The sandy beaches, rocky shorelines, water, and waves of coastal areas are perhaps most readily associated with recreation and natural beauty. Coastal ecosystems, however, have an economic value beyond their aesthetic benefit, supporting human lives and livelihoods through the provision of food and materials, nutrient cycling, waste processing, and other essential goods and services.
By one estimation, the combined global value of goods and services from coastal ecosystems is over US$12 trillion annually (1997 dollars; Costanza et al., 1997)--a figure larger than the United States' Gross Domestic Product in 2004. Yet many of these services are not explicitly priced in world markets, leaving governments, businesses, and individuals with few incentives to maintain them.
Ecosystem Services and The Relative Contributions of Different Coastal System Subtypes.
Larger circles represent a higher relative magnitude.
Source: Millennium Ecosystem Assessment.
The current state of coastal ecosystems was thoroughly documented in the Millennium Ecosystem Assessment (MA), a five-year study involving more than 1,300 experts in 95 countries. The study identified coastal ecosystems as "among the most productive yet highly threatened systems in the world" (MA, Coastal Systems). Population growth and technological advances have fueled an unprecedented and unsustainable exploitation of coastal resources in the past century. The MA revealed dramatic declines in the overall health of many different types of coastal ecosystems: coral reefs, mangroves, and estuaries (all discussed below) as well as marshes, dunes, deltas, seagrass beds, and kelp forests.