Extreme sea-level rise and adaptation options for coastal resort cities: A qualitative assessment from the Gold Coast, Australia

Abstract

The Gold Coast, Australia is a coastal resort city whose urban environment has evolved through a series of human interventions on the natural shoreline. Such cities rely on a perceived high quality environment which in turn is reliant on continuing maintenance (e.g. beach nourishment, inlet dredging, drainage). Climate change consequently holds particular challenges for coastal resort cities. Sea-level rise impacts are likely to be manifest in increased frequency of flooding and beach erosion episodes. Here we consider adaptation options for the city under various future sea-level rise (SLR) scenarios at the high end of current predictions for the next century (+1 m, +2 m and +5 m) with the proviso that the beach and waterways must be preserved to enable the city to continue to exist as a resort.

We conclude that pre-planned adaptation would probably enable the city to survive SLR of 1 m. An unplanned response to the same SLR would likely be characterised by periodic crises, growing uncertainty and public unease and would have marginal chances of success. For a 2 m SLR we contend that even with an adaptation plan in place, the scale of measures required would severely stretch the city's resources. Under a 5 m SLR over the next century we do not believe that any amount of planning would enable the city to survive as a coastal resort.

Any adaptation to SLR would involve increased cost to maintain the artificial coastal environment. Adaptation options are particularly constrained by the widespread development around the waterways of the back-barrier area. Unlike other coastal cities, resorts depend on a public perception of a high quality environment. Maintaining this perception under SLR imposes particular adaptation constraints on resort cities.