Virginie Duvat

La Rochelle Université · LIttoral ENvironnement et Sociétés (LIENSs)

Coastal erosion occurs along many of the world’s shorelines, but is of particular concern to small islands. In response, island shorelines are often armoured through engineered structures such as seawalls, rip-raps, dikes or similar. Such hard protection is rarely successful in island contexts; rather than stop erosion, hard protection often simply...

Atoll islands face increasing coastal risks (coastal erosion and marine flooding) due to climate change, especially sea-level rise. To face increasing coastal risks, various adaptation options are considered by atoll countries and territories, including in particular hard protection (preferred option to date), Nature-based Solutions (increasingly u...

More international incentives and coordination are needed

Sea level rise (SLR) will increase adaptation needs along low-lying coasts worldwide. Despite centuries of experience with coastal risk, knowledge about the effectiveness and feasibility of societal adaptation on the scale required in a warmer world remains limited. This paper contrasts end-century SLR risks under two warming and two adaptation sce...

This paper discusses whether existing coastal risk reduction policies in French Polynesia—a French Overseas Territory with a high degree of political autonomy—(i) consider current and future coastal risks from climate variability and change, and (ii) are designed to evolve as new knowledge on climate change emerges. The analysis relies on the study...

This report presnets the results of the pilot phase (2021) of the GAP-Track (Global Adaptation progress Tracker). See https://www.iddri.org/en/project/assessing-global-progress-climate-adaptation-gap-track-2021.

The three recent Special Reports of the IPCC provide an opportunity to understand overarching climate risk, as they cover a wide diversity of risks to natural and human systems. Here we develop a scoring system to translate qualitative IPCC risk assessments into risk scores that, when aggregated, describe global risk from climate change. By the end...

The 2017 hurricane season in the Caribbean Basin recorded 18 events (storms and hurricanes), including Category 5 hurricane Irma on which this article focuses. The aim of this study is to analyse the ‘window of opportunity’ of the post-Irma reconstruction in Saint Martin. Located 250 km north of Guadeloupe, Saint Martin is a small bi-national islan...

This article proposes a comprehensive methodology considering geomorphic, ecological and human variables to assess atoll island physical robustness in the face of climate-ocean pressures. Six variables are considered, including island size, elevation, shape, structure, vegetation and the influence of human activities on island natural capacity to a...

Recent assessments of future risk to atoll habitability have focused on island erosion and submergence, and have overlooked the effects of other climate‐related drivers, as well as differences between ocean basins and island types. Here we investigate the cumulative risk arising from multiple drivers (sea‐level rise; changes in rainfall, ocean–atmo...

Owing to their high shoreline-to-land-area ratios, islands are especially sensitive to coastal change and their inhabitants especially vulnerable to associated impacts. In places along island coasts where shoreline recession is particularly noticeable and/or its impacts most severe, perhaps because adjacent population densities are unusually high,...

This study calls upon recently discovered aerial photographs for two atolls in the Indian Ocean Chagos Archipelago. Pairing these vintage data with modern satellite imagery allows the coastline dynamics of a suite of islands to be quantified over a 36-to-50-yr. period. Peros Banhos represents one of the few atolls globally where natural island dyna...

This empirical and interdisciplinary study investigates the contribution of deeply enrooted social-political factors to the accumulation of exposure and vulnerability and amplification of cascading impacts of disasters, with implications on the creation and reinforcement of path dependency maintaining social-ecological systems on a maladaptive traj...

Le projet TIREX (Transfert des apprentissages de retours d'expérience scientifiques), dirigé par Pr. Frédéric LEONE, part du constat que les résultats des retours d'expérience scientifiques ne sont pas assez communiqués aux acteurs des territoires concernés. En analysant la saison cyclonique 2017 dans les Petites Antilles, TIREX répond à la fois à...

This study assesses changes in coastal risk reduction and adaptation-labelled responses in Mauritius Island since the 1960s. Using research documents, interviews, field observations, image analysis, and case studies, it analyses evolutions in public and private stakeholders’ strategies, and the levers and barriers at play. Based on 60 beach sites,...

Coastal areas host a significant part of the world population and of humankind’s adaptation needs in the face of effects of climate change, especially sea-level rise and ocean warming and acidification. Atoll islands illustrate frontline situations due to their biophysical (low elevation, small land area, 360°-exposure to waves, limited natural res...

Purpose of Review -- This paper discusses three scientific frontiers that need to be advanced in order to support decision-makers and practitioners in charge of operational decisions and action on the design and implementation of concrete adaptation policies and actions. These frontiers refer to going beyond the (1) incremental vs. transformational...

This study assesses the evolution of 104 inhabited and 82 resort islands across the Maldives between 2004-2006 and 2014-2016 and investigates the contribution of human drivers. Using multi-date satellite imagery, we show that 59.1 % of these islands expanded as a result of human intervention, including mainly land reclamation (often associated with...

