Ozone hole to start shrinking and will close in 50 years, say scientists

Ozone hole to start shrinking and will close in 50 years, say scientists (2002/09/20)

環保終見成效，南極臭氧空洞50年內"填滿" (2002/09/20)

The hole in the ozone layer over Antarctica is about to start shrinking and will close by 2050, Australian researchers say.

Government scientists in Tasmania said scientific data showed the level of ozone-depleting chlorine in the atmosphere was declining because of the ban on the use of chlorofluorocarbons (CFCs) in fridges and air conditioners, agreed under the Montreal Protocol in 1987.

Dr Paul Fraser, the chief atmospheric research scientist with the Commonwealth Scientific and Industrial Research Organisation, said: "This is big news. We have been waiting for this. We think the trend is definite now. It is very significant."

Dr Fraser said that after the ban was adopted, the atmospheric level of chlorine continued to rise, peaking in 2000. "That was simply due to old refrigerators and old air-conditioners in cars," he says.

Since then, the level had stabilised and was now declining, albeit slowly, Dr Fraser said. He predicted that the hole in the ozone layer would contract steadily from about 2005 and disappear by mid-century, although the ozone would be vulnerable for a decade.

Under the Montreal Protocol, developing countries committed themselves to halving consumption and production of CFCs by 2005 and achieving an 85 per cent cut by 2007. The hole in the ozone layer, which protects Earth from the Sun's ultraviolet rays, was first detected nearly 30 years ago. It was then three times the size of Australia, itself covering nearly 3 million square miles.

(Agencies)

澳大利亞一研究小組9月17日向全世界報告了一條好消息：南極洲上空的臭氧層空洞呈現出縮小的趨勢，預計到2050年之前，這個巨大空洞就可以完全恢復了。

據塔斯馬尼亞的科學家介紹，數據表明在大氣層的消耗臭氧物質中，氯的含量正在下降。這應該歸功于自1987年通過《蒙特利爾議定書》以來，人們在冰箱和空調設備中對吞噬臭氧的罪魁禍首--氟氯碳化物(CFCs) （一種含有氯、氟、碳三種元素的有機化合物，俗稱"氟里昂"）實行了全面的控制。

澳洲科學及工業研究機構（CSIRO）大氣研究的主要負責人保羅·弗雷澤博士說："這是個激動人心的消息。我們一直盼望著這一天。毫無疑問現在我們正在朝著這個方向前進，這個意義非比尋常。"

弗雷澤博士還介紹說，即便在控制使用氟里昂后，大氣中的氯含量還是在不斷攀升，并在2000年達到了頂峰。他說："這主要是由于冰箱和車載空調的普及所造成的。"

直到2000年以后，氯氣含量才停止增加并呈現緩慢下降的趨勢。弗雷澤博士預測說，臭氧空洞將于2005年開始收縮變小，直到本世紀中期被完全填滿，但填滿后仍有十年屬于比較容易被破壞的過渡期。

根據《蒙特利爾議定書》，到2005年，發展中國家氟里昂產品的消耗量和生產量都將減半，到2007年則減少85%，以此來保護我們的大氣層。人們是在約30年前發現這個臭氧層空洞的。而臭氧層的作用主要是保護我們不直接受到太陽的紫外線輻射。30年來，臭氧層的這個空洞面積達到澳大利亞本土面積的3倍。而澳大利亞的本土面積為300萬平方英里。

(中國日報網站譯)

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