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Management of the Coastal Zone

Planning and protection

Each year an estimated 46 million people risk flooding from storm surges. Coasts in many countries currently face severe problems of sea-level rise as a consequence of tectonically and human-induced subsidence. Climate change will exacerbate these problems, leading to potential impacts on ecosystems and human coastal infrastructure. Large numbers of people also are potentially affected by sea-level rise - for example, in the absence of adaptation measures, tens of millions of people in Bangladesh would be displaced by a 1 m increase in sea-level (the top IPCC Working Group I estimate for 2100). A growing number of extremely large cities are located in coastal areas, which means that large amounts of infrastructure would also be affected.

Beaches, dunes, estuaries, and coastal wetlands adapt naturally and dynamically to changes in prevailing winds and seas, as well as sea-level changes. In areas where infrastructure development is not extensive, planned retreat and accommodation to changes may be possible. It may also be possible to rebuild or relocate capital assets at the end of their design life. In other areas, however, accommodation and a planned retreat are not viable options. Protection using hard structures (e.g., dikes, levees, floodwalls, and barriers) and soft structures (e.g., beach maintenance, dune restoration, and wetland creation) will be necessary.