Ranking of national-level adaptation options. An editorial comment

de Bruin et al. (Clim Change, 2009) report on an expert assessment aimed at prioritizing adaptation options in several climate-sensitive sectors of the Netherlands. Their results show that even in a country with high economic, institutional and technical capacity, it is not currently feasible to prioritize national-level adaptation options based on social cost-benefit analysis because of methodological difficulties and insufficient quantitative data. Multi-criteria analysis based on qualitative indicators can help prioritizing adaptation options but the analysis detected strong conflicts between priority and feasibility criteria. The specific results of the ranking exercise should be treated with caution due to weaknesses in the selection of adaptation options and the definition of evaluation criteria. The authors assert that their methods can be transferred to other regions but substantial modifications are likely required in developing countries with large current climate risks, fewer economic resources, and substantial social inequalities.     

An architecture for government action on adaptation to climate change. An editorial comment

An architecture of government adaptation programs is presented. Components include leadership, institutional organization, stakeholder involvement, climate change information, appropriate use of decision analysis techniques, explicit consideration of barriers to adaptation, funding for adaptation, technology development and diffusion, and adaptation research. This architecture is a useful heuristic for identifying, evaluating, and reevaluating the needs of decision makers as they improve management of climate-sensitive resources in a changing environment.     

On the economics of coastal adaptation solutions in an uncertain world

The economics of adaptation to climate change relies heavily on comparisons of the benefits and costs of adaptation options that can range from changes in policy to implementing specific projects. Since these benefits are derived from damages avoided by any such adaptation, they are critically dependent on the specification of a baseline. The current exercise paper reinforces this point in an environment that superimposes stochastic coastal storm events on two alternative sea level rise scenarios from two different baselines: one assumes perfect economic efficiency of the sort that could be supported by the availability of actuarially fair insurance and a second in which fundamental market imperfections significantly impair society’s ability to spread risk. We show that the value of adaptation can be expressed in terms of differences in expected outcomes damages only if the effected community has access to efficient risk-spreading mechanisms or reflects risk neutrality in its decision-making structure. Otherwise, the appropriate metric for measuring the benefits of adaptation must be derived from certainty equivalents. In these cases, increases in decision-makers’ aversion to risk increase the economic value of adaptations that reduce expected damages and diminish the variance of their inter-annual variability. For engineering and other adaptations that involve significant up-front expense followed by ongoing operational cost, increases in decision-makers’ aversion increase the value of adaptation and therefore move the date of economically efficient implementation closer to the present.     

Environmental non-migration as adaptation in hazard-prone areas: Evidence from coastal Bangladesh

Despite suffering significantly from the adverse impacts of climate change and human-induced hazards, many people at risk deliberately choose not to migrate from hazard-prone areas in coastal Bangladesh. As many of them encounter significant challenges in maintaining their livelihoods, ascertaining how and under what circumstances voluntary non-migration decisions occur is crucial. Only a handful of studies have investigated whether individuals and groups who decide to stay put in the face of climatic hazards consider their decision to be an adaptive action. In this regard, this study contributes to the existing literature by empirically investigating the voluntary non-migration decision as an adaptation strategy through an exploration of the factors affecting this decision. We employed a systematic random sampling technique and selected 627 respondents from two climatic hazard-prone coastal districts: Khulna and Satkhira. Using the Generalized Structural Equation Model (GSEM), we found that voluntary non-migrants (84% of total respondents) appeared to enjoy the significant advantage of access to their communities' basic need provision and social support. Furthermore, the social, psychological, and economic opportunities found at their existing location (e.g., better income prospects, affordable living costs, receipt of financial help during post-disaster periods, and skills allowing them to stay in that location), as well as their access to local natural resources, strengthened their social capital and thus influenced their desire to stay. Together, these factors enhanced people’s adaptability to climatic shocks and motivated them to choose voluntary non-migration as an adaptation option.     

