TRICUSO: Three Research Infrastructures: Carbon Uptake Southern Ocean

The ocean plays a key role in the Global Carbon Cycle, taking up about 25% of the carbon dioxide we emit to the atmosphere, thus slowing climate change and giving us more time to put in place mitigation and adaptation actions. We know this because of a linked series of activities, the ocean carbon value chain, which begins with in water observations of ocean CO₂ levels, then links these to data synthesis and mapping / product generation actions. This then allows multiple estimates of ocean CO₂ uptake to be made annually which are reported to the COP by the Global Carbon Budget. The Ocean component of the Integrated Carbon Observing System (ICOS) plays a key role in the European element of this data gathering exercise via providing high quality reference observations to sit alongside similar observations from different regions. Key areas of action underway to improve this system include:

• The urgency of the climate crisis has lead the WMO to propose the construction of a ‘Global Greenhouse Gas Watch’, or G3W. This will require an ocean element operating across the globe and to this end we have proposed that GOOS (the Global Ocean Observing System) should endorse a surface ocean CO₂ network (SOCONET) that will form the core of the WMO effort, incorporating ICOS and other observing networks.
• The Global C Project estimates of Ocean C uptake based on in water observations are systematically higher than those made by models. There are (at least) 2 ways that this issue can be addressed: model analyses suggest that a much greater density of observations in undersampled regions such as the Southern Ocean can address this, in addition expanding the set of platforms used to acquire data to include ARGO and GOSHIP is likely to be beneficial.

Both actions 1 and 2 are being supported by an ICOS lead project TRICUSO, Three Research Infrastructures: Carbon Uptake Southern Ocean which will initiate in Jan 2025.