A new United Nations assessment says the world’s oceans are under “severe and accelerating” pressure from human activities, including pollution, large-scale industrial fishing, and the climate crisis. The report finds that stresses are cumulative and intensifying, contributing to widespread biodiversity loss and placing ocean systems under “severe strain.” The UN’s third World Ocean Assessment compiles findings from nearly 600 scientists across 86 countries and evaluates ocean conditions from 2021 to 2025. It compares its conclusions with earlier assessments, which found persistent degradation of the marine environment. One highlighted change is the acceleration of sea-level rise: the rate increases from about 2 millimeters per year before 2015 to about 4.3 millimeters per year in 2023, according to the report summarized in the coverage. The assessment also describes continued ocean warming, including that a notable share of global ocean heat increase since 1955 occurs after 2018, and notes that some ocean regions experience relatively greater warming. The report emphasizes remaining knowledge gaps, including limited mapping of the ocean floor and limited understanding of deep-sea ecosystems.