Coastal erosion and climate change



by LORENZO CIOTTI

Coastal erosion and climate change

"Coastal erosion is a normal process of nature. However, the rate of coastal erosion, and the frequency and intensity of coastal flooding events, are now on the rise around the world due to the changing climate. Current responses to coastal erosion are primarily determined by site-specific factors, such as coastal elevation, coastal slope, coastal features, and historical coastline change rate, without a systematic understanding of the coastal-change processes in the context of climate change, including spatiotemporal changes in sea level, regional changes in wave climate, and sea ice coverage.

In the absence of a clear understanding of the coastal-change processes, most of the current coastal responses have been built upon a risky assumption and are not resilient to future climate change. Here, we conduct a literature review to summarize the latest scientific understanding of the coastal-change processes under climate change and the potential research gaps towards the prediction of future coastal erosion.

Our review suggests that a coupled coastal simulation system with a nearshore wave model can play a critical role in both the short-term and long-term coastal risk assessment and protective measure development." This is explained in the new study entitled Coastal erosion and climate change: A review on coastal-change process and modeling, published on the Ambio website.

About eriosion

The intensity and speed with which the erosive action takes place and the prevalence of physical or chemical action depend on a series of factors, the main one being the climate. In fact, the extent and speed of erosion of a certain type of rock varies depending on whether it is found in an arid or humid, windy climate, with regular or irregular rains, in hot or cold environments or again with strong or no excursions.

A classic example is the way in which a granite placed in different climatic contexts is processed by atmospheric agents. In a mountain environment, where the freezing and thawing mechanism and the erosive action of the glaciers prevail and where the chemical action is inhibited by the low temperatures, the granite takes on a rugged morphology, made up of sharp peaks and ridges.

Conversely, in a hot humid climate such as the equatorial one, the granite will quickly be covered with a clayey blanket due to chemical alteration, it will be eroded much more quickly and will tend to assume an arched or slightly raised shape compared to the surrounding rocks.

Erosion exposes the land to landslides due to the indiscipline of flowing rainwater and can therefore be the cause of an increased hydrogeological risk on a territory in the event of intense precipitation phenomena, such as floods, or even situations of full-blown hydrogeological instability .

The stabilization works tend to reduce if not eliminate the possibility of landslides and erosion and belong to the field of environmental engineering or even geoengineering. Erosion phenomena following extreme weather events or conditions, such as for example floods or strong constant winds (meteorisation and corrosion) can also favor soil desertification processes in some areas at risk, while in coastal areas erosion is more problematic typically it is linked to wave motion which erodes cliffs and sandy beaches and for which, in the latter case, the possible interventions are the use of preventive artificial coastal barriers and subsequent beach nourishment.