MANAGEMENT OF THE

MEDITERRANEAN

COASTLINE TO COPE WITH

THE RISKS ASSOCIATED

WITH THE SEA AND

FLOODING

Public thematic report

January 2025

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Executive Summary

The management of the Mediterranean coastline as it was shaped before the

decentralising laws, and since then mainly through strong intervention by local authorities, is

now being called into question. Local authorities, which have the main planning tools at their

disposal, have not yet fully appreciated the consequences of their territories’ exposure to the

unpredictable risks of the sea and flooding, or to the foreseeable mobility of the coastline,

phenomena which will be amplified by the effects of climate change. In any case, the most

committed of them quickly come up against a lack of available resources to meet these

challenges.

A form of development threatened by all the risks associated with the sea

and flooding

The development of the Mediterranean coast is largely based on the maritime economy

and the attractions of the seaside. It attracts tourists to ageographical area that is already

home to the majority of the region's population. It is accompanied by urban sprawl and the

growth of metropolitan areas, mainly in Provence-Alpes-Côte d'Azur. Human intervention or

anthropisation has many negative effects linked to the over-consumption of space and to

artificialisation, i.e. the continuous transformation of natural soils into impermeable urbanised land.

As well as exerting heavy pressure on fragile natural environments, they have the effect of

concentrating development on areas already exposed to coastal risks and flooding, and therefore

increase the economic and human stakes that can be affected by these phenomena.

Climate change is also having an impact, increasing the risk of submersion and flooding

from overflowing waterways or run-off, particularly due to the increased frequency of moderate

or exceptional storms. It also results in a rise in sea level, which increases the physical

vulnerability of the Mediterranean coast and accentuates the mobility of the coastline. Coastal

planning must take these phenomena into account and anticipate them.

Insufficient knowledge of coastal vulnerability and associated costs

The economic attractiveness of the Mediterranean coast has been built on the

transformation of natural spaces, the fight against perils and proactive public intervention. The

consequences of this intervention in terms of preventing and mitigating the risks associated

with the sea and flooding are still under-documented.

A shift has begun in the way we understand these risks and coastal erosion, thanks to the

establishment of warning sites and observatories. Although there are many of them, in practice

they are not very accessible and generally remain confined to the study of a specific

phenomenon and do not consolidate data relating to all the perils affecting the coastline. Coastal

residents, and sometimes elected representatives, do not appreciate the degree of the threat.

Similarly, the evaluation of the cost of the impact of these perils on buildings, networks,

infrastructures and populations, and its economic repercussions, remains imprecise. However,

if they are to be properly taken into account in the development of planning policies, this

vulnerability needs to be defined and assessed, and its evolution monitored over time, with the

addition of a financial dimension.

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Estimated market value of buildings by département in 2028 (€M), housing in 2050

(€M) and in 2100 (€Bn) following coastline projection

Source: Court of Accounts based on data from Cerema, studies on coastline projections and

analysis of issues at national level, for 2028, 2050 and 2100 horizons

Public action not commensurate with the stakes

The State has successfully introduced flood risk prevention plans, which are original and

relevant tools. Coastal risk prevention plans have reinforced them, and they were updated

following the Xynthia storm in 2010.

However, these do not cover the entire Mediterranean coastline. In addition, greater

account could be taken of the risks of flooding and coastal erosion. What's more, the provisions

of these plans are occasionally undermined in order to allow local development projects to go

ahead, with no regard for the identified risk.

This wait-and-see attitude can also be seen in regional planning documents. These do

not address or do not explicitly address the overexposure of the Mediterranean coastline to

the risks associated with the sea and flooding and do not take into account spatial restructuring,

which is one of the levers to be mobilised in the longer term. However, a recent initiative by

the Occitanie region, at the end of 2023, deserves to be highlighted, as it has joined forces

with the State and the Banque des Territoires to support, through an action plan, local

authorities in implementing local strategies for the management of the coastline.

The response from the municipal block also remains hesitant and scattered, and struggles

to propose solutions on the relevant geographical scale, which

at the very least

would be the

intermunicipal level. Territorial coherence plans do not take sufficient account of risks and have

also not been adopted everywhere. The refusal of a large number of local authorities to transfer

responsibility for town planning to the public inter-municipal cooperation bodies (EPCI) does not

encourage a vision of the issues at the appropriate level. In fact, town planning documents often

continue to ignore risks – when they do not exacerbate them.

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Local authorities have mainly focused on reinforcing defence works, even though the

efficiency of the latter appears relative compared to the cost of maintaining them in good condition.

The responsibility for managing aquatic environments and preventing flooding, which includes the

management of sea defences, should also be combined with the issue of coastline erosion, as

these two risks interact.

