Coastal Changes in the Balearic Islands and the Wider Western Mediterranean
The rising sea level off the coast of Spain is increasingly noticeable and its impact will intensify in the coming years. A recent public study highlights the Balearic Islands as a clear example of broader Mediterranean trends: beaches are under threat, and many could shrink dramatically or disappear by the end of the century.
Projections for the Balearic beaches suggest a retreat of seven to fifty meters by century’s end. If sea level climbs between 57 and 75 centimeters, as outlined in the latest Balear Sea Report released by regional institutions, many shorelines already under 50 meters wide will vanish within the next eight decades.
Scientific observations indicate that sea level rise in the western Mediterranean has accelerated. After a long period averaging 1.32 mm per year over 134 years, the rate has risen to 3.00 mm per year in the last 39 years. In the most recent 26 years the pace is 3.29 mm annually, signaling ongoing acceleration and stronger potential impacts on coasts and beaches.
The report identifies the areas most at risk as the southwestern, southern, and eastern parts of Ibiza and Mallorca.
The Balearic Sea Report, a collaborative effort of major marine research centers, the Balearic Government and the Marilles Foundation, was published in its 2021 edition after wide participation from public and private institutions. It encompasses around 150 indicators and involved about 98 professionals, including researchers and administrative staff. The document underscores that the coastal natural environment is under pressure not only for its scenic value but also for tourism, which relies heavily on pristine beaches.
Beyond sea level rise, ongoing coastal development such as marinas, parking facilities and other infrastructure, along with sustained tourist use, alters sediment dynamics and coastal currents. These combined pressures can cause the sand to recede substantially. A striking example is Es Trenc in Mallorca, where sand loss averaged 5.7 meters from 1956 to 2015, with portions of the beach losing up to 19 meters during the same period.
One criticism highlighted by the report is the inadequate management of dry posidonia meadows on beaches. These underwater and shoreline meadows help shield coastlines from storms; their removal weakens beaches and makes them more vulnerable to wave action, often driven by tourism pressures.
The Plastic Footprint and Fishing in the Balearics
The Balearic coast remains a hotspot for plastic accumulation in the Mediterranean. Surface trawls documented plastic debris across sampling sites, and plastic was found on the seafloor in a majority of the areas studied. In the Serra de Tramuntana region on Mallorca, the seafloor carried notable quantities of plastic debris, ranging from 30 to 40 kilograms per square kilometer. Overall, 66 percent of sampling points showed plastic presence on the seafloor, with densities averaging between 2.7 and 0.3 kilograms per square kilometer. Yet, 82 percent of Balearic coastal points in 2020 were rated as having excellent bathing water quality, though urban beaches often displayed lower water quality readings.
Meanwhile the region’s professional fishing industry has faced decline since 1950, with a 78 percent drop in boats and a 90 percent drop in crew. Between 2002 and 2020, commercial catch fell from 3,900 tons to 2,400 tons. The record of marine life continues to be tracked, with a 1993–2020 window noting 1,000 turtle strandings in Balearic waters, including 1,058 individuals, of which 512 were alive and 546 were deceased. In 2020, 83 stranded turtles were recorded, with 30 dead and 53 alive, and 47 surviving. Deeper waters harbor endangered and near threatened deep-sea corals such as bamboo coral, sea fans, red coral, and black coral, which sustain biodiversity where light is scarce and provide essential habitats for marine ecosystems. These species underscore the ecological importance of offshore habitats and the need for protective measures to maintain biodiversity and coastal resilience.
The Human Pressure on the Islands During the Pandemic
The COVID-19 health crisis in 2020 left a clear mark on indicators of human pressure, including shipping, underwater noise, beach use and the overall human pressure index. The peak HPI figure in 2020 was over 1.6 million, compared with over 2 million in the prior high in 2017. The index dropped by roughly 21 percent versus 2019 as travel and tourism slowed dramatically. Tourist numbers fell from about 16.5 million to around three million in 2020, a reduction exceeding 80 percent, and passenger ship movements decreased by approximately 95 percent. The Balearic advisory council that supports the Balearic Sea Report includes multiple institutions, ranging from oceanographic centers and universities to environmental observatories and government agencies. The full report can be explored through the official Balearic Sea Report portal, with the citation noted for reference. [Cited: Balearic Sea Report, 2021 edition] The environmental department maintains ongoing monitoring efforts and data collection to inform policy decisions and conservation strategies.
Overall, the Balearic Islands face a convergence of threats: coastal erosion from sea level rise, altered sediment regimes due to construction and traffic, pollution pressures from plastic, and changing ecological conditions in shallow and deep waters. The ongoing research and public reporting aim to support resilient coastlines, sustainable tourism, and the protection of marine biodiversity for generations to come.