Environmental Change in Coastal Areas and Islands

Abstract

The environments of coastal areas are more changeable than many because of their location at the interface of the lithosphere, hydrosphere and atmosphere. Coastal areas are affected by changes in any of these, ranging from regular minor change linked to short-term perturbations to rapid change associated with extreme events. Syntheses of coastal environmental changes have emphasized the uniqueness of the processes involved in these locations (Bird, 1985. Harff et al., 2007; Woodroffe, 2002). Islands exhibit considerable environmental diversity, depending largely on their size. In evaluating the causes of environmental changes, most smaller oceanic islands can be regarded as entirely coastal while most parts of larger oceanic islands will typically experience environmental changes arising from maritime influences (Menard, 1986; Nunn, 1994). Sea-level change is perhaps the most important cause of long-term environmental change in coastal areas and islands (Tooley and Shennan, 1987). Late Quaternary sea-level oscillations transformed such environments, often to the point of shifting coastlines considerable distances laterally or causing islands to alternately emerge (as sea level fell) or become submerged (as sea level rose). Future sea-level rise will impact coastal areas and islands profoundly. In acknowledgement of their often abundant food resources, modern humans ('Homo sapiens') have been routinely interacting with coastal areas for more than 10,000 years, something that increased in most such places during the Holocene as population densities rose and sea-level rise reduced habitable coastal area (Nunn, 2007a). Within the past few hundred years, more people have come to occupy many coastal areas than can be sustained by their environments. High coastal population densities have led to a range of deleterious environmental impacts that will be exacerbated in the future by further population concentration in such areas and by climate change (Nicholls et al., 2007).