Background and concepts

Abstract

The coast is one of the vastest, active and varied of Earth's geomorphological features. It may be simply defined as the physical interface between land and sea, that area where atmospheric, terrestrial and marine processes act collectively to produce distinctive landforms. It provides a dynamic canvas for a multitude of human activities, and has done so ever since the early history of mankind. Man's relationship with the sea has always been complex and tumultuous. It serves as a divisive force, maintaining distances between cultures across opposing sides of the sea, whilst at the same time serving a connecting function, as a medium for communication, for the spread of civilization, and for commerce and trade. It is a constructive force, gently and gradually creating complex landforms and nourishing fragile ecosystems. Yet its destructive force has also been all too evident throughout history, with vast human tragedies unfolding in a short span of time. The coastal region has very often been the focus of this drama. The drama continues to unfold in the present day. Oceans and seas cover 71 % of the Earth's surface, and the world's total coastline exceeds 1.6 million kilometres (Burke et al., 2001). Coasts harbour over half the world's population in less than 0.05% of the global terrestrial land area, and as a result, have been extensively modified and impacted upon by the broad range of human activities occurring therein. The socio-cultural dimension is of immense importance in any analysis of the coast. One conclusion of the landmark Millennium Ecosystem Assessment published in 2005 was that coastal lands produce disproportionately more services relating to human well being than most other systems, even those covering larger total areas. The diversity of habitats in coastal areas, ranging from wetlands and coral reefs to beaches, dunes and estuaries, host a variety of functions that are of direct benefit to humankind. It is therefore not surprising that coastal communities end to aggregate close to systems providing such services. For some communities, the maintained provision of ecosystem services is literally a matter of life or death, as these provide subsistence resources on which their livelihood depends. For others, coastal areas provide employment and income, often sustaining national economies. The economic significance of coastal resources across the world is immense. Different ecosystems directly and indirectly generate billions of pounds worth of income annually. In a seminal work on the valuation of biodiversity, Costanza et al. (1997) showed that while the coastal zone covers only 8% of the world's surface, the goods and services provided by it are responsible for approximately 43% of the estimated total value of global ecosystem services.