Simplified method for scenario-based risk assessment adaptation planning in the coastal zone

The development of successful coastal adaptation strategies for both the built and natural environments requires combining scenarios of climate change and socio-economic conditions, and risk assessment. Such planning needs to consider the adaptation costs and residual damages over time that may occur given a range of possible storm conditions for any given sea level rise scenario. Using the metric of the expected value of annual adaptation costs and residual damages, or another metric that can be related to the elevation of flooding, a simplified method to carry this out is presented. The approach relies upon developing damage-flooding depth probability exceedance curves for various scenarios over a given planning period and determining the areas under the curves. While the approach does have limitations, it is less complex to implement than using Monte Carlo simulation approaches and may be more intuitive to decision makers. A case study in Maine, USA is carried out to illustrate the method.     

Regional assessment of climate change impacts on coastal and fluvial ecosystems and the scope for adaptation

Ecosystem changes in floodplains could be a major issue during the twenty-first century as designated habitat areas are affected by climate change and floodplain management options. As part of the RegIS project, a Regional Impact Simulator has been developed to investigate these potential changes. This paper presents the methodologies and results of biodiversity metamodels used within the Regional Impact Simulator for two regions of the UK: East Anglia and North West England. Potential impacts and adaptations to future climate and socio-economic scenarios are analysed for three habitat types in floodplains (saltmarsh, coastal grazing marsh and fluvial grazing marsh) and selected species. An important finding is that management choices, which can be linked to socio-economic futures have a greater potential impact on habitat viability than climate change. The choices society makes will therefore be key to protection and conservation of biodiversity. The analyses also show that coastal grazing marsh is the most vulnerable habitat to sea-level rise, although there is a scope for substituting losses with fluvial grazing marsh. These results indicate that these methods provide a useful approach for assessing potential biodiversity changes at the regional scale, including the effect of different policies.     

Global assessment of the effectiveness of adaptation in coastal areas based on RCP/SSP scenarios

Climatic Change - The objective of this study is to assess the global impact of sea level rise and to evaluate the effectiveness of adaptation. Global areas of inundation due to sea level rise are...     

Climate change and coastal flooding in Metro Boston: impacts and adaptation strategies

Sea level rise (SLR) due to climate change will increase storm surge height along the 825 km long coastline of Metro Boston, USA. Land at risk consists of urban waterfront with piers and armoring, residential areas with and without seawalls and revetments, and undeveloped land with either rock coasts or gently sloping beachfront and low-lying coastal marshes. Risk-based analysis shows that the cumulative 100 year economic impacts on developed areas from increased storm surge flooding depend heavily upon the adaptation response, location, and estimated sea level rise. Generally it is found that it is advantageous to use expensive structural protection in areas that are highly developed and less structural approaches such as floodproofing and limiting or removing development in less developed or environmentally sensitive areas.     

The economic value of delaying adaptation to sea-level rise: An application to coastal properties in Connecticut

The magnitude and frequency of coastal storms are expected to increase with rising global sea levels, which necessitates evaluating coastal flood adaptation measures. This study examines an important issue in the context of coastal flood protection, namely, the decision when to adopt protection measures. For any given coastal region, our benefit-cost framework allows us to determine the optimal timing of initiating protection that maximizes expected net benefits. We present an application of this framework to a coastal area in Connecticut. Our results suggest that the optimal timing of adopting protection may vary across different census blocks within the study area. We find that using a relatively low discount rate in the benefit-cost analysis implies greater heterogeneity in the timing decisions and earlier overall adoption, whereas, with higher discount rates, the timing decisions are reduced to a choice between early protection and no protection at all. If possible negative environmental and aesthetic impacts of sea barriers are taken into account, delaying protection would become more desirable, with the extent of delay being sensitive to the relative magnitude of one-time costs (e.g., loss of ocean view and recreational opportunities) vs. continuous costs (e.g., shoreline erosion and loss of wetlands).