Manolo, age 10: "Will we still be able to live on the beaches in 30 years?"
In general, to put it simply, the answer is no! But in reality, it's a complicated question that encompasses at least three issues.
Frédéric Bouchette, University of Montpellier
Firstly, the retreat of the shoreline separating the sea and the land (known as the coastline) is a phenomenon that everyone can see. In 30 years' time, 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 the beach depends in part on the movement of the coastline, which changes over time in a completely unpredictable way!
Surprisingly, these changes in the coastline are one of the most complex issues in coastal research. It is therefore possible to live near the beach for a long time when the coastline is stable. However, in highly dynamic areas, a house facing the beach can find itself far from the water or even under water within a few years.
On the other hand, it is often said that rising sea levels due to global warming are reducing the size of beaches. In fact, beaches are adapting by rebuilding themselves higher and higher, compensating for the rise in water levels. But they can only adapt in this way if there is sufficient sand in the area in question. Where sand is lacking, the beach shrinks as quickly as the water rises.
Furthermore, even if the beach reconfigures itself with the sea level, nothing prevents the water from passing behind the beach and entering the wetlands located inland, which cannot react in the same way as the beach system. This phenomenon is gradually transforming certain coastal areas into islands, and it is not easy to live on an island for many reasons, such as access, water resources, and exposure to storms.
Finally, your question is undoubtedly as much a matter of law, morality, ecology, and economics as it is of physics. How far are we willing to go in developing technologies and investing resources in order to live by the water?
There is much debate on these issues among scientists proposing solutions, local authorities concerned with preserving their territory, and the government, which must oversee all of this. We will inevitably be living near beaches in 30 years' time, but it is now that we must decide how.
Frédéric Bouchette, Professor, University of Montpellier
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