VOA慢速英语2014 AS IT IS 2014-05-15 Why is the Antarctic cooling?

 

AS IT IS 2014-05-15 Why is the Antarctic cooling?

Many scientists believe climate change exists.  They say temperatures on Earth’s surface are rising.  And they say human beings are largely responsible for the warmer conditions.  But the opposite seems to be happening in Antarctica.  Surface temperatures there are falling. A new study that explains these changes. 

Like the folksinger Bob Dylan said, "The answer my friend is blowin' in the wind."

Nerilie Abram is the lead author of the study.  She works as a climate scientist with the Australian National University.  She says the most important influence on weather in Antarctica is the wind. 

“They control how far north the rain bands go out of the Southern Ocean.  And they are also really important for temperature and, in particular, for the temperature of Antarctica and also the Antarctic Peninsula, which is the bit of Antarctica that juts¹ out right out into the path of those westerly winds.”

The westerly winds travel around the continent.  The study found that they are now stronger and their path tighter than at any time in the past 1,000 years.  That change has been especially noticeable since the 1940s. 

The study was published in the journal Nature Climate Change.  Ms. Abram and her team attempted to recreate Antarctica’s climate history with ice taken from the continent.  They found the wind has kept large parts of the continent cold.

“But we can explain that because as those westerly winds are getting stronger, they are actually tying the cold air over Antarctica, and it stops warm air masses from being able to get over the continent and help to warm Antarctica.  So this example of something that seems like a climate change paradox², we can actually explain by these greenhouse gases that are strengthening the westerly winds and isolating³ parts of Antarctica.”

Greenhouse gases trap energy from the sun in Earth’s atmosphere.  

However, the westerly winds are not having the same effect on the Antarctic Peninsula and parts of the Western Antarctic ice sheet.

“So as those winds have strengthened and pulled in tighter around Antarctica, they are actually bringing warmer air over those parts. And we see really quite marked warming, particularly over the Antarctic Peninsula.  And this is the part of the southern hemisphere⁴ that is warming faster than anywhere else on Earth at the moment.”

Nerilie Abram says the westerly winds have changed direction from their normal path.  Usually, those winds would have forced cold air into the southern hemisphere.  Instead, the air is trapped over Antarctica, and keeps rain from falling on Australia.

“What has been happening over the recent decades is that those westerly winds have been shifting south and we are getting fewer of those cold fronts and storms coming up and giving that really important rain.  And so that is why Australia is experiencing these very severe droughts.”

She adds that the Southern Ocean winds have intensified⁵ because of the warmer atmosphere.  She says the winds could return to a more normal pattern if action is taken to reduce greenhouse gases.

1 juts   

v.（使）突出( jut的第三人称单数 )；伸出；（从…）突出；高出

参考例句：

• A small section of rock juts out into the harbour. 山岩的一小角突入港湾。 来自辞典例句
• The balcony juts out over the swimming pool. 阳台伸出在游泳池上方。 来自辞典例句

2 paradox   

n.似乎矛盾却正确的说法；自相矛盾的人(物)

参考例句：

• The story contains many levels of paradox.这个故事存在多重悖论。
• The paradox is that Japan does need serious education reform.矛盾的地方是日本确实需要教育改革。

3 isolating   

adj.孤立的，绝缘的v.使隔离( isolate的现在分词 )；将…剔出（以便看清和单独处理）；使（某物质、细胞等）分离；使离析

参考例句：

• Colour filters are not very effective in isolating narrow spectral bands. 一些滤色片不能很有效地分离狭窄的光谱带。 来自辞典例句
• This became known as the streak method for isolating bacteria. 这个方法以后就称为分离细菌的划线法。 来自辞典例句

4 hemisphere   

n.半球，半球地图

参考例句：

• This animal is to be found only in the Southern Hemisphere.这种动物只有在南半球才能找到。
• In most people,the left hemisphere is bigger than the right.多数人的左脑比右脑大。

5 intensified   

v.（使）增强， （使）加剧( intensify的过去式和过去分词 )

参考例句：

• Violence intensified during the night. 在夜间暴力活动加剧了。
• The drought has intensified. 旱情加剧了。 来自《简明英汉词典》