PBS高端访谈:南极臭氧层空洞有所缩小

 　　HARI SREENIVASAN, PBS NEWSHOUR WEEKEND ANCHOR: Scientists studying climate change in Antarctica reported this week that the hole in the protected ozone¹ layer of the earth's atmosphere has shrunk. The discovery of the hole in the mid-1980s led to a worldwide facing out of ozone-depleting chemicals known as chlorofluorocarbons, which had been used in products ranging from hairspray to air conditioners.

　　Joining me now from Denver to discuss how that policy has worked and how the hole is healing is Alexandra Witze, a reporter for "Nature Magazine".

　　So, I guess the first thing is, is that this is sort of a success story. I mean, humanity actually together, did something and that we're seeing some results.

　　南极臭氧层空洞有所缩小

　　ALEXANDRA WITZE, NATURE MAGAZINE: Yes, it's a pretty rare environmental success story. I mean, you can say that we caused the problem in the first place by emitting all these chemicals, but the world basically got together and in 1987, put together a global treaty called the Montreal Protocol² that essentially³ banned these chemicals that had been chewing away at the ozone layer.

　　So, yes, it's good news. It's a good story for once in the environment.

　　HARI SREENIVASAN: And this — I should be sure to mention that this doesn't mean that everything is fixed⁴. This is a long slow process. They're just finding that it's gotten better.

　　ALEXANDRA WITZE: Sure. What the scientists announced this week is that year over year, on average, the ozone hole is getting just a little bit smaller every year. From 2000 to 2015, it shrank by 4 million square kilometers over that whole period. It doesn't sound like a whole lot, but it means that overtime⁵, this opening that is letting all these nasty ultraviolet radiation is gradually shrinking and that's good news for us here in earth.

　　HARI SREENIVASAN: This is the hole that they measure is primarily over the South Pole. The ozone layer, of course, is over the entire planet, right?

　　ALEXANDRA WITZE: Yes. So, ozone is kind of like a protected shield in the upper atmosphere. You can think of it like a blanket enveloping⁶ the earth and protecting us from these ultraviolet rays. What happens is these chemicals that are emitted get caught up into the upper atmosphere and they get transported towards the Polar Regions. And over the South Pole, they start to trigger these chemical reactions that chew away at this protected blanket.

　　So, even though ozone is all around the planet, and even though we're emitting stuff, you know, around cities, what happens is these chemicals get transported down to the South Pole. And so, that's where we see the hole opening up every year.

　　HARI SREENIVASAN: And last year, or maybe it was a year before, I can't remember, some volcanic⁷ eruptions⁹ actually had a negative impact on this. So, even though we weren't cranking out the hairspray cans, the earth still has the ability to disrupt the ozone layer.

　　ALEXANDRA WITZE: Yes, this was one of the really puzzling things last year. In October, scientists saw one of the biggest ozone holes on record, and they didn't really understand why, because we've been phasing out these chemicals and everything seemed to be on track to healing. It turned out it was a volcano to blame. There was an eruption⁸ in Chile in April of last year, and basically, the particles that this eruption put out go into the upper atmosphere and they also start to trigger the same ozone-destroying reactions.

　　So, even though we've been cleaning up our act, volcanoes can still get in there and cause trouble as well.

　　HARI SREENIVASAN: It seems that perhaps it's the narrow focus of the chemicals in terms of why this worked. I mean, because a lot of people will ask, well, why can't humanity get together like this around climate change and carbon emissions¹⁰ overall?

　　ALEXANDRA WITZE: Yes, this was sort of a tractable¹¹ problem, as environmental problems go. I mean, there is a huge industry, of course, that made these air conditioners and refrigerants that had these chemicals. But basically, technology came up with alternatives. And so, we were able to swap¹² out the air conditioners and the refrigerants that had these nasty ozone-destroying chemicals with ones that didn't.

　　So, that was a fairly easy problem — not easy but a doable problem to solve. It's harder with greenhouse gasses and carbon pollution because they're so many sources, right? Power plants, deforestations, cement production. It's not just one thing to swap out for the climate change and carbon emissions.

　　So, that's — there might be lessons to learn, I think, from the ozone success story but it's going to be a lot bigger challenge with climate change.

　　HARI SREENIVASAN: All right. Alexandra Witze from "Nature" — thanks so much for joining us.

　　ALEXANDRA WITZE: Thank you.

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 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。

3 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

4 fixed   

adj.固定的，不变的，准备好的；(计算机)固定的

参考例句：

• Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗？
• Once the aim is fixed,we should not change it arbitrarily.目标一旦确定，我们就不应该随意改变。

5 overtime   

adj.超时的，加班的；adv.加班地

参考例句：

• They are working overtime to finish the work.为了完成任务他们正在加班加点地工作。
• He was paid for the overtime he worked.他领到了加班费。

6 enveloping   

v.包围，笼罩，包住( envelop的现在分词 )

参考例句：

• Always the eyes watching you and the voice enveloping you. 那眼睛总是死死盯着你，那声音总是紧紧围着你。 来自英汉文学
• The only barrier was a mosquito net, enveloping the entire bed. 唯一的障碍是那顶蚊帐罩住整个床。 来自辞典例句

7 volcanic   

adj.火山的；象火山的；由火山引起的

参考例句：

• There have been several volcanic eruptions this year.今年火山爆发了好几次。
• Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。

8 eruption   

n.火山爆发；（战争等）爆发；（疾病等）发作

参考例句：

• The temple was destroyed in the violent eruption of 1470 BC.庙宇在公元前1470年猛烈的火山爆发中摧毁了。
• The eruption of a volcano is spontaneous.火山的爆发是自发的。

9 eruptions   

n.喷发，爆发( eruption的名词复数 )

参考例句：

• There have been several volcanic eruptions this year. 今年火山爆发了好几次。 来自《简明英汉词典》
• Over 200 people have been killed by volcanic eruptions. 火山喷发已导致200多人丧生。 来自辞典例句

10 emissions   

排放物( emission的名词复数 )； 散发物（尤指气体）

参考例句：

• Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
• Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。

11 tractable   

adj.易驾驭的；温顺的

参考例句：

• He was always tractable and quiet.他总是温顺、恬静。
• Gold and silver are tractable metals.金和银是容易加工的金属。

12 swap   

n.交换；vt.交换，用...作交易

参考例句：

• I will swap you my bicycle for your radio.我想拿我的自行车换你的收音机。
• This comic was a swap that I got from Nick.这本漫画书是我从尼克那里换来的。