Simulating the Impacts of an Applied Dynamic Adaptive Pathways Plan Using an Agent-Based Model: A Tauranga City, New Zealand, Case Study

Abstract

Climate change and relative sea-level rise (RSLR) will increasingly expose coastal cities to coastal flooding, erosion, pluvial and fluvial flooding, episodic storm-tide flooding and eventually, permanent inundation. Tools are needed to support adaptive management approaches that allow society to adapt incrementally by making decisions now without creating path dependency and compromising decision-making options in the future. We developed an agent-based model that integrates climate-related physical hazard drivers and socio-economic drivers. We used it to explore how adaptive actions might be sequentially triggered within a low-elevation coastal city in New Zealand, in response to various climate change and socio-economic scenarios. We found that different adaptive actions are triggered at about the same RSLR level regardless of shared socio-economic pathway/representative concentration pathway scenario. The timing of actions within each pathway is dictated mainly by the rate of RSLR and the timing and severity of storm events. For the representative study site, the model suggests that the limits for soft and hard protection will occur around 30 cm RSLR, fully-pumped water systems are viable to around 35 cm RSLR and infrastructure upgrades and policy mechanisms are feasible until between 40 cm and 75 cm RSLR. After 75 cm RSLR, active retreat is the only remaining adaptation pathway.

Measuring Social Vulnerability to Climate Change at the Coast: Embracing Complexity and Context for More Accurate and Equitable Analysis

“…Our current research supports this type of complex, inclusive, and grounded adaptation decision-making. Drawing on the most frequently used indicators of social vulnerability to climate change that are found within the indices reviewed for the Resilience Challenge work described above and our combined 50 years of social and climate research in coastal communities [123,[136][137][138][139][140][141][142][143][144][145][146][147][148][149], we developed a framework for creating personas. The framework (Figure 2 below) comprises a series of identity markers (such as socio-economic status, education, race, renter, or homeowner) that contribute to social vulnerability and that we call "positionality", a range of adaptive capacities, skills, or assets that offset vulnerability, and a category for beliefs and values.…”

Coastal Adaptation Pathways and Tipping Points for Typical Mediterranean Beaches Under Future Scenarios

“…A sequential adaptation with a multirisk assessment [26] enables a flexible set of interventions to enhance coastal resilience, avoid TPs and, in the approach here proposed, demonstrating the shared benefits of nature-based solutions (NbS) or living shorelines. The developed dynamic adaptation plans [27] consider climate and management evolution, proposing a set of actionable interventions and estimating their contribution to risk reduction in terms of key and robust physical parameters, simpler to project than ecologic or socioeconomic ones.…”

Coastal Adaptation Pathways and Tipping Points for Typical Mediterranean Beaches under Future Scenarios

“…Such consensus and the convergence of stakeholder criteria are based on an explicit assessment of synergies and tradeoffs for the proposed coastal interventions, including estimations of costs, impacts and carbon footprint. Based on the proposed dynamic adaptation plans and risk assessments [28][29][30], the actionable interventions can be assessed and ranked according to risk reduction, estimated as a function of key physical parameters that integrate the complex social-ecological dynamics of the coastal system.…”