Goneri Le Cozannet

• Engineer
• Programm leader: vulnerability, resilience & climate change at Geological and Mining Research Bureau

This perspective paper reports the results of a collaborative survey of French research institutes concerned with environmental issues, which examined the potential for a market uptake of climate services for adaptation in France. The study is based on a review of existing reports on the market of climate services, and on interviews of 68 climate s...

The potential of correlating high-resolution SAR images to estimate local water-level variations is analyzed based on observing the motions of floating structures. By computing range and azimuth offsets on a Cosmo-Skymed multi-temporal dataset in an area of the French Atlantic Coast, displacement signatures were detected in several harbors of the r...

Despite progresses in climate change science, projections of future sea-level rise remain highly uncertain, especially due to large unknowns in the melting processes affecting the ice-sheets in Greenland and Antarctica. Based on climate-models outcomes and the expertise of scientists concerned with these issues, the IPCC provided constraints to the...

Sea-level rise (SLR) can modify not only total water levels, but also tidal dynamics. Several studies have investigated the effects of SLR on the tides of the western European continental shelf (mainly the M2 component). We further investigate this issue using a modelling-based approach, considering uniform SLR scenarios from −0.25 m to +10 m above...

With growing concerns regarding future impacts of sea-level in major coastal cities, the most accurate information is required regarding local sea-level changes with respect to the coast. Besides global and regional sea-level changes, local coastal vertical ground motions can substantially contribute to local changes in sea-level. In some cases, su...

Multi-model ensembles (MME) are key ingredients for future climate projection and the quantification of its uncertainty. Developing robust protocols to design balanced and complete computer experiments for MME is a matter of active research. In this study, we take advantage of a large-size MME produced for Greenland ice sheet contributions to futur...

Sea level rise (SLR) will affect Europe's coasts over the coming decades and beyond, giving rise to ongoing challenges in governing coastal and marine areas. Progress is being made in adapting to and addressing these challenges at both national and sub-national levels across all major European sea basins. This paper assesses progress in coastal ada...

With climate change and accelerating sea-level rise (SLR), long-term predictions of shoreline evolution are crucial to assess climate adaptation plans in coastal areas. Meanwhile, knowledge gaps in the physics of shoreline response to the combined action of waves and SLR hinder making reliable long-term shoreline projections. Equilibrium beach theo...

Beside climate‐change‐induced sea‐level rise (SLR), land subsidence can strongly amplify coastal risk in flood‐prone areas. Mapping and quantifying contemporary vertical land motion (VLM) at continental scales has long been a challenge due to the absence of gridded observational products covering these large domains. Here, we fill this gap by using...

Recent coastal flooding events such as those induced by the Hayian cyclone in 2013 in the Philippines highlight the vulnerability of coastal zones to flooding. The risk associated with such events is likely to increase in the future for two reasons: first, many coastal zones worldwide are either already urbanized or rapidly developing; second, sea...

Sea level rise due to climate change is an ongoing process that will continue for centuries and millennia. In response to this, France is increasingly considering sea level rise in its coastal risks and land use policies. Here, we show that despite real progress in coastal adaptation policies made so far, major challenges remain. We report progress...

Coastal erosion and flooding are projected to increase during the 21 st century due to sea-level rise (SLR). To prevent adverse impacts of unmanaged coastal development, national organizations can apply a land protection policy, which consists of acquiring coastal land to avoid further development. Yet, these reserved areas remain exposed to floodi...

Plain Language Summary Sea levels are predicted to rise for hundreds to thousands of years, even if emissions are reduced. Decisions about how to adapt to more frequent and severe coastal flooding need predictions showing a range of possible futures. However, few computer modeling studies of the contributing factors to sea level rise extend as far...

As sea levels are rising, the number of chronic flooding events at high tide is increasing across the world coastlines. Yet, many events reported so far either lack observational evidence of flooding, or relate to coastal areas where ground subsidence or oceanic processes often enhance climate change-induced sea-level rise (SLR). Here we present ob...

The latest IPCC report estimates that approximately 1 billion people will be at risk from coastal hazards in the near term due to coastal population increase, sea-level rise and other coastal changes. This will occur in a world that is changing rapidly due to climate change, ecosystem decline, human development and the projected transformations of...

