美国国家公共电台 NPR Is There A Ticking Time Bomb Under The Arctic?

 

DAVID GREENE, HOST:

Come with us on a journey inside the Earth. Well, inside a special layer in the Earth. A quarter of the Northern Hemisphere is covered with what's called permafrost, and for the first time in centuries, the permafrost is beginning to warm up because of climate change.

TOM DOUGLAS: And that's a mammoth¹ bone right there.

MICHAELEEN DOUCLEFF, BYLINE²: Whoa. It's just sticking out of the wall.

DOUGLAS: Just sticking out of the wall.

GREENE: As it thaws³, the permafrost is unleashing⁴ something that could affect the whole world. NPR's Michaeleen Doucleff reports.

DOUCLEFF: We start off 40 feet underground inside a tunnel about as wide as an SUV. All around us are signs of extinct creatures. Tusks⁵ are sticking out from the ceiling, and a skull⁶ pokes⁷ out from the ground. Ancient bones.

DOUGLAS: Where we are here has been dated at about 14,000 years ago.

DOUCLEFF: I think this is one of the coolest places I've been to.

DOUGLAS: Really? All right. Cool. Neat.

DOUCLEFF: That's Tom Douglas, a geochemist with the U.S. Army. He says, back in the 1960s, the Army dug this tunnel so they could study the permafrost. All the walls are covered in a soft brown dust, but what's underneath⁸ is hard as concrete.

DOUGLAS: If I tap on this now, you'll see it's hard as a rock.

DOUCLEFF: Yeah.

DOUGLAS: That's permafrost. Anything in there is frozen. You can even see the little marks on there. It's pretty hard.

DOUCLEFF: Permafrost is technically⁹ frozen soil, but think of it in terms of chocolate cake. Typically that cake is spongy, soft. But if you take that cake and dip it into water and freeze it, it turns hard. That's exactly what happens to soil when you freeze it. You get permafrost. We walk deeper into the tunnel.

DOUGLAS: All right. So keep going.

DOUCLEFF: Those woolly mammoth bones aren't the only bizarre thing hidden in permafrost. Just then we walk right through another one.

OK.

DOUGLAS: So here's a nice wedge.

DOUCLEFF: It looks like a giant wall of ice, but it's really an upside down iceberg¹⁰ buried in the earth, and the tunnel cuts right through it.

It's a huge chunk¹¹ of ice all around us.

DOUGLAS: Yeah. I mean, it's basically the size of a house or something.

DOUCLEFF: Wow.

These icebergs¹² are buried throughout Alaska. They're buried under homes, under office buildings, bridges. And they've been frozen solid for centuries, even longer. They actually hold the ground together. Here's the problem.

DOUGLAS: That's about 99 percent water ice by volume.

DOUCLEFF: So when the ground warms up...

DOUGLAS: Imagine turning that into water. You'll leave a trench¹³ in the ground that people could fall into, right?

DOUCLEFF: Or, this whole tunnel could collapse¹⁴?

DOUGLAS: Exactly.

DOUCLEFF: That's exactly what's happening across Alaska. A study in 2016 found that these giant buried icebergs are melting rapidly. New lakes are forming in some places. They're draining in others. Rivers are appearing where they never were before, and the land is sinking. Clearly this is going to be a big problem for Alaskans and other people up North. But that's not what worries Tom Douglas the most. There's something else hidden here that could affect the whole world.

DOUGLAS: Keep going down. Watch your head.

DOUCLEFF: Douglas takes me deeper down into the tunnel.

DOUGLAS: This is really an amazing feature of the tunnel. It's the only place we see it.

DOUCLEFF: He shines his flashlight up to the ceiling.

DOUGLAS: What does that look like to you?

DOUCLEFF: Like grass.

DOUGLAS: Green grass, right?

DOUCLEFF: Yeah. It's green?

DOUGLAS: It's green grass.

DOUCLEFF: Whoa.

