Calais and Dunkirk under water. According to an established classification through Le Figaro, the cities of Pas-de-Calais and the North are likely to be the hardest hit in France by the rise in sea level due to global warming.

According to the calculations, Calais should face a submersion of 98% of its surface and nearly 82% of the territory of Dunkirk covered by the sea. With 30% of surface under water, Boulogne-sur-Mer, in Pas- de-Calais also slips into 10th place among threatened cities.

An area dotted with wateringues

The reason: the two municipalities form with Saint-Omer, inland, a triangle representing a vast polder where approximately 1,000 km2 are located below sea level. This area is dotted with wateringues, this network of canals, locks and pumping stations, responsible for regularly evacuating water to the sea.

However, this device which makes it possible to keep the sector dry is increasingly expensive and has not been as well maintained as in Belgium or the Netherlands where the same problem of marine submersion exists. In Calais, a multi-year investment plan exists and the inhabitants finance part of it through a specific tax which has just increased.

Coastal risk prevention plan

In fact, the catastrophic scenario of a massive submersion has been known for a long time, but in the Nord and Pas-de-Calais, the public authorities took time to react. In November, a public inquiry was conducted by the Nord prefecture to establish a new coastal risk prevention plan between Dunkirk and Bray-Dunes, in the North. The previous one had become obsolete. In Dunkirk, as in Calais, systems of dykes authorize the coast. But this system is not infallible.

“The territory of Dunkirk, for example, has been affected on several occasions by exceptional storms, in particular those of 1949 and 1953, which led to the rupture of the Allied dike and the flooding of certain districts, recalls the prefecture. Although work to reinforce the Allied dyke has been carried out, the risk remains in the context of climate change”.

Fear of the elected representatives of the northern coast with the transfer of competence concerning the risk of marine submersion with the Audomarois soon to be submerged?