ENVIRONMENT REPORT - Shrinking Ozone Hole over Antarctica

ENVIRONMENT REPORT - November 1, 2002: Shrinking Ozone¹ Hole over Antarctica

By Cynthia Kirk

This is the VOA Special English ENVIRONMENT REPORT.

Australian researchers say the hole in the ozone layer over Antarctica probably would start closing within five
years. They say it may be completely closed within fifty years. The ozone layer protects the Earth from
dangerous radiation from the sun. The hole in the ozone layer was discovered over Antarctica almost thirty years
ago. At the time, it was three times the size of Australia.

Paul Fraser is chief researcher of the Commonwealth² Scientific and Industrial Research Organization in
Australia. Mister Fraser led a study about the ozone layer for the United Nations and the World Meteorological
Organization.

The report found that ozone-destroying gases in the upper atmosphere had been at or near their highest levels in
the year two-thousand. But since then, there has been continued progress toward recovery of the ozone layer.
Satellite information showed levels of ozone-destroying gases in the atmosphere are slowly decreasing.

Chlorine from chlorofluorocarbons, or C-F-C’s, is responsible for destroying part of the ozone layer over
Antarctica. C-F-C’s have been widely used since the nineteen-thirties in cooling devices such as refrigerators
and air conditioners. C-F-C’s remain in the atmosphere for years.

Government scientists say the level of chlorine in the atmosphere is decreasing because of restrictions³ on the use
of chlorofluorocarbons. The chemicals were restricted under an international agreement called the Montreal
Protocol⁴ in nineteen-eighty-seven.

Under the Montreal agreement, developing countries promised to cut their use of chlorofluorocarbons in half by
the year two-thousand-five. They also agreed to an eighty-five percent cut by the year two-thousand-seven.

The ozone hole forms over Antarctica in August and September, when the temperatures are coldest. Thin clouds
form in these cold conditions. Chemical reactions on the cloud particles help chlorine-based chemicals to rapidly
destroy ozone. By early October, temperatures begin to warm and the ozone layer begins to recover.

At its largest this year, the ozone hole covered more than fifteen-million square kilometers. That is down from an
average of twenty-three-million square kilometers over the last six years.

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

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1 ozone   

n.臭氧，新鲜空气

参考例句：

• The ozone layer is a protective layer around the planet Earth.臭氧层是地球的保护层。
• The capacity of ozone can adjust according of requirement.臭氧的产量可根据需要或调节。

2 commonwealth   

n.共和国，联邦，共同体

参考例句：

• He is the chairman of the commonwealth of artists.他是艺术家协会的主席。
• Most of the members of the Commonwealth are nonwhite.英联邦的许多成员国不是白人国家。

3 restrictions   

约束( restriction的名词复数 )； 管制； 制约因素； 带限制性的条件（或规则）

参考例句：

• I found the restrictions irksome. 我对那些限制感到很烦。
• a snaggle of restrictions 杂乱无章的种种限制

4 protocol   

n.议定书，草约，会谈记录，外交礼节

参考例句：

• We must observe the correct protocol.我们必须遵守应有的礼仪。
• The statesmen signed a protocol.那些政治家签了议定书。