Volto, N. and Duvat, V.K.E., 2020. Applying directional filters to satellite imagery for the assessment of tropical cyclone impacts on Atoll Islands. Journal of Coastal Research, 36(4), 732–740. Coconut Creek (Florida), ISSN 0749-0208.This paper highlights the major insights provided by directional filters using ENVI® software for detecting and map...

In Mauritius island in the Indian Ocean, as in most low-lying coastal areas and Small Island Developing States in particular, coastal risks affect community livelihood, economic prosperity and the degradation of natural ecosystems. Risks of coastal erosion and marine flooding result both from climate-related ocean changes and anthropogenic drivers...

Based on the study of nine atolls of the Tuamotu Archipelago, French Polynesia, this article assesses the anthropogenic disturbances that disrupt atoll island natural dynamics and thereby undermine the ability of these islands to naturally adjust to climate-related pressures. It more specifically investigates to what extent the existing legal frame...

Institutional actors have a crucial role in adaptation to climate change, especially for highly vulnerable territories such as small tropical islands. Here, we emphasize their major role in the co-design of tailored coastal climate services (CCS) based on a case study of French Polynesia. In this perspective, we assessed climate change perceptions...

While the geomorphic impacts of extreme climate events, including in particular tropical cyclones and distant-source swells, on atoll islands are widely acknowledged, the influence of moderate climate events, such as tropical lows that do not reach the cyclone stage and low-magnitude distant-source swells, has to date been overlooked. Based on mult...

Recent assessments of future risk to atoll habitability have focused on island erosion and submergence, and have overlooked the effects of other climate-related drivers, as well as differences between ocean basins and island types. Here we investigate the cumulative risk arising from multiple drivers (sea-level rise; changes in rainfall, ocean-atmo...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

L'élévation du niveau de la mer, en se superposant au signal de marée, aura pour conséquence des submersions chroniques, à marée haute, par conditions météorologiques normales. Dans le cadre du projet INSeaPTION, un service climatique côtier évaluant ce risque de submersions chroniques a été co-construit avec les autorités et les opérateurs portuai...

Most studies addressing the future of atoll islands focused on ocean-climate drivers of risk, especially sea-level rise, and disregarded the role of local human disturbances. However, the future habitability of these countries will critically depend on the response of inhabited and exploited islands to ocean-climate pressures. Here, using the Maldi...

Tropical cyclone (TC) impacts on small islands can be divided into four main categories that are common to both low‐lying atoll islands and high mountainous islands. This chapter investigates both the impacts of and the stakeholders' responses to TC Bejisa, which, in January 2014, affected Saint‐Paul, the second most populated municipality of Reuni...

The unique coping capacities and other attributes that Pacific island nations have been developing for centuries have sustained them in the face of an enormous range of local and global challenges. These include climate change-related hazards, and especially tropical cyclones and high-wave incidents that notably generate landslides and river and co...

Based on an approach coupling geomatics (i.e. satellite imagery analysis) and fieldwork, this paper provides an indepth analysis of the impacts of September 2017 hurricanes on the beaches of Saint-Barthélemy Island. First, it highlights the key role of low-frequency high-intensity events in driving high rates of changes on coastal systems. Importan...

Relative sea-level rise and the influence of vertical land motion at Tropical Pacific Islands (Supplementary material)

French coastal policies have recently put greater emphasis on the need to better inform coastal populations about coastal risks in the context of climate change, in particular in French overseas territories that are nationally recognized as hotspots. It is therefore critical to further assess local populations' knowledge and perceptions of climate-...

The paper is available online until March 21: https://authors.elsevier.com/a/1YU7q7tFrJI-ov

This study investigates the relative sea–level changes and the influence of vertical land movements at South Western Tropical Pacific Islands. The dataset consists of tide gauge records, remote satellite altimetry observations and GPS records. After evaluating the uncertainties and the nature of vertical land movements, we focus on the present and...

Over the past decades, atoll islands exhibited no widespread sign of physical destabilization in the face of sea‐level rise. A reanalysis of available data, which cover 30 Pacific and Indian Ocean atolls including 709 islands, reveals that no atoll lost land area and that 88.6% of islands were either stable or increased in area, while only 11.4% co...

This paper characterizes the current exposure of people leaving on the low-lying atoll reef islands to the risk of marine inundation induced by various sea-related hazards (i.e. cyclones, distant swells and local storms). It offers one of the rare scientific studies that go beyond the general assertion on atoll populations’ exposure to sea-related...

Cet article représente l’une des rares études scientifiques cherchant à dépasser le discours général sur l’exposition des populations des atolls face aux risques liés à la mer, en l’occurrence ici à la submersion marine, en mesurant concrètement le degré réel d’exposition actuelle des populations et en observant les stratégies locales de protection...