Sea-level rise will fundamentally change coastal zones worldwide. A global two meters rise of sea level will be exceeded sooner or later within a time window ranging from one century to as long as two millennia, depending on future greenhouse gas emissions and polar ice-sheet melting. Here, we show that in addition to climate mitigation to slow the...

While the prioritisation of scarce resources for climate adaptation is becoming a priority for low and middle income countries, the climate service literature addressing adaptation prioritisation decisions is scarce. This paper contributes to filling this gap by presenting a co-creation process carried out in the Maldives among representatives of g...

Cost-effective coastal flood adaptation requires a realistic valuation of losses, costs and benefits considering the uncertainty of future flood projections and limited resources for adaptation. Here we present an approach to quantify the flood protection benefits of beaches accounting for the dynamic interaction of storm erosion, long-term shoreli...

We produce projections of global mean sea-level rise to 2500 for low and medium emissions scenarios (Shared Socioeconomic Pathways SSP1-2.6 and SSP2-4.5), based on extending and combining model ensemble data from current literature. We find that emissions have a large effect on sea-level rise on these long timescales, with a difference of 0.95 m at...

Process-based projections of the sea-level contribution from land ice components are often obtained from simulations using a complex chain of numerical models. Because of their importance in supporting the decision-making process for coastal risk assessment and adaptation, improving the interpretability of these projections is of great interest. To...

Getting a deep insight into the role of coastal flooding drivers is of great interest for the planning of adaptation strategies for future climate conditions. Using global sensitivity analysis, we aim to measure the contributions of the offshore forcing conditions (wave–wind characteristics, still water level and sea level rise (SLR) projected up t...

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...

Due to climate change, coastal subarctic environments are facing rising temperatures and sea levels, which exacerbate coastal erosion and flooding during extreme events , challenging coastal societies’ resilience . Based on doctoral research on Saint-Pierre-and-Miquelon archipelago, we studied the acceptability of various possible adaptation measur...

Process-based projections of the sea-level contribution from land ice components are often obtained from simulations using a complex chain of numerical models. Because of their importance in supporting the decision-making process for coastal risk assessment and adaptation, improving the interpretability of these projections is of great interest. To...

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...

The original version of this Article contained an error in the Acknowledgements section.

Reconstructing the responses of low-lying, atoll-rim islands to future environmental changes due to global warming requires a robust knowledge of the building history of reef rims through time. In the northwest of Tuamotu Archipelago, atolls have experienced opposite vertical motions (uplift versus subsidence) in response to differential tectonic c...

The Working Group II contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) provides a comprehensive assessment of the scientific literature relevant to climate change impacts, adaptation and vulnerability. The report recognizes the interactions of climate, ecosystems and biodiversity, and human societie...

Atoll islands are among the places most vulnerable to climate change due to their low elevation above mean sea level. Even today, some of these islands suffer from severe flooding generated by wind-waves, that will be exacerbated with mean sea-level rise. Wave-induced flooding is a complex physical process that requires computationally-expensive nu...

Coastal areas are highly diverse, ecologically rich, regions of key socio-economic activity, and are particularly sensitive to sea-level change. Over most of the 20th century, global mean sea level has risen mainly due to warming and subsequent expansion of the upper ocean layers as well as the melting of glaciers and ice caps. Over the last three...

Climate services are ideally co-developed by scientists and stakeholders working together to identify decisions and user needs. Yet, while climate services have been developed at regional to local scales, relatively little attention has been paid to the global scale. Global climate services involve decisions that rely on climate information from ma...

Climate change is projected to challenge adaptation capacity in small islands worldwide due to rising temperatures, sea-level rise, extreme events and changing rainfall patterns. However, adaptation planning and implementation may be delayed where people perceive a lack of urgency and put forward competing priorities such as economic development. H...

Getting a deep insight into the role of coastal flooding drivers is of high interest for the planning of adaptation strategies for future climate conditions. Using global sensitivity analysis, we aim to measure the contributions of the offshore forcing conditions (wave/wind characteristics, still water level and sea level rise (SLR) projected up to...

Populated coastal areas worldwide have a legacy of numerous solid waste disposal sites. At the same time, mean sea level is rising and likely to accelerate, increasing flooding and/or erosion. There is therefore concern that landfill sites located at and near the coast pose a growing risk to the environment from the potential release of liquid and...

Long-term (>decades) coastal recession due to sea-level rise (SLR) has been estimated using the Bruun Rule for nearly six decades. Equilibrium-based shoreline models have been shown to skillfully predict short-term wave-driven shoreline change on time scales of hours to decades. Both the Bruun Rule and equilibrium shoreline models rely on the equil...

