Limits to capital works adaptation in the coastal zones and islands: Lessons for the pacific

Abstract

From seawalls to levees and desalination plants to dams, capital works projects have become a widely accepted climate adaptation strategy in the coastal zone. With the reality of anthropogenic climate change and associated rising sea levels and an increase in the intensity of extreme weather events, there is a growing need for a range of adaptation interventions. The use of capital works for shoreline stabilisation has a long history and is an established engineering response to the protection of buildings and infrastructure from erosion or long term recession. While capital works often succeed in their primary objective of shoreline stabilisation to protect built assets from damage by erosion or inundation, by interrupting coastal processes they are often responsible for unintended consequences in other locations and at other times. In addition to these unintended consequences, case studies of New Orleans during Hurricane Katrina and Sendai prefecture during the 2010 Tokoku earthquake illustrate how the engineering design process, and particularly the need for a ‘design storm’, is a critical adaptation limit for capital works projects in the face of ongoing global climatic disruption. A key research problem is to identify the precise circumstances under which use of capital works is an appropriate and cost effective coastal climate change adaptation strategy, those where a soft-engineering approach that makes use of natural processes such as beach nourishment is preferable, and the situations where an ecosystem-based approach, that draws upon the ecosystem services of natural ecosystems to mitigate climate change impacts, is likely to be more cost effective or resilient.