题目内容
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A．The West Antarctic region was once an open ocean.
B．The West Antarctic ice sheet was about 7, 000 feet thick.
C．The West Antarctic ice sheet was once floating ice.
D．The West Antarctic region used to be warmer than today.
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听力原文： Among global warming's most frightening threats is the prediction that the polar ice-caps will melt, raising sea level so much that coastal cities from New York to Los Angles to Shanghai will be flooded.
Scientists agree that key player in this scenario is the West Antarctic ice sheet, a Brazil-size mass of frozen water that is as much as 7, 000 feet thick. Unlike floating ice shelves which have little impact on sea level when they break up, the ice sheet is anchored to bedrock well blow the sea surface. Surrounded by open ocean, it is also vulnerable, but Antarctic experts disagree strongly on just how unstable it is.
Now, new evidence reveals that all or most of the west Antarctic ice sheet collapsed at least once during the past 1. 3 million years, a period when global temperatures probably were not significantly higher than they are today. And the ice sheet was assumed to have been stable. In geological time, a million years is recent history. The proof, which was published last week in Science, comes from a team of scientists from Uppsala University in Sweden and the California Institute of Technology who drilled deep holes near the edge of the ice sheet. Within samples collected from the solid substance lying beneath the ice,they found fossils of microscopic marine plants which suggest that the region was once an open ocean, not solid ice. As Herman Englehart, a co-author from the California Institute of Technology says, "the West Antarctic ice sheet disappeared once, and can disappear again. "
26. Q: What is one of the most frightening threats of global warming according to the passage？
27. Q:What did scientists disagree on？
28. Q:What does the latest information reveal about the West Antarctic ice sheet？
29. Q:What does the scientists' latest finding suggest？
(32)
A．The whole Antarctic region will be submerged.
B．Some polar animals will soon become extinct.
C．Many coastal cities will be covered with water.
D．The earth will experience extreme weathers.
A．How humans are to cope with global warming.
B．How unstable the West Antarctic ice sheet is.
C．How vulnerable the coastal cities are.
D．How polar ice impacts global weather.
Which of the following statements is true according to the article？
A．There is a cluster of island west of the Transantartic Mountain.
B．Scientific research on Antarctica only centers on the ice and snow there.
C．Dry valleys may be a place to dispose of our pollutants.
D．All the countries on earth should be concerned about the health of the West Antarctic Ice Sheet.
Earth: Melting in the Heat？
Glaciers are melting; the ice caps are disappearing into the oceans; sea levels may rise by many meters as a consequence. Indigenous(本土的) Arctic peoples will find their food stocks gone, while flesh water supplies in Asia and south America will disappear as the glaciers which provide them melt away; penguins, polar bears and seals will find their habitats gone, their traditional lives unlivable.
But how realistic is this picture？ Is the world's ice really disappearing, or is it unscientific hot air？
A European satellite named Cryosat was designed to provide definitive answers to some of these questions. A launcher fault destroyed the mission in October 2005, hut the European Space Agency has approved a replacement, in the meantime, here is our global snapshot.
The Antarctic
Huge, pristine(质朴的), dramatic, unforgiving--the Antarctic is where the biggest of all global changes could begin.
There is so much ice here that if it all melted, sea levels globally would rise hugely-perhaps as much as 80m. Say goodbye to London, New York, Sydney, Bangkok...in fact, the majority of the world's major cities.
But will it happen？ Scientists divide the Antarctic into three zones: the east and west Antarctic ice sheets; and the Peninsula, the tongue of land which points up towards the southern tip of South America.
"Everybody thinks that the Antarctic is shrinking due to climate change, but the reality is much more complex," says David Vaughan, a principal investigator at the British Antarctic Survey in Cambridge, U.K. "Parts of it appear to be thickening as a result of snowfall increases, but the Peninsula is thinning at an alarming rate due to warming. The West Antarctic sheet is also thinning, and we're not sure of the reason why."
On the Up
Temperatures in the Peninsula appear to be increasing at around twice the global average—about 2℃ over the last 50 years. Those figures are based on measurements made by instruments at scientific stations.
Earlier this year, David Vaughan's group published research showing that the vast majority of glaciers along the Peninsula--87% of the 244 studied--are in retreat. The ice dumped into the ocean as the glaciers retreat should not make much difference to global sea levels--perhaps a few centimeters.
More worrying, potentially, are the vast ice sheets covering the rest of Antarctica. Making temperature measurements for the continent as a whole is difficult; it is a vast place--more than 2,000 km across---there are few research stations, and temperatures vary naturally by 2-3 ℃ from year to year. But measurements indicate that in the west, melting is underway.
"About one-third of the West Antarctic ice sheet is thinning," says Dr. Vaughan, "un average by about 10 cm per year, but in the worst places by 3～4m per year."
