The ocean carbon sink in the Global Carbon Budget and a sneak preview in development and use cases of the ocean biogeochemical model FESOM-REcoM

Based on the 2020 assessment of the Global Carbon Project, the ocean took up on average, 2.5 ± 0.6 PgC yr⁻¹ or 22 ± 5% of the total anthropogenic CO₂ emissions over the decade 2010–2019. This sink estimate is based on simulation results from global ocean biogeochemical models and is compared to data-products based on observations of surface ocean pCO₂ (partial pressure of CO₂) accounting for the outgassing of river-derived CO₂. As the estimate of the ocean sink is not tied to an observational estimate any more since the Global Carbon Budget 2017, an accurate simulation of the mean ocean carbon sink by the models is crucial. In this presentation, I report on an assessment of the models and highlight consistencies and challenges across models and data-based pCO₂ mapping methods.

In the second part of the presentation, I will give an overview of current research and development activities with the ocean biogeochemical model FESOM-REcoM in the framework of the Helmholtz Young Investigator Group MarESys at AWI. This involves simulations of carbon sequestration with Antarctic Bottom Water formation, decadal changes in Arctic primary productivity, the role of polar microzooplankton for carbon transfer to the interior ocean, multiple driver effects on phytoplankton, and fully coupled simulations with the AWI climate model (AWI-CM).