1A.1

Vulnerability and Adaptation Assessments Hands-On

Training Workshop

Coastal Resources: Analytical Approaches

Outline

Introduction Sea level rise

Predictions and uncertainties Scenarios Global processes Local uncertainties Impacts

Adaptation and shoreline management

Outline (continued)

Methods to assess impacts of sea level rise Levels of assessment

Screening Vulnerability Planning

Review of African region situation Models Data sources DIVA

Climate Change and Coastal Resources

Coastal resources will be affected by a number of consequences of climate change, including: Higher sea levels Higher sea temperatures Changes in precipitation patterns and coastal

runoff Changes in storm tracks, frequencies, and

intensities

The Main Biophysical Effects of Relative Sea Level Rise

Table 5.2. The main biophysical effects of relative sea level rise, including relevant interacting factors. Some factors (e.g., sediment supply) appear twice because they may be influenced by both climate and nonclimate factors (adapted from Nicholls, 2002).

Biogeophysical effect

Other relevant factors

Climate Nonclimate

Inundation, flood and storm damage

Surge Wave and storm climate, morphological changes, sediment supply

Sediment supply, flood management, morphological changes, land claim

Backwater effect (river)

Runoff Catchment management and land use

Wetland loss (and change) CO2 fertilization

Sediment supply

Sediment supply, migration space, direct destruction

Erosion Sediment supply, wave and storm climate Sediment supply

Saltwater intrusion

Surface waters Runoff Catchment management and land use

Groundwater Rainfall Land use, aquifer use

Rising water tables/impeded drainage Rainfall Land use, aquifer use

Some Climate Change Factors

Sea water temperature (of surface waters)

Increase Increased coral bleaching; migration of coastal species toward higher latitudes; decreased incidence of sea ice at higher latitudes

Precipitation intensity/run-off

Intensified hydrological cycle, with wide regional variations

Changed fluvial sediment supply; changed flood risk in coastal lowlands; but also consider catchment management

Wave climate Poorly known, but significant temporal and spatial variability expected

Changed patterns of erosion and accretion; changed storm impacts

Storm track, frequency, and intensity

Poorly known, but significant temporal and spatial variability expected

Changed occurrence of storm flooding and storm damage

Table 5.1. Some climate change and related factors relevant to coasts and their biogeophysical effects (taken from Nicholls, 2002)

Climate factor Direction of change Biogeophysical effects

Atmospheric CO2 Increase Increased productivity in coastal ecosystems; decreased CaCO3 saturation impacts on coral reefs

Current Global Predictions of Sea Level Rise

IPCC Third Assessment Report (TAR) range for global-mean rise in sea level is between 9 cm and 88 cm by 2100

Change outside this range is possible, especially if Antarctica becomes a significant source

There is a “commitment to sea level rise” even if atmospheric GHG concentrations are stabilized

Global-Mean Sea Level Rise 1990 to 2100 (SRES scenarios)

Houghton et al., 2001

Processes Controlling Sea-LevelChange

Relative sea-level changes

Ocean Water Volume

Controlled by: Ocean temperature – thermal expansion Melting of land-based ice

Small glaciers Greenland Antarctica

The hydrological cycle (including human influence)

Uncertainty in Local Predictions

Relative sea level rise: global and regional components plus land movement Land uplift will counter any global sea level rise Land subsidence will exacerbate any global sea

level rise Other dynamic oceanic and climatic effects cause

regional differences (oceanic circulation, wind and pressure, and ocean-water density differences add additional component)

Sea Level Rise at New York City1850 to 2100

IPCC TAR range due to SRES emission scenarios

McCarthy et al., 2001

Land Subsidence

Other Climate Change(Hurricane Katrina)

Elevation and Population Density Maps for Southeast Asia

Population and Population Density vs.

