Sea level change significantly influences coastal erosion by modifying both the intensity and frequency of wave action along coastlines.

Whether it involves a rise or a fall, changes in sea level have a profound impact on coastal erosion dynamics. When sea levels rise—primarily due to global warming and thermal expansion—the coastline experiences intensified wave action. This occurs because waves can advance further inland, affecting areas that were previously shielded. The increased energy from these waves accelerates erosion, as they break down and transport material from the shoreline, resulting in the loss of beaches, cliffs, and various coastal features.

Conversely, a decline in sea level also affects coastal erosion, albeit in a different manner. A drop in sea level exposes new land along the coast, which is often made up of loose, unconsolidated materials that are particularly vulnerable to erosion. Consequently, the coastline may experience rapid retreat until more resistant geological formations are reached.

Additionally, fluctuations in sea level can impact the sediment supply to coastal areas. Rising sea levels can inundate rivers, diminishing their capacity to deliver sediment to the shore. This sediment deficit can deprive beaches of the necessary materials for natural replenishment, leading to heightened erosion. On the other hand, falling sea levels can steepen river gradients, enhancing their ability to transport sediment toward the coast. This process can contribute to the development of deltas and other coastal landforms.

In summary, sea level change is a critical factor in coastal erosion processes. It affects the intensity and frequency of wave action, alters the exposure of various materials to erosion, and influences the sediment supply to coastal regions. Understanding these dynamics is essential for predicting and managing future changes to our coastlines.