The polar regions are key components of the intricate puzzle of the Earth’s climate system. Fairly small temperature changes in the polar regions can have major effects on global climate. Shifts in both polar terrestrial (e.g. glaciers) and marine ecosystems (e.g. sea ice) do not stay within the high latitude zones, but have profound effects throughout the globe, triggered by an intricate set of environmental reactions via atmospheric and oceanographic teleconnections. Over the last several decades, the Arctic region has seen accelerated climate and environmental changes. The cryosphere is responding fast to the rapidly changing climate, and so do the glaciers. The Arctic includes still today a large surface covered by glaciers, including ice-sheets, ice-caps, mountain glaciers as well as other smaller glacial features. However, the amount of ice stored in the Arctic during the Quaternary has undergone large variations depending on the prevailing climate conditions. Retreating glaciers leave a wide range of landforms and deposits that can be used to trace the deglaciation history. These include landforms of glacial origin, including depositional (moraines, erratic boulders, till) and erosional features (polished bedrock). There are also several other paleoenvironmental sources that preserve the signal of past glacial advances and retreats (marine and lacustrine sediments, peat bogs, etc.). Recent advances in dating techniques have refined their chronological accuracy when constraining past glacial oscillations using absolute (e.g. Cosmic-Ray-Exposure, Optically-Stimulated Luminescence, lichenometry, etc) and relative dating techniques (e.g. Schmidt hammer). Recent glacier changes have been also increasingly reconstructed using aerial and satellite imagery. A better understanding of the spatio-temporal patterns of Late Quaternary glacial advances and retreats in the Arctic is essential to: (i) learn from the consequences of past glacial oscillations on ice-free ecosystems: vegetation/fauna colonization, geomorphology (e.g. permafrost, glacio-isostatic uplift, paraglacial processes) and sea level changes, (ii) the magnitude of recent changes within the geological record, (iii) validate ice-sheet models and tune coupled Earth System Models to better reproduce past ice-land-ocean interactions, (iv) infer the climate factors responsible for glacial oscillations, and (v) reconstruct the geographical scope of glacial oscillations and their connection with other regions. We welcome abstracts dealing with these topics from all Arctic and Subarctic regions. The main purpose of this session is to report on the state of the art and on the latest developments on reconstructing past glacial oscillations in the Arctic in order to identify gaps and areas for future research.
Arctic, Subarctic, glacial oscillations, climate variability
Marc Oliva | University of Barcelona, Catalonia, Spain
José María Fernández-Fernández | Universidade de Lisboa, Portugal
David Palacios | Complutense University of Madrid, Spain
The Arctic is constantly changing in many aspects. For example, the ice cover in the Arctic has been changing both in the terrain and the ocean, repeating shrinking and growing. Permafrost extent and the depth of the active layer are undergoing changes, and the microbial communities and activity in the permafrost are also changing. Changes in air temperature, precipitation, vegetation, etc. as well as microbes are affecting greenhouse gas fluxes. The fjords distributed along the coastlines of the Arctic host sediments eroded and transported by glaciers and meltwater that record changes in ocean circulation, advance, and retreat of tidewater glaciers, development of sea-ice, fluctuating sea level, and coastal erosion. From the past and current climate changes in the Arctic, we try to get scientific clues to predict future changes. In this session, we are going to share and discuss the latest data on the impacts of climate change across the atmosphere/permafrost/fjord in the Arctic.
Aerosol, biogenic precusor, fjord sediment, glacier, permafrost microbes
Yoo Kyung LEE | inst.
Jiyeon PARK | Korea Polar Research Institute
Min Jung KWON | le Laboratoire des Sciences du Climat et de l'Environnement
The natural variability in the Earth’s climate system and recent anthropogenic stresses have led to important changes of climate and environmental conditions in arctic and subarctic ecosystems at various time scales. In this session, we aim to examine the last decades to millennia in order to better document and understand (1) the causes and feedback mechanisms at the origin of climate events, natural or anthropogenic; (2) the rates of changes in the different components of the ecosystem; (3) their resilience and vulnerability, and ;(4) their impact from societal and cultural points of view. We welcome contributions based on observations, historical data, proxy-reconstructions and/or modelling that address issues related to the dynamics of ecosystems in a context of rapid climate change. Special attention will be given to coastal areas and epicontinental environments such as Hudson Bay, the North Water Polynya and the Labrador and Greenland coasts.