Territories at significant risk of flooding (TRI)

Source: Court of Accounts based on data from the Directorate for Risk Prevention (DGPR)

A coastal management policy and its financing need to be reviewed

To meet the challenges of climate change and exceptional events with potentially

increasing costs, it is essential that all public players start preparing now for the inevitable

changes that lie ahead for their regions.

The value of property exposed to rising sea levels by 2100 on the Mediterranean coast

alone could be as much as €11.5 billion, if we assume that protective structures are erased as

a result of this rise. In the short term and with a constant framework, the insurance and

compensation system will not be able to cover the increase in risks. Over a thirty-year period,

the cumulative cost of compensation for this type of damage would amount to €54 billion,

according to a projection made by insurers covering all the properties compensated for this

type of damage in France.

Long-term solutions are therefore needed, particularly in the context of Mediterranean

coastal management.

Local authorities must therefore make up for lost time in implementing local integrated

coastline management strategies. The aim is to provide a flexible time perspective for the

necessary adaptation, defence and reorganisation measures, choices that may be guided by

the relocation or displacement of public facilities. To do this, it must be possible to put a figure

on the cost of adapting and dismantling these facilities.

The State also has a key role to play in developing a regional or inter-regional vision of

the issues, alongside the coastal local authorities. In particular, they must endeavour to involve

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their inland areas in a process of reflection that cannot ignore the issue of spatial

reorganisation.

In this respect, the funding of measures to defend against the sea and adapt the coastline

would be strengthened by appropriate use of the tax on the management of aquatic environments

and flood prevention and by an increase in specific resources linked to the occupation of the

coastline.

To ensure that public players, including the State, are not faced with unsustainable costs

when exceptional events occur, a support approach for prevention and rehousing could

replace the approach of compensation for loss suffered. It would make it possible to limit

national solidarity by redirecting it towards long-term responses, giving priority to measures to

relocate primary residences.

Lastly, the measures accompanying spatial reorganisation could be carried out by

specific land establishments, which have the capacity to be self-financing in the long term, and

whose initial contribution could be made up of a mix of solutions involving national, local and

coastal use solidarity. In the meantime, short-term safety and defence measures should

involve greater inter-municipal solidarity.

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Recommendations

In conclusion, the financial jurisdictions call for an energetic and rapid response from the

State and all public players in order to adapt planning policies to the risks and threats

associated with the sea and flooding. This means making reducing vulnerability a priority for

local public action and adapting current funding mechanisms and initiating new ones.

In this respect, the Court of Accounts makes the following recommendations:

1.

Reinforce the requirement for buyers of property to be informed in advance that their property

is likely to suffer a reduction in value or even a total loss of value as a result of the natural risk

to which it is exposed

(ministry of ecological transition, energy, climate and risk prevention,

ministry of partnership with the territories and decentralisation)

.

2.

Supplement the cartographic knowledge of the physical vulnerability of an area with a financial

dimension projecting the costs of destruction, interruption, return to normal activities and

reconstruction

(ministry of ecological transition, energy, climate and risk prevention, ministry

of partnership with the territories and decentralisation).

3.

Eliminate the possibility for member municipalities ofpublic establishments for inter-municipal

cooperation in coastal areas previously identified as threatened to oppose the transfer of

competence for local town planning to the inter-municipality

(ministry for ecological transition,

energy, climate and risk prevention, ministry for partnership with territories and decentralisation)

.

4.

Make it compulsory to draw up a local strategy for the integrated management of the coastline

in the most threatened coastal areas

(ministry for ecological transition, energy, climate and

risk prevention, ministry for partnerships with territories and decentralisation)

.

5.

Generalise partnership-based development projects involving coastal municipalities and their

inland areas

(ministry for ecological transition, energy, climate and risk prevention, ministry

for partnerships with territories and decentralisation, Corsica, Occitanie and Provence-Alpes-

Côte d'Azur regions)

.

6.

Mobilise the proceeds of the tax for the management of aquatic environments and flood

prevention in line with real needs in terms of flooding and protection against the sea

(ministry

for ecological transition, energy, climate and risk prevention, ministry for partnership with

territories and decentralisation, ministry for the budget and public accounts, ministry for the

economy, finance and industry)

.

7.

Set up new land subsidiaries within the Provence-Alpes-Côte d'Azur and Occitanie public land

establishments, with resources dedicated to coastal management and redevelopment

(ministry for the ecological transition, energy, climate and risk prevention, ministry for

partnerships with territories and decentralisation, ministry for the budget and public accounts,

ministry for the economy, finance and industry)

.