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Castelldefels and Barcelona’s coastline lead the rise in heatwaves
Barcelona’s coastline will be one of the places in Spain where heatwaves will increase most over the coming decades. A new climate atlas places Castelldefels, Vilanova i la Geltrú, El Prat de Llobregat and Gavà as the four Spanish municipalities with more than 40,000 inhabitants where these days will increase most by 2050.
The difference compared with the beginning of the century will be considerable. Across the 161 cities analysed, the number of heatwave days could triple on average between 2000 and 2050. In Castelldefels, the projection points to around 80 additional days of extreme heat; in Vilanova i la Geltrú, 73; in El Prat, 72; and in Gavà, 71.
The map leaves Baix Llobregat and Garraf particularly exposed. Viladecans also appears among the ten municipalities with the greatest projected increase, while Badalona ranks 19th, Barcelona 24th and Mataró 29th. Warming will therefore not be limited to the Catalan capital, but will affect a large part of the metropolitan coastal strip.
The study was prepared by the Barcelona Supercomputing Center and the 300.000 Km/s urban laboratory, based on up to 70 climate simulations. The projections are cross-referenced with factors such as housing type, income, the amount of urban greenery and access to services, to measure not only how much the temperature will rise, but which cities will have more difficulty adapting.
The effect will be felt directly in everyday life. More extreme days mean homes that accumulate heat for longer, nights with poorer sleep, greater pressure on swimming pools and climate shelters, and more difficulty working or travelling during the middle of the day. Older people and those living in poorly ventilated flats start at an obvious disadvantage.
The need for domestic cooling will grow by around 65% on average in the Spanish cities studied, although the greatest energy increase is expected in the south of the Iberian Peninsula. In Catalonia, the main problem will be the frequency of the episodes: homes and streets will have to be protected against heat that will cease to be exceptional for much of the summer.
Vulnerability will not be the same in every neighbourhood either. A street with trees, renovated buildings and well-insulated homes responds very differently from one with little greenery and flats that retain heat. That difference makes urban planning, shade and housing quality part of the climate response.
The figure leaves the metropolitan area with an uncomfortable image: some of the municipalities where people now seek the sea to escape the heat will be precisely those accumulating the most extreme days within 25 years. The challenge will be to ensure that beaches, squares, homes and transport are ready for a summer that will occupy an ever-greater part of the calendar.