Coastlines are sinking
- Urban visions
- Oct 24
- 13 mins
Imagine New York City without the Statue of Liberty, Copenhagen without The Little Mermaid, Guangzhou without the Canton Tower, St. Mark’s Square in Venice submerged, Easter Island without its 900 moai or Barcelona without the Sant Sebastià beach. This isn’t science fiction – these are potential outcomes of rising sea levels and extreme weather conditions.
Towards the end of last year, the independent organisation Climate Central, comprising scientists and environmental organisations, developed an interactive map[1] detailing areas of the planet at risk of submersion. Tokyo, New York, Jakarta, London, Lisbon, Sydney, Punta Cana and up to 36 other cities across the globe are set to be significantly impacted, placing 226 million people at risk of being displaced or losing their livelihoods in coastal zones.
Regarding Catalonia’s coastline, it is currently in a critical state, with the coastal landscape (reduction of beaches, disappearance of dunes, degradation and habitat loss) having undergone significant transformation in recent years.
The scientific community agrees that sea level rise is unavoidable. The debate centres on potential scenarios. A little over a year ago, a report from the United Nations Intergovernmental Panel on Climate Change estimated that over the next two thousand years, average sea levels will rise between two and three metres if global warming is kept to 1.5 degrees. If temperatures rise by an additional two degrees, the increase could reach six metres. The document, summarising studies conducted by the Intergovernmental Panel on Climate Change between 2015 and 2023, emphasises that “the effects of accelerated global warming are unavoidable in the coming centuries or millennia and will result in ecological and humanitarian disasters”. However, it also highlights that “deep, rapid and sustained reductions” in carbon dioxide and other greenhouse gas emissions could mitigate the rate of sea level rise.
John Church, a professor at the Climate Change Research Centre at the University of New South Wales (Australia) and an internationally recognised expert, asserts that data shows sea levels are rising by three millimetres each year, faster than previously anticipated. If this trend continues without reductions in greenhouse gas emissions, sea levels could rise by 0.9 metres by the end of the century. Nevertheless, if we achieve the goals of the Paris Agreement, by 2050 sea levels may have risen only slightly compared to current levels. The Paris Agreement (2016) was the first international treaty to establish the target of keeping the global average temperature increase below 2 degrees Celsius compared to pre-industrial levels and to promote all possible actions to limit global warming to 1.5 degrees Celsius.
By 2035, only 54% of current beaches will have sufficient width to accommodate leisure activities.
The Catalan coastline, at breaking point
In December 2021, the Government of Catalonia’s Advisory Council for Sustainable Development (CADS) published the report Un litoral al límit[2] on the state of the coastline. Coordinated by biologists Puri Canals and Carles Ibáñez, the study concludes that the Catalan coast is in a critical state. The report synthesises several academic studies and presents alarming data. Among other figures, it details that:
- Only 20% of the Catalan coastline has adequate room to retreat in response to rising sea levels. Since 2017, there has been a notable decline in beach areas in certain parts of the Catalan coast. Badalona has experienced an average retreat rate of 9.8 metres per year, while Montgat has seen a retreat of 7.5 metres per year.
- Between 2002 and 2010, authorities supplied 775,000 m3/year of sand to the entire coastline, predominantly focusing on beaches along the Barcelona coast. This policy of mechanical regeneration comes with significant economic and environmental costs and is deemed unsustainable in the long term.
- By 2035, only 54% of current beaches will have sufficient width to accommodate leisure activities, with 9% completely eroded.
- In 2023, Catalonia welcomed 18 million foreign tourists, 90% of whom stayed in coastal municipalities. Climate change is a key factor affecting the future of the tourism sector, particularly sun and beach tourism, which is heavily influenced by beach availability and climatic conditions.
- The rising sea levels, marine storms and torrential rains are climate change impacts that will affect energy, sanitation and transportation infrastructures, as well as protective structures and ports, as many are situated in flood-prone areas. Consequently, according to several studies, the Maresme Rodalies railway line should be relocated further inland within municipalities.
The CADS report also outlines ten proposals for the sustainability of the Catalan coast.
