PBS高端访谈:南极洲的融化速度超过了科学家的预期

 　　Scientists are predicting a 110-mile sheet of ice -- a chunk¹ the size of the state of Delaware -- will break off Antarctica in the coming days or weeks.

　　The cause is warming ocean waters, and the ice melt has implications for sea level rise well beyond the South Pole region.

　　"The National Geographic²" July issue cover story is called "Antarctica is Melting, and Giant Ice Cracks are Just the Start".

　　Joining me now from Birmingham, Alabama, to discuss this is Robert Kunzig, the senior environmental editor for "National Geographic."

　　Thanks for joining us. First of all, a chunk of ice the size of Delaware seems almost impossible to, you know,

　　put our heads around, but that's actually a small piece when you think of the size of Antarctica.

　　Yes, it is, and it's even just a small piece, Hari, of the Larsen C Ice Shelf that it's breaking off of.

　　Larsen C is a floating slab³ of ice size that's the size of Vermont and New Hampshire combined.

　　And what's happening there is that a rift⁴ that has been growing for years now, this year really accelerated. As you said, it's about 15 miles wide,

　　it--and it's been growing from south to north, basically going to slice a big chunk of ice off the ice shelf and that chunk will be the size of Delaware.

　　You know, we have a picture of one of the cracks that are going through. Scientists have been looking and studying and trying to get at some of these cracks for a long time.

　　How deep does it go down and why are they so concerned?

　　The crack in Larsen C where Larson C meets the sea, it's about 600 feet thick. And most of that is under water.

　　So, there's an ice cliff of about 60 feet that towers above the waves. So, the crack goes about, at least 600 feet.

　　If this iceberg⁵ goes, the worry is that the whole ice shelf might collapse⁶ as other ice shelves on the Antarctic Peninsula have already collapsed⁷.

　　And ice shelves there and elsewhere around Antarctica are really kind of the canaries in the coal mine that they're a sign of what's happening all over,

　　which is that Antarctica is melting faster than scientists had expected.

　　So, this isn't just about the fact that the water is already in the water and it's just melting in a glass of water, say.

　　We're actually adding new ice cubes to that glass, which is what makes, what, the sea level rise?

　　Well, yes. That's the perfect analogy. This ice, the Larsen C Ice Shelf is floating. It is like an ice cube in a glass of water.

　　So, even if all of it collapses⁸, that, itself, does not add to sea level.

　　But the thing about ice shelves is that they function like corks⁹. They're bottling up a much larger amount ice that's on the ground, on the land in this case behind them.

　　And when -- that's the glaciers¹¹ that are carrying ice from the interior of Antarctica towards the sea. The ice shelves are really just sort of the floating ends of the glaciers.

　　And so, when that flow increases, more ice is falling into the sea and raising sea level.

　　In the article, it talks about how scientists measure what's happening kind of under water.

　　What's happening underneath¹² these ice sheets? How is there warmer water and what's the interaction of salt water do to this all?

　　Well, the big thing that's been happening in recent years is that warmer ocean water, and when I say warm, warmer, I don't mean really warm. We're talking about four, five degrees above freezing.

　　That water is penetrating¹³ further up towards the coast of Antarctica under the ice shelf and it is undermining the ice shelves.

　　It's melting them and thinning them from below and weakening them.

　　You know, you have a large map that you have in "The National Geographic" article that kind of puts this in perspective and there's areas of kind of purple that are the areas that are kind of floating off.

　　And there's a couple of patches of red, where it's really happening at an incredible rate.

　　Tell us about how fast it's happening in, say, the Pine Glacier¹⁰.

　　Basically, it's been an acceleration¹⁴ by several times.

　　All over Antarctica, the loss of ice from the floating ice shelves has increased by a factor of 12 in the past two decades.

　　So where in the mid¹⁵ '90s, they were losing six billion tons of ice. Now, they are losing 74.

　　What it is, it's natural for these glaciers to float in the sea. But what's happening is the speed has increased.

