The 2025 Annual Report of the Coastal Observation System of the Balearic Islands (SOCIB) confirmed that the Balearic Islands experienced the warmest year in their history in terms of sea surface temperature, in a context of continued ocean warming throughout the Mediterranean basin.
The waters reached up to 6.5 °C above the historical average (1982-2015) in some areas, and 190 days of marine heatwaves were recorded across the Mediterranean.
Monitoring Tools
The report Annual Report 2025: Global Warming Impacts in the Mediterranean Sea and Balearic Islands Region was prepared with:
- Satellite observations from the Copernicus program.
- Coastal buoys.
- Underwater gliders.
- Autonomous profiling floats.
These systems allowed for the measurement of key oceanic indicators such as temperature, salinity, and sea level.
Ocean Records in 2025
SOCIB scientist Mélanie Juza highlighted that the year brought new records in:
- Ocean temperatures.
- Salinity in the eastern Mediterranean.
- Sea level, with an acceleration in the upward trend.
Since 1993, the basin has recorded an average increase of 3.4 cm per decade, with higher rates in some subregions. In the Balearic Islands, 2025 surpassed the records of 2023 and 2024.
Marine Heatwaves
Marine heatwaves are defined as periods when the surface temperature exceeds the 90th percentile of historical values for at least five consecutive days.
In 2025:
- The Mediterranean accumulated 190 days under these conditions.
- Average intensities exceeded 4 °C above the historical average.
- In the Liguro-Provençal area, on July 2, values of 6.5 °C above normal were reached, reaching nearly 8 °C in coastal areas of the Gulf of Lion.
- In the Balearic Islands, during the extreme heatwave of June-July, the regional surface temperature reached 28.4 °C, and coastal buoys recorded values close to 31 °C.
Global Context
The period 2023-2025 marked the first three-year average above 1.5 °C compared to pre-industrial levels. Globally, 2025 was the third warmest year on record, even without the influence of El Niño.
The Mediterranean shows a warming rate of 0.4 °C per decade since 1982, with marked regional variability.
Ecological and Social Impacts
SOCIB warns that the increase in ocean temperatures and the intensification of marine heatwaves generate far-reaching effects:
- Greater stratification of the water column.
- Lower oxygen availability.
- Threats to key habitats, such as Posidonia oceanica meadows.
- Risks to fishing and tourism, vital sectors in the region.
- Increased exposure to extreme events, coastal flooding, and risks to human health.
The Mediterranean Sea is consolidating as an epicenter of ocean warming, with impacts that go beyond the environmental and directly affect the economy and daily life in coastal communities.
Scientific evidence reinforces the need for urgent adaptation and mitigation strategies, both locally and globally, to face a future marked by increasingly frequent and intense marine heatwaves.
