Transcript Coastal resources

Vulnerability and Adaptation
Assessments Hands-On
Training Workshop
Coastal Resources:
Analytical Approaches
1A.1
Outline
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Introduction
Sea level rise
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Predictions and uncertainties
Scenarios
Global processes
Local uncertainties
Impacts
Adaptation and shoreline management
Outline
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Methods to assess impacts of sea level rise
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(continued)
Levels of assessment
 Screening
 Vulnerability
 Planning
Review of African region situation
Models
Data sources
DIVA
Climate Change and
Coastal Resources
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Coastal resources will be affected by a
number of consequences of climate change,
including:
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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).
Other relevant factors
Biogeophysical effect
Climate
Inundation, flood
and storm
damage
Nonclimate
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
Surface waters
Runoff
Catchment management and land
use
Groundwater
Rainfall
Land use, aquifer use
Rainfall
Land use, aquifer use
Saltwater
intrusion
Rising water tables/impeded drainage
Some Climate Change Factors
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
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
Atmospheric CO2
Increase
Increased productivity in coastal ecosystems;
decreased CaCO3 saturation impacts on coral reefs
Current Global Predictions
of Sea Level Rise
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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-Level
Change
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Relative sea-level
changes
Ocean Water Volume
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Controlled by:
Ocean temperature – thermal expansion
Melting of land-based ice
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Small glaciers
Greenland
Antarctica
The hydrological cycle (including human
influence)
Uncertainty in Local Predictions
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Relative sea level rise: global and regional
components plus land movement
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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 City
1850 to 2100
8
Sea Level (m)
Observations
6
1850
McCarthy et al., 2001
Scenarios
IPCC TAR range
due to SRES
emission scenarios
1900
1950 2000 2050
Time (yrs)
2100
Land Subsidence
Other Climate Change
(Hurricane Katrina)
Elevation and Population Density
Maps for Southeast Asia
Population and
Population
Density vs.
Distance and
Elevation
in 1990
Coastal Megacities (>8 million people)
Forecast for 2010
Tianjin
Dhaka
Seoul
Osaka
Istanbul
Tokyo
New York
Shanghai
Manila
Los Angeles
Bangkok
Lagos
Mumbai
Lima
Karachi
Buenos Aires
Rio de Janeiro
Madras
Jakarta
Calcutta
National Vulnerability Profiles
WITH MEASURES
NO MEASURES
WITH MEASURES
NO MEASURES
people
affected
people
at risk
capital
value
at loss
land
at loss
wetland
at loss
people
at risk
protection
costs
people
affected
MAURITIUS
ANTIGUA
NETHERLANDS
ARGENTINA
NEVIS
BANGLADESH
NIGERIA
BENIN
POLAND
EGYPT
SENEGAL
GUYANA
SEYCHELLES
JAPAN
TONGA
KIRIBATI
URUGUAY
MARSHALLS
VENEZUELA
based on analyses
people
at risk
CRITICAL
HIGH
MEDIUM
based on expert judgement
Vulnerability profile classes
LOW
capital
value
at loss
land
at loss
wetland
at loss
people
at risk
protection
costs
Deltaic Regions
Atolls
Biogeophysical Effects
of Sea Level Rise
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Displacement of coastal lowlands and
wetlands
Increased coastal erosion
Increased flooding (frequency and depth)
Salinization of surface and groundwaters
Plus others
Socioeconomic Impacts
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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
Sea level rise
Potential impacts
Anticipatory adaptation
Initial impacts
Reactive adaptation
Residual impacts
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)
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Retreat
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Accommodation
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Protect
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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
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Retreat
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Managed retreat
Relocation from high risk zones
Accommodation
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Public awareness
Natural disaster management planning
Adaptation Methods
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Protect
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Hard options
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Revetments, breakwaters, groins
Floodgates, tidal barriers
Soft options
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Beach/wetland nourishment
Dune restoration
(continued)
Example Approach to
Adaptation Measures
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Caribbean small island developing country
Climate change predictions
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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)
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Coastal impacts
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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)
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Adaptation (retreat, protect, accommodate)
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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
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Sea level rise scenarios
Levels of assessment
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Screening assessment
Vulnerability assessment
Erosion
Flooding
Coastal wetland loss
Planning assessment
Coastal Vulnerability and
Risk Assessment
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Three levels of assessment
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Screening assessment (3-6 months)
Vulnerability assessment (1-2 years)
Planning assessment (ongoing)
Screening Assessment
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Rapid assessment to highlight possible impacts
of a sea level rise scenario and identify
information/data gaps
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Qualitative or semiquantitative
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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
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Step 1: Collation of
Existing Data
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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
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Four impacts are considered
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Increased storm flooding
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Beach/bluff erosion
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Wetland and mangrove inundation and loss
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Salt water intrusion
Step 3: Implications of Future
Developments
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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
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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
Biophysical Impact
of Sea
Level
Tourism
Rise
Inundation
Erosion
Flooding
Salinization
Others?
