In the framework of the Paris agreement, various countries set up their own Net-Zero emission goal (e.g., China 2060 and Germany 2045). However, even with the most ambitious emission reduction and avoidance effort, there will still be residual emissions, which need to be compensated by the Carbon Dioxide Removal (CDR) methods in order to achieve the 1.5-degree warming climate target (IPCC, 2022). Therefore, both China and Germany have included CDRs into their national Net-Zero strategy (He et al., 2022; Luderer et al., 2021).

Implementation of any type of CDR requires a careful assessment from various perspectives, including the effectiveness of CDR and its environmental impacts (Förster et al., 2022; GESAMP, 2019). The National Academies of Sciences (2022) report on marine-based CDR suggests that the knowledge base in various methods is inadequate. They emphasize that the effectiveness in the time-scale relevant to the societal policy decisions need further investigation, and the environmental impacts should be identified and quantified. Ideally, primary field tests for a CDR should be conducted followed up with the up-scaling experiment in order to advance our understanding, yet, the London Protocol discourages such endeavor (GESAMP, 2019). Meanwhile business cannot wait to tap into the emerging market of CDR (e.g., the Vista project, olivine dissolution in Southampton, New York). This increases the demand for models to provide information, beyond the general proof of concept research that has so far been conducted. Such work into the implementation details and the intended effects and the possible side effects raises the question of whether or not current models include the necessary process understanding of various CDR approaches.  

Earth system models have great potential to investigate the effectiveness, the long-term fate of the sequestrated carbon, and the biogeochemical implications for large-scale CDR deployments (e.g., Reith et al., 2016; Sonntag et al., 2018; Wu et al., n.d.). Here we present the preliminary results from a meta-analysis of scientific publications on modeling a selection of marine-based CDR options (e.g., alkalinity enhancement, blue carbon, artificial upwelling, and iron fertilization). We have identified modelling gaps by comparing the list of information required by an existing CDR assessment framework (i.e., Hicam; Förster et al., 2022) with the capacity of the “state-of-the-art” models. We will then make recommendations for further model developments amending those gaps.