Ice cores provide a wealth of information about past climate and environmental conditions as well as direct records of the composition of the atmosphere on timescales from decades to hundreds of millennia. This comprises deep ice cores from both polar ice sheets and from high-altitude glaciers, with the latter responding most sensitively to human interaction with the Earth system.

In October 2022 the 3rd Open Science Conference of the International Partnerships of Ice Core Sciences (IPICS) takes place in Crans-Montana, Switzerland, providing the opportunity to document the status quo of ice core research including comparative studies on other climate archives and climate models in this joint special issue of Climate of the Past and The Cryosphere: "Ice core science at the three poles".

Potential topics of contributions include the latest results from polar and high-altitude ice cores, integrative science on ice cores, climate models and other climate archives, new proxies, and other ice-core-related technology developments. In particular, we invite ice-core-related contributions on the following themes.

1. Glacial–interglacial dynamics, interglacials, and sea level
2. Holocene and the last 2000-year climate forcings and variability
3. Progress in proxy development and interpretation
4. Ice dynamics, ice sheet instability, and geophysics
5. High-alpine ice cores
6. Ice biology, basal ice, and subglacial lakes
7. Pollution records
8. Advances in drilling engineering and borehole observations
9. Timescales and methods for ice dating
10. Rapid changes and teleconnections
11. Biogeochemical cycles in the Earth system – data and models
12. New ice archives
13. The Oldest Ice challenge and the preservation of climatic signals in the deepest ice.

The glacial–interglacial cyclicity of the climate system varied in the past, most notably during the transition from a 40 ka to a 100 ka world in the mid-Pleistocene. Gases trapped in Antarctic ice are the most direct access available to investigate the composition of the paleo-atmosphere of that age and processes related to climate variability. The International Partnerships in Ice Core Sciences (IPICS) Oldest Ice endeavour aims at obtaining an undisturbed ice-core record older than 1 Ma. In addition to ice cores, time slices of paleo-records, available, for example, in Antarctic blue-ice fields, provide further valuable information, which complements continuous time series based on ice cores. This special issue will assemble contributions dedicated to the preparatory phase of this global effort to obtain ice samples and time series older than 700 000 years. This includes a consideration of glaciogical and geophysical settings which allow the presence of old ice, results from pre-site surveys and modelling studies, aspects of ice-core and other sampling techniques and analyses, and requirements for drilling and core handling.

The Weddell Sea and the ocean off Dronning Maud Land, constituting the Weddell Gyre, are representative of the high-latitude Southern Ocean due to its pronounced seasonality, circumpolar currents, deep-water formation and seasonal sea-ice cover. The Weddell Gyre connects water masses from the Antarctic Circumpolar Current with those shaped by the large ice shelves and sea-ice formation in the southern perimeter of the Weddell Gyre. Biological and biogeochemical processes are strongly influenced by these conditions and contribute to a unique Weddell Sea ecosystem.

A portion of the western Weddell Sea is already experiencing consequences of climate change, including the acceleration of mass loss from ice shelves, enhanced ocean warming and freshening, rising air temperatures, and changes in wind patterns. This likely has an emerging influence on the local biological and biogeochemical processes. The eastern part of the Weddell Gyre, off Dronning Maud Land, however, appears relatively stable but is expected to experience warming, sea-ice retreat and ice-shelf loss in the course of this century. The re-emergence of the Maud Rise Polynya, with a potentially significant impact on regional water masses and biogeochemistry, underscores the importance of observing and understanding this region. Establishing knowledge of the present biological and biogeochemical processes and coupling with physics prior to major changes in this region is essential.

This special issue emerged from an October 2020 workshop organized by the Southern Ocean Observing System (SOOS) Weddell Sea and Dronning Maud Land Regional Working Group that brought together numerous scientists across multiple disciplines. However, the issue is open to anyone and we welcome additional contributions.

Ice cores provide a wealth of information about past climate and environmental conditions as well as direct records of the composition of the atmosphere on timescales from decades to hundreds of millennia. This comprises deep ice cores from both polar ice sheets and from high-altitude glaciers, with the latter responding most sensitively to human interaction with the Earth system.

In October 2022 the 3rd Open Science Conference of the International Partnerships of Ice Core Sciences (IPICS) takes place in Crans-Montana, Switzerland, providing the opportunity to document the status quo of ice core research including comparative studies on other climate archives and climate models in this joint special issue of Climate of the Past and The Cryosphere: "Ice core science at the three poles".

Potential topics of contributions include the latest results from polar and high-altitude ice cores, integrative science on ice cores, climate models and other climate archives, new proxies, and other ice-core-related technology developments. In particular, we invite ice-core-related contributions on the following themes.

1. Glacial–interglacial dynamics, interglacials, and sea level
2. Holocene and the last 2000-year climate forcings and variability
3. Progress in proxy development and interpretation
4. Ice dynamics, ice sheet instability, and geophysics
5. High-alpine ice cores
6. Ice biology, basal ice, and subglacial lakes
7. Pollution records
8. Advances in drilling engineering and borehole observations
9. Timescales and methods for ice dating
10. Rapid changes and teleconnections
11. Biogeochemical cycles in the Earth system – data and models
12. New ice archives
13. The Oldest Ice challenge and the preservation of climatic signals in the deepest ice.

The Weddell Sea and the ocean off Dronning Maud Land, constituting the Weddell Gyre, are representative of the high-latitude Southern Ocean due to its pronounced seasonality, circumpolar currents, deep-water formation and seasonal sea-ice cover. The Weddell Gyre connects water masses from the Antarctic Circumpolar Current with those shaped by the large ice shelves and sea-ice formation in the southern perimeter of the Weddell Gyre. Biological and biogeochemical processes are strongly influenced by these conditions and contribute to a unique Weddell Sea ecosystem.

A portion of the western Weddell Sea is already experiencing consequences of climate change, including the acceleration of mass loss from ice shelves, enhanced ocean warming and freshening, rising air temperatures, and changes in wind patterns. This likely has an emerging influence on the local biological and biogeochemical processes. The eastern part of the Weddell Gyre, off Dronning Maud Land, however, appears relatively stable but is expected to experience warming, sea-ice retreat and ice-shelf loss in the course of this century. The re-emergence of the Maud Rise Polynya, with a potentially significant impact on regional water masses and biogeochemistry, underscores the importance of observing and understanding this region. Establishing knowledge of the present biological and biogeochemical processes and coupling with physics prior to major changes in this region is essential.

This special issue emerged from an October 2020 workshop organized by the Southern Ocean Observing System (SOOS) Weddell Sea and Dronning Maud Land Regional Working Group that brought together numerous scientists across multiple disciplines. However, the issue is open to anyone and we welcome additional contributions.

The glacial–interglacial cyclicity of the climate system varied in the past, most notably during the transition from a 40 ka to a 100 ka world in the mid-Pleistocene. Gases trapped in Antarctic ice are the most direct access available to investigate the composition of the paleo-atmosphere of that age and processes related to climate variability. The International Partnerships in Ice Core Sciences (IPICS) Oldest Ice endeavour aims at obtaining an undisturbed ice-core record older than 1 Ma. In addition to ice cores, time slices of paleo-records, available, for example, in Antarctic blue-ice fields, provide further valuable information, which complements continuous time series based on ice cores. This special issue will assemble contributions dedicated to the preparatory phase of this global effort to obtain ice samples and time series older than 700 000 years. This includes a consideration of glaciogical and geophysical settings which allow the presence of old ice, results from pre-site surveys and modelling studies, aspects of ice-core and other sampling techniques and analyses, and requirements for drilling and core handling.