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Abstract
The benefits of coastal adaptation depend on both the conservation of coastal assets and effects on other ecosystem services. Evaluating these benefits requires approaches that can disentangle values related to the assets that are conserved and the methods through which conservation is achieved. This article illustrates paired theoretical and empirical models designed to quantify values related to the methods and outcomes of coastal adaptation. Particular attention is given to valuation challenges associated with dual outcomes that influence human welfare both directly and indirectly. An illustrative empirical application is drawn from a stated preference, discrete choice experiment implemented in the coastal communities of Waterford and Old Saybrook, Connecticut, United States, grounded in storm and flooding scenarios developed for the Coastal Resilience decision-support platform. Results enable estimation of households’ willingness to pay for outcomes such as the reduction of flood risk for coastal homes and the protection of services from coastal marshes and beaches. These estimates enable the evaluation of tradeoffs in social value related to the use of alternative adaptation strategies. Comparison across communities illustrates how differences in context can lead to variations in values and tradeoffs.
Notes
Notes
1 As noted by Bridges et al. (Citation2015, 239), “there are numerous uncertainties regarding the performance, timing, and scale of NNBF needed to provide flood risk reduction and decrease storm damages. NNBF are typically more responsive to storms, and the risk reduction services provided often depend on local conditions.” Urban areas, for example, may sometimes require hardened defenses to provide flood protection (Temmerman et al. Citation2013).
2 WTP is a commonly used measure of monetary value in economics, reflecting the maximum amount of money that an individual or group would be willing to give up in exchange for more of something else. WTP is bounded by income (or ability-to-pay), and hence is conditional on the current distribution of income. This has led to critiques related to the equity implications of welfare analysis. Hence, “while economic welfare analysis should be viewed as an integral step in policy formulation and evaluation, it is not the only component’” (Just, Hueth, and Schmitz Citation2004, 11). Other issues, such as equity and social justice, are relevant. In some cases one can also estimate willingness to accept (WTA) measures of welfare, which are not bounded by income (Freeman, Herriges, and Kling Citation2014).
3 For example, residents may hold positive values for the aesthetic properties of nearby coastal marshes (Johnston et al. Citation2005), or negative values for the aesthetic properties of hardened defenses such as concrete seawalls.
4 Intermediate services are ecological conditions or processes that only benefit humans through effects on other final services. They hence may be viewed as inputs into the production of final services. As such, all social value related to intermediate services is derived through the production of final services (Johnston et al. Citation2017b).
5 There are also a large number of studies that estimate values associated with a single economic aspect of flood risk or adaptation, for example the effect of flood risk on property values (e.g. Bin and Polasky Citation2004; Troy and Romm Citation2004; Bin et al. Citation2008; Daniel, Florax, and Rietveld Citation2009).
6 The assumed baselines for valuation also influence the relevance of value estimates for adaptation decisions. For example, multiple studies have evaluated the flood attenuation services provided by marshes, generally relative to a baseline in which these NNBF are not present (e.g. Barbier et al. Citation2011; Shepard, Crain, and Beck Citation2011). However, a more relevant basis for comparison in many instances is an alternative in which hardened defenses are applied.
7 For example, land cover data in Coastal Resilience indicates that Old Saybrook has approximately 477 acres of coastal marsh remaining today, whereas Waterford has approximately 77 acres remaining (Makriyannis Citation2017).
8 Considering another example, a WTP estimate for an attribute on seawall length would reflect the direct WTP for aesthetic and other immediate properties of seawalls alone, apart from any value related to the causal, indirect effects of seawalls on utility (e.g. due to coastal asset protection, effects on natural habitats, etc.). WTP for these other, causally related outcomes would be captured by other direct outcomes included in the choice experiment scenario (e.g. attributes reflecting effects on valued habitats and protection of built assets from flooding).
9 For example, marginal changes in salt marsh acreage within Waterford – of the type likely given changes in current adaptation planning – are unlikely to cause measurable change in neighboring Long Island Sound water quality or fish populations, despite the fact that wetlands provide fish production and water filtration services.
10 As discussed above, outcomes with purely intermediate effects on welfare are excluded. For example, scenarios do not include an attribute on residential zoning regulations in flood-prone areas, because the primary way that these regulations affect welfare (for most residents) is through an intermediate effect on homes expected to flood.
11 For example, the attribute representing the number of homes expected to flood in a Category 3 storm (homes) is presented both as a cardinal number and as a percentage relative to the total number of homes in each town.
12 An analysis of sample representativeness is provided by Johnston and Abdulrahman (Citation2017).
13 This assumption is required to ensure model convergence.
14 For example, focus group results and prior research by the authors (e.g. Johnston et al. Citation2005; Johnston, Ramachandran, and Parsons Citation2015) suggest that the public values beach and marsh protection, corresponding to negative coefficients for beach and marsh loss.
15 Because these estimates reflect ongoing annual WTP they are not discounted values. Assumptions regarding the discount rate are required when aggregating such estimates over time (Johnston et al. Citation2017a). Egan, Corrigan, and Dwyer (Citation2015) discuss the role of discounting in the design if stated preference scenarios.
16 Following Adamowicz et al. (Citation1998), this estimate does not include WTP associated with the alternative specific constant (neither). If included, this would result in an additional WTP of $175.82 per household, per year, associated with any nonstatus quo adaptation plan.