Socioeconomic impacts
Human
Settlements
Agriculture
Water
Supply
Fisheries
Financial
Services
Human
Health
Others?
Vulnerability Assessment
Autonomous
Adaptation
Susceptibility
Resilience/
Resistance
Planned
Adaptation
Natural
Vulnerability
Other
Climatic and
Non-Climatic
Stresses
Biogeophysical
Effects
Natural System
Autonomous
Adaptation
Accelerated
Sea-Level Rise
Impact Potential
Ability to
Prevent or Cope
Planned
Adaptation
Socio-Economic
Vulnerability
Residual Impacts
Socio-Economic System
The Coevolving
Coastal System
Historic
SENSITIVITY
ADAPTIVE
CAPACITY
EXPOSURE
NATURAL SYSTEM
BOUNDARY
CONDITIONS
SENSITIVITY
EXPOSURE
ADAPTIVE
CAPACITY
SOCIOECONOMIC
SYSTEM
Future
Barriers to Conducting
Vulnerability Assessments
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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 sociopolitical conditions
Controls on Coastal Position
antecedent
physiography
sea-level
change
littoral sediment
supply (±ve)
boundary conditions (external)
fluvial-delta inlet bypassing
C
D resuspension & inlet bypassing
lagoon basin mud
mid-shelf mud
lower shoreface
marine sand wedge
bypassing
A
inlet
inner-shelf sand
B
upper
shoreface
transport
cross-shelf
backbarrier
coastal tract
Beach Erosion
Bruun Rule
Bruun Rule
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where:
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(continued)
R = G(L/H)S
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
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Only describes one of the processes
affecting sandy beaches
Indirect effect of mean sea level rise
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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
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Increase in flood levels due to rise in sea
level
Increase in flood risk
Increase in populations in coastal floodplain
Adaptation
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Increase in flood protection
Management and planning in floodplain
Coastal Flood Plain
Global Incidence of Flooding
No Sea Level Rise
People Flooded (Millions/yr)
30
20
10
0
1990
2020s
2050s
Time (years)
2080s
Vulnerable Regions
Mid-estimate (45 cm) by the 2080s
Caribbean
Pacific
Oc ean
SMALL
ISLANDS
A
C
PEOPLE ATRISK
(millions per region)
A
> 50 million
B
10 - 50 million
C
< 10 million
region boundary
vulnerable island region
C
Indian
Oc ean
SMALL
ISLANDS
B
Impacts of Flooding on Arable
Agriculture in 2050 – No Adaptation
Reference (1990)
Low climate change
Land
unavailable for
arable
Agriculture
(% cell)
High climate change
Global Impacts of Coastal Flooding in
2050 – Effects of Mitigation
People flooded (Millions/yr)
The Thames Barrier
Flood Methodology
Global Sea-level
Rise Scenarios
Subsidence
Storm Surge
Flood Curves
Coastal
Topography
Relative Sea-Level
Rise Scenarios
Raised Flood Levels
Population
Density
Size of Flood
Hazard Zones
Protection Status
People in the
Hazard Zone
(“EXPOSURE”)
Average Annual
People Flooded,
People to Respond
(“RISK”)
(1in 10, 1 in100, etc.)
