科学家们指出，在很大程度上归功于1987年的《蒙特利尔议定书》，对南极上空臭氧层的侵蚀放慢。(© AP Images)

一项研究显示，南极（Antarctica）上空的臭氧层破洞终于开始弥合。

这项研究指出，臭氧层——对致癌的太阳紫外线具有抵挡作用的地球大气保护层——的破洞正在缩小，在一年中形成的时间推迟。在国际社会共同采取行动前，制冷剂，即氯氟烃（CFC），曾在不断侵蚀臭氧层。因此，这项最新发现堪称是国际社会在解决人类导致的环境问题上打赢的一场胜仗。

研究报告的主要执笔人、麻省理工学院（MIT）科学家苏珊·所罗门（Susan Solomon）说，“这不仅仅是病人病情有所缓解，而是他确实在开始复元。这个病人在我们大量释放氯化学物质的80年代病情非常严重。”

她表示，在解决其他环境问题上，例如人类造成的气候变化，“我认为有极大理由充满希望”。

“一个了不起的成就”

1987年，国际社会谈判达成被视为是最成功的有关全球环境问题的条约《蒙特利尔议定书》（Montreal Protocol），致力于逐步取消多种破坏臭氧层的化学物质的使用。由于这项条约，厂家公司必须开发不损害臭氧层的新产品。

虽然臭氧破洞要到大约2050年才能完全弥合，但所罗门说，开始弥合的时间比科学家预期的要早。

这项研究发现，自从2000年以来，在最关键的9月份，臭氧洞缩小了大约450万平方公里，也就是缩小了大约五分之一。

在上个世纪70年代，科学家曾对可能出现的灾难性后果发出警告：臭氧层减少意味着全球患皮肤癌的人数会急剧增多，作物会被破坏，并且会产生其他一系列问题。

在上个世纪80年代初，南极上空的臭氧层开始在10月——而后在9月和10月——出现破洞，使问题变得更加紧迫。

南极臭氧破洞犹如一个巨大的伤口，立即引起全球关注。

马里兰州大学（University of Maryland）的罗斯·萨拉维契（Ross Salawitch）说，“所以说，历经28年后，《蒙特利尔议定书》展示出世界所能取得的成就。我要称它是了不起的成就。”

虽然今天使用的化学制冷物质氢氟碳化物（HFC）或许不会像其前代在70年代那样严重损害臭氧层，但它们仍然是严重的温室气体。为提高空调制冷系统效率和更有利于保护环境，中国、加拿大、沙特阿拉伯和美国正在致力于通过“先进制冷挑战”项目，限制氢氟碳化物。

Bright spot: Antarctica’s ozone hole is starting to shrink

Antarctica’s ozone hole finally is starting to heal, a new study finds.

In a triumph of international cooperation over a man-made environmental problem, research shows that the hole in the ozone layer, Earth’s atmospheric shield that helps protect the planet from the sun’s cancer-causing ultraviolet rays, is getting smaller and forming later in the year. Refrigerants called chlorofluorocarbons, or CFCs, had been eating away at the ozone layer, before the international community took action.

“It isn’t just that the patient is in remission,” said Susan Solomon, MIT scientist and the lead author of the study. “He’s actually starting to get better. The patient got very sick in the ’80s when we were pumping all that chlorine” into the atmosphere.

“I think it’s a tremendous cause for hope” for fixing other environment problems, such as man-made climate change, she said.

‘A remarkable achievement’

In 1987, countries negotiated the Montreal Protocol, considered the world’s most successful global environmental treaty, to phase out many of the ozone-depleting chemicals. As a result, companies had to develop new products that didn’t harm the ozone layer.

The hole won’t be completely closed until about 2050, but the healing is appearing earlier than scientists expected, Solomon said.

The hole has shrunk by about 4.5 million square kilometers in the key month of September since 2000 — a decline of about one-fifth, the study found.

In the 1970s, scientists warned of potentially catastrophic effects: A depleted ozone layer meant dramatic worldwide increases in skin cancer, crop damage and a host of other problems.

In the early 1980s, a hole in the ozone layer over Antarctica started appearing in October — and then September and October — making the problem more urgent.

The Antarctic ozone hole was the gaping wound that grabbed the world’s attention.

“So, 28 years after the agreement, the Montreal Protocol shows what the world can accomplish, said Ross Salawitch of the University of Maryland. “I’d say this is a remarkable achievement.”

Today’s chemical refrigerants, hydrofluorocarbons or HFCs, may not damage the ozone layer as much as their predecessors in the 1970s, but they remain potent greenhouse gases. To make air conditioning more efficient and better for the environment, China, India, Canada, Saudi Arabia and the United States are looking to limit HFCs through the Advanced Cooling Challenge.