Coastal Environments
Coast lines are interfaces between lands and oceans. A lot of natural and human exchanges happen in these environments, which makes them especially exposed regarding to climate changes.
1- They are used to natural changes
Coast lines can be very different: sand or rocks beaches, cliffs, but also mangroves and wetlands such as marshes, salty meadows, estuaries... Because they are the place where seawater meets fresh water (or land), they often show very specific habitats which are impossible to find anywhere else. Thus, they are essential for the survival of many animal and plant species.
Seashores are sensitive to disturbances, the simple movement of the waves and the tides are enough to modify the landscape by erosion or deposit of sand and other sediment. Storms and cyclones are natural risks which are able to affect coast lines, precisely because of their strong erosion capacity. Sand beaches are the most concerned, but a cliff can collapse under the effect of erosion. A storm or a earthquake can also cause tidal wave and tsunami, with large rises in the water level and flooding. The coastal ecosystems are used to these frequent natural changes and the species are adapted to varying environments.
2- They are fragilised by humans
About 50% of the global population lives on seashores, and most of the world's metropolis are built near the sea. People come for the climate, because it's generally warmer compared to the one on the main lands. It is also easy to communicate with the word and to find a job. Indeed, business activities, harbours, fisheries and aquaculture contribute to the high economic dynamism on coasts. Moreover, industries are also close, for the exportations and importations. Coasts are also often favourable for agriculture.
Coast lines strongly attract tourism. Holiday-makers look for climate, leisure activities and landscapes, and seaside resorts multiply on seashores. Infrastructures are then built like harbours, hotels, swimming pools and associated large transport links (airports, highways).
All theses activities create a lot a pollution sources: domestic wastes, industrial flows, chemical fertilizers brought by rivers and sometimes oil spills. Overfishing is also a major problem in these very populated areas, as well as the mangrove deforestation to have more farmable lands. Moreover, humans constructions alter the landscapes and impoverish the natural side of these environments.
Humans severely impact coasts, and a space share in the different human's activities in a sustainable development spirit is more than necessary.
3- They are the first impacted by climate changes
General vulnerability of coast lines are worsen by present global climate changes. Indeed, the planet rapid warming leads for instance to a rise in sea levels, which provokes larger coastal erosion. Rising of sea water temperature, changes in the rain activity, increase of the storms force, are other phenomena modified by climate changes. Ecosystems and human population will have to deal with them. Ocean acidification, a problem just arrived to fame to the public in the last years, will have major impacts on the planet as well.
It is essential to better study these stressed environments and to better manage their space and resources, to better protect them in the future.
