4.4. Coastal erosion

The term “erosion” refers to the set of actions that lead to the disintegration and demolition of the Earth’s surface, in particular the coastal zone. Coastal erosion involves the breaking down and removal of material along a coastline by large storms, flooding, strong wave action, sea level rise and human activities.

The impacts of climate change are likely to worsen problems that coastal areas already face. Global warming causes sea-level rise as oceans expand, and makes storm patterns more energetic. Increasing sea level (1,7 mm/year) changes the shape of coastlines, contributes to coastal erosion and leads to flooding and more underground salt-water intrusion.

Photo 4.4.1. Coastal erosion – waves. Fondazione Cetacea

One of the natural causes of coastal erosion is the subsidence – slow movement of the earth’s crust due to the weight of sediments accumulated, which is emphasized by the extraction of methane from the seabed.

Photo 4.4.2. Dredging of the coast. Blue World Institute

The Mediterranean has various types of the coast and above all the sandy coasts are the ones most affected by erosive phenomena, which are expected to worsen as a result of climate change. Additionally, all throughout the Mediterranean, excessive coastal overdevelopment is increasing vulnerability to erosion. The information on the use and degradation of the basin’s coastal areas are limited. However, it is estimated that approximately 25% of the Italian Adriatic coast and 7.4% of the Aegean coast show evolutionary erosion trends, while around 50% of the total coastline of the Euro-Mediterranean area is considered stable.

Photo 4.4.3. Coastal erosion. Fondazione Cetacea

In order to prevent risk of erosion, some coastal communities are constructing various types of barriers such as bulkheads and seawalls. When designed and sited correctly, such measures can help reduce risks from erosion and storms, but they also impact neighboring properties and harm coastal ecology. Over time, the construction of these structures can result in the loss of beaches and critical habitats. Sand dunes and their vegetation cover are the best natural protective measures against coastal flooding and erosion.