As sea levels rise over the next century many coastal settlements will face an increased threat from periodic flooding and permanent erosion. Planning policy in Australia and elsewhere is already starting to address this issue by defining coastal zones and placing specific controls on new development in these zones. But the question of how policy deals with existing development in threatened coastal areas remains problematic. Several locations in Australia have faced this problem in recent years and policy has begun to emerge as a result of experience. Much of this policy may be viewed as a reactive to specific circumstances. This paper reviews a range of issues and using three case studies from New South Wales and South Australia, seeks to outline the data requirements for proactive decision making. The discussion covers technical, legal and financial aspects. Using the results of a global literature review and interviews with Australian local councils facing coastal inundation and erosion problems, the paper proposes a decision mapping approach to analyse the threat of sea level rise to existing development and to generate robust policy. It suggests this methodology may also be appropriate to locations outside Australia.Jon Kellett, Jacqueline Balston, Steven Li, Geoff Wells and Mark Wester
