Actions should aim at developing innovative approaches to:

• improve the monitoring, understanding, reporting and projections of essential biogeochemical oceanic processes related to climate and changes over time at regional or sea basin scale (oxygen, nutrients, inorganic carbon, transient tracers, nitrous oxide, ocean color, particulate matter, dissolved organic carbon, elemental and isotopic tracers, stable carbon isotopes, marine debris); integrate multidisciplinary observation systems (in-situ, airborne, satellite) and improved models;
• inform models and improve predictions of the Earth system response to ocean acidification and to the ocean biological pump, including the long-term trends in ocean chemistry, beyond the observational record (paleo-ocean acidification), for a better understanding of the multi-decadal reversibility or the hysteresis of ocean processes (like the AMOC). Links should be made with ocean stratification that acts as barrier for water mixing or carbon sequestration;
• support the development of the ocean component of climate models through a better representation of essential biogeochemical processes, microbe biomass and diversity and enable a better understanding of the links between ocean physical and biogeochemical variability and ocean stratification; the action should contribute to the integration of more biogeochemical parameters, assimilation techniques, models and assessment strategies into ESMs;
• combine GHG measurements in regions especially critical for GHG fluxes with relevant biogeochemical measurements (e.g., oxygen, nutrients, carbon) to support GHG data analyses and model simulations to improve the understanding of ocean biogeochemical fluxes and turnover of carbon and nitrogen and the quantification of fluxes between basins/regimes and across interfaces (air-sea, water-sediment); focus should be on quantifying GHG reservoir size and change, and potential subsequent impact on GHG fluxes, ocean productivity, ocean acidification, carbon sequestration, oxygen demand and carbonate system.

The action should also address the interplay between carbonate chemistry and a variety of biogeochemical and physical processes, including eutrophication and freshwater inflow and outflow in coastal zones. The action should further research the net response of natural ocean CH4 and N2O sources to future warming, including permafrost, and predict the magnitude and timing of the responses of each individual process.

Where appropriate, the combination of multiple drivers and/or hazards that contribute to societal and/or environmental risk should be assessed. Actions should identify safe operating spaces for the ocean to provide life-support systems for humanity and the planetary ecosystems, accompanied – where relevant – with long-term strategies for preventing or mitigating impacts.

International cooperation will be essential in integrating and coordinating these different scaled approaches.

This topic is part of a coordination initiative between the European Space Agency and the European Commission on Earth System Science. Under the initiative, both institutions aim at coordinating efforts to support complementarities between the Horizon Europe and the European Space Agency FutureEO programmes, and their projects. Proposals under this topic should address networking and collaborative research activities with relevant European Space Agency actions. Proposals should address the collaboration with ongoing or future ESA projects, including those that will be funded through dedicated coordinated invitations to tender, and should towards this end include sufficient means and resources for effective coordination.