Letting wetlands disappear

What happens when wetlands are not protected and conserved? Wetlands perform such vital services for an ecosystem, if they are drained and developed, the knock-on effects are far reaching and long lasting.

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Developments on wetlands and changes to waterflow can impact on nature's ability to deal with excess rainwater. Danube water breaks through dykes to reach the second floor of a hotel built in its floodplain, Romania. (customized)
© Alexandra Tanasie

Life without wetlands?

Wetlands have a vast capacity to absorb chemicals, filter pollutants and sediments, and cleanse millions of litres of life-bearing water. They even act as highly effective sewage treatment works, and are quite capable of breaking down suspended solids and neutralising harmful bacteria. Floodplains alongside rivers naturally absorb rainfall and prevent harmful and potentially devastating floods.

Take these important functions away, and chaos ensues. Polluted water kills fish. Migratory birds abandon the area and either go elsewhere or die out. The disappearance of wildlife eventually leads to people's food supplies being disrupted or destroyed and their livelihoods ruined.

Wetland pollution ultimately brings death and disease to human, plant, and animal communities across the world.

Aral Sea

A case in point is the Aral Sea in central Asia - the most polluted area of water on Earth. Once known as the Blue Sea, it was the world's fourth largest freshwater lake. But in just 30 years, it has shrunk to less than half its size and has become as salty as any ocean.

As the water retracted and evaporated, it left in its wake 3.6 million ha of polluted soil that is swept up by fierce storms and dumped on the surrounding land. Food is now scarce, infant mortality is on the increase and life expectancy is declining - by as much as 20 years, according to some experts.

This ecological catastrophe has been caused by decades of mismanagement and neglect, such as the excessive diversion of water for irrigation schemes, the indiscriminate pollution of rivers that flow into the sea, and the abstraction of vast amounts of water for power generation.

The United Nations, World Bank, and European Union are working with concerned governments in an international effort to restore the Aral Sea's ecological balance, replenish natural resources, and deal with public health, water, pesticides, and other urgent matters before it really is too late.

Watch video of the dramatic evaporation of the Aral Sea from 1973 to 2001 (Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio)

A ship sits abandoned in the Aral Sea, which shrank dramatically after rivers were diverted for irrigation.

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