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Vulnerability and Adaptation Assessments Hands-On Training Workshop Coastal Resources: Analytical Approaches 1A.1 Outline Introduction Sea level rise Predictions and uncertainties Scenarios Global processes Local uncertainties Impacts Adaptation and shoreline management Outline Methods to assess impacts of sea level rise (continued) 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). 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 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 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 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 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 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) 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 Protect Hard options Revetments, breakwaters, groins Floodgates, tidal barriers Soft options Beach/wetland nourishment Dune restoration (continued) 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 and Risk 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 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 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 where: (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 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 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 Inundation and displacement of wetlands Areas provide 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 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 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 Problem Cliff Protection Has Local and Wider Effects Erosion Often Exported Alongshore Coastal Flood Risk Exacerbated by Declining Sediment Input Sediments Changing impacts Beach evolution Defense degradation/upgrades Changing loads Socioeconomic changes Sea level rise Increased storminess 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 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 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 GTOPO30 Global 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