The rate of global mean sea-level rise reached 4.3 mm per year in 2023, up from 2 mm per year before 2015, the UN’s third World Ocean Assessment finds; the report also calculates that 16% of the increase in ocean heat since 1955 occurred after 2018. The assessment, reflecting work by nearly 600 scientists from 86 countries over 2021–25, notes that only 27% of the ocean floor had been mapped by 2025, leaving deep-sea ecosystems poorly understood, and that 52.1 million tonnes of plastic enter the ocean annually, contributing to 24.4 trillion microplastic particles affecting more than 4,000 marine species. The warning arrives less than a week after the U.S. National Science Foundation moved to dismantle the Ocean Observatories Initiative’s in-water infrastructure and scientists cautioned the loss would leave the world “flying blind.”
Context
National Science Foundation moved to dismantle the Ocean Observatories Initiative’s in-water infrastructure and scientists cautioned the loss would leave the world “flying blind.”
