Extreme weather events and hydrogeological instability — a deadly combination from Southern Italy to Europe: we are witnessing it right now
The iconic Arco di Sant'Andrea, also known as the "arch of love", along the Adriatic coast of Melendugno, in Salento, collapsed on Valentine's Day itself, symbolically dedicated to those in love. According to Giovanni Caputo, president of the Ordine dei Geologi della Puglia, the collapse is not the result of human neglect or hydrogeological instability, but the natural outcome of a millennia-long erosion process caused by the sea, winds and rain. "This is not a static formation – he explains – the arch crumbled due to the same erosive action that shaped it over time, a phenomenon that can affect other sites as well, such as the faraglioni dell'Arco di Diomede", where yesterday a demonstration by citizens and Italia Nostra activists took place: we are still in Puglia, 400 kilometres from Melendugno, but the problem is the same.
Just a month ago, there were the collapses at Tricase Porto and Marina Serra. Given the high vulnerability of the Puglia coastline — 53 per cent of which is at risk of erosion — Caputo underlines the need to map the entire shoreline, with the contribution of geologists and environmental engineers, to identify where to intervene safely and, where necessary, relocate buildings and settlements: "We cannot stop natural events, and we cannot keep calling them 'exceptional', because they are now becoming the norm. Where we must start talking about hydrogeological instability is in the inland areas, the populated ones: that is where we need to be concerned."
"In Puglia, 53 per cent of the coastline is at risk of erosion and we have recorded 839 landslides," Caputo reiterates. Is climate change to blame? That too, of course. And yet "we must not attribute everything to climate change. The climate is merely amplifying vulnerabilities that were already there." The figures speak for themselves: in Puglia alone, 63,000 people live in areas affected by landslides, with around 17,280 buildings, 5,752 businesses and 849 cultural heritage sites exposed to risk. On the flood front, 135,932 residents live in potentially floodable areas, with 36,600 buildings and 409 cultural heritage sites involved. And then there is Calabria, Campania with the recent collapse along the Costiera Amalfitana, Emilia Romagna, Liguria, and of course Sicily, where what has been happening in Niscemi for weeks is there for all to see.
Across Europe too, this winter has shown just how much natural systems are under stress. Never before this winter — and in particular between January and February — had western Europe experienced such volumes of rainfall concentrated over just a few weeks, with four storms in succession — Kristin, Leonardo, Marta and Nils — unleashing unprecedented quantities of water. Many locations in Spain exceeded 400 millimetres of rainfall since the start of February, with peaks of 500 millimetres in Castile and a record of 2,300 millimetres in Andalusia over 21 days: in practice, an entire year's worth of rain falling within a few weeks. Exceptional rainfall also affected France, particularly in the Pyrenees area.
The European toll speaks of thousands of evacuees, widespread power outages, extensive flooding and billions of euros in damage. According to authorities, at least 25 people have died since the start of 2026 in extreme weather events linked to these waves of occurrences — storm surges, heavy rainfall, coastal erosion — whose scale is amplified by climate change. From Salento to the Iberian coasts, from the Pyrenees to the French river basins, western Europe is experiencing a pattern of extreme precipitation that is placing infrastructure, ecosystems and communities under severe stress.
Climate change and hydrogeological instability are therefore two phenomena that feed off each other (and which are both caused by human action). What is happening in the Mediterranean and in western Europe is certainly also strongly linked to the new climate dynamics: at the root of the anomalous distribution of rainfall are the so-called atmospheric rivers, enormous bands of air laden with water vapour originating from subtropical latitudes that carry exceptional quantities of moisture towards Europe.
But as mentioned, the collapse of the Salento arch and all the other hydrogeological phenomena must each be read for their own significance. With regard to coastal erosion, for example, "Constant monitoring and geological analysis are needed," Caputo emphasises. "Stability studies must be carried out to assess the causes of collapses, nature-based engineering interventions must be implemented, and work must be done on coastline stabilisation." Among the possible measures: restoration of coastal vegetation (and on this front Italy is working to implement the European regulation), breakwaters, lightweight protective structures, and an integrated plan involving geologists, engineers, marine biologists and local authorities. But also education and awareness-raising, to foster an understanding of the fragility of coastal ecosystems and the importance of sustainable land management. The key point, experts warn, is that the intensification of rainfall — concentrated in brief, violent events — acts upon territories already made vulnerable by land consumption, urbanisation in at-risk areas, and insufficient maintenance of river basins. The result is an exponential increase in landslides, flash floods and coastal erosion.
