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1 BRGM, 2 Météo-France, 3 MEEDDM/SGDD/SoES, 4 CETMEF, 5 MEEDDM/CGDD/SEEI,

Climate Change impacts, adaptation, and associated costs for coastal risks in France G. Le Cozannet 1 , N. Lenôtre 1 , M. Yates Michelin 1 , P. Nacass 2 , B. Colas 3 , C. Perherin 4 , C. Peinturier 5 , C. Vanroye 6 , C. Hajji 7 , B. Poupat 3 , C. Azzam 8 , J. Chemitte 7 , and F. Pons 9.

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1 BRGM, 2 Météo-France, 3 MEEDDM/SGDD/SoES, 4 CETMEF, 5 MEEDDM/CGDD/SEEI,

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  1. Climate Change impacts,adaptation, and associated costs for coastal risks in FranceG. Le Cozannet1, N. Lenôtre1, M. Yates Michelin1, P. Nacass2, B. Colas3, C. Perherin4, C. Peinturier5, C. Vanroye6, C. Hajji7, B. Poupat3, C. Azzam8, J. Chemitte7, and F. Pons9 1 BRGM, 2 Météo-France, 3 MEEDDM/SGDD/SoES, 4 CETMEF, 5 MEEDDM/CGDD/SEEI, 6 DREAL/LR, 7 MRN, 8MEEDDM/DGPR/BRM, 9 CETE Méditerranée

  2. Context: application of the French Climate Plan (2006) • Objective: initiate an evaluation of potential damages and possible mitigation strategies to limit the cost of impacts • An interministerial working group, « Climate change impacts, adaptation, and associated costs for coastal risks in France », was created to address this objective. • Within which, an oversight committee was: • responsible for the methodological guidelines • guaranteed the homogeneity of the assessment methods • and 7 sectoral groups were created, one of which is: “Natural Risks, Insurance, and Adaptation to Climate Change” (RNACC) led by the MEEDM/DGPR/SRNH (Ministry of Ecology, Energy, Sustainable Development and Seas/Directorate General for Risk Prevention/Service des risques naturels et hydrauliques) Sub working groups: - Swelling and shrinking of clays - Lanslides - Floods - Coastal risks Estimate costs of damages caused by coastal erosion and inundation, and identify what is specifically caused by climate change

  3. RNACC Project: Coastal Risks Inundation during Xynthia, March 2010. Source: Régis Duvigneau Damage to port structures (île de Ré, port de La Flotte). Source: Pedreros et al. (2010) • Currently, 25% of the French coastline is eroding • Vulnerability to coastal inundation has been highlighted by the impacts of several severe storms: • Lothar in 1999 and Xynthia in 2010 along the Atlantic coast • 1982, 1997, and 2003 storms on the Mediterranean coast • Climate change impacts will exacerbate existing coastal erosion and inundation hazards in the 21st century (Nicholls et al., 2007) • Common guidelines for all working groups: • A2, B2 IPCC emissions scenarios • Three time periods: 2030, 2050, 2100 • Hypothesis of no changes to the economy or to stakes at risk >3

  4. Coastal Risks Methodology Evaluation of potential impacts to people, residences, and public and private assets in 2100 Climate change hypothesis Current demographic and economic statistics in coastal areas Coastal inundation and erosion hazards in 2100

  5. Methodology applied in Languedoc-Roussillon region in France Languedoc-Roussillon • 215 km of French Mediterranean coastline between the border with Spain and the Rhône Delta, characterized by: • Hard rock cliffs with pocket beaches in the southern portion • Sandy beaches separated by three rocky outcrops • Coastal lagoons separated from the Mediterranean Sea by lidos, or narrow strips of beach with low-lying dunes

  6. Evaluation of potential climate change impacts Source: Charlotte Grimbert Climate change hypothesis Le Havre, France, December 2007 La Faute-sur-Mer and Aguillon, France, February 2010 • Potential climate change impacts • Sea level rise • Storm regime • Storm surges • Wave climate • Precipitation >6

  7. Evaluation of potential climate change impacts • Potential climate change impacts • Sea level rise increase in sea level rise (Meehl et al., 2007; Rahmstorf, 2007; Grinsted et al., 2009;Ullman et al., 2007; EUROSION, 2004; MICORE, 2009) • Storm regimes regional climate models have not shown • Storm surges significant changes (Déqué et al., 2003; Ullman, • Wave climate 2008 ; Lionello et al., 2008; MICORE, 2009) • Precipitation potential decrease in total precipitation potential increase in number of days with more than 10mm of precipitation (IMFREX, 2002) Climate change hypothesis ?

  8. Evaluation of potential climate change impacts Climate change hypothesis • Scenario adopted : • 1 m sea level rise in 2100 • other climate change impacts are unable to be quantified and are not taken into account in this study • Potential climate change impacts • Sea level rise increase in sea level rise (Meehl et al., 2007; Rahmstorf, 2007; Grinsted et al., 2009;Ullman et al., 2007; EUROSION, 2004; MICORE, 2009) >8

  9. Coastal erosion hazard zones Current trends in Languedoc-Roussillon: Decrease in supply of large-grained sediments Increase in shoreline erosion Future trends in Languedoc-Roussillon: Uncertain, but likely to show at least a continuation of current trends Landward migration of lidos and breaching during storm events (Paskoff, 2001) Current situation In 2100, with adequate sediment supplies In 2100, with a depletion of sediment supplies Erosion hypothesis: partial opening of lidos and erosion of sandy coastline, estimated with a 500m buffer zone landward of the current shoreline Coastal inundation and erosion hazards in 2100 Photo from 2003, Messina (2004) Paskoff, 2001

