Population growth threatens East Asian coasts

Posted: 16 October 2006

Growing populations and their migration to coastal areas, dynamic economic growth, and rising global demands for fishery and aquatic products have combined to exert tremendous pressure on East Asia's marine environment and coastal resources, according to a new UN report.

A combination of high population density and growth, rapid industrialization and urbanization, as well as poverty has accelerated environmental degradation through the removal of coastal habitats, leading to a substantial increase in marine pollution in East Asia.

Blast fishing, Bohol, Philippines© ReefBase
Blast fishing, Bohol, Philippines© ReefBase
Blast fishing, Bohol, Philippines.© Reefbase
In most of the countries, more than 60 per cent of some habitats, particularly mangroves and coastal wetlands, have been modified causing severe loss of biodiversity. About three-quarters of known or suspected species extinctions have occurred on isolated islands in the region. Estimates of the economic costs of environmental degradation in Asia range from 1 - 9 per cent of Gross National Products.

In addition, natural hazards (e.g., cyclones, floods, storm surges, earthquakes, droughts, landslides, and volcanic eruptions) that regularly affect the region have extremely damaging impacts on both the environment and the fragile economies.

The report, The State of the Marine Environment, published by the UN Environment Programme, notes that the sources of pollution and their contribution to the national aquatic environments in the South China Sea countries identified in the 1990s remain basically the same today. However, with the rapid pace of industrialization in the region, fisheries, mangrove swamps, reefs, coastal wetlands and sea grass beds are all threatened, the report says.

"Studies warn that at the current rates of degradation, the region's coral reefs face total collapse within 20 years, while mangroves could be gone within 30 years," it adds. Large areas of mangrove in Indonesia and Vietnam have been removed to make way for shrimp farms or to convert into farmland.

Some of the main causes of marine pollution in the region are from untreated sewage, and from rubbish and fertilizers - problems also faced in other regions.

The current level of sewage treatment in the region is low, with large quantities of sewage discharged into the environment. For example, in the South China Sea, China, Indonesia, Malaysia, Philippines, Thailand, and Vietnam release a minimum of about 430,000 tonnes/yr of biochemical oxygen demand (BOD) into aquatic systems interacting with the sea. BOD is a measure of the amount of oxygen used by the micro-organisms in breaking down the sewage into stable compounds.

"Despite international agreements, we keep pumping raw sewage into the sea," commented Veerle Vandeweerd, coordinator of the U.N.'s Global Programme of Action for the Protection of the Marine Environment from Land-Based Activities. "We keep on using more and more plastic, and at the end of the day it all ends up in the sea, and plastic cannot be degraded so it stays there," she said.

Emerging issues in the region include transboundary movement of pollutants, coral bleaching, climate change through global warming, and electronic waste (e-waste).The impacts of transboundary movement of pollutants and e-waste will be felt in the coastal and marine waters of the region in the next decade.

The natural resource base of coastal areas worldwide is under growing pressure, says UNEP. Some 70 per cent of mega-cities with populations over 8 million are located on the coast; in some developing countries, as much as 90 per cent of sewage is dumped directly into the sea; half the world's coastal wetlands have disappeared.

In addition, 38 per cent of the global human population lives along a narrow fringe of coastal land, which constitutes only 7.6 per cent of the earth's total land area. Coastal populations are beneficiaries of this resource base and therefore vulnerable to pressures on it: tourism, fisheries and the health of the local population can all be undermined by pollutants originating from the land.