The third United Nations Ocean Conference (UNOC3) provided an opportunity to discover the first annual global report on the health of the oceans. The report, which uses advanced digital modelling methods to reconstruct past trends and project future developments in ocean systems, paints an alarming picture. Each peer-reviewed finding is robustly reflected in the design of a new tool: the Starfish Barometer. This health barometer, shaped like a starfish, is more than just a snapshot of the current situation. It ranks anthropogenic pressures and highlights the interactions between these factors and marine ecosystems. This new barometer is intended to serve as a long-term indicator for monitoring the health of the ocean.
by Laurie Henry
Cover photo : Starfish barometer © M. Lévy et al., 2025
Health indicators flashing red
For the moment, data from the Starfish Barometer reveals a worrying trajectory for the ocean. Since 1901, the average sea level has risen by 23 centimetres, an acceleration attributed to global warming and thermal expansion of the waters, as well as the melting of ice caps. By 2024, it will reach a record high, increasing the vulnerability of coastal areas, where nearly 40% of the world’s population lives. Ocean temperatures are following the same trend, with 2024 exceeding the previous record by 0.25°C at the surface, illustrating an unprecedented accumulation of heat recorded over more than 64 years of measurements.