Steering local government in Australia towards better informed long-term coastal adaptation decisions
Introduction and background
Sea level rise has the potential to alter coastal flooding patterns around the world causing more frequent nuisance flooding and extreme sea-level events that may ultimately be a precursor to permanent inundation. Yet assessing the threat of changing coastal flood patterns across multi-decadal timeframes is complex for many reasons, including knowledge uncertainty, multi-decadal climate variability and conflicting risk perceptions amongst the coastal community stakeholders.
Local government in Australia are at the forefront of community decision-making and play an important role in promoting long-term climate change adaptation. With coastal flooding in Australia projected to cost billions of dollars towards the latter part of this century, local government are faced with an increasing burden to better understand their vulnerability to coastal flooding and consider what adaptation options might ensure the ongoing sustainability of their communities.
In our first study, we reviewed current decision support methods being used by local government to evaluate long-term coastal adaptation options in Australia, examining six characteristics of each case. These included the decision objective, time horizon of the assessment, approach used for risk identification, management of uncertainty, decision process and decision metrics. Drawing on the characteristics of two state-of-the-art decision support methods – robust decision making and dynamic adaptive policy pathways – we benchmarked current Australian practice and identified opportunities to improve coastal adaptation planning.
Additionally, planning for sea-level rise often focuses on ameliorating physical rather than social impacts, which can underestimate the overall risk to the community. To address this research gap we undertook a second study where we compared the explanatory value of the lived values approach – which looks at what aspects of people’s everyday lives are important – and the landscape values approach – which looks at where certain values are associated with coastal landscapes – to assess whether either or both approaches are likely to meet local adaptation planning needs and achieve more socially-oriented adaptation responses.
This article captures some of the key messages from these two studies by Ramm et al. “A review of methodologies applied in Australian practice to evaluate long-term coastal adaptation options” was published in Climate Risk Managementon 15 June 2017 (open access) and can be found here. “Advancing values-based approaches to climate change adaptation: A case study from Australia” was published in Environmental Science and Policy on 6 July 2017 (restricted access) and can be found here.
For study 1, a representative selection of local government, corporate and peer-reviewed publications were collected from around Australia (Figure 1). Literature published after 2010 was used to focus the review on recent case studies and allow relevant work from the 2011-2012 Australian Government funded coastal adaptation decision pathways program to be included. A systematic review was then undertaken to assess the characteristics of each decision support methodology used in the case studies.
For study 2, lived values and landscape values data was obtained from a mail-out and online survey. To inform the development of the survey questions, eight place-based observations were undertaken that revealed those values enacted by residents. Then ten semi-structured interviews were done to capture the values voiced by residents. A total of 322 survey responses were received and the lived value responses were collated and ranked. The significance of association between resident values and landscapes was assessed using a chi-squared test for independence. Following this, a cluster analysis was used to segment the community into groups based upon life characteristics such as gender, employment status and community group membership. A chi-square test of independence then allowed the team to evaluate whether there was significant differences between the groups with regard to lived and landscape values.
Key findings: Methods used in Australia to evaluate long-term adaptation options
The small sample of existing case studies available in Australia suggests that long-term coastal adaptation planning and decision-making is a reasonably new field for local government. Therefore, this is a timely opportunity to guide future planning in local government towards robust methodologies.
Cost-benefit analysis was the most common decision support method used. Economic evaluations were most frequently undertaken in the case studies to assess the costs and benefits of adaptation up to the year 2100. Such methods aimed to maximise adaptation benefits – and tended to follow a ‘top-down’ risk assessment approach – however, this relied on upfront assumptions being made about the future state of sea levels, probability of extreme sea-level events, discount rates and damage costs. Although a well-established approach to evaluate government policy, care needs to be taken since investments can cause maladaptive outcomes over long timeframes if the future deviates from those initial (underlying) assumptions. Economic methods can also undervalue intangible social impacts.
Many assumptions about the future were too simplistic for the evaluation timeframes. The timeframe over which assessments are made is an important consideration. This is because multiple futures become possible as planning horizons increase. The majority of case studies assumed the uncertain parameters, such as sea level rise, could be described deterministically or stochastically toward the end of this century. Planning and decision-making that is underpinned by such assumptions are risky because our ability to predict the future diminishes over long planning horizons.
Australian practice could use more non-probabilistic scenarios to manage uncertainty across multi-decadal timeframes. The use of non-probabilistic scenarios to explore a much larger uncertainty space over multi-decadal timeframes should be increased to identify risk and evaluate adaptation options. This would allow for a much broader uncertainty ‘space’ to be explored. It can also be inclusive of parameters like population growth or damage costs, not exclusively limited to change in climate related variables like sea level rise, which was the case in most studies.
