The successful deployment of carbon capture and storage as a means to mitigate greenhouse gas emissions requires the availability of significant geological storage capacity. Assessments that identify suitable sedimentary basins and their capacity are the first logical step in defining global carbon capture and storage potential. This paper presents a collation and summary of the current status of storage assessments worldwide known as the Global Storage Portfolio. The analysis found that there are substantial storage resources available in most regions of the world. Almost all nations that have published regional assessments have identified sufficient storage resources to support multiple carbon capture and storage projects. This analysis also found that the methods to determine and classify resources are highly variable across regions despite reliable assessment methodologies being available. Case studies on Europe and Southeast Asia discuss the different approaches being undertaken for their respective regional assessments and their progression towards being ready for the deployment of CCS.