Low tides in the Manche region reveal ancient submerged forests, preserved for thousands of years by peat bogs, now exposed by rising seas and storms.
Ancient forest stumps revealed by low tide
Low tide in the Manche region has exposed darkened, twisted tree stumps on certain beaches in the Cotentin. These stumps, around 6,000 years old, are remnants of a forest that was submerged by rising sea levels.Submerged forests found elsewhere
Similar submerged forest remnants have been discovered in other locations, such as the forest of Quintefeuille in the Calvados and the forest of Borth in Wales. In Borth, the forest was revealed by storms in 2013-2014.Preservation by peat bogs
The preservation of these stumps is due to the formation of peat bogs, where stagnant water deprives the environment of oxygen. This significantly slows the decomposition of wood and plants, allowing them to fossilize over time.Historical context of submersion
To understand the submersion of the Cotentin forest, one must go back to the last glaciation, 20,000 years ago, when the sea level was about 120 meters lower than today. The warming that followed melted the ice caps and raised the oceans, eventually submerging the forest around 6,000 years ago.Rising sea levels threaten the region
The Manche department reports that the sea level continues to rise at a rate of nearly 3 millimeters per year. This threatens agricultural lands and thousands of residents in the Cotentin, with projections suggesting a possible rise of one meter by 2100.Impact on local communities
The consequences of rising sea levels are already visible, with significant erosion along the western coast of the Manche since 1947. In Montmartin-sur-Mer, a farmer lost 1.5 hectares of pasture to the sea, and nearly 1,000 businesses in areas like Saint-Vaast and Carentan are at risk.