Distance and Elevationin 1990

Istanbul

LagosLima

Buenos Aires Rio de JaneiroMadras

KarachiJakarta

Calcutta

MumbaiBangkok

ManilaShanghai

Osaka

Tokyo

Seoul

Tianjin

Dhaka

New York

Los Angeles

Coastal Megacities (>8 million people)Forecast for 2010

National Vulnerability Profiles

ANTIG UA

WITH M EASURES

WITH M EASURES

NO M EASURES

NO M EASURES

p e o p lea ffe c te d

p e o p lea ffe c te d

p ro te c tio nc o sts

p ro te c tio nc o sts

p e o p lea t risk

p e o p lea t risk

we tla nda t lo ss

we tla nda t lo ss

la nda t lo ss

la nda t lo ssc a p ita l

va luea t lo ss

c a p ita lva luea t lo ss

p e o p lea t risk

p e o p lea t risk

ARG ENTINA

NIG ERIA

VENEZUELA

b a se d o n e xp e rt jud g e m e nt

b a se d o n a na lyse s

LO W

Vulne ra b ility p ro file c la sse s

M EDIUMHIG HC RITIC AL

URUG UAY

TO NG A

SEYC HELLES

SENEG AL

PO LAND

NEVIS

NETHERLANDS

M AURITIUS

M ARSHALLS

KIRIBATI

J APAN

G UYANA

EG YPT

BENIN

BANG LADESH

Deltaic Regions

Atolls

Biogeophysical Effects of Sea Level Rise

Displacement of coastal lowlands and wetlands

Increased coastal erosion Increased flooding (frequency and depth) Salinization of surface and groundwaters Plus others

Socioeconomic Impacts

Loss of property and land Increased flood risk/loss of life Damage to coastal protection works and other

infrastructure Loss of renewable and subsistence resources Loss of tourism, recreation, and coastal habitats Impacts on agriculture and aquaculture through

decline in soil and water quality

Definition of Impacts

Potential impacts

Sea level rise

Initial impacts

Residual impacts

Reactive adaptation

Anticipatory adaptation

Shoreline Management and Adaptation

Proactive Adaptation

Coastal Adaptation (IPCC)

Shoreline Management (Defra)

Increasing robustness

Protect Hold the line

Increasing flexibility Accommodate Advance the line

Enhancing adaptability

Retreat Managed realignment

No active intervention

Reversing maladaptive trends

(Project appraisal methods)

Improving awareness and preparedness

(Flood plain mapping and flood warnings)

Responding to Coastal Change(including sea level rise)

Retreat

Accommodation

Protect Soft Hard

Shoreline Management and Adaptation (2)

Proactive Adaptation

Coastal Adaptation (IPCC)

Shoreline Management

Increasing robustness

Protect Hold the line

Increasing flexibility Accommodate Advance the line

Enhancing adaptability

Retreat Managed realignment

No active intervention

Reversing maladaptive trends

(Project appraisal methods)

Improving awareness and preparedness

(Flood plain mapping and flood warnings)

Adaptation Methods

Retreat Managed retreat Relocation from high risk zones

Accommodation Public awareness Natural disaster management planning

Adaptation Methods (continued)

Protect Hard options

Revetments, breakwaters, groins Floodgates, tidal barriers

Soft options Beach/wetland nourishment Dune restoration

Example Approach to Adaptation Measures

Caribbean small island developing country Climate change predictions

Rise in sea level Increase in number and intensity of tropical

weather systems Increase in severity of storm surges Changes in rainfall

Example Approach to Adaptation Measures (continued)

Coastal impacts Damage to property/infrastructure Damage/loss of coastal/marine ecosystems Destruction of hotels and tourism facilities Increased risk of disease Damage/loss of fisheries infrastructure General loss of biodiversity Submergence/inundation of coastal areas

Example Approach to Adaptation Measures (continued)

Adaptation (retreat, protect, accommodate) Improved physical planning and development

control Strengthening/implementation of EIA

regulations Formulation of Coastal Zone Management

Plan Monitoring of coastal habitats, including

beaches Formulation of national climate change policy Public awareness and education

Methods to Assess Impacts of Sea Level Rise

Sea level rise scenarios Levels of assessment

Screening assessment Vulnerability assessment Erosion Flooding Coastal wetland loss Planning assessment

Coastal Vulnerability andRisk Assessment

Three levels of assessment Screening assessment (3-6 months) Vulnerability assessment (1-2 years) Planning assessment (ongoing)

Screening Assessment

Rapid assessment to highlight possible impacts of a sea level rise scenario and identify information/data gaps

Qualitative or semiquantitative

Steps Collation of existing coastal data Assessment of the possible impacts of a 1-m

sea level rise Implications of future development Possible responses to the problems caused by

sea level rise

Step 1: Collation of Existing Data

Topographic surveys Aerial/remote sensing images – topography/

land cover Coastal geomorphology classification Evidence of subsidence Long-term relative sea level rise Magnitude and damage caused by flooding Coastal erosion Population density Activities located on the coast (cities, ports,

resort areas and tourist beaches, industrial and agricultural areas)

