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This paper provides an overview of the papers published in this Special Issue « Coastal Evolution under Climate Change along the Tropical Overseas and Temperate Metropolitan France» of Journal of Coastal Research. This special issue reflects the large diversity of mainland and tropical French coast and highlights the complex, site- and timescale-specific, combination of factors driving coastal evolution. Many contributions reveal a strong climate control on storm wave activity and, in turn, coastal response. In some contributions, the inherited geology and anthropogenic factors clearly appear affect coastal change. This special issue emphasises the need to monitor the coast combining different means to improve our understanding and predicting capacities of the natural variability of coastal response in a changing climate. [ABSTRACT FROM AUTHOR]

Le Cozannet, G., Ait-Kaci, H., Colas, S., De Lacaze, X., Lecacheux, S., Mirgon, C., Peinturier, C., Garcin, M., and Oliveros, C., 2013. Recent GIS based national assessments of climate change consequences in France: methods, results and lessons learnt This paper reviews two recent assessments undertaken in France for evaluating national scale consequences of global change for coastal hazards and risks, namely marine submersion and coastal erosion. In a first approach, the potential consequences of climate change were evaluated in a direct quantitative way, however with high uncertainties in the final evaluation. Recognizing that uncertainties could hardly be reduced, a second assessment based on a multi-criteria evaluation was then undertaken. Geomorphological and marine factors that account for physical vulnerability to coastal hazards were evaluated for 21 coastal entities in metropolitan France. The evaluation was structured using the analytical hierarchy process (AHP). The results highlighted the fact that in some specific regions such as Languedoc-Roussillon (Mediterranean coast) and Pertuis (Atlantic coast), the population is expected to increase more than the mean average, while the coastal zone are also likely to be more strongly affected by coastal hazards. While such national scale evaluations in highly diversified coastal environments are still arguable, they may help identifying unsustainability in current trends and help defining priorities for future adaptation strategies. [ABSTRACT FROM AUTHOR]

In recent years the interest for coastal hazards has increased significantly due to extreme events, sometimes related to climate change, that frequently occur in different parts of the world, often inducing high risk situations. This paper outlines the objectives, perspectives and preliminary results of a research project entitled "Coastline at risk: Methods for multi-hazard assessment" which aims at providing useful knowledge for the mitigation of coastal instability. The project is managed by the European Centre on Geomorphological Hazards (Centre Européen sur les Risques Geomorphologiques, CERG) and funded by the EUR-OPA Major Hazards Agreement. Investigations are focused on coastal landslides in three different morpho-climatic European environments: Malta (Mediterranean coastline), Lower Normandy (Channel coastline) and Central Portugal (Atlantic coastline). The research outputs are expected to provide a significant opportunity for scientific discussion based on the comparison of data regarding instability situations in the context of multi-hazards assessment. The latter has until now dealt slightly with the coasts of Malta, Normandy and Portugal on which the investigations will be focused, despite significant risk issues present there, as evidenced from a series of accidents and damages recorded after landslide events. The aims of the project will be pursued through multidisciplinary investigations which foresee geomorphological and engineering-geological approaches. Integrated avant-garde research techniques, both traditional and innovative, will be applied with special reference to mapping, monitoring and modelling of coastal instability phenomena. The final objective is to propose a method for coastal multi-hazard assessment that can be used to face and manage coastal hazards. [ABSTRACT FROM AUTHOR]

ABSTRACT Gabarrou, S.; Le Cozannet, G.; Parteli, E.J.R.; Pedreros, R.; Guerber, E.; Millescamps, B.; Mallet, C., and Oliveros, C., 2018. Modelling the Retreat of a Coastal Dune under Changing Winds. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 166–170. Coconut Creek (Florida), ISSN 0749-0208. Coastal dunes can move in response to winds and cause serious hazard to human assets. Changes in wind patterns, potentially occurring as a consequence of climate change or variability, could affect rates of aeolian transport and migration velocity of coastal dunes. However, most of previous modeling studies were conducted assuming that aeolian bedforms are subject to constant wind velocities. This article presents a modeling of the mobility of the Dune du Pilat in Aquitaine, a coastal transverse dune exposed to winds of varying intensity. It applies well-established models and empirical formula for aeolian dune migration, including a model previously validated against measurements of real profiles of desert and coastal dunes. The average migration velocity of Pilat dune predicted by the models is about 3m/year, which is in good agreement with in-situ measurements. To test the response of transverse dune mobility to changing winds, virtual wind time series are generated using a stochastic model. Modelling experiments suggest that more frequent storms have less impacts than more intense winds. Due to the size of the Pilat Dune (altitude of about 100m), these result in moderate changes in the average dune velocity. This study shows that the approach of combining a stochastic model for winds with a morphodynamic dune model can provide valuable insight into how aeolian bedforms respond to changes in flow conditions potentially caused by climate change. [ABSTRACT FROM AUTHOR]

Concern is growing in France about climate change and the related issue of accelerated sea-level rise (ASLR). Although a national vulnerability assessment has not been produced, available information is sufficient to clearly identify the coastal zones which are at risk. On the Mediterranean coast, the most vulnerable area corresponds to the deltaic plain of the Rhône River, chiefly because of human actions (e.g., shortage of sediment supply as a result of dam construction; river embankments). Coastal erosion, lowland flooding, and ground water salinisation are the main impacts expected from ASLR. The Languedoc coastal barriers will move landward faster than at present, thus jeopardising dense tourist facilities. On the Atlantic coast, enhanced erosion of the Aquitaine sandy beaches is expected. Existing salt marshes do not appear threatened because mud sedimentation from soil erosion is active, but reclaimed areas will be at risk of flooding. Moderate salt intrusion is expected into the Loire estuary. The Normandy chalk cliffs may not recede faster than at present. Existing laws and regulations dealing with coastal management are sufficient to address the potential impacts which may affect populations and economic activities in the forthcoming decades as sea level rises. [ABSTRACT FROM AUTHOR]