Coastal erosion is a weathering process that occurs naturally along all shorelines. The removal, transportation and deposition of sediments fluctuates in a state of dynamic equilibrium. The equilibrium, however, is easily unbalanced, and the rates of coastal erosion can change dramatically based on a few factors that range in scale from global to local.
Sea Level Rise
Scientists with the International Panel on Climate Change agree that global sea level rise is one of the most definitive consequences of climate change. As sea levels increase, beaches and dunes are submerged under the encroaching seas, exposing sensitive inland ecosystems to coastal erosion forces. Beach loss reduces the buffer capacity of shorelines and increases the vulnerability of coastal environments to erosion damages caused by storms and flooding.
Many coastal environments experience seasonal changes in the rate of erosion as storm seasons come and go. Variations in coastal winds, size of waves and ocean currents caused by seasonal storms all amplify the erosion process. The Environmental Protection Agency (EPA) forecasts that climate change will increase both the frequency and intensity of seasonal storms in the future, leading to even higher rates of coastal erosion.
Human Activity Away from the Coast
While dams are often constructed to minimise local environmental damages caused by flooding or to generate clean hydroelectric power, they can have detrimental impact on coastal environments many miles away. Dams restrain sediment flow from headwaters, cutting off an important source of materials needed to replace coastal materials lost to erosion processes along the coast, expediting the rate of beach loss.
Human Activity Along the Coast
Many coastal communities create structures to reduce the loss of beaches and slow the rate of coastal erosion. Manmade structures such as offshore breakwaters, seawalls and groynes all reduce erosion in the locations where they are constructed, but they disrupt the sediment transportation of the entire coastal system and will often increase rates of erosion in other locations along the coast.