Manolo, age 10: “In 30 years, will we still be able to live on the beaches?”
Generally speaking, to put it simply, the answer is no! But in reality, it’s a complicated question that involves at least three issues.
Frédéric Bouchette, University of Montpellier
First of all, the retreat of the shoreline that separates the sea from the land (known as the coastline) is a phenomenon that everyone has noticed. In 30 years, this retreat will be even more pronounced in many places.
In other places, beaches are getting wider every year—sometimes by several meters. In fact, the width of a beach depends in part on shifts in the shoreline, which changes in completely unpredictable ways over time!
Surprisingly enough, these changes in the shoreline are one of the most complex issues in coastal research. People can therefore live near the beach for a long time when the shoreline is stable. In highly dynamic areas, however, a house facing the beach can, within a few years, end up far from the water or even completely underwater.
On the other hand, it is often said that rising sea levels caused by global warming are reducing the size of beaches. In fact, beaches adapt by rebuilding themselves higher and higher, compensating for the rising water level. But they can only adapt in this way if there is a sufficient amount of sand at the location in question. Where sand is lacking, the beach shrinks all the more rapidly as sea levels rise.
Furthermore, even though the beach reshapes itself in response to sea level changes, there is nothing to prevent the water from flowing behind the beach into the inland wetlands, which cannot adapt in the same way as the beach system. This phenomenon is gradually turning certain coastal areas into islands, and living on an island is not easy for many reasons, such as access, water supply, and exposure to storms.
Finally, your question is undoubtedly as much a matter of law, ethics, ecology, and economics as it is of the physical sciences. To what extent are we willing to develop technologies and invest resources to live along the waterfront?
There is a great deal of discussion on these issues among scientists, who propose solutions; local governments, which are concerned with preserving their territories; and the national government, which must provide a framework for all of this. We will inevitably be living near beaches 30 years from now, but it is now that we must decide how.
Frédéric Bouchette, Professor, University of Montpellier
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