the overall mass budget of Arctic glaciers, as well as an important source of freshwater and calved ice for marine ecosystems. We present a detailed analysis of frontal ablation for all Svalbard’s ~200 tidewater glaciers for 2013-2024, a period with abundant availability of satellite imagery. We account for changes in frontal position, surface velocity and ice thickness at time scales from monthly to yearly, and we separate the results into components of glacier retreat and ice discharge. Although the ice discharge can be high year-round, especially for surging glaciers, we find that almost all frontal ablation occurs from late summer to autumn when the ocean is warmer. This represents a delayed freshwater flux to the fjords and open ocean compared to surface meltwater runoff which is more confined to the peak of the atmospheric summer season. Annual frontal ablation was exceptionally high during 2016-2018 and 2022-2024, which coincides with periods of high inflow of Atlantic water and warmer temperatures in the upper ocean. Links with air temperature and meltwater runoff are less clear. The observed variability in frontal ablation demonstrates how reactive these glaciers are to ocean warming and that this should be considered in studies of marine environments and future glacier retreat.

• unfold_moreThaw ponds as sentinels of localized permafrost destabilization: development of Utqiaġvik aquatic sensor array to examine effects of natural-built interactions through temporal changes in nearby ponds — MacKenzie Nelson

  MacKenzie Nelson ¹; Claire Griffin ²; Valentina Ekimova ²; Howard Epstein ^{2
  1} University of Virginia; ² Allegheny College

  Format: Poster in-person

  Poster number: #496

  Abstract:

  Changes in hydrologic conditions due to climatic warming are of critical concern to Arctic communities. Permafrost largely controls hydrology in Arctic environments; it is much less permeable and acts as a hydrologic confining layer. Water limited to infiltration from permafrost remains at the surface or within the shallow subsurface. Additionally, the limited relief of the tundra impedes drainage, allowing lakes and ponds to form. As part of the NSF Navigating the New Arctic, our project of multi-disciplinary researchers and community participants in Utqiaġvik, Alaska, addresses how the presence of surface and subsurface waters influences hydrology and water quality through the lens of nearby thaw ponds. Tundra “thaw ponds” are ideal proxy indicators or sentinels, given each is an individual catchment for meteoric, anthropogenic, and terrestrially-derived runoff, acting as arbiters of nearby change (Schindle and Smol, 2006). Changes like increased permafrost degradation and erosion lead to higher ionic concentrations and mineral mobilization/input to these nearby waters, providing a conductive response that can be measured and monitored using water loggers. In the open-water seasons of 2022-2024, over twenty thaw ponds in areas of varying infrastructure loads were instrumented with HOBO conductivity and water level loggers and repeated water sampling Lachat analysis. Preliminary results indicate elevated concentrations of NH4+, PO4-, and NO3- and persistently higher conductive responses for ponds near areas of higher infrastructure loading. Fluctuations in water level and ionic strength during this period capture significant impacts of weather patterns, ecological shifts, and anthropogenic influences on local hydrology.

• unfold_morePolar Exploration with Multiple Purposes: Exploring the permafrost, natural species, and astronomical research of the polar regions — Exodus Chun-Long Sit

  Exodus Chun-Long Sit ^{1
  1} National Astronomy Education Coordinator Team (Hong Kong, China), International Astronomical Union

  Format: Poster virtual

  Poster number: #368

  Abstract:

  In recent years, there has been an increasing focus on environmental concerns within the Polar Regions. Following the COVID-19 pandemic, this trend has motivated numerous experts in natural sciences to embark on a range of expeditions to these areas. The primary goal of this presentation is to recount my experiences from the last six years of multiple expeditions to the polar regions, spanning the Arctic (including Iceland and the Nordic countries within the Arctic Circle), the Third Pole (encompassing the Tibetan Plateau and Sichuan Basin), and the neighboring Antarctic region (Tasmania in Australia). I will address the conservation of the night sky and aurora phenomena across various locations, sharing insights from encounters with natural ecosystems, unique species in high-altitude regions, the natural panoramas of polar territories, and visual records of diverse glaciers encountered during these polar journeys.