In recent years, events like Storm Gloria (January 2020) or the storms Aline (October 2023) and Nelson (April 2024) have shown that the climate emergency is now a reality in our country. Between 20 and 23 January 2020, Storm Gloria brought accumulated rainfall of between 200 and 500 litres per square metre in Vallès Oriental, Girona and the Terres de l’Ebre. Rivers such as the Ter, Fluvià and Tordera overflowed, leading to residents in Baix Ter needing to be confined. The River Onyar in Girona reached the brink of overflowing. In the Ebro Delta, water surged three kilometres inland, flooding 3,000 hectares of rice fields. It also submerged the Trabucador sandbar, preventing fishing boats from leaving the port of Deltebre due to shifting sands. The repairs to ports, beaches and seafront promenades due to the effects of Storm Gloria cost more than 75 million euros.
As a result of Storm Aline in October 2023, metropolitan beaches lost between 20 and 40 metres of their width.
In mid-October 2023, Storm Aline swept across Spain, impacting Catalonia with heavy rains, waves exceeding four metres and wind gusts reaching twenty metres per second. Within a month, metropolitan beaches lost between 20 and 40 metres of width, experiencing substantial volume reduction. The worst-hit were the Barques de Montgat and Nova Mar Bella beaches in Barcelona.
The recent Storm Nelson wrought extensive damage on the Costa Brava, particularly affecting Calonge and Sant Antoni, and on the Costa Daurada, where Calafell and Cambrils experienced substantial sand losses. In Barcelona, Mayor Jaume Collboni reported that the city’s beaches had lost between 15% and 30% of their sand. In response to the storm’s impact, the Ministry for Ecological Transition and the Demographic Challenge activated an emergency plan to protect the Catalan coastline, allocating 1.5 million euros for this purpose.
Mitigation and adaptation measures
Faced with the climate emergency, the authorities have begun to respond, although the division of responsibilities between the Central Government’s Directorate General for the Coast and Sea, the Generalitat Government of Catalonia’s Directorate General for Coasts and town councils complicates coastal management. This is because there is no unified and consensus-driven approach: each administration acts independently according to its own capabilities and priorities. The European Union is also involved, with initiatives like the European IMPETUS project, which engages seven European bioregions. “It’s a substantial project aimed at sharing knowledge through a participatory approach, which is developing a digital platform. The goal is to identify actions to adapt the Catalan coast to the impacts of climate change,” explains Joana Díaz, a chemist, sociologist and governance researcher at Eurocat, the institution leading the project in Catalonia.
As for Barcelona City Council, in 2018 it adopted the Climate Plan (2018-2039), which sets out goals and measures across four strategic pillars: mitigation, adaptation/resilience, climate justice and fostering citizen action. The document highlights the city’s major challenges in the years ahead, including rising temperatures, decreasing water availability, increased flooding and beach erosion.
People strolling and exercising along Barcelona’s waterfront promenade. © Imatges Barcelona / Edu BayerRegarding the Generalitat Government of Catalonia, in January of last year, it approved the Catalan Climate Change Adaptation Strategy and has a technical office that devises policies for both mitigating and adapting to this phenomenon. A few months ago, this office presented a report prepared by the Hydraulic and Maritime Engineering Laboratory at the Universitat Politècnica de Catalunya (UPC), focusing on Catalonia’s Port Plan and how to plan investments to make them less vulnerable to the impacts of climate change. The report also analyses 33 iconic seafront promenades in Catalonia and proposes measures for their adaptation.
In fact, one of the reasons that prevents sand from reaching the beaches is the construction of ports, which obstruct its natural flow. However, groynes have been built that disrupt the longitudinal transport of sand. Furthermore, drought and human activities have also impeded sediment transport through rivers and streams, further reducing the amount of sand reaching the beaches.
The critical condition of Catalonia’s coastline still isn’t adequately prioritised on the political agenda. Over the past 30 years, sea levels in Catalonia have risen by 10 centimetres, with forecasts predicting an increase of up to 80 centimetres by the end of the century. Concerns will escalate when we inevitably have to relocate infrastructure and buildings currently situated along the coast inland.
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