Step 2: Assessment of Possible Impacts of 1-m Sea Level Rise

Four impacts are considered Increased storm flooding

Beach/bluff erosion

Wetland and mangrove inundation and loss

Salt water intrusion

Step 3: Implications of Future Developments

New and existing river dams and impacts on downstream deltas

New coastal settlements Expansion of coastal tourism Possibility of transmigration

Step 4: Responses to the Sea Level Rise Impacts

Planned retreat (i.e., setback of defenses) Accommodate (i.e., raise buildings above

flood levels) Protect (i.e., hard and soft defenses,

seawalls, beach nourishment)

Screening Assessment Matrix Biophysical vs. Socioeconomic Impacts

Biophysic-al Impact of Sea Level Rise

Socioeconomic impacts

Tourism Human Settlements

Agriculture Water Supply

Fisheries Financial Services

Human Health

Others?

Inundation

Erosion

Flooding

Salinization

Others?

Vulnerability Assessment

SusceptibilityResilience/Resistance

AutonomousAdaptation

Planned Adaptation

Natural Vulnerability

Biogeophysical Effects

Impact PotentialAbility to

Prevent or Cope

AutonomousAdaptation

PlannedAdaptation

Socio-EconomicVulnerability

Residual Impacts

AcceleratedSea-Level Rise

OtherClimatic and Non-Climatic

Stresses

Socio-Economic System

Natural System

BOUNDARYCONDITIONS

NATURAL SYSTEM

SENSITIVITY ADAPTIVE CAPACITY

SOCIOECONOMIC SYSTEM

SENSITIVITY ADAPTIVE CAPACITY

EXPOSURE

EXPOSURE

Future

Historic

The Coevolving Coastal System

Barriers to Conducting Vulnerability Assessments

Incomplete knowledge of the relevant processes affected by sea level rise and their interactions

Insufficient data on existing physical conditions

Difficulty in developing the local and regional scenarios of future changes

Lack of appropriate analytical methodologies Variety of questions raised by different socio-

political conditions

Controls on Coastal Position

littoral sedimentsupply (±ve)

sea-levelchange

antecedentphysiography

boundary conditions (external)

lower shorefacebackbarrier

uppershoreface

bypassingcr

oss-

shel

f

transportinlet

resuspension & inlet bypassing

fluvial-delta inlet bypassing

coastal tract

B

DC

A

inner-shelf sand

mid-shelf mud

marine sand wedge

lagoon basin mud

Beach Erosion

Bruun Rule

Bruun Rule (continued)

R = G(L/H)Swhere: H = B + h*

R = shoreline recession due to a sea-level rise S

h* = depth at the offshore boundary B = appropriate land elevation L = active profile width between boundaries G = inverse of the overfill ratio

Limitations of the Bruun Rule

Only describes one of the processes affecting sandy beaches

Indirect effect of mean sea level rise Estuaries and inlets maintain equilibrium Act as major sinks Sand eroded from adjacent coast Increased erosion rates

Response time – best applied over long timescales

Flooding

Increase in flood levels due to rise in sea level

Increase in flood risk Increase in populations in coastal floodplain Adaptation

Increase in flood protection Management and planning in floodplain

Coastal Flood Plain

Global Incidence of Flooding No Sea Level Rise

0

10

20

30 P

eop

le F

lood

ed (

Mill

ion

s/yr

)

1990 2020s 2050s 2080sTime (years)

Vulnerable RegionsMid-estimate (45 cm) by the 2080s

C

A

C

B

PEO PLE AT RISK(m illio ns p e r re g io n)

> 50 m illio n

10 - 50 m illio n

< 10 m illio n

re g io n b o und a ry

vulne ra b le isla nd re g io n

Pa c ificO c e a nSM ALLISLAN D S

C a rib b e a n

Ind ia nO c e a nSM ALL ISLAN D S

C

B

A

Reference (1990)Land unavailable for arable Agriculture (% cell)

Low climate change High climate change

Impacts of Flooding on Arable Agriculture in 2050 – No Adaptation

0

20

40

60

Peo

ple

Flo

ode

d (M

illio

ns/y

r)

No Sea-Level Rise

Unmitigated Emissions

Kyoto Protocol

20% Emissions Reduction

30% Emissions Reduction

Global Impacts of Coastal Flooding in 2050 – Effects of Mitigation

People flooded (Millions/yr)

The Thames Barrier

Flood Methodology

Relative Sea-LevelRise Scenarios

Raised Flood Levels

Global Sea-levelRise Scenarios

Size of Flood Hazard Zones

People in theHazard Zone

Subsidence

Storm SurgeFlood Curves

Coastal Topography

PopulationDensity

Protection Status(1in 10, 1 in100, etc.)

