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ENVIRONMENT

French riviera: Unesco tsunami warning for Marseille and Cannes

Unesco has announced that the Mediterranean - including the French cities of Marseille and Cannes - will be at risk of tsunamis within the next 30 years, and therefore has included it in its tsunami protection program

French riviera: Unesco tsunami warning for Marseille and Cannes
Archival photo of boats in the Port of Nice in 1979 after the tsunami. (Photo by ERIC GAILLARD / ARCHIVES / AFP)

The risk of tsunamis in the Mediterranean Sea is real – on October 16th, 1979, a tsunami, caused by a landslide, hit the coast of Nice and killed a dozen people. More recently, the Greek island of Samos in the Aegean Sea was hit by a tsunami in 2020.

But the climate crisis and rising sea levels mean that experts fear that in the future they will no longer be rare events along the Mediterranean coast.

Unesco has therefore announced that it will be adding thousands of communities to its Tsunami Ready Plan, including the French cities of Marseille and Cannes.

Experts fear that tsunamis in the Mediterranean could reach up to a metre in height and are almost guaranteed in the next 30 years.

According to Unesco’s calculations, “there is a 100% chance” that tsunamies will occur in the Mediterranean “over the next thirty years.” Therefore, the UN organisation has called for public authorities to institute their multistep programme, which would encourage awareness, warning, and prevention mechanisms for at-risk coastal communities. 

The preparedness program seeks to ensure that these cities and towns, like Marseille and Cannes, will have the necessary response mechanisms in place by 2030.

The Tsunami Ready program, which has already been piloted in dozens of communities across the Caribbean, Pacific and Indian Ocean regions and was prepared by Unesco experts, establishes twelve indicators to be respected by the communities concerned. This means that Marseille and Cannes will be expected create plans for identifying tsunamis threats and build community awareness and preparation for how to cope with tsunamis.

The twelve readiness indicators are shown in the graphic below:

Communities must meet all 12 indicators, which cover Assessment, Preparedness, and Response, will be recognized as ‘Tsunami Ready’ by the UNESCO/IOC.

Tsunamis are usually caused by seismic activity (78 percent of them) – like the deadly Indian Ocean tsunami in 2004 that killed over 210,000 people, but 10 percent are also caused by volcanic activity and landslides, like the tsunami that hit the Pacific island of Tonga in January. Meanwhile, the rare 2 percent are caused by meteorological activity.

However, the increased concern for tsunamis along France’s Mediterranean coast is in part due to rising sea levels (resulting from the climate crisis) and the need to better monitor underwater volcanos.

Rising sea levels can lead to an increase in the power of tsunamis – up to tenfold. In some parts of the world, such as Macao, scientists estimate that  tsunamis will have twice their current impact by 2050.

Even a tsunami of 50cm high can do a lot of damage – what sounds like a small flow of water is actually capable of lifting a car and depositing it several dozen meters away.

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CLIMATE CRISIS

How France plans to minimise future droughts

The 2022 drought is already the worst in 60 years, but these exceptional events are predicted to become more common, so France is considering long-term solutions to deal with punishingly dry periods.

How France plans to minimise future droughts

Recent headlines in drought-ridden France have made for sobering news: “More than 100 French villages without tap water in ‘unprecedented’ drought”; “‘Water will run out in 25 days’ – Corsica imposes strict new drought restrictions”; “French drought intensifies as River Loire dries up”.

The list goes on.

Environment Minister Christophe Béchu said France has experienced its driest month of July “since 1959”, while Prime Minister Elisabeth Borne activated an interministerial crisis unit to coordinate the resources of the State in the face of the “exceptional drought”.

READ ALSO Ask the expert: Why is France’s drought so bad and what will happen next?

The lack of water is affecting agriculture, food production, France’s famous wine industry, and is stoking tensions between residents and visitors in popular tourist areas.

A senior researcher at the European Drought Observatory told AP on Friday that the current drought affecting large parts of Europe could be worse than the previous one in 2018 – which was so bad that there had been no similar events in the previous 500 years.

And latest weather predictions suggest that drought conditions will continue for up to three months and the ongoing climate crisis means that ‘exceptional’ events such as the 2022 are set to become more regular.

While water restrictions have already been imposed on local authorities to combat the risk of water shortages, are there any long-term plans for protecting France’s water resources?

Companies are looking at ways of concentrating their water use, including by reusing water multiple times where possible, while measures such as trickle irrigation could help reduce water loss in agriculture.

Agroecology, which has been developed over the last few years, is also leading adapted practices on better soil conservation, which could allow water to be better retained.

“We need to accelerate the implementation of these innovative techniques and work on training personnel in the field,” hydrogeologist Marie Pettenati told Franceinfo.

Drinking wastewater

It’s possible. For the past 50 years or so, Namibia has produced a percentage of its drinking water by treating waste water. But it’s not necessarily the first step.

READ ALSO ANALYSIS: Is water likely to be rationed as France’s drought worsens?

A group of farmers in Clermont-Ferrand use water that has passed through the city’s wastewater treatment plant for several years. But schemes like this are highly local and very rare – only a handful exist across the country.

A decree has existed in France allowing the use of treated wastewater for agricultural purposes since 2010, but – with the Clermont-Ferrand exception – is rarely used. The rules and the tools exist. All that remains is to use them.

Groundwater

In total, 62 percent of France’s drinking water is taken from groundwater, according to a Bureau de Recherches Géologiques et Minières study. 

Pettenati said: “We also need to think more deeply about water storage in the ground, which would make it possible to retain resources and make them available for future use. 

“This would mean storing very large volumes of water at times when it is most available (in winter, for example, during periods of heavy rainfall) to be reused later, when it is most needed.”

Treated wastewater could also be stored underground for agricultural use, according to some suggestions.

“Groundwater is an invisible resource. We have trouble understanding how to preserve it, but it is essential,” Pettenati said.

Water reservoirs – often used by farmers – lead to significant losses to evaporation during periods of high temperatures, and risk contamination. 

Moreover, the basins hold a large volume of water in a very localised area, which can have consequences on river levels and impact on wildfire in wetland areas.

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