DOUGLAS: Yeah. See that?

DOUCLEFF: Wait. We have to tell people that, like, the grass is actually growing down.

DOUGLAS: Upside down.

DOUCLEFF: Yeah.

DOUGLAS: This was in ice, and had been preserved that way for 25,000 years. I mean, if I...

DOUCLEFF: Wait. This is 25,000-year-old grass?

DOUGLAS: Yeah.

DOUCLEFF: That's incredible.

DOUGLAS: Yeah. Really amazing.

DOUCLEFF: You see, the thing is, basically anything that's died in the Arctic over the past hundred-thousand years is buried and preserved down here. The permafrost is packed with plants, like this grass, and dead animals, like those woolly mammoths we saw earlier. All this life is made of carbon. In fact, there's a massive amount of carbon down here. There's more carbon trapped in this permafrost than all the carbon humans have spewed into the atmosphere, first with steam trains then with their cars, planes, coal plants, everything we've done since the Industrial Revolution.

DOUGLAS: The permafrost contains twice as much carbon as is currently in Earth's atmosphere, 1,600 billion metric tons.

DOUCLEFF: Right now this carbon is trapped, frozen. So the big question is what happens to this carbon as the permafrost thaws? Because, you see, there's not just dead creatures in the permafrost. Down here, we are also surrounded by something that's coming back to life.

DOUGLAS: See, that white flag right there is where you've got the 27,000-year-old material.

DOUCLEFF: A few years ago, Douglas and his colleagues ran a very simple experiment. They brought big drills into the tunnel and cut out chunks¹⁵ of ice.

DOUGLAS: We collected basically pieces about the size of a Coca-Cola can.

DOUCLEFF: They took the ice back to the lab...

DOUGLAS: Let it slowly come up to room temperature.

DOUCLEFF: ...And then looked for signs of life. A few days later, something started growing like gangbusters - ancient bacteria.

DOUGLAS: This is material that stayed frozen for 25,000 years old, and, given the right environmental conditions, came back alive again vigorously.

DOUCLEFF: Once the bacteria warmed up, they were hungry, and they started eating the dead plants and animals, turning their carbon into gases.

DOUGLAS: Both carbon dioxide and methane¹⁶.

DOUCLEFF: Those are the two main gases that cause climate change. Now, that was in the lab. But imagine these bacteria waking up as the permafrost thaws all around the Arctic - in Canada, Greenland, Russia, here in Alaska. Charles Miller¹⁷ is a chemist at NASA's Jet Propulsion Laboratory who studies permafrost. He says that in the past few years they've started seeing the microbes here waking up, warming up and releasing gases.

CHARLES MILLER: There's been quite a tremendous change in the temperature of the permafrost. This warming is causing carbon dioxide to be liberated¹⁸ from the land surface so we see a net release of carbon from the land back to the atmosphere.

DOUCLEFF: Miller says they don't know yet how much carbon will get released from thawing¹⁹ permafrost or how fast it will happen. It's a big wild card of climate change. But once gases start coming off, it could form this type of feedback loop.

MILLER: Over which we would have essentially²⁰ zero control.

DOUCLEFF: Where the gas coming from the ground warms the Earth, in turn causing more gas to be released, and more and more warming.

Michaeleen Doucleff, NPR News.

1 mammoth   

n.长毛象；adj.长毛象似的，巨大的

参考例句：

• You can only undertake mammoth changes if the finances are there.资金到位的情况下方可进行重大变革。
• Building the new railroad will be a mammoth job.修建那条新铁路将是一项巨大工程。

2 byline   

n.署名；v.署名

参考例句：

• His byline was absent as well.他的署名也不见了。
• We wish to thank the author of this article which carries no byline.我们要感谢这篇文章的那位没有署名的作者。

3 thaws   

n.（足以解冻的）暖和天气( thaw的名词复数 )；（敌对国家之间）关系缓和v.（气候）解冻( thaw的第三人称单数 )；（态度、感情等）缓和；（冰、雪及冷冻食物）溶化；软化

