In the West Indies, flash floods will intensify as displacement

“It is estimated that 6% of the coast of Guadeloupe that is occupied by man today could become uninhabitable. So we will have to prepare to give up areas where the population will not be able to sustain themselves. All this presupposes a global resettlement plan. It is today and now. Now we have to prepare for these changes,” warns expert Virginie Duphat.

Virginie Duphat, Professor of Geography at the University of La Rochelle, lead author of the chapter devoted to the effects of global warming on small islands in Part II of the Sixth Report of the Intergovernmental Panel on Climate Change, the intergovernmental panel on climate change. Virginie Duvat with her team on a mission to the West Indies as part of the Adaptom Project. For three years, you will assess the potential of nature-based solutions to reduce coastal risks and promote adaptation to climate change in the French overseas territories. The first year of this program is dedicated to the West Indies.

Overseas Planet: What do you think about the interpretation of the floods of April 30, 2022 in Guadeloupe?

Virginia Duvet: This flash flood phenomenon is explained by very heavy rain in the developed low areas in which water accumulates more easily and is closed off.

These phenomena testify to planning errors that occurred in the past. It was necessary to visualize drainage systems on the high amounts of water that could accumulate in these sectors.

Virginia Duvat, geography teacher

Are these heavy rains part of the phenomena that could intensify with climate change?

Virginia Duvet: Yes, we expect an increase in heavy rain events, and they are more severe.

What are the other effects of climate change in the West Indies?

Virginia Duvet: In addition to heavy rainfall events, we can expect sea level rise, in Guadeloupe as in Martinique, sea level will rise by 82 cm by 2100 if we based on the pessimistic scenario of the Intergovernmental Panel on Climate Change (RCP8.5). This will be added to the intensification of hurricanes. These three factors combined will increase the risk of flooding. In sectors such as Gary and some areas of Pointe-a-Pitre that have been built on very low land, there will be chronic flooding. By 2060, these areas will be prone to flooding for half a year. And exposed coasts will be exposed to the phenomenon of storms.

In Saint Martin, Nettle Bay, after Hurricane Irma in 2017

© Virginie Duvat

Will climate change change our use of coastlines?

Virginia Duvet: Yes, due to more rapid coastal erosion than ever before, climate change will modify our use of coasts. The impacts on human societies will be more significant because the coasts of Guadeloupe and Martinique concentrate a large part of the population, population, tourists, activities and infrastructure such as ports and airports.

Erosion of Raisins Clairs Beach in Saint-François in Guadeloupe

Erosion of Raisins Clairs Beach in Saint-François in Guadeloupe

© Caroline Marie

Erosion of Caravelle Beach in Sainte-Anne in Guadeloupe

Erosion of Caravelle Beach in Sainte-Anne in Guadeloupe

© Virginie Duvat

How can we adapt today?

Virginia Duvet: To avoid flooding, drainage systems should be reviewed to improve evacuation of this water wherever there is a risk of flooding. Of course, beyond these technical solutions, where we are concerned about the phenomena of flooding and sea inundation, we will have to consider the resettlement of human construction in the interior, because some of the lower regions would not be habitable if we evolved on a climate scenario of relatively rapid warming.

About the map of Guadeloupe, geographer specializing in coastlines, Virginie Duvat and Alain Brundo

About the map of Guadeloupe, Virginia Duvat, geographer specializing in coastal areas and Alain Brundo, delegate overseas at the Conservatoire du Littoral

© Caroline Marie

Everywhere offshore and especially in the West Indies, there are many projects to restore mangroves and coral reefs to reduce land erosion. So far, we’ve seen mainly engineering work. Can these nature-based solutions work?

Virginia Duvet: The urban coasts of Martinique and Guadeloupe are bordered by reprap ropes that were put in place to repair the coastline and protect developed areas. These heavy protections are not enough to stop corrosion, and sometimes even exacerbate the phenomenon. Over the past 10 years, we have seen an increased use of nature-based solutions. It consists in better protecting, restoring and even re-establishing coastal and marine ecosystems in terms of the protection service they provide to the local population. They are our best breakwater against storm waves and our best corrosion protection.

