A carbon dioxide sequestration method characterised in that it comprises: - a step of producing at least one macrophytic plant species floating on an expanse of fresh water in order to form a raft of plant biomass; - a step of transporting said raft of plant biomass from said expanse of fresh water to a sea; - a step of dispersing and decomposing said raft of plant biomass on an expanse of said sea; at least one of said production step, transport step and dispersion and decomposition step being carried out with human assistance.