Average AnnualPeople Flooded,

People to Respond

(“EXPOSURE”)

(“RISK”)

Relative Sea-LevelRise Scenarios

Raised Flood Levels

Global Sea-levelRise Scenarios

Size of Flood Hazard Zones

People in theHazard Zone

Subsidence

Storm SurgeFlood Curves

Coastal Topography

PopulationDensity

Protection Status(1in 10, 1 in100, etc.)

Average AnnualPeople Flooded,

People to Respond

(“EXPOSURE”)

(“RISK”)

Ecosystem Loss

Inundation and displacement of wetlands e.g., mangroves, saltmarsh, intertidal areas

Areas provide Flood protection Nursery areas for fisheries Important for nature conservation

Loss of valuable resources, tourism

KEY: mangroves, o saltmarsh, x coral reefs

Coastal Ecosystems at Risk

(a) no hard defenses (b) hard defenses

Sea Level Rise

Coastal Squeeze (of coastal wetlands)

Mangrove Swamp

Areas Most Vulnerable to Coastal Wetland Loss

Present day loss rate

High Climate Change

Low ClimateChange

Saltmarsh Losses to 2050

Wetland Loss Model Structure

Relative Rate of Sea Level

Rise Scenarios

Rate of Sea Level Rise Scenarios

Vertical Wetland

Response

Wetland Loss

Tidal Range

NoLoss

Coastal Geomorph

-ology

Migration Potential

Corrected wetland loss

Coastal Population

Density

Horizontal Migration Assessment

Wetland Vertical Response Model

RSLR* = RSLR/TR

where:RSLR = the rate of relative sea level rise

(meters/century)

TR = the mean tidal range on spring tides in meters

RSLR* > RSLR*crit loss

RSLR* ≤ RSLR*crit no loss

Planning Assessment

Ongoing investigation and formulation of policy Requires information on

Role of major processes in sediment budget Including human influences Other climate change impacts

Example of assessment from the UK Combined flood hazard and erosion assessment

The ProblemCliff Protection Has Local and Wider Effects

ErosionOften Exported Alongshore

Beach evolution

Defense degradation/upgrades

Socioeconomic changes

Sea level rise

Increased storminess

Changing impacts

Sediments

Changing loads

Coastal Flood Risk Exacerbated by Declining Sediment Input

Goals for Planning Assessment

For future climate and protection scenarios, explore interactions between cliff management and flood risk within sediment sub-cell (in Northeast Norfolk)

In particular, quantify Cliff retreat and associated impacts Longshore sediment supply/beach size Flood risk Integrated flood and erosion assessment

Climate Change,Sea-Level Rise

Scenarios

RegionalWave/Surge

Models

Protection,Socio-economic

Scenarios

SCAPERegional

Morphological Model

SCAPE GISData Storage

FloodRisk Analysis

(LISTFLOOD-FP)

Cliff ErosionAnalysis

Scenarios

IntegratedCell-scale

Assessment

Analysis OverallAssessment

Climate Change,Sea-Level Rise

Scenarios

RegionalWave/Surge

Models

Protection,Socio-economic

Scenarios

SCAPERegional

Morphological Model

SCAPE GISData Storage

FloodRisk Analysis

(LISTFLOOD-FP)

