Ocean-Cryosphere Exchanges in ANtarctica: Impacts on Climate and the Earth System (OCEAN:ICE)

Start date
1 November, 2022
End date
31 October, 2026


OCEAN:ICE will assess the impacts of key Antarctic Ice Sheet and Southern Ocean processes on Planet Earth, via their influence on sea level rise, deep water formation, ocean circulation and climate. An innovative and ambitious combination of observations and numerical models, including coupled ice sheet-climate model development, will be used to improve predictions of how changes in the Antarctic and Greenland ice sheets impact global climate. It will make new circumpolar and Atlantic observations in observational gaps. It will assimilate these and existing data into improved ice sheet boundary conditions and forcing, producing new estimates of ice sheet melt and impacts on ocean circulation, including the Atlantic Meridional Overturning circulation. It will develop, calibrate and assess models used to predict the future evolution of the giant ice sheets. It will reduce the deep uncertainty in the impact of their melt on societally relevant environmental changes on decadal to multi-centennial time scales. It will assess the potential for passing ice sheet ‘tipping points’ and their consequences for ocean circulation and climate.




Uncertainty in sea-level rise (SLR) predictions is dominated by the unknown future rate of Antarctic Ice Sheet (AIS) mass loss. Key to this are the processes that deliver heat from the Southern Ocean to the AIS, govern ice sheet response to the resultant melting, and control meltwater feedbacks onto ocean circulation. These processes currently have large uncertainties, due to our limited understanding of and ability to model the ice-covered polar oceans, the ice sheets, and their response to changes in the atmosphere and the ocean. Many of the knowledge gaps concerning heat delivery to the AIS and consequences thereof originate in the paucity (or complete absence) of relevant observations. Recent mass loss from the AIS has accelerated, believed to be driven by increased ocean heat transport to the base of the ice shelves and retreat of their grounding lines. However, the processes controlling this ocean heat transport are not well understood.

In addition to SLR impacts, increased freshwater discharge from the ice sheets into the ocean carries the potential for profound impacts on global ocean circulation. The deep circulation is of key importance for global storage of heat, CO2, oxygen and nutrients: Once in the abyss, they may be stored for decades to centuries. Critically, existing climate models do not adequately represent the feedbacks between ocean and ice sheets, and often neglect them altogether. Progress requires improved understanding of key ocean-ice processes, including the oceanic delivery of heat, dynamic response of ice sheets to melting beneath floating ice shelves and icebergs, surface driven melt, supraglacial/subglacial runoff, and the thinning and collapse of ice sheets in response to instabilities generated by such melting.

Building on an extensive network of European and international collaborations, OCEAN:ICE will deploy an ambitious and innovative combination of remote sensing, ocean and ice sheet observations, novel data processing techniques and numerical models to significantly improve our understanding and ability to predict these processes and their impacts. A defining feature of OCEAN:ICE will be the use of this deeper understanding to inform, evaluate and refine coupled ice sheet-ocean-climate models, the principal and rapidly developing scientific tools used to study these regional and global feedbacks. Using these models, as well as robust numerical approaches to uncertainty, we will produce the most comprehensive assessment to date of how increased freshwater discharge and oceanic feedback will impact global SLR and other critical climate parameters over the coming decades and centuries. This will directly reduce the present ‘deep uncertainty’ in key socio-economic metrics, such as SLR, global surface temperature, ocean heat and carbon content and acidification. It provide policy relevant advice to support decadal to multi-centennial planning horizons and assess the potential for rapid ice sheet melt to trigger cascades of tipping points, e.g. involving changes in the Atlantic Meridional Overturning Circulation (AMOC).

OCEAN:ICE has drawn together a truly interdisciplinary consortium, connecting world-leading European ice sheet and ocean modellers with in situ and remote sensing scientists specialising in polar and global ocean circulation and ice-ocean-atmosphere interactions, as well as specialist policy experts and communicators. By doing so, OCEAN:ICE will advance state-of-the-art coupled ice sheet-climate modelling delivered by the developers of leading European climate models. Through the consortium’s strong European and international connections and memberships within international research programs, OCEAN:ICE has assembled a constellation of project partners to provide logistical and scientific collaboration across the remote and challenging Antarctic, Southern Ocean and Atlantic. The regional-circumpolar-global view of the role of Antarctica, the Southern and global ocean in Earth’s climate thus obtained will deliver a milestone assessment of the oceanic and polar process contribution to climate change. To ensure efficient coordination, delivery and communication of the project objectives at the international climate assessment and policy level OCEAN:ICE will interface with and directly contribute to: European and international observing initiatives (e.g. the All-Atlantic Ocean Research Alliance); international science coordinating bodies (e.g. the Global/Southern Ocean Observing System (G/SOOS)); intercomparsion projects (e.g. Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6/7)) and assessments (e.g. the Intergovernmental Panel on Climate Change (IPCC), World Ocean Assessment (WOA)); and European data centres (e.g. Copernicus Marine Environment Monitoring Service (CMEMS), EMODnet) and policy interface bodies (e.g. EU-PolarNet 2).

