Swelling Seas: Planning for sea level rise Westley Owers Bachelor of Town Planning Faculty of the Built Environment University of New South Wales November 2006 Abstract Emissions of greenhouse gases into the atmosphere over the last hundreds of years have placed us in a precarious position, in that we have forced change upon one of the world’s most important systems: climate. This climate change will have devastating impacts around the world. Of all the impacts of human induced climate change, it is sea level rise that is regarded as the most certain. Sea level is expected to rise in a best case scenario of one metre by the year 2100. However, there is still uncertainty surrounding how the environment will react to greenhouse gas emissions, and therefore a sea level rise of up to six metres above current levels by the year 2100 cannot be ruled out. As sea level rises it will bring with it debilitating impacts such as inundation of coastal areas, increased coastal erosion and an increased flooding of inland areas in storm surge occurrences. The scope and magnitude of this environmental issue is such that these impacts will seriously alter human settlement and fragile ecosystems in nations throughout the world. The only way of reducing the impacts of this environmental issue is for government to prepare coastal policy and legislation to address this issue now. The extent at which the impacts of sea level rise are experienced at a local, state and national level within nations will be a direct result of the adaptive response that governments implement to address this environmental issue. Sea level rise needs to be addressed now so we can ensure the preservation of the coastline for future generations. i Table of contents Chapter 1: Introduction 1.1 Waves at our doorsteps 2 1.2 Problem Statement and Objectives 3 Research Statement 3 Research Objectives 4 1.3 Theoretical context 4 Scientific sea level rise 5 Coastal planning and policy 5 1.4 Limitations 6 1.5 Methodology 7 Discourse analysis 7 In-depth interviews 7 1.6 Summary of Chapters 8 Chapter 2: Unchartered waters 8 Chapter 3: Impacts of sea level rise 8 Chapter 4: Planning for sea level rise 9 Chapter 5: Broken bridges over troubled waters 9 Chapter 6: Recommendations, Conclusion 10 Chapter 2: Uncharted waters 2.1 Introduction 12 2.2 Definition of sea level and its measurement 12 2.3 Causes of natural sea level fluctuations 14 2.4 Sea level fluctuations throughout the earth’s history 16 ii 2.5 Unchartered waters: Current projections of future sea level rise 19 2.6 Conclusion 23 Chapter 3: Impacts of sea level rise 3.1 Introduction 25 3.2 General impacts of sea level rise 25 Inundation 25 Storm surge flooding 26 Erosion 27 3.3 Vulnerable ecosystems 27 Beaches 27 Wetlands 28 Coral reefs 30 3.4 Impacts of sea level rise on human settlement 31 General Impacts on human settlement 31 Vulnerable nations 32 The Netherlands 33 Bangladesh 35 Australia 36 3.5 Conclusion 38 Chapter 4: Planning for sea level rise 4.1 Introduction 40 4.2 Human responses to sea level rise 40 4.3 A question of scale 42 4.4 Intergovernmental and international coastal planning & management 42 4.5 National coastal planning within Australia 43 iii 4.6 Coastal planning and management in New South Wales 44 4.7 Conclusion 54 Chapter 5: Broken bridges over troubled waters 5.1 Introduction 56 5.2 Issues in the NSW system and policy 56 Existing knowledge 56 Responsibility 58 Guiding documents 60 Legislative enforcement 62 Funding 63 5.3 Conclusion 64 Chapter 6: Recommendations Conclusion 6.1 Introduction 66 6.2 Recommendations 66 Existing knowledge 67 Responsibility 67 Guiding documents 68 Legislative enforcement 70 Funding 70 6.2 Conclusion 71 Bibliography 74 iv Figures Figure 1: Tide gauge stations that have been operating continuously for more than 30 years. 14 Figure 2: Outline of Australia and the islands to the north about 18,000 years ago prior to the Later Quaternary 17 marine transgression. Figure 3: Walsh’s estimated contributions to sea level rise over the twentieth century (in cm) 18 Figure 4: Intergovernmental Panel on Climate Change’s estimated contributions to sea level rise over the twentieth 18 century. Figure 5: Unmitigated and stabilisation scenarios for global mean rise in sea level including effects of climate 20 sensitivity. Figure 6: The IPCC’s reasons for uncertainty. 21 Figure 7: Satellite images of the break-up of the Larsen B ice shelf in 2002. 22 Figure 8: Inundation. a) normal scenario, b) sea level rises, wetland retreats converting dry land to wetland and 25 wetland to open water. Figure 9: The contribution of storm surges exacerbating sea levels on the coast. 