Revegetation facilities installed by the ONF in Guadeloupe

The plant species that grow naturally on the beach repair sand and thus reduce erosion. To reduce trampling, the ONF has placed a revegetation container at the Pointe des Châteaux with a sign that reads “Let’s stop erosion by helping the forest to regenerate”.

© Caroline Marie

You may have seen some nature-based solutions projects, what do you think of them?

Virginia Duvet: Here in Guadeloupe there are many pilot projects of nature-based solutions. We can cite the Sargassum conservation project on the Saline Beach in Le Gosier to limit its degradation, which was carried out by the Conservatoire du Littoral and the Town Hall. In Gary, the Conservatoire du littoral has recreated areas of swampy forest illegally occupied by companies that are better protected from floods. The Carib Coast project consists, among other things, of renovating the upper beaches. ONF has placed revegetation containers at Pointe des Châteaux and on other beaches on the island to reduce trampling until plants grow back and can repair sand. There are also marine ecosystem restoration projects like the one implemented by Grand Port Maritime which is installing eco-berths to prevent boats from dragging seaweed beds with their moorings. Today, we do not know how to assess the effectiveness of these nature-based solutions in the face of climate change.

The rate of warming will largely determine the chances of success of these solutions based on the nature and how long they can be used where they will operate.

Virginia Duvat, geography teacher

pool in running

In my neighborhood in Guadeloupe, a pond where a service station was installed illegally on this space before it was reclaimed by the Conservatoire du littoral as part of its JA-RIV programme. “This service station is equipped with a pump that collects water 24 hours a day to flush it out. Today, nature has taken back its rights” Alain Brundieu, Overseas delegate at the Conservatoire du Littoral

© Caroline Marie

My neighbor in Guadeloupe is built on a swampy forest

My neighborhood in Guadeloupe is built on a swampy forest. The Gary region, which concentrates a large part of the island’s economic activity, is particularly vulnerable to floods and sea floods.

© Caroline Marie

Have public authorities and the state taken the bets measures?

Virginia Duvet: Public authorities have taken action bets in these areas. As evidence of the various transportation projects being implemented. In Martinique, the municipality of Le Prechor, in Guadeloupe, the municipality of Cabestre and Petit Bourg where there are resettlement projects for families occupying dwellings that go to the sea. In these critical situations, public authorities recognize, but in general, adaptation efforts are very inadequate and fall short of climate challenges, so there is a need to move the pace and put in place more ambitious, proactive and inclusive policies at larger spatial scales. Significant investments must be made in this reorganization and this regional revolution. Overseas regions are on the front lines of influences.

How do you speed up the process?

Virginia Duvet: Today, funding for adapting regions to the impacts of climate change comes primarily from public funds. They are not enough. So it is now necessary to convince the private actors that these issues should be addressed on stage. This is more important because it is not just a financial obligation. The work that the Conservatoire du littoral has done in Jerry with companies clearly shows how a public institution must collaborate with private actors in order to be able to successfully implement its own adaptation measures.

There are already several plans to relocate residents abroad. At Le Prêcheur in Martinique, Guadeloupe, Capestre and Petit-Burg, but also in Guyana where the Awala Yalimbo district and finally the Micolon village of Saint-Pierre and Miquelon must be moved. Do you think that population movements abroad will increase?

Virginia Duvet: “Resettlement will develop abroad, that’s for sure. I really see the current projects as small pilot projects that allow you to learn by doing, but you will have to move on a much larger scale than we do today because it will be, for example, entire areas of Pointe à Pitre Which will find itself threatened. It is estimated that 6% of the coast of Guadeloupe occupied by man today could become uninhabitable. So we will have to prepare to give up areas where the population will not be able to sustain themselves. All this presupposes a global transport plan. We need Really to a global reflection on the size of the area to find the possibilities and how to articulate the transportation necessities of the different municipalities that will be affected.Now we must prepare.

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