Sandy shorelines morphodynamics responds to a myriad of processes interacting at different spatial and temporal scales, making shoreline predictions challenging. Shoreline modeling inherits uncertainties from the primary driver boundary conditions (e.g., sea‐level rise and wave forcing) as well as uncertainties related to model assumptions and/or m...

Global mean sea level rise and its acceleration are projected to aggravate coastal erosion over the 21st century, which constitutes a major challenge for coastal adaptation. Projections of shoreline retreat are highly uncertain, however, namely due to deeply uncertain mean sea level projections and the absence of consensus on a coastal impact model...

This study provides a literature‐based comparative assessment of uncertainties and biases in global to world‐regional scale assessments of current and future coastal flood risks, considering mean and extreme sea‐level hazards, the propagation of these into the floodplain, people and coastal assets exposed, and their vulnerability. Globally, by far...

Non-stationary extreme value analysis is a powerful framework to address the problem of time evolution of extremes and its link to climate variability as measured by different climate indices CI (like North Atlantic Oscillation NAO index). To model extreme sea levels (ESLs), a widely-used tool is the non-stationary Generalized Extreme Value distrib...

The Maldives, with one of the lowest average land elevations above present-day mean sea level, is among the world regions that will be the most impacted by mean sea-level rise and marine extreme events induced by climate change. Yet, the lack of regional and local information on marine drivers is a major drawback that coastal decision-makers face t...

Sea-level rise (SLR) will be one of the major climate change-induced risks of the 21st century for coastal areas. The large uncertainties of ice sheet melting processes bring in a range of unlikely – but not impossible – high-end sea-level scenarios (HESs). Here, we provide global to regional HESs exploring the tails of the distribution estimates o...

Predicting long-term beach morphodynamics is one of the largest challenge for Coastal Scientists. Limited knowledge of physical processes, modelling assumptions, lack of data, prediction of the future forcing factors, and future climate scenarios make model predictions hardly reliable. Probabilistic approaches allow quantifying the level of confide...

Global scale assessments of coastal flood damage and adaptation costs under 21st century sea-level rise are associated with a wide range of uncertainties, including those in future projections of socioeconomic development (shared socioeconomic pathways (SSP) scenarios), of greenhouse gas concentrations (RCP scenarios), and of sea-level rise at regi...

Sea-level rise due to anthropogenic climate change is projected not only to exacerbate extreme events such as cyclones and storms but also to cause more frequent chronic flooding occurring at high tides under calm weather conditions. Chronic flooding occasionally takes place today in the low-lying areas of the Petit Cul-de-sac marin (Guadeloupe, We...

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...

Global mean sea-level rise and its acceleration are projected to aggravate coastal erosion over the 21st century, which constitutes a major challenge for coastal adaptation. Projections of shoreline retreat are highly uncertain, however, namely due to deeply uncertain mean sea-level projections and the absence of consensus on a coastal impact model...

Chronic erosion of sandy coasts is a continuous potential threat for the growing coastal communities worldwide. The prediction of shoreline evolution is therefore key issue for robust decision making worldwide, especially in the context of climate change. Shorelines respond to various complex processes interacting at several temporal and spatial sc...

As space-based Earth observations are delivering a growing amount and variety of data, the potential of this information to better support disaster risk management is coming into increased scrutiny. Disaster risk management actions are commonly divided into the different steps of the disaster management cycle, which include: prevention, to minimize...

Coastal zones have large social, economic and environmental values. They are more densely populated than the hinterland and concentrate large economic assets, critical infrastructures and human activities such as tourism, fisheries, navigation. Furthermore, coastal oceans are home to a wealth of living marine resources and very productive ecosystem...

Coastal floods are driven by many hydro-meteorological forcing factors, among which are mean sea levels, tides, atmospheric storm surges, and waves. Depending on these conditions, wave overtopping may occur and, in some cases, lead to a significant flood. In the present study, we investigate the effect of the stochastic character of waves on the fl...

Chronic flooding, occurring at high tides under calm weather conditions, is occasionally taking place today in the low-lying areas of the Petit-Cul-de-sac marin (Guadeloupe, West Indies, French Antilles). This area includes critical industrial, harbor and major economic infrastructures for the island. As sea level rises, concerns are growing regard...

