Over half of the world's coastlines face environmental pressures from population growth and economic development. A rising tide of pollution threatens the seas. Coastal and ocean fisheries—containing most of the world's wild food harvest—are fast being depleted.

About half of all coastal areas face moderate to severe environmental stress from population growth and development pressures, according to a 1995 review by the World Resources Institute (WRI) (26, 274). The coastlines of most developed countries—particularly Japan, Australia, the US, Europe, and the European part of Russia—suffer degradation. Developing countries fare little better.

About half the world's population occupies a coastal strip 200 kilometers wide—only 10% of the world's land surface. Two-thirds of the world's people live within 400 kilometers (240 miles) of a seacoast. Given such population density, human activities are eroding close to 70% of the world's beaches at greater than natural rates (4). Erosion is a natural process, but it can be made worse by coastal development such as construction, urban expansion, sand dredging, and harvesting coral reefs for building material (102, 230, 255).

The world's coastal wetlands are disappearing. Around the world, about 182,000 square kilometers of mangrove wetlands provide a habitat for over 2,000 species of fish, shellfish, invertebrates, and plants. In the past century over half the world's original mangrove area has been destroyed or degraded, been converted to agricultural land or fish ponds, or fallen victim to urban and industrial development (102).

Seagrass beds also are vanishing. These underwater ocean meadows support a wide variety of commercially valuable species of fish and shellfish. Although no overall estimates of damage are available, these ecosystems appear to be shrinking near virtually all inhabited coastal areas (79).

D. Hinrichsen

Coasts along the Philippine island of Negros suffer from erosion caused by rising seas and poor land-use practices. Over half of the world's coastlines face environmental degradation from population growth and development.

Development activities are destroying most of the world's coral reefs. Of the world's 600,000 square kilometers of reefs in tropical and semi-tropical seas, scientists estimate that 70% could be lost within 40 years (102, 251). Coral reefs are being buried by sediment washed off the land, poisoned by industrial and agricultural chemicals, reduced to rubble by fishermen using dynamite, damaged by boat anchors and careless divers, excavated for use as building material, and bleached white by warming ocean temperatures.

Coral reefs provide humankind with many benefits. Reefs support upwards of 1 million species. They provide feeding, breeding, and nursery areas for fish and shellfish and offer humanity a pharmacopoeia of potential medicines. They buffer waves and protect shorelines from storms. Coral reefs have been valued at US$47,000 per square foot of shoreline for their protection functions alone (40).

In 1997 a global effort to assess the status of coral resources was carried out by Reef Check, organized by Hong Kong University. The study engaged professional and recreational divers to chart the health of 300 coral reefs in 30 countries. Less than one-third of all reefs studied had healthy, living coral cover (101). According to a 1998 assessment by WRI, the world's most degraded reefs are in Southeast Asia and the Caribbean (24).

Few people recognize how important reefs are. In Indonesia, for example, less than half of respondents surveyed in 2000 viewed coral reefs as a marine resource. In urban areas less than one-third of respondents knew that coral reefs were declining. Even in coastal communities, despite widespread reliance on fish, few people connected healthy coral reefs with the supply of food from the sea (211).