Using multi-date satellite imagery and field observations, this paper assesses the inferred impacts of September 2017 cyclones on the beaches of Saint-Martin Island. Twenty-two beaches out of 30 predominantly exhibited shoreline retreat, with the highest retreat value (−166.45 m) recorded on the north-eastern coast. While erosion predominated on be...

The study of recent past trajectories of vulnerability to climate-related hazards allows for highlighting the prevailing environmental and anthropogenic drivers that operated over the last fifty to sixty years and given latency phenomena in social systems, therefore have the potential to continue driving a system's vulnerability in the coming decad...

Le projet INSeaPTION, soutenu par l’Europe au travers du projet ERANET-ERA4CS (« European Research Area for Climate Services »), vise à co-concevoir et co-développer, avec les utilisateurs, des services climatiques côtiers fondés sur la connaissance scientifique sur l’élévation du niveau de la mer, ses impacts et l’adaptation. Les services climatiq...

Composed of biodetritic sediments and lying just a few meters above present sea-level, atoll reef islands are liable to be highly exposed to coastal flooding and shoreline erosion. Nevertheless, the analysis of multi-decadal shoreline change has shown that most reef islands either remain stable in area or are expanding within the context of current...

Composed of biodetritic sediments and lying just a few meters above present sea-level, atoll reef islands are liable to be highly exposed to coastal flooding and shoreline erosion. Nevertheless, the analysis of multi-decadal shoreline change has shown that most reef islands either remain stable in area or are expanding within the context of current...

Cet article démontre l'intérêt d'une approche de la résilience des territoires par la reconstruction de « chaînes d'impacts » d'événements passés. Proposé au Ministère de l'Ecologie comme composante du référentiel national d'adaptation au changement climatique [ONERC, 2012], ce concept a fait l'objet d'applications à des cyclones tropicaux ayant to...

Based on two case studies located in French overseas territories, this paper aims to investigate how to base coastal risk management policies on natural coastal system protection. The in-depth analysis of the impacts of and resilience to cyclones Oli in Tubuai Island (French Polynesia, Feb. 2010) and Bejisa in Reunion Island (Jan. 2014), raised the...

INSeaPTION starts with analysing and understanding the user needs in terms of coastal climate services using sea level projections. Since early March 2018, a number of meeting have been organised by the INSeaPTION project partners in French Polynesia, namely CREOCEAN, the University of La Rochelle and BRGM. These meetings included: Individual inte...

This paper provides new insights on the impacts of a category 5 tropical cyclone on Indian Ocean atoll reef islands. Using multi-date aerial imagery and field observations, the contribution of tropical cyclone Fantala to shoreline and island change, and to sediment production and transport, was assessed on Farquhar Atoll, Seychelles Islands. Result...

This paper increases by around 30% the sample of atoll reef islands studied from a shoreline change perspective, and covers an under-studied geographical area, i.e. the French Tuamotu Archipelago. It brings new irrefutable evidences on the persistence of reef islands over the last decades, as 77% of the 111 study islands exhibited areal stability w...

This article advocates for a dynamic and comprehensive understanding of vulnerability to climate‐related environmental changes in order to feed the design of adaptation future pathways. It uses the trajectory of exposure and vulnerability (TEV) approach that it defines as ‘storylines of driving factors and processes that have influenced past and pr...

Atoll reef islands are considered highly vulnerable to the impacts of climate change. While accelerated sea-level rise is expected to destabilize reef islands, ocean warming and acidification are considered as major threats to coral reef growth, which is of primary importance for the persistence of islands and of food supply to islanders. Using mul...

Cette étude présente les résultats de la reconstruction de 6 trajectoires de vulnérabilité des littoraux de quatre communes de l’île de la Réunion (sud-ouest de l’océan Indien). La période couverte est 1950-2011 et définit des trajectoires dites « courtes ». Les résultats montrent l’importante contribution des facteurs anthropiques (aménagement du...

This paper highlights the high variability of the nature and severity of the impacts of Tropical Cyclone Bejisa (January 2014, category 3) along the 20-km-long beach–dune systems of the western coast of Reunion Island. Erosional impacts were reported on 17 out of 26 topographic transects, while nine transects exhibited accretion. Sediment loss and...

Coastal risks induced by climate change in tropical islands Based on a literature review, this article analyses the implications of climate change on the evolution of coastal risks, namely coastal erosion and marine inundation, in small tropical islands. Examination of theoretical knowledge and available instrumental data combined with case studies...

This paper provides baseline data on absolute and relative sea level variations and shoreline changes in the Scattered Islands region of the Indian Ocean, based on aerial image analysis, satellite altimetry and field observations and in situ measurements from the 2009 and 2011 TAAF scientific expeditions. The analysis shows the importance of regula...