英语听力：自然百科 北极陷入“死亡螺旋”

 According to scientists from the National Snow and Ice Data Center and NASA, Arctic sea ice appears to have reached its minimum for the year at nearly 1.7 million square miles. A chilling fact, considering that this is only about 10 % more than the lowest minimum ever, recorded in September of last year.

 

The levels of perennial¹, or year-around sea ice, have been dropping rapidly. According to NASA, the drop in ice levels has averaged nearly 10% each decade since NASA began satellite imaging in 1979.

 

Between the winters of 2005 and 2007, the amount of perennial ice that was lost was equivalent to an area the size of Texas and California combined. While perennial sea ice used to cover up to 60% of the Arctic, it now only covers about 30%.

 

Perennial sea ice is the thick ice that remains² solid throughout the year and provides important habitat and hunting grounds for polar bears, while the surrounding seasonal³ ice melts and reforms each year. This data further reinforces previous evidence that the minimum level of perennial sea ice in the Arctic is dropping nearly every year.

 

An Arctic climate expert at the National Snow and Ice Data Center tells National Geographic⁴ News the ice is in a death spiral. Mark Sered says Arctic summer ice could be completely lost by the year 2030. The drop-off in sea ice can have global ramifications⁵ both on land and in the water.

 

Sea ice works as a mirror, reflecting the Sun's rays. The more sea ice that exists, the more the Sun's rays are reflected off the Earth’s surface. But when sea ice levels decline, more of the Sun's rays can be absorbed by the seas and by land. This can then lead to a rise in global temperatures and disrupt the fragile equilibrium⁶ of the world's climate. Worse yet, this can result in what scientist called, ice-albedo feedback, meaning the more the sea ice declines, the more likely it will continue to decline.

1 perennial   

adj.终年的；长久的

参考例句：

• I wonder at her perennial youthfulness.我对她青春常驻感到惊讶。
• There's a perennial shortage of teachers with science qualifications.有理科教学资格的老师一直都很短缺。

2 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

3 seasonal   

adj.季节的，季节性的

参考例句：

• The town relies on the seasonal tourist industry for jobs.这个城镇依靠季节性旅游业提供就业机会。
• The hors d'oeuvre is seasonal vegetables.餐前小吃是应时蔬菜。

4 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

5 ramifications   

n.结果，后果( ramification的名词复数 )

参考例句：

• These changes are bound to have widespread social ramifications. 这些变化注定会造成许多难以预料的社会后果。
• What are the ramifications of our decision to join the union? 我们决定加入工会会引起哪些后果呢？ 来自《简明英汉词典》

6 equilibrium   

n.平衡，均衡，相称，均势，平静

参考例句：

• Change in the world around us disturbs our inner equilibrium.我们周围世界的变化扰乱了我们内心的平静。
• This is best expressed in the form of an equilibrium constant.这最好用平衡常数的形式来表示。