African Oceans and Coasts, a Summary
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The African Science-base for Coastal Adaptation: a continental approach. A report to the African Union Commission (AUC) at the United Nations Climate Change Conference in Copenhagen (7-18 December 2009). Item Type Report Authors Abuodha, P. Publisher Intergovernmental Oceanographic Commission Download date 04/10/2021 02:16:24 Link to Item http://hdl.handle.net/1834/9427 The African Science-Base for Coastal Adaptation: A Continental Approach A report to the African Union Commission (AUC) at the United Nations Climate Change Conference in Copenhagen (7-18 December 2009) INTERGOVERNMENTAL OCEANOGRAPHIC COMMISSION OF UNESCO November 2009 Pamela Atieno Abuodha The African Science-Base for Coastal Adaptation: A Continental Approach Table of Contents Table of Contents ii List of Figures iv List of Tables vi Executive Summary vii Acknowledgements xvi PART I CLIMATE IMPACTS AND VULNERABILITIES IN 1 COASTAL LOW-LYING AREAS 1.1 Climate-change effects: the continental view 1 1.1.1 Overview of relevant work in IPCC AR4 2 1.1.2 Overview of more recent science 7 1.1.3 Consequences of climate change on the African coast 8 1.1.4 The most important effects and uncertainties in 12 Africa’s Climate-change adaptation Primary effects of Climate-change 13 1.1.4.1 Atmospheric and ocean temperature rise and acidification 13 1.1.4.2 Sea-level rise and coastal erosion 14 1.1.4.3 Precipitation and Floods 16 1.1.4.4 Drought and Desertification 18 1.1.4.5 Ocean-based hazards and change in currents 21 Compound issues affecting the coastal zone of Africa 24 1.1.4.6 Coastal Population and livelihoods 24 1.1.4.7 Fisheries, Resource Management and Biodiversity 27 1.1.4.8 Coastal Tourism 29 1.1.4.9 Fresh water, Food Security, Pollution and Sanitation 31 1.2 Climate-change impacts: the regional view 31 1.2.1 Impacts in Region 1 in West Africa 33 1.2.1.1 Atmospheric and ocean temperature rise and acidification 35 1.2.1.2 Sea-level rise and coastal erosion 35 1.2.1.3 Precipitation and Floods 40 1.2.1.4 Drought and Desertification 43 1.2.1.5 Coastal Population and livelihoods 43 1.2.1.6 Fisheries, Resource Management and Biodiversity 46 1.2.1.7 Coastal Tourism 47 1.2.1.8 Fresh water, Food Security, Pollution and Sanitation 47 1.2.2 Impacts in Region 2 in West Africa 48 1.2.2.1 Sea-level rise and coastal erosion 50 A report to the AUC at the UN Climate Change Conference in Copenhagen ii The African Science-Base for Coastal Adaptation: A Continental Approach 1.2.2.2 Precipitation and Floods 52 1.2.2.3 Drought and Desertification 54 1.2.2.4 Coastal Population and livelihoods 54 1.2.2.5 Fisheries, Resource Management and Biodiversity 56 1.2.2.6 Fresh water, Food Security, Pollution and Sanitation 57 1.2.3 Impacts in Region 3 in West Africa 58 1.2.3.1 Sea-level rise and coastal erosion 59 1.2.3.2 Fisheries, Resource Management and Biodiversity 61 1.2.4 Impacts in Region 4 in East Africa 61 1.2.4.1 Sea-level rise and coastal erosion 65 1.2.4.2 Precipitation and Floods 68 1.2.4.3 Coastal Population and livelihoods 69 1.2.4.4 Fisheries, Resource Management and Biodiversity 69 1.2.4.5 Coastal Tourism 72 1.2.4.6 Fresh water, Food Security, Pollution and Sanitation 73 1.2.5 Impacts in Region 5 in Western Indian Ocean Islands 74 1.2.5.1 Sea-level rise and coastal erosion 77 1.2.5.2 Precipitation and Floods 78 1.2.5.3 Coastal Population and livelihoods 78 1.2.5.4 Fisheries, Resource Management and Biodiversity 79 1.2.5.5 Coastal Tourism 79 1.2.6 Summary of regional impacts from the DIVA database 80 1.2.7 Adaptation measures against climate change impacts 85 on coastal population Adaptation costs against climate change impacts on 89 coastal population 1.2.7.1 Coastal Planning/zoning 96 1.2.7.2 Bathymetric and inundation mapping against extreme 97 events and flooding 1.3 Existing science-based tools and methods for coastal 99 adaptation 1.3.1 Monitoring: in situ and remote sensing 99 1.3.2 Decision support tools 101 1.3.3 Risk/Vulnerability assessment 103 1.3.3.1 Dynamic Interactive Vulnerability Assessment Tool 103 1.3.3.2 Coastal Vulnerability Index (CVI) 104 1.3.3.3 Geomorphic Stability Mapping (GSM) Approach 105 1.4 DIVA applied to Kenyan coastal issues – a case study 107 1.4.1 DIVA projections on impacts from climate change 107 A report to the AUC at the UN Climate Change Conference in Copenhagen iii The African Science-Base for Coastal Adaptation: A Continental Approach 1.4.2 DIVA projections on adaptation from climate change 110 References 111 List of Figures Figure 1 A conceptual framework for coastal vulnerability assessment 1 Figure 2 Topographic map of Africa 7 Figure 3 Projected 100-year effects of global warming in Africa 14 Figure 4 Sea-level rise impact on the African coast 15 Figure 5 An overview of total