Ecosystem Loss
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Inundation and displacement of wetlands
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Areas provide
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e.g., mangroves, saltmarsh, intertidal areas
Flood protection
Nursery areas for fisheries
Important for nature conservation
Loss of valuable resources, tourism
Coastal Ecosystems at Risk
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KEY:
mangroves, o saltmarsh, x coral reefs
Coastal Squeeze
(of coastal wetlands)
Sea Level Rise
(a) no hard defenses
(b) hard defenses
Mangrove Swamp
Areas Most Vulnerable to
Coastal Wetland Loss
Saltmarsh Losses to 2050
Present day loss rate
Low Climate
Change
High Climate
Change
Wetland Loss Model Structure
Tidal Range
Horizontal Migration
Assessment
Coastal
Geomorph
-ology
Coastal
Population
Density
Migration
Potential
Relative Rate of
Sea Level
Rise Scenarios
Rate of Sea
Level Rise Scenarios
Vertical
Wetland
Response
Wetland Loss
Corrected wetland loss
No
Loss
Wetland Vertical
Response Model
RSLR* = RSLR/TR
where:
RSLR =
TR =
the rate of relative sea level rise
(meters/century)
the mean tidal range on spring tides
in meters
RSLR* > RSLR*crit
RSLR* ≤ RSLR*crit
loss
no loss
Planning Assessment
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Ongoing investigation and formulation of policy
Requires information on
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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 Problem
Cliff Protection Has Local and Wider Effects
Erosion
Often Exported Alongshore
Coastal Flood Risk
Exacerbated by Declining Sediment Input
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Sediments
Changing
impacts
Beach evolution
Defense
degradation/upgrades
Changing
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loads
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Socioeconomic changes
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Sea level rise
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Increased storminess
Goals for Planning Assessment
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For future climate and protection scenarios,
explore interactions between cliff
management and flood risk within sediment
sub-cell (in Northeast Norfolk)
In particular, quantify
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Cliff retreat and associated impacts
Longshore sediment supply/beach size
Flood risk
Integrated flood and erosion assessment
Method for Planning
Assessment
Scenarios
Climate Change,
Sea-Level Rise
Scenarios
Protection,
Socio-economic
Scenarios
Overall
Assessment
Analysis
Regional
Wave/Surge
Models
SCAPE
Regional
Morphological
Model
Flood
Risk Analysis
(LISTFLOOD-FP)
SCAPE GIS
Data Storage
Cliff Erosion
Analysis
Integrated
Cell-scale
Assessment
Bathymetry and
Wave Modelling
Offshore sandbank
Nearshore
sandbank
SCAPE Model of
Cliff Retreat
Waves
System
Morphological
Model
Tides
Tides
Waves
Wave transformation
Wave transformation
Inshore waves
Inshore waves
Cross-shore
Cross-shore
erosion
erosion
Beach
Beach
volume
volume
Cross-shore
Cross-shore
shape
shape
Cliff
Cliff
retreat
retreat
Section n
Section n
Longshore
Longshore
sediment
sediment
transport
transport
Q3D shore
Q3D shore
shape
shape
Inshore waves
Inshore waves
Beach
Beach
volume
volume
Cross-shore
Cross-shore
erosion
erosion
Cliff
Cliff
retreat
retreat
Cross-shore
Cross-shore
shape
shape
Section n+1
Section n+1
Future Policy
Maintain Defenses, 6 mm/yr Sea Level Rise
Distance along baseline, km
5 year stages
Average over 50 years
35
35
30
30 S
Sheringham
25
25
Cromer
20
20
C
O
Overstrand
Trimmingham
T
15
15
Mundesley
M
10
10
Bacton
B
5
0
-150
5
-100
-50
Recession distance
0
0
Happisburgh
H
0
0.5
1
1.5
2
Recession rate (m/A)
2.5
Future Policy
Abandon All Defenses, 6 mm/yr Sea Level Rise
Distance along baseline, km
5 year stages
Average over 50 years
35
35
30
30 S
Sheringham
25
25
Cromer
20
20
Do Nothing
Open Coast
C
Overstrand
Trimmingham
O
T
15
15
Mundesley
M
10
10
Bacton
B
5
0
-150
5
-100
-50
Recession distance
0
0
Happisburgh
H
0
0.5
1
1.5
2
Recession rate (m/A)
2.5
Policy Comparison
Maximum Retreat at Abandoned Defenses
5 year stages
Distance along baseline, km
30
Average
5 over
year 50
stages
years
35 35
Hold existing
defenses
30 30
S
Distance along baseline, km
35
25
Abandon all
defenses
25 25
C
O
20 20
20
15
10 10
B
5
0
-150
5 5
H
-100
-50
Recession distance
0
0 0
0-1500.5 -100
1
1.5 -502
2.5 0
Recession
Recession
ratedistance
(m/A)
Do No
Open
30 S
Sheringham
Cromer
25
C
Overstrand
O
20
Trimmingham
T
15 15
M
10
Average over 50 ye
35
T
15
Mundesley
M
10
Bacton
B
5
H
Happisburgh
0
0
0.5
1
1.5
Recession rate (m
Erosion Visualization
Protection Abandoned (10 year time steps)
Conclusions
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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
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DIVA: Dynamic and Interaction Vulnerability
Assessment
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Project: DINAS-Coast
RegIS2 : Development of a metamodel tool for
regional integrated climate change management
COSMO
RamCo
Data Sources
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IPCC Data Distribution Centre
Sea level data
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Permanent service for mean sea level
GLOSS – Global Sea-Level Observing
System
Remotely sensed data
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Land Processes Distributed Active Archive
Centre (NASA)
Shuttle radar topography mission
GLOSS Tide Gauges
GTOPO30
Global Digital
Elevation
Model
SRTM Data – Morocco and Gibraltar
(vertically exaggerated)
Data Sources
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Local observational data
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Sea level measurements
Elevation/topography
Wave recording
Aerial photography
Habitat mapping
Concluding Remarks
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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