Paleoclimatology, cimate change, ecosystems, impacts, processes
Natasha Roy | UQAM - ArcTrain
Jennifer Wesselbaum | U. Bremen - ArcTrain
Joshua Evans | U. of New-Brunswick - ArcTrain
Clouds, water vapour and aerosols are closely linked through various dynamic, microphysical and chemical processes and feedbacks, and strongly control the climate, especially in the Arctic. Atmospheric aerosols, natural or anthropogenic ones, are needed to form clouds since thy act as cloud condensation nuclei (CCN). Aerosols in the Arctic are mainly known through observations of the Arctic Haze phenomenon and long-range transport studies. Less is known about natural Arctic aerosol sources, such as primary marine aerosol or new particle formation. Additionally, strong seasonal impact from biomass burning aerosol can occur. Clouds and the relative influence of aerosols and atmospheric dynamics on their microphysical and radiative properties are not well understood yet. The session is dedicated to the interplay of these key players in the Arctic atmosphere. It will cover latest results from currently ongoing experimental efforts investigating of clouds, aerosols and climate at Ny-Ålesund, Svalbard, by various international research groups from e.g. Germany, Korea, Japan, Switzerland and Sweden (NASCENT campaign https://www.aces.su.se/research/projects/the-ny-alesund-aerosol-cloud-experiment-nascent-2019-2020/), long-term observations, and modelling studies throughout the Arctic.
Aerosols, clouds, chemical composition, seasonal cycle, field observations
Claudia Mohr | Stockholm University
Paul Zieger | Stockholm University
Sophie Haslett | Stockholm University
The purpose of the Paleoclimate Action Group in T-MOSAiC is to bring together new and existing lake sediment-derived paleoecological and paleoclimate records from across the circumpolar North. These records will provide a long-term, multi-millennial ecological and climate context for more process-oriented terrestrial and atmospheric T-MOSAiC studies. This session will focus on using lake sediments (paleolimnology) to address questions such as: 1) What are the main modes of natural variability over the last >10 000 years?2) Can we detect human impacts on the environment (recent warming, land-use changes, atmospheric pollution)? 3) Do these changes have spatial and temporal variability? Can we identify critical thresholds? 3) How can we use these impacts to anticipate future changes? How can we manage these changes?
paleolimnology, paleoclimatology, arctic lakes, lake sediments, arctic change, T-MOSAiC
Bianca Perren | British Antarctic Survey
John Smol | Queen's University
Kathryn Hargan | Memorial University
Arctic glaciers and ice caps and the Greenland Ice Sheet are changing dramatically in response to climate change, accounting for more than 1 mm/yr of global sea level rise in recent years. Arctic amplification of climate change, reduced sea ice, warmer ocean waters, and increased atmospheric heat transport are all contributing to this, along with additional glaciological feedbacks associated with ice-ocean interactions, glacier/ice sheet hydrology, and mass balance processes. This session solicits presentations concerning ice dynamics, mass balance conditions, and glacier-climate processes on Arctic glaciers, ice caps, and the Greenland Ice Sheet. We welcome contributions based on field-based, remote sensing, and glaciological modelling studies or a combination of these methods to understand the recent behaviour and inform future projections of Arctic ice masses. Greenland Ice Sheet, Arctic glaciers, ice caps, sea level, glacier mass balance, ice-ocean interactions
Greenland Ice Sheet, Arctic glaciers, ice caps, sea level, glacier mass balance, ice-ocean interactions
Shawn Marshall | University of Calgary, Canada
Samantha Buzzard | Georgia Tech, USA
Al. Ramanathan | Jawaharlal Nehru University, India
Guðfinna Th Aðalgeirsdóttir | University of Iceland
Closed on December 10, 2020