The SCAR/CliC Expert Groups Antarctic Sea-Ice Processes & Climate (ASPeCt) and Arctic Sea Ice Working Group (ASIWG) held their first in-person meetings after a 4-year, Covid19-related hiatus. Over 60 experts from 41 institutes and 14 countries worldwide met for their 2023 Annual Meeting. The meeting was hosted by the Alfred Wegener Institute for Polar and Marine Research.
Sea ice is reducing globally at an unprecedented rate, with serious implications for not only Earth’s polar environments and inhabitants but also global weather and climate. In particular, Antarctic sea ice has declined since 2015 at a rate not observed since the beginning of satellite records in the 1970s — a phenomenon that is concerning the scientific community and one that is currently not well understood. In response to these new developments, the international community calls for an urgent stepping up of existing national efforts and an intensification of international collaboration and coordination to enhance observational capabilities.
Recent Antarctic and Arctic events and targeted observables:
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2023 Extreme Antarctic Sea Ice Minimum – Sea-ice extent reached another record low in February 2023, following hard on the previous record lows of February 2017 and 2022. This rapid succession of extremes prompts grave concerns of a change in state of the Antarctic sea ice within the Ocean-Sea Ice-Snow-Atmosphere and the wider Earth system. Even now as mid winter approaches, the Antarctic sea-ice extent remains at record low values.
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For the first time in the observational record, Antarctic landfast ice has exhibited a significant drop, meaning coastal regions are now ice-free where they never were observed to be before.
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Observations from novel autonomous instrumentations currently deployed on fast ice, point towards increased contributions from ocean-sea ice-atmosphere interactions, such as wave damping and ice breakup, in reshaping the Antarctic sea ice.
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The Antarctic Treaty Consultative Meeting (ATCM), concurrently held in Helsinki 2023, hosted its inaugural climate-change submeeting. A group of ATCM member states proposed a major cross-disciplinary year-round Antarctic international initiative to be developed and executed in near future.
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2023 continued a pattern of low Arctic sea ice minima. The last 16 years (2007-2022) are the lowest 16 years in the 44-year satellite record.
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A notable ice-free area opened near the North Pole in July 2022 and persisted for several weeks, a result of the thinner and less compact ice cover that has developed over the last several years.
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Pilot studies in both hemispheres using airborne and satellite-derived information elucidate sea-ice processes that were previously hidden.
Call to action:
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ASPeCt and ASIWG are calling for sustained long-term observatories enhanced by agile marine-science research opportunities to fill the information gaps in both polar sea-ice zones. These will provide information to increase our collective knowledge of Earth system processes, from process understanding to large-scale and long-term effects, such as the effect of loss of sea ice on land ice.
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This will assist in overcoming the recent loss of observing opportunities due to the impacts of the Covid19 pandemic and a general reduction of marine-based science opportunities.
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ASPeCt and ASIWG call for increased climate model-observation collaborations through standardization of sea-ice measurements, revisiting sea-ice nomenclature across sea-ice communities (i.e. jointly with relevant sections in the World Meteorological Organisation), and establishing Essential Sea-Ice Climate Variables, along-side other Essential Climate Variables in the ocean and atmosphere.
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ASPeCt and ASWIG call for stronger distinction, coordination, and complementary linkages across international sea-ice working groups and initiatives. Concurrently, training opportunities, especially for early-career researchers and students and technical staff should be expanded. Together with the Association of Polar Early Career Scientists (APECS), pathways to increased early-career research engagement and leadership opportunities need to be identified.
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ASPeCt and ASIWG note the loss of Copernicus Sentinel-1B (December 2021) severely affecting a range of sea-ice studies. Other satellite-based sensors are currently operating beyond their planned lifetimes without an imminent replacement available, rendering a high risk of losing important long-term climate records.
ASPeCt was founded in 1996 to improve our understanding of the Antarctic sea-ice zone through focussed and ongoing field programmes, remote sensing and numerical modelling. ASPeCt members hail largely from the science community. ASPeCt is an Expert Group under the Scientific Committee for Antarctic Research (SCAR). For more information about ASPeCt, refer to https://aspect.antarctica.gov.au/, contact Dr Petra Heil.
Founded in 2007, ASIWG concentrates on improving the coordination between the sea-ice observation and modelling communities to establish protocols for standardizing and archiving data across the different national and international activities. ASIWG is sponsored by the World Climate Research Programme (WCRP)’s Climate and Cryosphere. For more information about ASIWG, refer to https://climate-cryosphere.org/arctic-sea-ice-wg/, contact Prof Melinda Webster.