sand loss from sea-level rise in Africa 16 Figure 6 Projected 100-year rainfall variations in Africa 17 Figure 7 An overview of coastal floodplain population in Africa 18 Figure 8 Water stress in Africa 19 Figure 9 People affected by natural disasters in Sub-Saharan Africa 20 Figure 10 Level of exposure to cyclone impact on the African coast 21 Figure 11 Projected incremental impact on land area in studied countries 22 Figure 12 Relative population density on the Africa continent 24 Figure 13 Projected incremental impact on population in studied countries 27 Figure 14 Projected incremental impact on urban extent in studied countries 28 Figure 15 An overview of net loss of wetland area in Africa 28 Figure 16 Projected incremental impact on wetlands in studied countries 29 Figure 17 Projected incremental impact on GDP in studied countries 30 Figure 18 Map of Africa showing the regions and countries studied 32 Figure 19 Map of island archipelago, Cape Verde 33 Figure 20 The Gambian coastal zone 34 Figure 21 Examples of coastal erosion in Region 1 36 Figure 22 Climate impacts in Region 1 38 Figure 23 Examples of further coastal erosion in Region 1 39 Figure 24 Examples of flooding in Cape Verde 41 Figure 25 Projected impacts of coastal flooding in Region 1 42 Figure 26 Drought in Cape Verde 43 Figure 27 Distribution of the Senegal population in 1999 44 Figure 28 Projected population at risk for the Senegal coast 45 Figure 29 Depletion of mangrove forests in Saloum-Sine Delta, Senegal 46 Figure 30 Map showing the coastal zone of Ghana 50 Figure 31 Examples of coastal erosion in Region 2 52 A report to the AUC at the UN Climate Change Conference in Copenhagen iv The African Science-Base for Coastal Adaptation: A Continental Approach Figure 32 Total land loss in Nigeria 53 Figure 33 Examples of coastal flooding in Region 2 53 Figure 34 Impact on coastal population from sea-level rise in Nigeria 55 Figure 35 Discharges into the sea from the jetty loading phosphate in Togo 58 Figure 36 Examples of coastal erosion in Region 3 60 Figure 37 Coastal ecosystems along the Kenya coast 63 Figure 38 Priority hot spots and sensitive areas along the Tanzanian coast 64 Figure 39 The Mozambique coast 65 Figure 40 Examples of coastal erosion in Region 4 67 Figure 41 Impact on coastal resources along the Kenyan coast 70 Figure 42 Decline of catch rates of Shrimp in Sofala Bank, Mozambique 72 Figure 43 Distribution of coastal land of Mauritius in 1998 74 Figure 44 Mauritian sites that may be affected with climate change 75 Figure 45 Island archipelago, Seychelles 76 Figure 46 Summary of coastal population density for the studied regions 81 Figure 47 Summary of segment vulnerability scores for the studied regions 82 Figure 48 Summary of GDP per capita for the studied regions 83 Figure 49 Summary of tourist added value for the studied regions 84 Figure 50 Projected total cost of protection for the Senegal coast 86 Figure 51 Coastal protection at Aného, Togo 87 Figure 52 Examples of coastal adaptation for Region 4 88 Figure 53 An overview of sea flood costs for the African coastal zone 89 Figure 54 Total annual cost of adaptation and share of costs 91 Figure 55 Total annual cost of adaptation 91 Figure 56 Summary of accommodation space for the studied regions 94 Figure 57 Summary of sea-dike height for the studied regions 95 Figure 58 Examples of methods of bathymetric and inundation mapping 97 Figure 59 Mozambique, Sofala province rapid response inundation map 99 Figure 60 Remote sensing used to monitor coastal flooding in Mozambique 100 Figure 61 Remote sensing applied to monitor rainfall variability in Africa 100 Figure 62 Coastal modelling applied on the coast of Tanzania 102 Figure 63 An example of the overall coastal sensitivity index 105 Figure 64 An example of the geomorphic stability mapping approach 106 Figure 65 Projected impacts on the Kenyan coastal zone 108 Figure 66 Projected further impacts on the Kenyan coastal zone 109 Figure 67 Projected adaptation costs on the Kenyan coastal zone 110 A report to the AUC at the UN Climate Change Conference in Copenhagen v The African Science-Base for Coastal Adaptation: A Continental Approach List of Tables Table 1 Top 8 cities in the studied regions at risk from storm surges 23 Table 2 Future storm surge impacts on top 6 coastal cities 23 Table 3 Sea-level rise and storm surges on the studied countries 26 Table 4 Summary of coastal threats along Region 1 countries 35 Table 5 Mortalities resulting from major floods in Cape Verde 41 Table 6 Statistics for region 2 West Africa 49 Table 7 Coastal threats along Region 2 countries 51 Table 8 Statistics for region 3 59 Table 9 Statistics for region 4 62 Table 10 Coastal threats along Region 4 countries 66 Table 11 Rates of coastline changes at Chinde Inlet, Mozambique 68 Table 12 Impacts