All roads lead to retreat: adapting to sea level rise using a trigger-based pathway

As coastal communities all over the world deal with the consequences of rising sea-level and more intense storm events, planners and managers continue to grapple with the optimal policy approach to managing increasing risks to coastal ecosystems, people and property. In this article, we describe a flexible pathway approach to adaptation derived in south west Australia for local government. While the issue is usually addressed using a conventional option analysis of the ‘retreat-accommodate-protect’ alternatives within a given timeframe (often until 2100), we argue that this approach is misleading in that it obfuscates the long term realities of climate change. Sea-level will be rising for hundreds if not thousands of years, meaning that retreat is ultimately inevitable for any coastlines currently determined to be vulnerable–the only uncertainty is when this will be necessary. Accordingly the focus should be on continual monitoring, updated hazard mapping, and the identification of sequential triggers that regulate land uses. We propose this simplified flexible pathway as a rational approach to dealing with the temporal uncertainty of future climate change that should be widely adopted.