Key findings: Using a values-based approach to inform climate change risk assessment
Climate change will not only affect Australia’s infrastructure and buildings, it will affect our beaches, our access to other coastal environments and is likely to have real impacts on where we socialise and undertake recreational activities.
What do communities value in their everyday lives? The top five lived values rated as most important to residents in our study area were the scenery and views, a safe place to live, relaxed lifestyle, peacefulness and natural environment (Figure 2). Such values were consistent with those identified in other south-eastern Australian studies.
Where are values assigned to low-lying coastal landscapes? We observed that respondents assigned specific values to the different low-lying coastal landscapes, for example the beach was most strongly associated with values relating to recreational opportunities, no access restrictions and providing a sense of identity. Such insights can help decision-makers understand what values could be threatened by inundation of low-lying landscapes.
For whom will sea level rise cause the greatest disruption? We segmented the community into six groups based upon their life stage, lifestyles and unique social values to understand how people in the community might be affected differently from sea level rise. In our case study, we found that whilst the local beach was highly important for recreational value to families and active younger residents, for others (e.g. community-minded volunteers or retirees) manmade features such as community halls and ovals were likely to be of greater importance as they facilitate important social interactions.
Conclusions: Lessons learnt
There is a unique opportunity in Australia to draw upon state-of-the-art methods from abroad to develop robust coastal adaptation planning. Notwithstanding the current barriers faced by local government in adaptation planning and decision-making, we identified four key principles could improve long-term adaptation strategies in the face of uncertain coastal change:
- Explore future change with hundreds to thousands of scenarios: Scenarios answer ‘what-if’ questions and support learning in an uncertain world. Each scenario reflects a different combinations of sea level rise, population change and other uncertain variables. Assessing physical impacts across many scenarios means a greater uncertainty ‘space’ can be explored to identify vulnerabilities within communities.
- Know what change can be accommodated: Assessing the impacts across many scenarios helps understand what change to the built and natural environment will cause unacceptable impacts to people, properties and the environment. This allows for tipping points to be identified that helps to understand when adaptation responses are needed.
- Develop plans that are flexible: Planning flexible adaptation strategies allows communities to focus on near-term actions, whilst keeping future options open in the face of uncertainty. As more information becomes available and the community evolves, they can iteratively update their strategies and adaptation actions.
- Favour robust adaptation responses across multi-decadal timeframes: Robust adaptation responses perform adequately across many different future scenarios. This is in contrast to optimal adaptation responses which maximise adaptation benefits based upon future assumptions. When adaptation responses are designed to last for many decades, optimisation methods can be risky as the future is likely to deviate from assumptions.
Viewing climate change risk from the lens of a resident can also help understand what aspects of people’s everyday lives are important, where certain values are associated with coastal landscapes, and what groups of people might be most disadvantaged by sea level rise – factors often overlooked in physical or economic risk assessments. Our work suggests that lived values and landscape values methods provide complementary information for adaptation planning, whilst segmenting the community into groups can help to cater for the needs of everyone in the community. This can improve the fairness of adaptation plans by better assigning the social and economic costs and benefits of adaptation.
It is imperative that local government continue to engage in coastal adaptation planning as sea levels will rise regardless of whether future greenhouse gas emissions are stabilised. A more holistic view of climate change adaptation is needed by local government so that their plans are flexible, robust and inclusive of intangible social impacts.
The suggested citation for both publications referred to in this article are as follows:
- Ramm, T.D., White, C.J., Chan, A., & Watson, C.S. (2017) A review of decision analysis methods used in long-term coastal adaptation studies in Australia. Climate Risk Management. 17, 35-51. https://dx.doi.org/10.1016/j.crm.2017.06.005
- Ramm, T.D., Graham, S., White, C.J., & Watson, C.S. (2017) Advancing values-based approaches to climate change adaptation: a case study from Australia. Environmental Science and Policy, 76, 113-123. https://doi.org/10.1016/j.envsci.2017.06.014
- Read a related brief: "Making Good Decisions Without Predictions: Robust Decision Making for Planning Under Deep Uncertainty"
- Learn more about 'Dynamic Adaptive Policy Pathways' (Deltares)
- Read a related blog: "Sea level is rising fast – and it seems to be speeding up"
- Read a related blog: "Rising seas bring a rising nuisance: coastal flooding"
- Read a related blog: "Hurt by sea: how storm surges and sea-level rise make coastal life risky"
- Report for the Australian Government: "Climate Change Risks to Coastal Buildings and Infrastructure"
- Read a related paper: "Local values for fairer adaptation to sea-level rise: A typology of residents and their lived values..."
- Read more about robust decision making
- Mediation training module: Robust Decision Making
- FRACTAL Working Paper reviewing 12 decision-making methods