Local adaptation responses to coastal hazards in small island communities: insights from 4 Pacific nations
Introduction
The risks from coastal hazards such as erosion and flooding are rising globally and, with them, the costs associated with maladaptation or not adapting (Lincke and Hinkel, 2018). Coastal communities in island nations, especially in the Pacific, are particularly vulnerable to coastal hazards (Nurse et al., 2014; Mycoo and Donovan, 2017). Rapidly rising sea levels and associated coastal hazards mean that communities in low-elevation coastal zones face unprecedented risks to their lands, livelihood, natural resources and cultural heritage (McGranahan et al., 2007; Aalst et al., 2014; Noble et al., 2014).
The hazards that coastal communities respond to vary considerably in relation to elevation, bathymetry, geology, regional climate, and in the case of reef islands, the underlying reef morphology and integrity (Forbes et al., 2013). Typical coastal hazards include erosion and loss of land due to strong currents and sea-level rise, repeated inundation due to high tides or subsiding land, and damage to shorelines and coastal structures from waves (Kumar et al., 2018). For many communities these hazards severely affect vital social, cultural and natural assets and resources. In addition to homes, roads and infrastructure, these could include important cultural assets like cemeteries and places of worship (Nunn et al., 2017). Another growing concern, especially in low-lying atoll island communities, is the increasing intrusion of saltwater into freshwater lenses in the ground on atoll islands which can contaminate critical drinking water sources and render the soil unusable for growing crops (Gingerich et al., 2017; Storlazzi et al., 2018).
Adaptation responses to coastal hazards can be of several types and can vary widely between high density urban cities versus more rural and remote villages and towns. At the local scale, coastal adaptation can involve multiple responses at the same time, including land reclamation, in situ protection using structures, ecosystem- based adaptation, raising elevations or retreating from the coastline (Nicholls and Cazenave, 2010; Oppenheimer et al., 2019). In urban areas adaptation responses can include technically complex and expensive solutions such as storm surge barriers, land reclamation or large shore-front levees and seawalls (e.g., Aerts et al., 2013). By contrast, rural coastal communities often respond to hazards with structures and other responses that can be built quickly and easily using local resources. These can include raising elevations of structures by building on stilts or elevating floors to keep the structures dry during periods of high water levels or heavy rain (Rasmussen et al., 2009; Jamero et al., 2018). Relocation and planned retreat are also coastal adaptation responses, though these are relatively rare and difficult to implement (Albert et al., 2017; Hino et al., 2017; Jamero et al., 2017).
Ecosystem-based adaptation responses are gaining increasing attention world-wide, particularly due to the multiple benefits they can provide in addition to coastal protection (Cheong et al., 2013; Temmerman et al., 2013; Beck and Lange, 2015; Bridges et al., 2015). Coastal mangrove and marsh wetlands and offshore coral reefs can protect shorelines by reducing wave heights and storm surges (Narayan et al., 2016, 2017; Storlazzi et al., 2019). These ecosystems also provide valuable co-benefits including recreation, carbon sequestration, fisheries production and food and timber production (Sutton-Grier et al., 2015). Ecosystem based adaptation responses are particularly suitable for contexts where moderate levels of hazard reduction is required in combination with other co-benefits (Arkema et al., 2015).
Adaptation responses, regardless of type, are constrained at the local scale by local needs and contexts. Broadly, these adaptive capacity needs can be technical, economic, financial or social (Hinkel et al., 2018) to strengthen elements within the key linked domains of assets, flexibility, organization, learning and agency (Cinner et al., 2018). There is growing focus on integrating ‘bottom-up’ local and community based adaptation actions with more top-down approaches (Butler et al., 2015; Bennett et al., 2016). Studies on bottom-up adaptation in small island communities have shown that adaptive capacities are also strongly influenced by local social and cultural considerations (Lin et al., 2017; Nunn et al., 2017; Rouse et al., 2017) and the availability of natural resources (Warrick et al., 2017; Cinner et al., 2018). Analyses of adaptation costs and benefits, however, primarily consider the financial aspects of reduction in the exposure and sensitivity of people and infrastructure but do not consider other factors that are more difficult to quantify. These include the immediate and long-term impacts of adaptation responses to the health of the coastal environment, or to the security, livelihoods and well-being of local, vulnerable populations (Jenkins and Jupiter, 2015).
