Oil and natural gas represent more than 50 percent of the worldwide energy supply, with high energy demand driven by population growth and improving standards of living. Despite significant progress in reducing the amount of oil in the sea from consumption, exploration, transportation, and production, risks remain. This report, the fourth in a series, documents the current state-of-knowledge on inputs, fates and effects of oil in the sea, reflecting almost 20 additional years of research, including long-term effects from spills such as the Exxon Valdez and a decade-long boom in oil spill...