Climate change threatens marine and coastal ecosystems in the Mediterranean region. Warming, sea level rise, and ocean acidification are occuring there more intensely and rapidly than the global average. A recent study led by GEOMAR Helmholtz Centre for Ocean Research Kiel investigated how strongly marine and coastal ecosystems in the Mediterranean Sea are already at risk, even under comparatively moderate additional warming. For this purpose, 131 scientific studies were evaluated in a thorough meta-analysis. The results have now been published in the journal Scientific Reports.

Temperatures in the Mediterranean are currently rising to record levels. Instead of a refreshing dip, holidaymakers in places like Greece, Italy, and Spain, among other places, are now facing water temperatures up to 28°C or even higher. With an average water temperature of 26.9°C, July 2025 was the warmest since records began for the Mediterranean Sea, according to the Copernicus Earth Observation Service. Warming caused by climate change is considered – alongside stressors such as overfishing, pollution, and habitat destruction – a major factor threatening marine and coastal habitats. “The consequences of warming are not only projections for the future, but very real damages we are witnessing now. The continuing rise in temperatures, sea level and ocean acidification cause severe risks for the environment in and around the Mediterranean Sea,” says Dr. Abed El Rahman Hassoun, Biogeochemical Oceanographer at the GEOMAR Helmholtz Centre for Ocean Research Kiel.

Meta-Study on Climate Change Scenarios

Together with Prof. Dr. Meryem Mojtahid, Professor of Paleo-Oceanography at the University of Angers and at Laboratory of Planetology and geosciences (France), they have investigated the effects of climate change on marine and coastal ecosystems in the Mediterranean region. The projections of the meta-study are based on recognized climate scenarios of the IPCC (Intergovernmental Panel on Climate Change). The research team analyzed 131 scientific studies on Mediterranean published up to August 2023. For the first time, this resulted in a so-called 'burning ember' diagram for Mediterranean marine and coastal ecosystems – a risk assessment tool originally developed by the IPCC.

“The diagram clearly shows how strongly climate change threatens key ecosystems. I hope our results will help raise awareness and inspire real action to protect these unique ecosystems,” says Meryem Mojtahid. The study also draws on the Research Initiative on Climate Change and Environmental Degradation in the Mediterranean Region (MedECC). In 2020, the initiative published the first Mediterranean Assessment Report under the name MAR1, thus playing a key role in consolidating knowledge on climate and environmental changes in the Mediterranean area.

Read the full article about the impacts of climate change on the Mediterranean Sea at GEOMAR.