Climate Change impacts,adaptation, and associated costs

for coastal risks in France

G. 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

Context: application of the French Climate Plan (2006)

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“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)

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:

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

RNACC Project: Coastal Risks

> 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

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Damage to port structures (île de Ré, port de La Flotte). Source: Pedreros et al. (2010)

Inundation during Xynthia, March 2010. Source: Régis Duvigneau

Coastal Risks Methodology

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Coastal inundation and erosion hazards in 2100

Climate change hypothesis

Current demographic and economic statistics

in coastal areas

Evaluation of potential impacts to people, residences, and public and private assets in 2100

Methodology applied in Languedoc-Roussillon region in France

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> 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

Languedoc-Roussillon

Evaluation of potential climate change impacts

> Potential climate change impacts• Sea level rise

• Storm regime

• Storm surges

• Wave climate

• Precipitation

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Climate change hypothesis

Le Havre, France, December 2007

Source: Charlotte Grimbert

La Faute-sur-Mer and Aguillon, France, February 2010

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)

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?

Climate change hypothesis

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)

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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

Climate change hypothesis

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)

Coastal inundation and erosion hazards in 2100

Photo from 2003, Messina (2004)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 hazard zones…

10-year return period event

100-year return period event

10-year return period event

100-year return period event

Sea level rise

In 2100 with 1 m of sea level rise

TODAY

Coastal inundation and erosion hazards in 2100

Hazard Evolution

HazardEffect of climate change

Type TimescaleReversibility

of effectsProposed estimation of the

impact zone

Erosion aggravation continuousintra-annual

to multiannual

irreversiblea buffer zone of 500 m inland

of erodible coastal zones

Permanent submersion

creation of a new hazard

continuousmultiannual to decadal

irreversiblethe zone from 0 to +1 m

elevation

Temporary submersion

aggravationdis-

continuousa few hours

to a few daysreversible

the zone between +1 and +3 m elevation

Characteristics of hazards considered in this study, adapted from Garcin et al. (2009)

Coastal inundation and erosion hazards in 2100

Exposure of people and buildings to coastal hazards

Current demographic and economic statistics in coastal areas

Reconstructed population density in the zones with an elevation of less than 5m above sea level in

Languedoc-Roussillon (Source : CGDD – SOeS, IGN)

Population density

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

4 zones affected by coastal erosion and inundation hazards

Potential impacts to people and residences in 2100

Evaluation of potential impacts to people, residences, and public and

private assets in 2100

WaterWetlandsOpen spaces (with little vegetation)Low-lying vegetationForestsPrairies and heterogeneous agriculturePermanent agricultureArable landArtificial green spaces (non-agricultural)Industrial zones, landfills, constructionUrban zones

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Surfaces en eau

Zones humides

Espaces avec peu de végétation

Milieux à végétation arbustive et/ou herbacée

Forêts

Prairies et zones agricoles hétérogènes

Cultures permanentes

Terres arables

Espaces verts artificialisés, non agricoles

Zones indus., réseaux, décharges et chantiers

Zones urbanisées

As the distance from the coast increases, the percentage of urban

zones decreases(i.e. population, residences, public

and private assets, etc.)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Distance from the shoreline Source : UE, SOeS, CORINE Land Cover 2000, Observatoire du littoral

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

Hazard

In 2100

Irreversible permanent inundation

or erosion hazard

Temporary inundation caused by a 10-year return

period storm

Temporary inundation caused by a 100-year

return period storm

Population 80,000 people 20,00 - 60,000 people 20,000 people

Residences 140,000 residences 40,000 - 100,000 residences 20,000 - 40,000 residences

Below 1m NGF: exposed to permanent

inundation in 2100

ORBetween +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

500m-wide buffer zone:

exposed to erosion in 2100

Potential impacts to public and private assests in 2100

Evaluation of potential impacts to people, residences, and public and

private assets in 2100

Distribution of public and private assets:- Artisans, merchants, and service providers 53%- Agricultural enterprises 17%- Industries 16%- Public establishments 14%

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

Below 1m NGF: exposed to permanent

inundation in 2100

ORBetween +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

Hazard

In 2100

Irreversible permanent inundation or erosion

hazard

Temporary inundation caused by a 10-year return period storm

Temporary inundation caused by a 100-year

return period storm

Total number of establishments

10,000 establishments3,000 – 9,000

establishments6,000 – 12,000 establishments

Number of employees impacted

26,000 employees8,000 - 25,000

employees16,000 – 33,000

employees

500m-wide buffer zone:

exposed to erosion in 2100

Associated costs

Estimations of annual and cumulative costs of coastal

risks caused by climate change

Cost of potential damages to residences

Cost of direct, tangible damages

(estimate)

Cost of direct and indirect, tangible

damages (estimate)

Coastal erosion and permanent inundation

(only destroyed buildings)150 Million € / year 300 Million € / year 600 Million € / year

Coastal erosion and permanent inundation

(buildings and land loss)350 Million € / year 700 Million € / year 1400 Million € / year

Temporary inundation 15 Million € / year 30 Million € / year 60 Million € / year

Examples of damages

Tangible Intangible

DirectDestruction of an economic asset(e.g.. buildings, public transportation or communication infrastructure, etc.)

Loss of human life, or loss of a natural space

IndirectLoss of use(e.g. losses due to non-use of property destroyed or damaged by a catastrophe) .

Increase in the vulnerability of the population affected by a crisis

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 risksInsufficient 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)

Limitations of this study: chain of errors

Climate change

Local sea level rise

Long term coastal evolution (erosion/accretion)

Ability to accurately identify affected zones

Accurate population and land use statistics

Ability to estimate associated costs

A continuation of this study investigates these

3 sources of error, to quantify and minimize the largest errors to improve

the RNACC method.

Limitations of this study: chain of errors

Climate change

Local sea level rise

Long term coastal evolution (erosion/accretion)

Ability to accurately identify affected zones

Accurate population and land use statistics

Ability to estimate associated costs

Sea level rise scenarios:0, 0.5, 1, and 1.5m

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

Quality of available topographic data:50m horizontal resolution, 1m vertical steps

5m horizontal resolution2m horizontal resolution

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

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)

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