The global ocean is experiencing “severe and accelerating” pressure from human activities, with the rate of sea-level rise more than doubling over the past decade. This is according to the third report from the UN’s World State of the Ocean Assessment. The document was compiled by nearly 600 scientists from 86 countries and covers the period from 2021 to 2025. The previous assessment, published in 2021 and analyzing data up to 2018, already documented a steady decline in the health of the marine environment. The new research indicates that negative trends are continuing to intensify.
The report’s authors highlight that the combined impact of pollution, climate change, intensive industrial fishing, and other anthropogenic factors is leading to biodiversity loss and exerting “serious pressure” on oceanic ecosystems. One of the most alarming indicators has been the accelerating pace of sea-level rise. While the global ocean rose by an average of 2 mm per year until 2015, by 2023, this figure had reached 4.3 mm annually. Furthermore, scientists estimate that 16% of all the heat energy accumulated by the ocean since 1955 occurred after 2018.
The most noticeable relative warming has been recorded in the Atlantic Ocean, as well as in the southern parts of the Indian and Pacific Oceans. The researchers emphasize that scientific understanding of many processes remains limited. By 2025, maps of only 27% of the ocean floor have been completed, leaving a significant portion of deep-sea ecosystems largely unexplored.
UN Secretary-General António Guterres stated that humanity can no longer afford to view the ocean as an inexhaustible resource. According to his remarks, as reported by The Guardian, urgent international cooperation is necessary to protect marine ecosystems, based on scientific evidence, international law, and shared state responsibility.
The report also notes some progress in marine environmental protection. Specifically, the treaty on the high seas, which establishes international rules for the protection of ocean areas beyond national jurisdictions, entered into force this year. According to the UN, this document, along with 56 other international agreements, has enhanced states’ capacity to conserve biodiversity, reduce harmful subsidies, and manage marine resources. However, the existing ocean governance system remains fragmented, both sectorally and regionally. The study’s authors consider strengthening coordination among countries and international organizations to be critically important.
The ocean covers over 70% of the Earth’s surface and plays a crucial role in regulating climate. The report indicates that it has already absorbed approximately 90% of the excess heat generated by global warming, as well as about 30% of the carbon dioxide released into the atmosphere from burning fossil fuels.
Researchers also draw attention to the issue of plastic pollution. They estimate that approximately 52.1 million tons of plastic waste enter the ocean annually. This contributes to the formation of 24.4 trillion microplastic particles, negatively affecting over 4,000 species of marine organisms. The report’s authors identify population growth, technological advancements, changes in governance systems, and socio-economic and geopolitical instability as long-term drivers of pressure on the ocean. The global population has increased from 7.7 billion people in 2017 to 8.2 billion by the end of 2024. More than a third of the planet’s inhabitants live within 100 km of the coast, and about 11% of the population resides in areas less than 10 meters above sea level.
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