BACKGROUND

Climate change influences beaches through alterations in wave patterns and sea level rise. These changes could shift the wave breaking zone towards the coast, thus affecting the submerged beach and its dynamic equilibrium. As a result, urban morphology and economic activities along the coast will be impacted.

Beaches, ecosystems that are highly vulnerable to mean sea level rise (MSLR) and shoreline erosion, face serious challenges due to climate change. The situation is exacerbated in urban beaches, whose adaptive capacity is restricted by the lack of accommodation space and the intense transformation they have undergone.

In the Mediterranean region, where population growth in areas exposed to SLR is higher than the global average, beaches are particularly prone to be impacted by these changes. The boom in sun and beach tourism has driven coastal urbanization, which further increases the vulnerability of these areas.

For the Balearic Islands in Spain, an island region with a significant tourism economy, the effects of climate change could have serious consequences. Recent studies project significant losses in the recreational value of the area, directly affecting the Gross Domestic Product (GDP) of the region.

Given the complexity of marine and coastal areas and the variety of actors involved in their management, an integrated and sustainable approach is essential to address adaptation measures. . It is urgent to implement transformative and consensual adaptations that protect both the environment and the economy of coastal settlements.

Beach after the 2016-2017 winter storm. . Image: Photo dossier January 2017 of the Town Hall of Sant Llorenç des Cardassar.

SOME SCIENTIFIC STUDIES AND ADAPTATION MEASURES TO PROTECT THE COASTLINE OF THE BALEARIC ISLANDS

Between 2018 and 2021, the Coastal Observation and Prediction System of the Balearic Islands (SOCIB), the Mediterranean Institute for Advanced Studies (CSIC-IMEDEA) and the University of the Balearic Islands (UIB) participated in the 'Coasts by Change' project, assessing the impacts and risks associated with sea level rise and extreme marine events. This scientific study contributed to the planning of adaptation measures to climate change in coastal areas, highlighting that permanent flooding will significantly affect residential land.

According to the analysis, the most adverse sea level scenario could affect 833 hectares permanently and 204 hectares temporarily by 2050, reaching a maximum of 3,465 hectares permanently and 427 hectares temporarily by 2100. In addition, it is projected that approximately 464 sandy beaches in the Balearic Islands could directly experience loss of dry beach area and other recreation-related environmental services.

In parallel, between 2019 and 2021, the Institute of Environmental Hydraulics of the University of Cantabria (IHCantabria), SOCIB and the network of Mediterranean coastal cities MedCities have worked on the Strategy for coastal protection in the Balearic Islands considering the effects of climate change, identifying governance requirements and essential scientific studies to protect the Balearic coast. The strategy highlights the need to strengthen cooperation between public administrations and proposes activities such as studies on the availability of sedimentary resources, hazard maps, systematic monitoring of the coast and participation and communication campaigns. Given the expected magnitude of the impact of sea level rise, it emphasizes the importance of a strategic line of research to ensure the viability of natural adaptation solutions in the short, medium and long term.

	IN THE SHORT TERM
	The socioeconomic sectors that are seeing how season after season the beaches are losing sand are calling for the regeneration of the beaches with artificial sediment input, a high-cost and short-lived solution that will be negatively affected by the rise in sea level predicted for the middle of this century. It is, therefore, a solution that has proven to be inefficient and unfeasible from an economic and environmental point of view. The actions to be developed in coastal systems must stop considering the short term and look for effective solutions in the medium and long term.
	IN THE MEDIUM TERM
	A recovery of dune systems can be considered, even on urban beaches. This can be done if there is space to retreat, but in most urban areas the beaches have been artificialized promenades that prevent the sand from retreating and settling. It is necessary, therefore, to change the traditional image of what an urban coastal landscape should look like: eliminate large boardwalks and concrete gardens and tend towards solutions that are closer to nature, such as dunes, which provide a sand reserve that is less vulnerable to storms.(30 years)
	IN THE LONG TERM
	With a climate change scenario, it will not be enough to go backwards by eliminating the promenade, it will be necessary to consider freeing up space on the beach by eliminating existing buildings, which implies a profound reconfiguration of the first coastline. All these actions will require political and social debate and a high level of citizen consensus due to the economic and social importance of the measures to be adopted and the high budget to be allocated. (60 to 100 years)