ENVIRONMENT: NASA Concludes Artificial Emissions Cause Ozone Hole

• by IPS Correspondents (washington)
• Monday, December 19, 1994
• Inter Press Service

WASHINGTON, Dic 19 (IPS) - Three years of targetted research by the U.S. National Aeronautics and Space Administration (NASA) have provided "conclusive evidence" that human-made chlorine in the stratosphere is the cause of the Antarctic ozone hole.

At a press conference at their headquarters just outside Washington, NASA scientists stressed there could no longer be any dispute about the role of chlorofluorocarbons (CFCs) -- artificial products used in electronics and refrigeration systems -- in the depletion of the protective ozone layer around the Earth.

"These new results confirm our theories about CFCs," said Mark Schoeberl, one of the scientists who took part in NASA's Upper Atmosphere Research Satellite (UARS) project.

"The detection of stratospheric fluorine gases, which are not natural, eliminates the possibility that chlorine from volcanic eruptions or some other natural source is responsible for the ozone hole."

He said the Research Satellite project has also detected hydrogen fluoride -- a product of the chemical breakdown of CFCS -- in the stratosphere where the Earth's ozone layer is found.

"Hydrogen fluoride has no natural source," said Anne Douglass, the Deputy Project Scientist.

The ozone layer protects life on the Earth's surface by blocking out damaging ultraviolet radiation from the sun. Exposure to such radiation weakens the immune system and can cause cancer and cataracts in animals, including humans.

It also destroys plankton, microorganisms in the ocean which form the base of the marine food chain.

The link between CFC emissions from refrigerants, spray cans, and foam packaging and ozone depletion over the Antarctic was first put forward in the 1980s. Most countries signed the Montreal Protocol in 1987 which called for a gradual phase-out of ozone- destroying chemicals.

Amid mounting evidence that ozone was being depleted at a faster rate than expected, signatories agreed two years to ago to push forward the phase-out date to the end of 1995.

The most dramatic ozone loss has taken place each winter over the Antarctic, although ozone thinning during the winter months over much of the northern hemisphere has become increasingly worrisome since the late 1980s.

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