This paper presents a methodology for developing a social Cumulative Effects Assessment (CEA) which analyses the impacts of climate change on maritime crime and maritime insecurities. The use of a CEA methodology, including the use of the Effect to Impact Pathway will enable mapping the relationships between certain ‘Activities’ (e.g. human-induced emissions of greenhouse gasses), the ‘Pressure’ engendered (e.g. warming sea temperatures) and their ‘Impacts’ (e.g. food shortages) via ‘Receptors’ (e.g. fishing communities) on specific sectors of society (in this case maritime migration and maritime crime, e.g. illegal fishing). This paper provides a Proof of Concept (PoC) for using such a methodology and shows the applicability of a multidisciplinary approach in understanding causal chains. In this PoC, the authors are generating a Non-Geographic Assessment Map that investigates the ‘Impacts’ that the human-induced greenhouse gas emissions have on maritime security. The proposed analytical tool can then be applied in further studies to assess the dependencies and synergies between climate change and the occurrence of maritime insecurity.