Island communities’ socio-cultural roots, traditional knowledge systems and connections to the natural coastal environment are all aspects that influence their adaptation responses (Fritz and Kalligeris, 2008; Hiwasaki et al., 2015; McMillen et al., 2017). Indeed, in many island communities decisions on adaptation responses are ultimately made at the scale of the village, ward or town and incorporate a multitude of local factors (Nunn et al., 2014). For example, in Samoa, the matai (chiefly) governance system plays the primary role and decision making in community adaptation projects (Crichton and Esteban, 2018). However, there is little understanding of the different factors that can shape local adaptation contexts and responses across multiple locations.
Adapting to coastal hazards is cheaper in terms of avoided damages over the long-term than not adapting (Lincke and Hinkel, 2018). Analyses of global adaptation costs and benefits, however, primarily consider the financial aspects of reduction in the exposure and sensitivity of people and infrastructure but do not consider other factors that are more difficult to quantify. These include the immediate and long-term impacts of adaptation responses to the health of the coastal environment, or to the security, livelihoods and well-being of local, vulnerable populations (Jenkins and Jupiter, 2015).
Understanding the environmental, social and other factors that shape local adaptation contexts is crucial to design effective and locally appropriate adaptation strategies (Brooks et al., 2005; Barnett and O’Neill, 2011; Kelman, 2018). There is now a widespread focus on national adaptation plans and actions (Betzold, 2015; Robinson, 2017). However, these national plans and actions face the challenge of ensuring they are relevant to adaptation actions which mostly occur at the local scale (Lissner et al., 2017). The importance of local factors has been well-studied for the governance and management of marine resources (Heck et al., 2011; Jupiter et al., 2014), but to a much lesser degree for coastal adaptation (Barnett et al., 2014). To date, there is little information or synthesized assessment of the factors that influence local adaptation responses in coastal communities in general (Measham et al., 2011; Lawrence et al., 2015), and rural island communities in particular (Kuruppu and Willie, 2015).
This study addresses this gap by exploring the factors that shape local adaptation contexts and the choices and implementation of adaptation responses in coastal communities in 43 locations across 4 island nations in the Pacific. The goals of the study are to: a) identify factors that determine adaptation needs and contexts in coastal villages and towns and; b) assess which factors influence local preferences for, and implementation of, adaptation responses in these locations.
Section snippets
Study sites
We compiled data on local perceptions of coastal hazards and adaptation responses across 43 rural communities in 4 Pacific Island Nations (Fig. 1). We include coastal communities in 2 provinces in Papua New Guinea, 4 provinces in Solomon Islands, 1 province in Philippines and 2 islands in Samoa (Table 1; SI 3 – Table 1). The locations comprise a varied mix of low-lying atoll islands and coastlines on larger high islands. Most of these locations are towns and villages with less than 500
Coastal hazards
Coastal erosion and loss of land was the most frequently mentioned hazard across all locations (74 %), followed by flooding from extreme high tides, storms and sea-level rise (Fig. 3). Some communities were severely affected by tectonic activity and subsequent tsunamis that drastically modified the coastal environment. Participants in a few locations also mentioned non-hazard related drivers of coastal change, such as excessive sedimentation due to upstream logging, resulting in the damage of
Discussion and conclusions
This study examines local adaption in the context of coastal hazards in 43 coastal towns and villages across four island nations in the Pacific. By integrating data on local-scale hazards, affected assets, and adaptation responses, the study provides insights into multiple factors that determine how communities in rural and remote island settings perceive and adapt to coastal hazards.
Across all our study locations, coastal erosion is an important hazard to communities, more so than flooding in
Funding sources
This work was supported by the Australian Government Department of Foreign Affairs and Trade (DFAT) grant #67196 to the Wildlife Conservation Society (WCS); the Science for Nature and People Partnership; the University of Tokyo; and Waseda University.
Declaration of Competing Interest
None.
Acknowledgements
The authors are most grateful to participants and individuals who helped in all the locations visited. The authors are also very grateful for the constructive comments of the reviewer that helped strengthen the manuscript.
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