参考例句：

• The sun at noon thaws the ice on the road. 中午的阳光很快把路上的冰融化了。 来自辞典例句
• It thaws in March here. 在此地化雪的季节是三月。 来自辞典例句

4 unleashing   

v.把（感情、力量等）释放出来，发泄( unleash的现在分词 )

参考例句：

• Company logos: making people's life better by unleashing Cummins power. 公司理念：以康明斯动力建设更美好的生活！ 来自互联网
• Sooner or later the dam will burst, unleashing catastrophic destruction. 否则堤坝将崩溃，酿成灾难。 来自互联网

5 tusks   

n.（象等动物的）长牙( tusk的名词复数 )；獠牙；尖形物；尖头

参考例句：

• The elephants are poached for their tusks. 为获取象牙而偷猎大象。
• Elephant tusks, monkey tails and salt were used in some parts of Africa. 非洲的一些地区则使用象牙、猴尾和盐。 来自英语晨读30分（高一）

6 skull   

n.头骨；颅骨

参考例句：

• The skull bones fuse between the ages of fifteen and twenty-five.头骨在15至25岁之间长合。
• He fell out of the window and cracked his skull.他从窗子摔了出去，跌裂了颅骨。

7 pokes   

v.伸出( poke的第三人称单数 )；戳出；拨弄；与（某人）性交

参考例句：

• He pokes his nose into everything. 他这人好管闲事。 来自《现代汉英综合大词典》
• Only the tip of an iceberg pokes up above water. 只有冰山的尖端突出于水面。 来自辞典例句

8 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。

9 technically   

adv.专门地，技术上地

参考例句：

• Technically it is the most advanced equipment ever.从技术上说，这是最先进的设备。
• The tomato is technically a fruit,although it is eaten as a vegetable.严格地说，西红柿是一种水果，尽管它是当作蔬菜吃的。

10 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。

11 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。

12 icebergs   

n.冰山，流冰( iceberg的名词复数 )

参考例句：

• The drift of the icebergs in the sea endangers the ships. 海上冰山的漂流危及船只的安全。 来自《简明英汉词典》
• The icebergs towered above them. 冰山高耸于他们上方。 来自辞典例句

13 trench   

n./v.(挖)沟，(挖)战壕

参考例句：

• The soldiers recaptured their trench.兵士夺回了战壕。
• The troops received orders to trench the outpost.部队接到命令在前哨周围筑壕加强防卫。

14 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。

15 chunks   

厚厚的一块( chunk的名词复数 )； （某物）相当大的数量或部分

参考例句：

• a tin of pineapple chunks 一罐菠萝块
• Those chunks of meat are rather large—could you chop them up a bIt'smaller? 这些肉块相当大，还能再切小一点吗？

16 methane   

n.甲烷，沼气

参考例句：

• The blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
• Methane may have extraterrestrial significance.甲烷具有星际意义。

17 miller   

n.磨坊主

参考例句：

• Every miller draws water to his own mill.磨坊主都往自己磨里注水。
• The skilful miller killed millions of lions with his ski.技术娴熟的磨坊主用雪橇杀死了上百万头狮子。

18 liberated   

a.无拘束的，放纵的

参考例句：

• The city was liberated by the advancing army. 军队向前挺进，解放了那座城市。
• The heat brings about a chemical reaction, and oxygen is liberated. 热量引起化学反应，释放出氧气。

19 thawing   

n.熔化，融化v.（气候）解冻( thaw的现在分词 )；（态度、感情等）缓和；（冰、雪及冷冻食物）溶化；软化

参考例句：

• The ice is thawing. 冰在融化。 来自《现代英汉综合大词典》
• It had been snowing and thawing and the streets were sloppy. 天一直在下雪，雪又一直在融化，街上泥泞不堪。 来自英汉文学 - 嘉莉妹妹

20 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。