Knowns and Unknowns in Future Human Pressures on the Ocean

Growing demands on ocean resources are placing increasing pressures on ocean ecosystems. To assess the current state of knowledge of future human pressures on the ocean, we conducted a literature review of recent and projected trends of 25 anthropogenic pressures, comprising most of the identified human pressures on the global oceans. To better understand gaps in the data, we developed a comprehensive framework of the activities contributing to each pressure. All pressures were allocated to five categories (biological disruption, disturbance and removal, altered ocean chemistry, pollution, and climate pressures). All pressures are expected to worsen in the future under business-as-usual scenarios (or similar) based on past trajectories and/or models of future scenarios. Eight of the pressures assessed have not been projected into the future (diseases and pathogens, introduced coastal wildlife predation, disruption to sediment dynamics, wildlife strikes, organic and inorganic chemical pollution, light and noise pollution), likely due to the limited availability of data describing current pressures, the challenges of modeling future pressures, and high levels of uncertainty. We thus recommend they receive priority attention to assess their likely future trajectories, given their potential magnitude of influence.