The situation is not unique to Portugal and is due to a number of factors, including human intervention in riverbeds, particularly dams that prevent sediments from moving to the coast, mistakes in coastal planning made over the decades, and the removal of sand from rivers for construction purposes.

Filipe Duarte Santos, from the University of Lisbon, highlighted that the Portuguese coast "is the most energetic coast in the world, at its latitude", with persistent winds predominantly from the north-west that push the waves in this direction.

When the sea reaches the coast, "it doesn't hit it from the front, but a little bit from the side", and this movement is permanent, wearing the coast down and "transporting sand from beaches in the north to the south, with an average of one million tonnes of sediment a year".

If the sediment from the rivers that used to reach the beaches do not arrive, the coast is constantly being worn down, he added.

"This problem is exacerbated in occupied areas.

According to the experts, "there is no definitive solution to the problem," and what can be done to minimise coastal erosion is being done, especially through sedimentary reinforcement, artificially feeding the beaches with sand.

"We have limitations from the point of view of investment, financial limitations that all countries have to some extent, our problem is a problem that is expensive to solve, but I think that within the possibilities that we have I would say that we are doing the best we can," said Filipe Duarte Santos.