Welcome to the Addressing Sargassum Challenge and Opportunity VCC. We aim to develop a concept for a value chain from sargassum in the ocean to end users of products created out of sargassum and to facilitate pilot projects in different locations as a proof of concept. We provide comprehensive information on sargassum and an assessment of the risks for the marine biosphere and humanity associated with the repeated blooms of sargassum. The risk assessment can inform risk governance and facilitate the development of interventions to adapt and mitigate the impacts of the blooms. The Sargassum VCC aims to support governmental and private economic activities to mitigate the sargassum risk and to explore opportunities and benefits.