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The IMCORE project ran from 2008 to 2011 and was funded under the EU Interreg IVB programme.

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Practical tips for following the IMCORE approach to planning to adapt to coastal climate change 

The Gulf of Morbihan is an enclosed or semi-enclosed sea connected to the Atlantic Ocean by a 900m-long outlet. It has a land and sea surface area of 750km² and 170km² respectively and a 500km-long coastline. Its landscape is very flat. Inside the Gulf there are around 60 islands whose sizes vary from a few square metres to whole villages (Ile d'Arz and Ile aux Moines). The three main physical features of the gulf are as follows:

(i) the three rivers that enter the Gulf (the Auray, Vannes and Noyalo rivers)

(ii) mud flats, salt marshes and small beaches in the north

(iii) rocky coast and small beaches in the south-west (entrance)

The Gulf of Morbihan is an area rich in biodiversity and diverse natural habitats. It is a designated Natura 2000 area and is also protected by various international and national regulations: Ramsar (for the protection of wetlands), decrees on biotope protection, and its designated statuses as a natural reserve, protected area and national heritage site.

The communes around the Gulf of Morbihan are densely inhabited with 230 inhabitants per km² which is twice the national average. There are 165,000 inhabitants and this figure is constantly rising. Over the last 40 years, the population of this area has doubled, whereas urbanized areas have experienced a ten-fold population increase which is attributed to summer houses and the building of larger detached properties.

The Gulf's natural beauty attracts two million visitors each year and as such, tourism is the main economic activity. Other economic activities are oyster farming (with 1,600 hectares given over to this activity) fishing, agriculture (in decline), and tertiary activities.

More details:

Click here for a bathymetry map of  Gulf of Morbihan

Click here for Pictures of Brittany and the Gulf of Morbihan

Click here for a map of the Gulf of Morbihan

Click here to download a presentation of the Gulf of Morbihan case study

Climate change drivers

The main climate change driver in the Gulf of Morbihan is potential sea-level rise. There is no firm scientific evidence in this respect, nonetheless, it has been identified a major driver because the Gulf of Morbihan is mainly flat and most of the 60 islands (only about 20 are inhabited) are threatened with submersion. Other significant drivers include (i) storms and (ii) variations in temperatures and rainfall. As for the former, this is due to the impact on waves, erosion and sea level rise. Once again, there is no scientific evidence to link climate change and an increase in storms. Nevertheless storm "Johanna" (10 March 2008) had a strong psychological impact on the inhabitants of the Gulf of Morbihan and it has been identified in the IMCORE project as a trigger for the elected representative tasked with managing its consequences. As for the latter, data on local simulations based on IPCC scenarios have been collected by ONERC- the French national observatory for the effects of global warming. Click here to view the website.



Figure 2: Simulations of temperature "1" (annual average) and rain fall "2" (June to August average) changes in the Vannes region (Gulf of Morbihan) according to two IPCC scenarios (A2 in red and B2 in green) and observed averages between 1960 and 1989 (blue line).


Impacts of climate change in the case study area

Climate change impacts (potential or observed) in the Gulf of Morbihan are presented below.

Physical impacts

Sea water flooding causes shoreline morphology through (i) erosion, (ii) riverflow cessation and (iii) the uprooting of trees that maintain the shoreline (a cause of erosion): entire islands are threatened with submersion.

Ecological impacts

The biodiversity of the sea is mainly affected by changes in air temperature, sea surface temperature and O2 concentration in the sea. These main drivers lead to species disappearing from certain areas and sightings of "new" non-endemic species. Observed or predicted examples of such species disappearance include gorgons (highly temperature-sensitive), various sponges (the disappearance of one species was recorded during the very hot summer of 2003), birds (whose southern boundary range limit is the Gulf of Morbihan), and plants. As for "new species", they can migrate from southern areas or, in the case of migrating species, be observed during "abnormal periods". For example, some birds remain in the Gulf during the winter whereas in the past they have migrated south. Furthermore, sea-level dependent ecosystems such as marshes are directly impacted by sea-level rise.

