Ocean Action Hub

The paradox between sedentary humans and dynamic shores

The coast forms a dynamic, interface zone where the land and sea realms meet and is characterised by some of the world’s most sensitive ecosystems, such as mangroves, wetlands, coral reefs, dunes and beaches. Unlike watersheds, coastal areas have no natural, clear nor precise boundaries. They are subjected continuously to the natural processes of weathering, coastal erosion, coastal flooding and sea-level rise. The impacts of these processes and events vary from one coastal zone to another depending on the geology and geomorphology of the coast and its exposure to natural processes.

As the interface between land and sea, coastal areas perform many essential functions like natural protection against storms, regulation of water exchange between land and sea, regulation of the chemical composition of sediments and water, storage and recycling of nutrients and maintenance of biological and genetic diversity. From socio-economic perspectives, coastal zones are important settlement areas which play a critical role in the wealth creation of many nations as they offer access to fisheries and commerce, proximity to rich agricultural lowlands, aesthetic landscapes as well as cultural and recreational opportunities.

On a global level, coastal zones comprise 20% of the Earth’s surface, yet they host approximately 50% of human population within 200 km of the sea (Ngoran and XiongZhi, 2015). Nearly 600 million people live in coastal areas that are less than 10 m above sea-level, and it is expected to increase by 50% over the next 25 years (McGranahan, Balk and Anderson, 2007). This rapid urbanisation – coupled with the fast-growing economy of coastal areas, their changing land use and land cover, the deterioration of ecosystems and runoff from upland land uses – is making coastal zones vulnerable to pollution, habitat degradation, overfishing, invasive alien species, severe weather events and coastal hazards, such as storms, coastal flooding and coastal erosion (Creel, 2003).

As the globe’s temperature rises more than it would naturally (Solomon et al., 2007), other climate changes have already started to generate additional pressures and adverse consequences on coastal environments due to climate and sea-level related hazards. All coastal zones are, to some extent, under threat of accelerated sea-level rise (SLR) and climate change; however, the effects are not uniform as they vary considerably regionally and over a range of temporal scales (IPCC, 2007). Even in highly-developed nations, unequal distribution of wealth along the coastal areas is leading to significant differences in social vulnerability (Martinich et al., 2013) but societal understanding of the distributional and equity implications of SLR impacts and adaptation actions remains limited. In many developing countries, the exposure of low-lying coastal urban and rural areas and of their populations to coastal flooding, storm surge, inadequate sanitation facilities and limited access to essential resources is all too common. When combined with the exposure to physical threats, such as those emerging or aggravated by climate change (IPCC, 2012), this phenomenon is more pronounced in densely-populated coastal areas where the high population growth rate places increasing stress on the coastal ecosystems (World Bank, 2017).

Given the growing challenges expected in coastal areas from accelerated sea-level rise, climate change and urbanisation, there is an urgent need for multidisciplinary long-term interventions and sustainable management to prepare for and minimise the growing risk with the ultimate aim of

What you will find in this publication

The objective here is to present how various hazards affecting coastal areas impact the local communities in selected countries, and how these matters are being managed by national, regional and local governmental institutions. This analysis was conducted for nine countries, namely Bangladesh, Costa Rica, Gabon, Ghana, Lebanon, Myanmar, Senegal, Uruguay and Venezuela. The information is organised in nine national chapters with a similar structure: first, a general presentation of the country and its coastal zone; secondly, an overview of the main natural hazards affecting their coasts; then, the management of such hazards is described at national and local level; this is followed by a description of concrete adaptation measures; and, to conclude, some final remarks to reinforce key ideas or set guidelines for future governance in the country.

Read the full article here: https://unesdoc.unesco.org/ark:/48223/pf0000378081

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Intergovernmental Oceanographic Commission
Thematic Area: 
Marine ecosystems