Funders and Participants

OCEAN:ICE is co-funded by the European Union, Horizon Europe Funding Programme for research and innovation under grant agreement Nr. 101060452 and by UK Research and Innovation. OCEAN:ICE brings together 17 centres from across the EU and UK, was well as numerous partner nations and organisations.

EU partners:

The project involves five associated partners located in UK:



  1. Silvano A, Purkey S, Gordon AL, Castagno P, Stewart AL, Rintoul SR, Foppert A, Gunn KL, Herraiz-Borreguero L, Aoki S, Nakayama Y, Naveira Garabato AC, Spingys C, Akhoudas CH, Sallée J-B, de Lavergne C, Abrahamsen EP, Meijers AJS, Meredith MP, Zhou S, Tamura T, Yamazaki K, Ohshima KI, Falco P, Budillon G, Hattermann T, Janout MA, Llanillo P, Bowen MM, Darelius E, Østerhus S, Nicholls KW, Stevens C, Fernandez D, Cimoli L, Jacobs SS, Morrison AK, Hogg AM, Haumann FA, Mashayek A, Wang Z, Kerr R, Williams GD and Lee WS (2023) Observing Antarctic Bottom Water in the Southern Ocean. Front. Mar. Sci. 10:1221701. doi: 10.3389/fmars.2023.1221701


Specific OCEAN:ICE objectives are to:

O1: Reduce the spatial and knowledge gaps in ocean observations around Antarctica, particularly relating to ice sheet-ocean interaction and deep water formation and export. This will assess the oceanic controls on heat and freshwater delivery to and from ‘cold’ (e.g. Weddell Sea) as well as ‘warm’ (Amundsen Sea) sites of ice sheet-ocean interaction around Antarctica, and the processes that control mixing, water mass formation and export over the continental shelves and subpolar basins.

O2: Improve critical ice sheet-ocean processes in numerical models, using historical observations and new data sets obtained in the project. Particularly under warm and cold ice shelves and around grounded icebergs, including vertical/horizontal mixing, ocean heat delivery, iceberg interactions with sea-ice and bathymetry and basal melt. Implement these improvements in coupled ice sheet-ocean and ice sheet-climate models.

O3: Improve representation of AIS dynamics and integrate this knowledge into ice sheet and coupled ice sheet-climate models. By using new and existing datasets to improve ice sheet model initialisation and quantifying the uncertainty in present day freshwater fluxes from Antarctica due to climate variability, dynamical processes (calving, ice flow) and surface/basal mass balance (surface runoff, basal melt).

O4: Quantify AIS melt sensitivity to climate forcing and reduce the ‘deep uncertainty’ in freshwater flux and SLR projections to 2300. By combining newly developed coupled ice sheet-ocean models with innovative quantification of uncertainty and improved initialisation setups. This will produce projections of the contributions by basal meltwater, iceberg calving and surface runoff for a range of future climate scenarios, including tipping points.

O5: Assess how global ocean circulation is impacted by freshwater discharge from the northern and southern ice sheets. Map the pathways and variability of Antarctic Bottom Water as it spreads north. Assess how this and other freshwater input modifies climatically relevant ocean features such as North Atlantic Deep Water formation, the deep overturning circulation, the Antarctic Circumpolar Current (ACC) and AMOC up to millennial timescales.

O6: Assess the ocean impact on, and feedbacks between, key global climate metrics (e.g. SLR, global mean surface temperature) and polar ice sheet melt to 2300 and beyond. This will be achieved by combining the improved melt scenarios, initialisation and model parameterisations, notably the representation of icebergs and ice shelf processes, within coupled ice sheet-climate models. It will establish the impact and likelihood of ice sheet melt scenarios, including passing tipping points, and global consequences such as SRL and AMOC state change.

O7: Deliver free and open access to all data obtained in the project and contribute to international assessments (e.g. IPCC), climate model development, multi-national ocean observing initiatives (e.g. SOOS, All-Atlantic Ocean Research Alliance) and policymakers. Data consolidation and delivery will be achieved through close integration with SOOS, EMODnet and Copernicus data delivery services and will follow FAIR principles and be INSPIRE compliant. Direct partnership with SOOS, SAMOC, EPB, EU Polar Cluster, EU-Polarnet 2, and other European and international programmes, as well as the high-level involvement of investigators in international science coordination, climate assessment and policy bodies will maximise the reach and impact of OCEAN:ICE.


ocean ice overview