Socio-economic impacts

At the urban planning level, various (potential) impacts include (i) buildings and waste-water systems on the shoreline that are vulnerable to sea-level rise. This means that housing and tourism infrastructure (e.g. campsites and beaches) are potentially affected (ii) the slump in house prices when risks increase and (iii) rainfall evacuation systems that are too small to manage the higher rainfall and therefore the risk of flooding increases.


Contemporary agricultural production methods are unsuitable for declining water resources – one such example is maize, as it is one of the very high-water consuming crops. This raises questions about (i) the use of earlier-germinating seeds to mitigate the impact of drought on crops, (ii) the appropriateness of cattle-rearing (i.e. in respect of the animals' CO2-emissions) and (iii) the preference for pastures for breeding livestock.

Any changes in climate imply changes in the use of phytosanitary products. However, as the use of these products is relatively new, it is still unclear as to which chemical elements will be released through the degradation process.


Various questions are raised in this respect such as, will tree species that have already been planted be able to adapt? Is it necessary to plant new tree species? How can biodiversity be preserved?

Shellfish farming

Is climate change responsible for the high oyster mortality rate? Should we consider cultivating new varieties of oysters that are adapted to the new conditions? Sea-level rise is a direct threat to the land- and marine-based infrastructures used in shellfish farming.


The Iberian peninsula is the biogeographical boundary between southern and northern fish populations and according to scientific data, this boundary line is currently moving in a northerly direction. Thus, the impact of global warming on a species is more visible at the species range boundaries. Changes in the fish population impact commercial and leisure fishing and additionally, as some local species have a cultural heritage value, their absence will be sorely missed by local communities who will feel a subsequent knock-on effect. At present, the field data from observations in the Gulf of Morbihan mainly focus on species that were not present in this area a few years ago, such as the arrival of Mediterranean species.

Leisure activities

Sea-level rise causes changes to the coastal morphology which in turn, give any bodies of water a new appearance. As such, all watersport activities and sea accesses (such as jetties) are liable to be affected.


Exceptionally heavy rainfall and storms cause a water surplus that does not drain away and this leads to an increase in the mosquito population. Any rises in temperature are also conducive to an increase in mosquito-borne diseases such as malaria, chikungunya fever and the West Nile virus. Additionally, the presence of phycotoxins in shellfish has been identified in previously unaffected zones. Even though there is no evidence to link such events to climate change, toxicologists suspect that there is a direct relationship and this possible interplay forms the basis of a World Health Organization (WHO) recommendation for follow-up.

Green spaces

New climate conditions must be taken into account if effective management of urban green spaces is to be achieved. This should include due consideration to (i) the species to be planted, (ii) water requirements and (iii) adaptation to increased hours of sunlight and higher temperatures

Integrated Coastal Zone Management (ICZM) and Institutional Context

In France, the issue of climate change has not been integrated as yet into overall coastal zone management approaches or local projects, with the exception of the Gulf of Morbihan Regional Nature Park Charter, the Breton Coastal Areas Charter, and more generally, future action plans to combat climate change.

• The Gulf of Morbihan Regional Nature Park Charter is a project in progress and therefore, its charter is not yet applicable. However, it does comprise a component for combating climate change and adapting to its effects.

• The Breton Coastal Areas Charter is a policy position paper setting out the Brittany Regional Council's main coastal zone management objectives. It has no current regulatory status, however, it does include an objective that focuses on climate change.

• Local climate and energy plan documents are the result of a voluntary, political and operational process based on a sustainable development approach that aims to reduce greenhouse gas emissions and provide local climate change adaptation solutions.

Local planning documents do not address the issue of climate change, but public policies, on the other hand, do cover this issue- mainly in the form of contingency plans for storm-induced flooding hazards.

As such, climate change is relatively low on the agenda for most local councils because of its long-term, as opposed to short-term, expected impacts that do not fit well within the timeframes for existing public policies. At present, local councils receive no specific funding that is earmarked for tackling climate change.

This learning portal brings together the results and lessons learned from the IMCORE project. This project was funded under the Interreg IVB programme from 2008 to 2011.

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