  10. Coastal inundation hazard zones… TODAY 100-year return period event 10-year return period event Coastal inundation and erosion hazards in 2100 In 2100 with 1 m of sea level rise 100-year return period event 10-year return period event Sea level rise

  11. Hazard Evolution Coastal inundation and erosion hazards in 2100 Characteristics of hazards considered in this study, adapted from Garcin et al. (2009)

  12. Exposure of people and buildings to coastal hazards 4 zones affected by coastal erosion and inundation hazards Population density Current demographic and economic statistics in coastal areas 500m-wide buffer zone: exposed to erosion in 2100 Below 1m NGF: exposed to permanent inundation in 2100 Between +1m and +2m NGF: exposed to temporary inundation by storms with a 10-year return period Between +2m and +3m NGF: exposed to temporary inundation by storms with a 100-year return period Reconstructed population density in the zones with an elevation of less than 5m above sea level in Languedoc-Roussillon (Source : CGDD – SOeS, IGN)

  13. Potential impacts to people and residences in 2100 Water Wetlands Open spaces (with little vegetation) Low-lying vegetation Forests Prairies and heterogeneous agriculture Permanent agriculture Arable land Artificial green spaces (non-agricultural) Industrial zones, landfills, construction Urban zones Distance from the shoreline Evaluation of potential impacts to people, residences, and public and private assets in 2100 As the distance from the coast increases, the percentage of urban zones decreases (i.e. population, residences, public and private assets, etc.) Source : UE, SOeS, CORINE Land Cover 2000, Observatoire du littoral

  14. Potential impacts to people and residences in 2100 (Résultats CGDD/SoeS) Evaluation of potential impacts to people, residences, and public and private assets in 2100 OR Between +1m and +2m NGF: exposed to temporary inundation by storms with a 10-year return period Between +2m and +3m NGF: exposed to temporary inundation by storms with a 100-year return period Below 1m NGF: exposed to permanent inundation in 2100 500m-wide buffer zone: exposed to erosion in 2100

  15. Potential impacts to public and private assests in 2100 • Distribution of public and private assets: • - Artisans, merchants, and service providers 53% • - Agricultural enterprises 17% • Industries 16% • - Public establishments 14% Evaluation of potential impacts to people, residences, and public and private assets in 2100

  16. Potential impacts to public and private assests in 2100 (Résultats MRN) Evaluation of potential impacts to people, residences, and public and private assets in 2100 OR Between +1m and +2m NGF: exposed to temporary inundation by storms with a 10-year return period Between +2m and +3m NGF: exposed to temporary inundation by storms with a 100-year return period Below 1m NGF: exposed to permanent inundation in 2100 500m-wide buffer zone: exposed to erosion in 2100

  17. Associated costs

  18. Adaptation recommendations Enhance knowledge, particularly with regular data collection at representative study sites to improve long term coastal evolution modeling Share knowledge with the public to accurately communicate risk perception Development of planning progams that take into account climate change (e.g. government risk prevention plans, inundation zone maps, local urban planning documents, land use planning management) Envisage protection, relocation, and adaptation strategies at all levels of management (local, regional, and national) Adopting « without regrets » adaptation measures addressing today’s risks as a first step toward addressing future coastal risks Insufficient data for robust cost-benefit analyses Increased risk of over-adaptation (high cost of adaptation) and under-adaptation (high cost of damages), both with strong economic consequences (Hallegatte et al., 2006)

  19. Limitations of this study: chain of errors Climate change Local sea level rise A continuation of this study investigates these 3 sources of error, to quantify and minimize the largest errors to improve the RNACC method. Long term coastal evolution (erosion/accretion) Ability to accurately identify affected zones Accurate population and land use statistics Ability to estimate associated costs

  20. Limitations of this study: chain of errors Climate change Sea level rise scenarios: 0, 0.5, 1, and 1.5m Local sea level rise • Long term coastal evolution: • The Bruun Rule • Extrapolation of historical trends • Extrapolation of historical trends with an ajustment based on the Bruun Rule • A fixed erosion rate (i.e. 500m in this study) • Scientific expertise Long term coastal evolution (erosion/accretion) Ability to accurately identify affected zones Quality of available topographic data: 50m horizontal resolution, 1m vertical steps 5m horizontal resolution 2m horizontal resolution Accurate population and land use statistics Ability to estimate associated costs

  21. Quality of Topographic Data • Datasets available in Languedoc-Roussillon include: • DTM of IGN, with 50m horizontal resolution and 1m vertical steps • DTM of Intermap, with 5m horizontal resolution • DTM - Lidar data, with 2m horizontal resolution

  22. Conclusions Costs of current risks are negligible in comparison to the cost of future risks Costs of potential damages due to erosion and permanent inundation are larger than those due to temporary inundation Emphasizes the importance of developing long-term coastal management plans at all levels of governance At a minimum, it is necessary to reduce short-term risks as a first step toward reducing long-term risks Highlights a number of limitations and sources of errors in climate change impact studies due to limited data availability (study in progress to quantify and reduce these errors)

  23. Thank you for your attention! Study financed by: French Ministry of Ecology, Energy, Sustainable Development, and the Sea (MEEDDM) and BRGM Research Division Photo: Yann Krien

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