The rock on which the West Antarctic ice rests is below sea level, and British Antarctic Survey researchers believe the thinning could be due to the ice sheet melting on its underside.
"It may be that the ocean is warming end that's causing the ice to melt, but there may be other reasons as well; for example, there's lots of volcanism in that area and so that could change how much heat is delivered to the underside of the ice sheet."
Cryosat should help to pin down what is happening at the West Antarctic fringe. The radar altimeters on board its predecessors ERS1 and ERS2 have been unable to map the steep slopes at the coast, whereas Cryosat's instrument should be able to cope.
If the entire West Antarctic ice sheet did melt, sea levels globally would rise, by around 5m. But at the moment, there is no sign of that happening.
One recant scientific paper attempted to calculate probabilities for how much West An
A．Y
B．N
C．NG
A．The ice in the Antarctic will never melt.
B．The disasters caused by icebergs are all over the world.
C．The Antarctic is hot with volcanoes.
D．Volcano can protect ice sheet from melting.
Earth: Melting in the Heat？
Glaciers are melting; the ice caps are disappearing into the oceans; sea levels may rise by many meters as a consequence. Indigenous (本土的) Arctic peoples will find their food stocks gone, while fresh water supplies in Asia and south America will disappear as the glaciers which provide them melt away; penguins, polar bears and seals will find their habitats gone, their traditional lives unlivable.
But how realistic is this picture？ Is the world's ice really disappearing, or is it unscientific hot air？
A European satellite named Cryosat was designed to provide definitive answers to some of these questions. A launcher fault destroyed the mission in October 2005, but the European Space Agency has approved a replacement. In the meantime, here is our global snapshot.
The Antarctic
Huge, pristine (质朴的), dramatic, unforgiving-the Antarctic is where the biggest of all global changes could begin.
There is so much ice here that if it all melted, sea levels globally would rise hugely—perhaps as much as 80m. Say goodbye to London, New York, Sydney, Bangkok … in fact, the majority of the world's major cities.
But will it happen？ Scientists divide the Antarctic into three zones: the east and west Antarctic ice sheets; and the Peninsula, the tongue of land which points up towards the southern tip of South America.
"Everybody thinks that the Antarctic is shrinking due to climate change, but the reality is much more complex," says David Vaughan, a principal investigator at the British Antarctic Survey in Cambridge, U.K. "Parts of it appear to be thickening as a result of snowfall increases, but the Peninsula is thinning at an alarming rate due to warming. The West Antarctic sheet is also thinning, and we're not sure of the mason why."
On the Up
Temperatures in the Peninsula appear to be increasing at around twice the global average—about 2℃ over the last 50 years. Those figures are based on measurements made by instruments at scientific stations.
Earlier this year, David Vaughan's group published research showing that the vast majority of glaciers along the Peninsula—87% of the 244 studied—are in retreat. The ice dumped into the ocean as the glaciers retreat should not make much difference to global sea levels—perhaps a few centimeters.
More worrying, potentially, are the vast ice sheets covering the rest of Antarctica. Making temperature measurements for the continent as a whole is difficult; it is a vast place--more than 2,000 km across--them are few research stations, and temperatures vary naturally by 2～3℃ from year to year. But measurements indicate that in the west, reciting is underway.
"About one-third of the West Antarctic ice sheet is thinning," says Dr. Vaughan, "on average by about 10cm per year, but in the worst places by 3～4m per year."
The rock on which the West Antarctic ice rests is below sea level, and British Antarctic Survey researchers believe the thinning could be due to the ice sheet melting on its underside.
"It may be that the ocean is warming and that's causing the ice to melt, but there may be other reasons as well; for example, there's lots of volcanism in that area and so that could change how much heat is delivered to the underside of the ice sheet."
Cryosat should help to pin down what is happening at the West Antarctic fringe. The radar altimeters on board its predecessors ERSI and ERS2 have been unable to map the steep slopes at the coast, whereas Cryosat's instrument should be able to cope.
If the entire West Antarctic ice sheet did melt, sea levels globally would rise, by around 5m. But at the moment, there is no sign of that happening.
One recent scientific paper attempted to calculate probabilities for how much West Antarct
A．Y
B．N
C．NG
Byrd did not agree with Ronald Amundsen in that ______.
A．the Antarctic is not a suitable place for human beings to survive
B．people cannot explore the Pole area from air
C．the airplanes would one day replace dogs and sledges
D．dogs and sledges need no human care
What is Larsen ice shelf？
A．The coldest part of Antarctica.
B．The most fragile part of Antarctica.
C．The closest part of Antarctica to Australia.
D．The part of Antarctic where most scientists live.
Which of the following conclusions does the passage support？
A．The Arctic will be more favorably explored than Antarctic.
B．The world will soon suffer from fresh water shortage.
C．The Arctic and Antarctic are promising for future fresh water supply.
D．It's not difficult to carry ice from the Arctic or Antarctic to other parts of the world.
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