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Gornitz, V., 2005: Natural hazards. In Encyclopedia of Coastal Science. M.L. Schwartz, Ed., Encyclopedia of Earth Sciences Series. Springer, pp. 678-684.
Natural hazards are physical phenomena that expose the coastal zone to risk of property damage, los of life, or environmental degradation. Rapid-onset hazards last over periods of minutes to several days. Examples include major cyclones, accompanies by high winds, waves, surges and tsunamis — giant sea waves set off by earthquakes, volcanic eruption, or submarine landslides. Slow-onset hazards develop incrementally over longer time periods. Examples include coastal erosion and sea-level rise.
The vulnerability of the world's coastlines to natural hazards varies considerably, because climate, tectonism, and other physical variables, such as bathymetry, shelf width, landform, lithology and coastal configuration change from place to place.
Rapid coastal development and urbanization expose increasing numbers of people to natural hazards in a dynamic and unstable environment. Globally, approximately 400 million people live within 20 m of sea level and within 20 km of a coast. In the United States, over 139 million people (53% of the population) live in coastal counties. Anticipated climate changes will greatly amplify risks to coastal populations. By the end of this century, rise in sea level by 2-5 times present rates could lead to more frequent flooding and inundation of low-lying regions, worsening beach erosion, as well as loss of ecologically productive coastal wetlands and saltwater intrusion into coastal aquifers and estuaries.
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