2.1 Planning for climate change Context Sea level Seaspray Lifesaving Club after a storm in 2005 C. MsCubbin The coast is dynamic and we see constant changes occurring in the sea level from day to day and from season to season. However, this century we will see further changes. Increased temperatures, caused by increased concentrations of greenhouse gases, trigger sea level rise. This is due to: thermal expansion of sea water as it heats up glacial and ice cap melt, and Greenland ice sheet melt, to a lesser extent. The most recent Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report states that 'human influences have very likely contributed to sea level rise [and other impacts] in the latter half of the twentieth century'. The IPCC concludes that: global average sea level has risen since 1961 at an average rate of 1.8 millimetres per year and since 1993 at 3.1 millimetres per year annual average ice extent has shrunk by 2.7 per cent per decade since 1978 (when records began) (IPCC, 2007). Locally, recording stations at Lorne and Stony Point have recorded sea level rises of 2.8 millimetres per year and 2.4 millimetres per year respectively since 1991 (National Tidal Centre, Bureau of Meteorology, 2006). Global sea level rose by about 0.17 metres during the last century (Church and White, 2006). In its Fourth Assessment Report the IPCC projected sea level rise of between 0.18-0.59 metres by 2090-2099 using a hierarchy of models plus additional ice sheet melt of 0.1-0.2 metres. however, the upper values of sea level rise (e.g. 0.59 metres) projected by the models were not considered to be the upper bounds of possible sea level rise by 2099. While there is uncertainty about the quantum of the sea level rise, data provided in the IPCC report shows that the sea level is rising and will continue to rise in the 21st century and in all likelihood beyond. Even if greenhouse gas emissions are stabilised, sea levels will continue to rise throughout this century and into the next. Uncertainty still exists in climate projections, including future green house gas emissions, climate sensitivity, speed of change and regional responses to global climate changes (CSIRO, 2007). Adoption of a precautionary strategy suggests that a policy of planning for sea level rise of not less than 0.8 metres by 2100 should be adopted. This policy will be reviewed as scientific data becomes available or when national benchmarks are established. Storm surges Sea level rise on its own will not have the greatest impacts on the coast: increased storm events and storm surges will result in damaging waves, erosion, wind and inundation occurring further inland. Flooding, erosion and damage to infrastructure and ecosystems will also occur. A storm surge is an elevated sea level caused by a low pressure system and intense winds. A storm surge will have maximum impact when combined with a high or king tide. Storm surges are likely to occur more frequently and with greater severity as weather patterns change due to changed wind patterns, rainfall and sea surface temperatures. Impacts to property and infrastructure are already occurring when storms strike, including: damage to and loss of boats damage to and loss of structures on the foreshore entry of water behind sea walls via storm water drains due to breaching of barriers salt water intrusion into fresh water aquifers coastal erosion and accretion inundation of low-lying areas and damage to coastal vegetation and habitats. Coastal processes The shape of the sea floor and adjacent bays, headlands and islands affect the height of storm surges. A wide gently sloping continental shelf will amplify storm surges while any features like bays and channels will funnel the storm surge and increase its height. Many natural barrier features on the coast which normally protect against erosion by storms and waves are likely to be affected by rising sea levels and increased storm events, including islands, seagrass, beaches and dunes. Coastal processes are complex and it is too simplistic to draw a line on a map at a contour and accurately predict sea level rise. Erosion could lead to significant recession of the coast taking it further inland, depending on the local geology. Sea temperatures Shifts in ranges and changes to algal, plankton and fish abundance are associated with sea water temperature increases, ice cover, sea water acidity, salinity, oxygen levels and circulation (IPCC, 2007). Adapting to climate change While significant effort is now focused on establishing mechanisms to decrease greenhouse gas emissions, the major challenge for coastal planners and managers now lies in getting prepared to adapt to climate change risks and impacts. There are three adaptation options: 1. protect (protection of beaches, dunes and infrastructure; land use and development) 2. accommodate (planning and building policies and provisions, redesign and rebuild) 3. retreat (relocation of infrastructure, land use and development). These three options together with emergency disaster and management must be considered for all vulnerable areas along the coast. On the basis of the IPCC projection and until national benchmarks for coastal vulnerability are established, a policy of planning for sea level rise of not less than 0.8 metres by 2100 should be implemented. As scientific data becomes available, the policy will be refined. This benchmark may be superseded by national benchmarks. Future Coasts (refer box) is seeking to provide a comprehensive vulnerability assessment of the risk of climate change to the Victorian coastline by the end of 2010. The program will also develop strategies, planning tools and other responses for coastal planners and managers to adequately manage the risks and minimise the impact of climate change. The program is part of the Victorian Climate Change Adaptation Program. In collaboration, national, state and local government will need to develop consistent benchmarks for coastal vulnerability assessments to determine the likely impact of climate change on the community. This strategy contains a range of policies and actions to help prepare Victoria's coastal communities for the impacts associated with climate change. In particular, it is policy in this strategy to apply the precautionary principle to planning and management decision making when considering the risks associated with climate change. The precautionary principle is a 'commonsense' notion that requires decision-makers to be cautious when