Interdisciplinary assessment of the risks and impacts associated with erosion, flooding, and sea-level rise in coastal natural world heritage sites

Abstract

Natural World Heritage Sites (NWHS) are social-ecological systems of Outstanding Universal Value and are increasingly threatened by natural and anthropogenic pressures. 88 (42%) of 210 NWHS worldwide are coastal, and their risks from coastal hazards will change with climate change and sea-level rise. This thesis aims to analyse the risk from past, present and future erosion and flooding on coastal NWHS by adopting a multi-scalar interdisciplinary mixed quantitative and qualitative approach to respond to the wicked problem at hand. Using consistent remote sensing data, a global analysis of historical exposure to shoreline change from 1984 to 2016 was undertaken. Significant erosions and accretions occurred within 52 (59%) coastal NWHS, these being composed of low-lying unconsolidated sediments in vegetated tidal systems and inlets. The most stable soft coasts were associated with the natural protection of coral reef ecosystems. Significant shoreline changes were associated with a range of natural and human-induced drivers situated outside or within the sites’ boundaries, such as the redistribution of sediments, the opening of inlets, sand nourishment and sediment starvation due to dams. Interviews with a global sample of NWHS managers were conducted to assess their perceptions of shoreline change impacts on the sites, and the implemented adaptation measures. Managers perceived that present shoreline change adversely affects NWHS communities and that potential future exacerbation of erosion and flooding by sea-level rise and climate change threaten the natural values and human benefits of NWHS. Although some NWHS managers were aware of multi-decadal coastal changes, most lacked comprehensive and systematic data on erosion and flooding at their sites. Several adaptation measures have been implemented along coastlines prone to particularly adverse impacts of erosion and flooding in high-income countries. However, systematic preparation for the potential increase of coastal changes is lacking across most NWHS. A case study analysing shoreline change perceptions of Imraguen coastal communities in the Banc d’Arguin National Park NWHS (Mauritania, Africa) indicates that erosion and flooding presently impact the indigenous communities' livelihood and traditional practices through the breaching of barriers, creation of channels, flooding and submergence of low land. These impact their human capital (health and capacity to work), social capital (culture, shared values and behaviours), natural capital (coastal land) and physical capital (accessibility and transportation of goods and people). In the future, improved emergency preparedness and strategically planned retreats supported by managers and local authorities represent better adaptive responses for the communities than forced relocations and retreats experienced at present. There is currently no mechanism in place to propose those responses. Greater multi-scalar, interdisciplinary, and mixed-method approaches can help identify risks and integrated adaptation measures and emergency responses in NWHS. Further research to assess complex risks from different drivers will help develop and design these responses.

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Identifiers

ORCID for Salma Sabour: orcid.org/0000-0003-2697-2994

ORCID for Ivan Haigh: orcid.org/0000-0002-9722-3061

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