Two key recommendations of the GESAMP report (2019) are the establishment of a comprehensive assessment framework for marine CDR and the formulation of a guidance document that can be used to elicit assessment criteria for marine CDR. ASMASYS is addressing these recommendations and will develop a holistic framework that includes indicators of environmental impact, benefits, risks, and scalability, as well as incorporating legal, political, societal, economic and ethical aspects, thus going beyond the assessment criteria presented in the 1.5°C Special Report (IPCC 2018).