assessing potential health or environmental harms in the absence of the full scientific facts. We need to understand the environmental, social and economic risks and impacts associated with climate change. We need to ensure that up-to-date information, adequate resources and guidance regarding climate change impacts are available to coastal planners and managers. This will enable planners and managers to incorporate adaptation considerations in land-use planning and management frameworks so that they can respond to unexpected changes or new scientific information as it comes to hand. The National Sea Change Taskforce in the publication, Planning for climate change: Leading Practice for Sea Change Communities in Coastal Australia, 2008 identifies two primary threats associated with climate change for coastal communities in Australia. The first is the physical exposure of many coastal settlements to increased natural hazards which threaten human safety, lifestyle, physical assets, biodiversity, and tourism and agriculture-based economies. The second is the particular socio-economic profile of coastal communities; many have higher levels of social vulnerability, reducing their capacity to adapt to climate change risk. www.seachangetaskforce.org.au   Victorian Government's Future Coasts project Future Coasts, led by the Department of Sustainability and Environment is seeking to provide a comprehensive vulnerability assessment of the risk of climate change to the Victorian coastline by the end of 2010. The program will also develop strategies, planning tools and other responses for coastal planners and managers to adequately manage the risks and minimise the impacts of climate change. The program is part of the Victorian Climate Change Adaptation Program. Currently the focus is on capturing high-resolution digital elevation modelling (DEM) for the Victorian coastline. About two thirds of the terrestrial coast has been assessed so far, including the bays, the west coast and some of the Gippsland coast. The next priority is to capture bathymetric (sea depth) data. Projections and digital elevation modelling (DEM) Climate change and sea level rise projections rely on high resolution modelling. DEM provides digital representation of terrain, above and below the water. DEM is being captured to 10 metres elevation on land, and to a depth of 20 metres beneath the sea. DEM can also be used to create high resolution relief maps and to create 3D visualisation models. This will allow more accurate modelling of storm surge, waves, coastal processes, recession and inundation along the coast under different sea level rise scenarios. The DEM data will be available in 2010 through the Department of Sustainability and Environment's Spatial Information Infrastructure division. Further information on the Future Coasts Program can be obtained from the Department of Sustainability and Environment's Climate Change Adaptation Branch at www.climatechange.vic.gov.au\futurecoasts. www.climatechange.vic.gov.au.   Policy 1. Plan for sea level rise of not less than 0.8 metres by 2100, and allow for the combined effects of tides, storm surges, coastal processes and local conditions, such as topography and geology when assessing risks and impacts associated with climate change. As scientific data becomes available the policy of planning for sea level rise of not less than 0.8 metres by 2100 will be reviewed. 2. Apply the precautionary principle to planning and management decision-making when considering the risks associated with climate change. 3. Prioritise the planning and management responses and adaptation strategies to vulnerable areas, such as protect, redesign, rebuild, elevate, relocate and retreat. 4. Ensure that new development is located and designed so that it can be appropriately protected from climate change's risks and impacts and coastal hazards such as: - inundation by storm tides or combined storm tides and stormwater (both river and coastal inundation) - geotechnical risk (landslide) - coastal erosion - sand drift. 5. Avoid development within primary sand dunes and in low-lying coastal areas. 6. Encourage the revegetation of land abutting coastal Crown land using local provenance indigenous species to build the resilience of the coastal environment and to maintain biodiversity. 7. New development that may be at risk from future sea level rise and storm surge events will not be protected by the expenditure of public funds. 8. Ensure that climate change should not be a barrier to investment in minor coastal public infrastructure provided the design-life is within the timeframe of potential impact. 9. Ensure planning and management frameworks are prepared for changes in local conditions as a result of climate change and can respond quickly to the best available current and emerging science. 10. Ensure all plans prepared under the Coastal Management Act 1995 and strategies relating to the coast, including Coastal Action Plans and management plans consider the most recent scientific information on the impacts of climate change. Actions Mornington boating facility during a storm in 2008. J. Hart a Establish an appropriate mechanism and/or instrument to support policy and decision-making in relation to the risks and impacts of climate change (DSE & DPCD). b Work through national and state processes to develop consistent national benchmarks for coastal vulnerability assessments (DSE). c Develop comprehensive vulnerability assessments for the whole Victorian coast (through the Future Coasts program) to provide guidance to all planners and manager as to how to apply the information for decision-making (DSE & DPCD). d Develop a methodology to provide guidance to all planners and managers as to how to apply the policy of planning for sea level rise of not less than 0.8 metres by 2100, and allow for the combined effects of tides, storm surges, coastal processes and local conditions for decision-making (DSE). e Upon completion of vulnerability assessments being undertaken as part of the Future Coasts program: Investigate opportunities within the Victoria Planning Provisions to address climate change risks and impacts and, if necessary investigate the development of new provisions to manage coastal climate change risks and impacts (DPCD, LG, & DSE). Develop appropriate adaptation strategies to support local and regional level decision-making in relation to the risks and impacts of climate change to the coastline (DSE, DPCD & RCB)

10 December 2008