　　Robert Kunzig, the senior environment editor for "National Geographic", thanks so much for joining us. Thank you, Hari. undefined

1 chunk   

n.厚片，大块，相当大的部分（数量）

参考例句：

• They had to be careful of floating chunks of ice.他们必须当心大块浮冰。
• The company owns a chunk of farmland near Gatwick Airport.该公司拥有盖特威克机场周边的大片农田。

2 geographic   

adj.地理学的，地理的

参考例句：

• The city's success owes much to its geographic position. 这座城市的成功很大程度上归功于它的地理位置。 来自《简明英汉词典》
• Environmental problems pay no heed to these geographic lines. 环境问题并不理会这些地理界限。 来自英汉非文学 - 环境法 - 环境法

3 slab   

n.平板，厚的切片；v.切成厚板，以平板盖上

参考例句：

• This heavy slab of oak now stood between the bomb and Hitler.这时笨重的橡木厚板就横在炸弹和希特勒之间了。
• The monument consists of two vertical pillars supporting a horizontal slab.这座纪念碑由两根垂直的柱体构成，它们共同支撑着一块平板。

4 rift   

n.裂口，隙缝，切口；v.裂开，割开，渗入

参考例句：

• He was anxious to mend the rift between the two men.他急于弥合这两个人之间的裂痕。
• The sun appeared through a rift in the clouds.太阳从云层间隙中冒出来。

5 iceberg   

n.冰山，流冰，冷冰冰的人

参考例句：

• The ship hit an iceberg and went under.船撞上一座冰山而沉没了。
• The glacier calved a large iceberg.冰河崩解而形成一个大冰山。

6 collapse   

vi.累倒；昏倒；倒塌；塌陷

参考例句：

• The country's economy is on the verge of collapse.国家的经济已到了崩溃的边缘。
• The engineer made a complete diagnosis of the bridge's collapse.工程师对桥的倒塌做了一次彻底的调查分析。

7 collapsed   

adj.倒塌的

参考例句：

• Jack collapsed in agony on the floor. 杰克十分痛苦地瘫倒在地板上。
• The roof collapsed under the weight of snow. 房顶在雪的重压下突然坍塌下来。

8 collapses   

折叠( collapse的第三人称单数 )； 倒塌； 崩溃； （尤指工作劳累后）坐下

参考例句：

• This bridge table collapses. 这张桥牌桌子能折叠。
• Once Russia collapses, the last chance to stop Hitler will be gone. 一旦俄国垮台，抑止希特勒的最后机会就没有了。

9 corks   

n.脐梅衣；软木( cork的名词复数 )；软木塞

参考例句：

• Champagne corks were popping throughout the celebrations. 庆祝会上开香槟酒瓶塞的砰砰声不绝於耳。 来自辞典例句
• Champagne corks popped, and on lace tablecloths seven-course dinners were laid. 桌上铺着带装饰图案的网织的桌布，上面是七道菜的晚餐。 来自飘（部分）

10 glacier   

n.冰川，冰河

参考例句：

• The glacier calved a large iceberg.冰河崩解而形成一个大冰山。
• The upper surface of glacier is riven by crevasses.冰川的上表面已裂成冰隙。

11 glaciers   

冰河，冰川( glacier的名词复数 )

参考例句：

• Glaciers gouged out valleys from the hills. 冰川把丘陵地带冲出一条条山谷。
• It has ice and snow glaciers, rainforests and beautiful mountains. 既有冰川，又有雨林和秀丽的山峰。 来自英语晨读30分（高一）

12 underneath   

adj.在...下面，在...底下；adv.在下面

参考例句：

• Working underneath the car is always a messy job.在汽车底下工作是件脏活。
• She wore a coat with a dress underneath.她穿着一件大衣，里面套着一条连衣裙。

13 penetrating   

adj.（声音）响亮的，尖锐的adj.（气味）刺激的adj.（思想）敏锐的，有洞察力的

参考例句：

• He had an extraordinarily penetrating gaze. 他的目光有股异乎寻常的洞察力。
• He examined the man with a penetrating gaze. 他以锐利的目光仔细观察了那个人。

14 acceleration   

n.加速，加速度

参考例句：

• All spacemen must be able to bear acceleration.所有太空人都应能承受加速度。
• He has also called for an acceleration of political reforms.他同时呼吁加快政治改革的步伐。

15 mid   

adj.中央的，中间的

参考例句：

• Our mid-term exam is pending.我们就要期中考试了。
• He switched over to teaching in mid-career.他在而立之年转入教学工作。