Along open coasts, wind waves are a key driver of coastal changes and can be major contributors to coastal hazards. Wind wave characteristics are projected to change in response to climate change, notably due to changes in atmospheric circulation patterns and the associated surface winds. Here, a first‐order estimate of projected 20‐yr mean wave se...

Sea-level rise (SLR) is a major concern for coastal hazards such as flooding and erosion in the decades to come. Lately, the value of high-end sea-level scenarios (HESs) to inform stakeholders with low-uncertainty tolerance has been increasingly recognized. Here, we provide high-end projections of SLR-induced sandy shoreline retreats for Europe by...

Sea-level rise magnifies flood hazards, raising the question when adaptation measures need to be taken. Here, we quantify when the recurrence of extreme water level events will double due to projected sea-level rise. Reproducing the most common method based on extreme water levels observed with tide gauges, at least one third of the coastal locatio...

European coastal databases contain information on the evolution of European shorelines in the 1990s and the 1980s. We investigate if a shift toward erosion has been observed between these two periods, as it could be expected as a consequence of contemporary sea-level rise or changing coastal management practices. We select comparable European coast...

Robinet, A.; Castelle, B.; Idier, D.; D'Anna, M., and Le Cozannet, G., 2020. Simulating the impact of sea-level rise and offshore bathymetry on embayment shoreline changes. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1263–1267. Coconut Creek (Florida), ISSN 0749-0208....

Rohmer, J.; Louisor, J.; Le Cozannet, G.; Naveau, P.; Thao, S., and Bertin, X., 2020. Attribution of extreme wave height records along the North Atlantic coasts using hindcast data: Feasibility and limitations. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1268-1272. Coc...

This is the COasTAUD framework, which allows: - to produce probabilistic shoreline change projections as in https://doi.org/10.1038/s41598-018-37017-4 : The zip file contains R codes allowing to perform retrospective and future shoreline change projections and to perform sensitivity analysis. Only codes developped by me are included. To run the mod...

Shoreline change is driven by various complex processes interacting at a large range of temporal and spatial scales, making shoreline reconstructions and predictions challenging and uncertain. Despite recent progress in addressing uncertainties related to the physics of sea-level rise, very little effort is made towards understanding and reducing t...

Developing future projections of shoreline change requires a good understanding of the driving coastal processes. These processes result primarily from the combination of mean sea level, waves, storm surges and tides, which are affected by global and regional climate change, and whose uncertainty increases with time. This paper reviews the current...

The characterisation of past coastal flood events is crucial for risk prevention. However, it is limited by the partial nature of historical information on flood events and the lack or limited quality of past hydro-meteorological data. In addition, coastal flood processes are complex, driven by many hydro-meteorological processes, making mechanisms...

The original article was published with erroneous placement of its figures. Following reports by the author group concerning the errors, the article was granted an update + correction to show the desired rendering of the work. This correction stands to support the update, and the original article has been corrected.

Shoreline change is driven by various complex processes interacting at a large range of temporal and spatial scales, making shoreline reconstructions and predictions challenging and uncertain. Despite recent progress in addressing uncertainties related to the physics of sea‐level rise, very little effort is made towards understanding and reducing t...

Significance This work provides a robust estimate of water-level (WL) changes in the Ganges–Brahmaputra–Meghna delta, driven by continental freshwater dynamics, vertical land motion, and sea-level rise. Through an unprecedented set of 101 gauges, we reconstruct WL variations since the 1970s and show that the WL across the delta increased slightly f...

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...

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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...

L’emploi de méthodes issues des sciences humaines et sociales a permis de poser un constat préliminaire sur les conditions de réalisation effective de l’adaptation au changement climatique de l’archipel de Saint-Pierre-et-Miquelon. A travers des méthodes d’enquête et une étude historique de données locales, il a été possible d’approcher les représe...

Social research has shown that people’s representations of climate change can either facilitate climate policies or act as a barrier to successful adaptation. Here, we explore how to integrate people’s perception and representations of their territories, of climate change and adaptation within the adaptation pathways framework, and we present a pre...

Changes in sea level lead to some of the most severe impacts of anthropogenic climate change. Consequently, they are a subject of great interest in both scientific research and public policy. This paper defines concepts and terminology associated with sea level and sea-level changes in order to facilitate progress in sea-level science, in which com...

In the author group at the start of the article and in the affiliations section at the end of the article.