With climate change causing an increased intensity and frequency of natural hazard events, coastal communities are realising the need for adequate adaptation to remain resilient. The limitations of traditional hard-engineered approaches as coastal protection are becoming more prevalent and evident. Recent scholarship emphasises the need for a paradigm shift towards incorporating nature into coastal adaptation, including sand dunes, salt marsh, and wetlands. Using coastal blue-green infrastructure (CBGI) as an adaption response provides a multitude of benefits that extend beyond coastal protection, though the complete CBGI values set is often not well understood or underrepresented. The low-lying delta city of Ōtautahi Christchurch, New Zealand, is at a critical point where a comprehensive approach to coastal adaption planning in a changing climate is being addressed for the first time. This process has started at a time when built infrastructure data is generally available and far more prioritised while CBGI data is relatively patchy to absent. In response, this study develops a methodology to assess the values of the New Brighton coastal sand dune system, a significant CBGI resource fringing the city’s open coast.

A CBGI assessment methodology was developed through a global review of the history and different types of CBGI, while critically analysing the potential applicability of approaches to the New Brighton coastal sand dune system. A 'Nature’s Contribution to People' approach was used to develop a set of appropriate valuation methods. This methodological development and selected assessment results for the New Brighton coastal sand dune system are then explained. Key findings are that sand dunes have a multitude of values with many of them requiring a contextual measurement approach. Despite the challenges of value determination, results clearly indicate that the New Brighton coastal sand dune system needs space for migration with climate change which currently does not exist due to urban development, and further plantings of native species, such as spinifex (Spinifex sericeus) and pīngao (Ficinia spiralis), to aid with the maintenance and enhancement of its ecology, aesthetic, and protection values.

This research is significant as it provides a baseline of the current dune system CBGI values for Ōtautahi, which can be used by the government and community to understand the benefits of existing CBGI as an adaptation response to climate change. It also highlights the work needed to recognise, value, enhance and further implement a nature based coastal protection approach at the core of coastal settlement climate change responses throughout New Zealand.