VOA标准英语2011--Polar Scientist Charts Melting Caused by

Polar Scientist Charts Melting Caused by Climate Change

Michael Gooseff follows water to the end of the earth. The Pennsylvania State University hydrologist works in remote regions of the Arctic and Antarctic, where ice and frozen ground are thawing¹. He expects polar warming and melting to continue at an accelerating pace if no significant reductions are made in climate-changing greenhouse-gas emissions².
At the annual convention of the Ecological³ Society of America in Austin, Texas this week he posed this question: “How are those polar systems responding to climate change?” 
The answer is based on his on-going research into how water crosses landscapes and what happens to it above and below ground.
“In the northern regions, of course, we have sea ice, but a smaller surface area than in the Antarctic where we have very large ice sheets. And that actually plays into the differences in climate change responses that we’re seeing at both of those places.”
According to Gooseff, the two regions also differ widely geologically and ecologically. He says the Antarctic McMurdo Dry Valleys station where he’s based “appears like a polar desert system with open exposed soils, with no vascular⁴ plants at the surface and with glaciers⁶ coming down from the mountains, whereas in northern Alaska, we have a lot of plants. The tundra⁷ is actually dense⁸ with vegetation and very green.”
Gooseff is documenting change over time, by observing patterns in polar rivers, streams and lakes. He recalls a 2003 visit to Alaska’s North Slope, when his team charted the course of an unusual muddy stream.
“We follow this up and finally we found a big gash⁹ in the hill slope essentially¹⁰, and all of this mud pouring out from underneath¹¹ it.”
Here’s what had happened: A massive ice wedge under the surface had melted, thawing the permafrost and causing the soil above it to collapse¹². That created a deep gully in the hillside.
A study of historic aerial photos of the area revealed that this dramatic change, as well as similar warming-induced changes to 25 other landscape features, had occurred over just two decades.
Gooseff explains that as water moves through these altered formations, it picks up sediment¹³ and nutrients¹⁴ normally locked up in the permafrost. As that flows into rivers, it could affect fisheries and coastal¹⁵ oceans.
Gooseff says the melting permafrost sets up another dangerous climate scenario¹⁶. “As we warm, we release more carbon, that carbon goes into the atmosphere, contributes to more warming, contributes to more permafrost degradation¹⁷ and the cycle sort of continues. In fact, permafrost itself is expected to hold about twice as much carbon as we currently have in the atmosphere.”
At the opposite end of the earth, near the McMurdo Dry Valleys station, Gooseff studies snow patches. Not much snow falls in Antarctica, but what little there is collects in cool shady spots, behind rocks and hills. These patches insulate the soil and may provide small amounts of moisture for microbes below.
Gooseff says the melt from this frozen precipitation, as well as from older snowpack and glacier⁵ ice, is happening faster and is more widespread than a decade ago. The remote sensing devices his research team has deployed¹⁸ are helping¹⁹ to track how that water moves across the land.
“We expect that there are going to be patterns in both time and space that will be somewhat predictable.”
Gooseff hopes his research of climate change at the poles underscores the regions’ interconnectedness with a global climate system that affects everyone on the planet.

1 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

2 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。

3 ecological   

adj.生态的，生态学的

参考例句：

• The region has been declared an ecological disaster zone.这个地区已经宣布为生态灾难区。
• Each animal has its ecological niche.每种动物都有自己的生态位.

4 vascular   

adj.血管的，脉管的

参考例句：

• The mechanism of this anomalous vascular response is unknown.此种不规则的血管反应的机制尚不清楚。
• The vascular changes interfere with diffusion of nutrients from plasma into adjacent perivascular tissue and cells.这些血管变化干扰了营养物质从血浆中向血管周围邻接的组织和细胞扩散。

5 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。

6 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）

7 tundra   

n.苔原，冻土地带

参考例句：

• The arctic tundra is at the top of the world around the North Pole.北极冻原是指北极点周边的地区，是世界最高的地方。
• There is a large amount of methane gas under the Siberian tundra.西伯利亚的冻土地带之下有大量的甲烷气体。

8 dense   

a.密集的，稠密的，浓密的；密度大的

参考例句：

• The general ambushed his troops in the dense woods. 将军把部队埋伏在浓密的树林里。
• The path was completely covered by the dense foliage. 小路被树叶厚厚地盖了一层。

9 gash   

v.深切，划开；n.(深长的)切(伤)口；裂缝

参考例句：

• The deep gash in his arm would take weeks to heal over.他胳膊上的割伤很深，需要几个星期的时间才能痊愈。
• After the collision,the body of the ship had a big gash.船被撞后，船身裂开了一个大口子。

10 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。

11 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。

12 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。

13 sediment   

n.沉淀，沉渣，沉积(物)

参考例句：

• The sediment settled and the water was clear.杂质沉淀后，水变清了。
• Sediment begins to choke the channel's opening.沉积物开始淤塞河道口。

14 nutrients   

n.（食品或化学品）营养物，营养品( nutrient的名词复数 )

参考例句：

• a lack of essential nutrients 基本营养的缺乏
• Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》

15 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。

16 scenario   

n.剧本，脚本；概要

参考例句：

• But the birth scenario is not completely accurate.然而分娩脚本并非完全准确的。
• This is a totally different scenario.这是完全不同的剧本。

17 degradation   

n.降级；低落；退化；陵削；降解；衰变

参考例句：

• There are serious problems of land degradation in some arid zones.在一些干旱地带存在严重的土地退化问题。
• Gambling is always coupled with degradation.赌博总是与堕落相联系。

18 deployed   

（尤指军事行动）使展开( deploy的过去式和过去分词 )； 施展； 部署； 有效地利用

参考例句：

• Tanks have been deployed all along the front line. 沿整个前线已部署了坦克。
• The artillery was deployed to bear on the fort. 火炮是对着那个碉堡部署的。

19 helping   

n.食物的一份&adj.帮助人的，辅助的

参考例句：

• The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
• By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。