Cliff ErosionAnalysis

Scenarios

IntegratedCell-scale

Assessment

Analysis OverallAssessment

Method for Planning Assessment

Nearshore sandbank

Offshore sandbank

Bathymetry and Wave Modelling

TidesWaves

Wave transformation

Longshoresediment transport

Q3D shore shape

Inshore waves

Cross-shore erosion

Cross-shore shape

Cliff retreat

Section n+1

Beach volume

Inshore waves

Cross-shore erosion

Cross-shore shape

Cliff retreat

Section n

Beach volume

TidesWaves

Wave transformation

Longshoresediment transport

Q3D shore shape

Inshore waves

Cross-shore erosion

Cross-shore shape

Cliff retreat

Section n+1

Beach volume

Inshore waves

Cross-shore erosion

Cross-shore shape

Cliff retreat

Section n

Beach volume

TidesWaves

Wave transformation

Longshoresediment transport

Q3D shore shape

Inshore waves

Cross-shore erosion

Cross-shore shape

Cliff retreat

Section n+1

Beach volume

Inshore waves

Cross-shore erosion

Cross-shore shape

Cliff retreat

Section n

Beach volume

TidesWaves

Wave transformation

Longshoresediment transport

Q3D shore shape

Inshore waves

Cross-shore erosion

Cross-shore shape

Cliff retreat

Section n+1

Beach volume

Inshore waves

Cross-shore erosion

Cross-shore shape

Cliff retreat

Section n

Beach volume

SystemMorphologicalModel

SCAPE Model of Cliff Retreat

-150 -100 -50 00

5

10

15

20

25

30

355 year stages

Recession distance

Dis

tanc

e al

ong

base

line,

km

H

B

M

T

O

C

S

0 0.5 1 1.5 2 2.50

5

10

15

20

25

30

35Average over 50 years

Recession rate (m/A)

H

B

M

T

O

C

S Sheringham

Cromer

OverstrandTrimmingham

Mundesley

Bacton

Happisburgh

Future PolicyMaintain Defenses, 6 mm/yr Sea Level Rise

-150 -100 -50 00

5

10

15

20

25

30

355 year stages

Recession distance

Dis

tanc

e al

ong

base

line,

km

H

B

M

T

O

C

S

0 0.5 1 1.5 2 2.50

5

10

15

20

25

30

35Average over 50 years

Recession rate (m/A)

H

B

M

T

O

C

S

Do NothingOpen Coast

Sheringham

Cromer

OverstrandTrimmingham

Mundesley

Bacton

Happisburgh

Future PolicyAbandon All Defenses, 6 mm/yr Sea Level Rise

-150 -100 -50 00

5

10

15

20

25

30

355 year stages

Recession distance

Dis

tance a

long b

aselin

e,

km

H

B

M

T

O

C

S

0 0.5 1 1.5 2 2.50

5

10

15

20

25

30

35Average over 50 years

Recession rate (m/A)

H

B

M

T

O

C

S

-150 -100 -50 00

5

10

15

20

25

30

355 year stages

Recession distance

Dis

tance a

long b

aselin

e,

km

H

B

M

T

O

C

S

0 0.5 1 1.5 2 2.50

5

10

15

20

25

30

35Average over 50 years

Recession rate (m/A)

H

B

M

T

O

C

S

Do NothingOpen Coast

Hold existing defenses

Abandon all defenses

Sheringham

Cromer

OverstrandTrimmingham

Mundesley

Bacton

Happisburgh

Policy ComparisonMaximum Retreat at Abandoned Defenses

Erosion Visualization Protection Abandoned (10 year time steps)

Conclusions

45 sea-level/wave/protection scenario combinations assessed

Used to assess implications for flood risk Data management, visualisation, and

stakeholder involvement used Further improvements to the overall method

are being developed

Models

DIVA: Dynamic and Interaction Vulnerability Assessment Project: DINAS-Coast

RegIS2 : Development of a metamodel tool for regional integrated climate change management

COSMO RamCo

Data Sources

IPCC Data Distribution Centre Sea level data

Permanent service for mean sea level GLOSS – Global Sea-Level Observing

System Remotely sensed data

Land Processes Distributed Active Archive Centre (NASA)

Shuttle radar topography mission

GLOSS Tide Gauges

GTOPO30Global Digital

Elevation Model

SRTM Data – Morocco and Gibraltar (vertically exaggerated)

Data Sources

Local observational data Sea level measurements Elevation/topography Wave recording Aerial photography Habitat mapping

Concluding Remarks

Sea level rise could be a serious problem, but the uncertainties are large

Impacts are strongly influenced by human choice

Reducing GHG emissions reduces but does not avoid sea level rise impacts

Preparing to adapt would seem prudent, in the context of multiple stresses and managing existing problems

1A.86