WASHINGTON-Two-thirds of the world’s polar bear population could be gone by 2050

WASHINGTON—Two-thirds of the world’s polar bear populationcould be gone by 2050 if predictions of melting sea ice hold true, the USGeological Survey reported on Friday.

The fate of polar bears could be even worse than thatestimate, because sea ice in the Arctic might be disappearing faster than theavailable computer models predict, the geological survey said in a report aimedat determining whether the big white bear should be listed as a threatenedspecies.

“There is a definite link between changes in the seaice and the welfare of polar bears,” said Steve Amstrup, who led the researchteam. He says Arctic sea ice is already at the lowest this year and is expectedto retreat(退却) farther this month.

That means that polar bears—some 16,000 of them --will disappear by 2050 from parts of the Arctic where sea ice is melting mostrapidly, along the north coasts of Alaska and Russia, researchers said in atelephone briefing(简报).

Other polar bears could survive beyond that date butmany of those could be gone by 2100, Amstrup said. By this century’s end, theonly polar bears left might live in the Canadian Arctic islands and along thewest coast of Greenland.

“It is likely to result in loss of approximatelytwo-thirds of the world’s current polar bear population by the mid 21stcentury,” the report’s executive summary said.

“Because the observed trajectory(轨迹)of Arctic sea ice decline appears to beunderestimated by currently available models, this assessment of future polarbear status may be conservative(保守的).”

In January, the US Fish and Wildlife Service proposedlisting the polar bear as a threatened species, noting polar bears depend onsea ice as a platform to hunt seals, their main food.

Without enough sea ice, polar bears would be forcedonto land, but they are poor hunters once they get out of the water and ice,the researchers said. The bears’ disappearance would probably take place asyoung cubs(幼兽)failed to survive to adulthood and femaleswere unable to reproduce successfully.

1.What was the US Geological Survey intended to do?

A．To determinewhether the polar bear was in danger.

B．To measurehow fast the sea ice melts in the Arctic.

C．To check thepredictions of the computer models.

D．To find outthe exact number of the polar bear.

2.What causes the polar bears to disappear by 2050?

A．The pollutionof the Arctic region.           B．The sea icemelting at high speed

C．Fewer foodsources being left.             D．Thetemperature getting colder.

3.The key to preventing polar bears dying out seems to_______________.

A．help youngpolar bears to survive the cold winter

B．have largenumber of seals living in the oceans

C．make surethere is enough sea ice in the Arctic

D．providechances for adult polar bears to reproduce

试题答案

【答案】

1.A

2.B

3.C

【解析】

试题分析:本文是一篇说明文，说明了美国地质专家预测到2050年，海冰融化导致北极熊列为濒危物种，但是北极熊比预计的更糟，因为在北极海水的消失比电脑预测的更快，地质勘察报告旨在确定是否将北极熊列为濒危物种

1.细节题，由第二段最后一句the geologicalsurvey said in a report aimed at determining whether the big white bear shouldbe listed as a threatened species可以知道答案，故选A。

2.细节题。由第一段Two-thirds of theworld’s polar bear population could be gone by 2050 if predictions of meltingsea ice hold true, the US Geological Survey reported on Friday.可以知道答案，所以选B。

3.推理题，由倒数第二段最后一句noting polarbears depend on sea ice as a platform to hunt seals, their main food.可以推出答案，所以选C

考点：本篇是一篇说明文

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