Research report

Climate adaptation within New Zealand’s transport system

Deep South Dialogue Report, Motu Economic and Public Policy Research (2019)

This note discusses climate change impacts and adaptation within New Zealand’s transport sector.

This paper was written after and informed by a facilitated dialogue, held at Motu Economic and Public Policy Research.

The Dialogue was held to identify high-priority research questions, which both address the unknowns identified in this paper and are tractable to high-quality research.

New Zealand’s transport system is inter-dependent. It comprises a network for which demand is derived from local communities and the wider economy. People use this network for economic and social purposes, such as commuting, shifting freight, and visiting friends and family.

Transport also provides critical links during emergencies.

Climate change affects the transport network itself. It causes damage, accidents and network disruption. These have wider effects on communities and the economy. Climate change also alters the spatial allocation of activities and consequently leads to changes in derived demand for transport infrastructure.

Climate change is important to consider in transport planning because transport assets are long-lived, and because the transport system is inter-twined with the wider economic and social systems. There are opportunities for adaptation in the normal cycle of infrastructure build and renewal.

However, there are also many challenges due to the costs involved, the uncertainties ahead and the need to coordinate the different institutions that make up the transport system.

This note discusses climate change impacts and adaptation within New Zealand’s transport sector. First, we describe the physical and institutional structure of New Zealand’s transport system. Second, we review the science behind, and impacts of, climate change related events that disrupt the transport network. Third, we discuss issues around climate change
adaptation and the many questions that are still to be addressed. Finally, we conclude by identifying opportunities for further research.

The key messages of this note are fourfold:

  • First, climate change will impact the transport network both directly by damaging infrastructure and indirectly by changing network use.
  • Second, the scale of this impact is determined by components’ relative criticality, but there is currently no system-wide measure of criticality that allows us to efficiently allocate adaptation effort.
  • Third, a systems approach to adaptation is necessary to account for the inter-dependencies between transport and other sectors.
  • Finally, this inter-dependency means that delaying adaptation decisions also delays investments and decisions made in other parts of the economy, and may therefore lead to poor placement of new infrastructure.