Pollution Threatens Water Cycle

This is the VOA Special English ENVIRONMENT REPORT.

A new report says pollution caused by people may be seriously threatening the Earth's water supply. Scientists say small particles of soot and other pollutants in the air could be reducing rainfall and world water supplies.

The findings were part of a new study by researchers at the Scripps Institution of Oceanography at the University of California, San Diego. The report is based on results gained during the international Indian Ocean Experiment, known as INDOEX.

The INDOEX project involved more than one-hundred-fifty scientists from eight countries. It used satellites, aircraft, balloons, ships and scientific centers on land. The twenty-five-million dollar project was designed to study chemical pollution over the Indian Ocean. It also examined the environmental effects of aerosol pollution in the area.

Aerosols are mostly made up of small particles of black carbon that enter the atmosphere as a gas. These gases are caused by burning fossil fuels such as oil and coal, and by burning trees and plants. Researchers say aerosols in the atmosphere may be slowly reducing the water supplies on which people and animals depend.

Scripps scientists V. Ramanathan and Paul Crutzen led the INDOEX study. They say aerosols are reducing the amount of sunlight going into the ocean. As sunlight heats the ocean, water escapes into the atmosphere and falls as rain. However, scientists say aerosols are blocking large amounts of sunlight. They say this reduction may be weakening the water cycle of the planet.

The scientists also say the aerosol particles may be suppressing rain over polluted areas. Aerosols can limit the size of rain droplets inside clouds. Scientists say a reduction of rain and snowfall caused by aerosol pollutants could affect the renewal of the world's major fresh water supplies. They say it could affect lakes, groundwater supplies, ice and snowfall in mountain areas.

A report last month by the United Nations Population Fund found that water use has increased by six times during the past seventy years. Scientists say that if usage continues at its current rate, the fresh water supply could become the most serious problem facing the world.

This VOA Special English ENVIRONMENT REPORT was written by Cynthia Kirk.