26 Figure 10: Beach erosion under a rising sea level: the Brunn Rule. 28 Figure 11: The accumulation of peat has protected sea level rise from inundating wetlands in the past. This process 29 will not be able to keep up with accelerated sea level rise in the future. Figure 12: Socio-economic impacts of sea level rise. 31 Figure 13: The coastal floodplain, including different levels of sea water flooding in storm surge occurrences. 32 Figure 14: Netherlands sea level rise scenarios. 34 Figure 15: Land at risk in Bangladesh from a 1m sea level rise. 35 Figure 16: Australian sea level rise scenarios. 37 Figure 17: Sydney after 6m sea level rise (under the melting of the West Antarctic Ice Sheet). 38 Figure 18: Wave energy dispersal a) without the presence of a hard sea defence, b) with the presence of a hard sea 41 defence (sea wall). Figure 19: Objective and actions of the National Cooperative Approach to Integrated Coastal Zone Management in 44 relation to planning and management of climate change in Australia. Figure 20: Acts, policies, strategies, manuals and guidelines relating to coastal planning and management in NSW 45 and their interrelationships. Figure 21: Definition of the coastal zone in the Coastal Protection Act 1979. 47 Figure 22: Strategic Actions in Part B of the NSW Coastal Policy 1997 aimed at addressing the impacts of climate 49 change. Figure 23: Aims of SEPP 71. 50 Figure 24: Regional Strategies actions to manage and plan the coastal zone. 52 Figure 25: Climate change associated with the coastline considered the primary responsibility of local government. 53 v Appendices Appendix A: Interviewees Curriculum Vitae Appendix B: Interview questions Appendix C: University of New South Wales FBE Ethics Approval Abbreviations ALGA Australian Local Government Association CP Act Coastal Protection Act 1979 CSIRO Commonwealth Scientific and Industrial Research Organisations DCP Development Control Plan EP & A Act Environmental Planning and Assessment Act 1979 GCM Geographic Climate Modellings GMSL Global mean sea level ICZM Integrated Coastal Zone Management LEP Local Environmental Plan LMSL Local mean sea level Major Projects SEPP State Environmental Planning Policy (Major Projects) 2005 Minister NSW Minister of Planning NCAICZM National Cooperative Approach to Integrated Coastal Zone Management NSW New South Wales SASAP South Asian Seas Action Plan SCCG Sydney Coastal Council Group SEPP State Environmental Planning Policy SEPP 14 State Environmental Planning Policy No. 14 - Coastal Wetlands SEPP 71 State Environmental Planning Policy No. 71- Coastal Protection WAIS West Antarctic Ice Sheet vi There have been a number of people who supported me throughout the preparation of this thesis including my family and Peri Muddle and to them I am eternally thankful. Thank you to my interviewees Angus Gordon and Brett Whitworth whose insights helped shape this thesis. Also a special thank you must also be extended to Kirk Osborne and Erik Jimenez. vii Introduction Swelling Seas: Planning for sea level rise 1 1.1 Waves at our doorsteps For hundreds of years humans have released greenhouse gases into the atmosphere without any concern for the effects that this would have on the future. We have now been forced into an age of enlightenment, understanding that our current actions are resulting in dramatic changes to our climate. This climate change is like no other that has been experienced before in the history of the earth; with the atmosphere expected to warm at an accelerated rate for a long time into the future. What was previously thought to be a natural process of warming has now been revealed as human induced climate change known as global warming. The impacts of global warming are of a global scale and include changes such as increased frequency and intensity of natural disasters including drought, cyclones, tsunamis and bushfire and altering of the global currents effecting the world’s largest ecosystem-the ocean. The impacts have the potential to devastate farming land, cities, infrastructure and natural ecosystems prompting the displacement of thousands of people throughout the nations of the world. Of all the impacts of human induced climate change “accelerated sea level rise is regarded as the most certain” (Douglas et al, 183:2001). Our past greenhouse emissions have ensured that sea level rise is inevitable and that it will rise for hundreds of years into the future. Even if we were to reduce our greenhouse gas emissions now this process would not be stopped immediately, due to the nature of the natural processes within the ocean. Initially, sea level will rise from glaciers and ice sheet melting as a response to an increased temperature in the atmosphere. Soon the consistent temperature increase in the atmosphere will be directly reflected through a heating of the oceans’ waters, forcing it to expand and dramatically increase sea level in the process. At present best estimates indicate that there could be up to one metre sea level rise by the year 2100.