Earth: Melting in the Heat? Glaciers are melting; the ice caps are disappearing into the o - 赤豆云问答

第1题

Although the fuel consumption is greater in the northern hemisphere, temperatures there se

em to be falling. This is ______.

A．mainly because the levels of carbon dioxide are rising

B．possibly because the ice caps in the poles are melting

C．exclusively due to the effect of the inenia of the earth's climate

D．partly due to variations in the output of solar energy

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第2题

On the basis of their models, scientists are of the opinion that______.A．the climate of th

On the basis of their models, scientists are of the opinion that______.

A．the climate of the world should be becoming Cooler

B．the new Ice Age will be postponed by the greenhouse effect

C．the warming effect helps to increase the solar effects

D．inertia of the earth's climate to take effect in thousands of years

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第3题

Earth: Melting in the Heat？Glaciers are melting; the ice caps are disappearing into the oc

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 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, "on 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 and that's causing the ice to melt, but there may be other masons 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 recent scientific paper attempted to calculate probabilities for how much West Antarctic melting woul

A．Y

B．N

C．NG

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第4题

The author believes that_____________.A.the motion of the plates corresponds to thar of th

The author believes that_____________.

A.the motion of the plates corresponds to thar of the earth's interior

B.the geological theory about drifting plates has been proved to be true

C.the hot spots and the plates move slowly in opposite directions

D.the movement of hot spots proves the continents are moving apart

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第5题

For all their great diversity of shapes and sizes, glaciers can be divided into two essent

ial types: valley glaciers, which flow downhill from mountains and are shaped by the constraints of topography (地貌), and ice sheets, which flow outward in all directions from dome--like centers of accumulated ice to cover vast expanse of terrain. Whatever their type, most glaciers are remnants of great shrouds of ice that covered the earth years ago. In a few of these glaciers the oldest ice is very ancient indeed; the age of parts of the Antarctic sheet may exceed 500,000 years.

Glaciers are born in rocky womb above the snow line, where there is sufficient winter snowfall and summer cold for snow to survive the annual melting. The long gestation period of a glacier begins with the accumulation and gradual transformation of snow flakes. Soon after they reach the ground, complex snowflakes are reduced to compact, roughly spherical ice crystals, and the basic components of a glacier. As new layers of snow and firm, snow that survives the melting of the previous summer, accumulate, they squeeze out most of the air bubbles trapped within and between the crystals below. This process of recrystallization continues throughout the life of the glacier.

The length of time required for the creation of glacier ice depends mainly upon the temperature and the rate of snowfall. In Iceland, where snowfall is heavy and summer temperatures are high enough to produce plenty of melt--water, glacier ice may come into being in a relatively short time--say, ten years. In parts of Antarctica, where snowfall is scant and the ice remains well below its melting temperature year round, the process may require hundreds of years.

The ice does not become a glacier until it moves under its own weight, and it cannot move significantly until it reaches a critical thickness--the point at which the weight of the piled-up layers overcomes the internal strength of the ice and the friction between the ice and the ground. This critica} thickness is about 60 feet. The fastest moving glaciers have been gauged at not much more than two and a half miles per year, and some cover less than 1/100 inch in that same amount of time. But no matter how infinitesimal the flow, movement is what distinguishes a glacier from a mere mass of ice.

Which of the following is NOT true about glaciers？

A．Glaciers are diversified in shapes and sizes.

B．Glaciers can be divided into valley glaciers and ice sheets.

C．Glaciers are remnants of great shrouds of ice that covered the earth years ago.

D．Few glaciers have a long history.

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第6题

ChangeAs relentlessly bad as the news about global warming seems to be, with ice at the po

Change

As relentlessly bad as the news about global warming seems to be, with ice at the poles melting faster than scientists had predicted and world temperatures rising higher than expected, there was at least a reservoir of hope stored here in Canada's vast forests.

The country's 1.2 million square miles of trees have been called the "lungs of the planet" by ecologists because they account for more than 7 percent of Earth's total forest lands. They could always be depended upon to suck in vast quantities of carbon dioxide, naturally cleansing the world of much of the harmful heat-trapping gas.

But not anymore. In an alarming yet little-noticed series of recent studies, scientists have concluded that Canada's precious forests, stressed from damage caused by global warming, insects and persistent fires, have crossed an ominous (危险的) line and are now pumping out more climate-changing carbon dioxide than they are sinking. Worse yet, the experts predict that Canada's forests will remain net carbon sources, as opposed to carbon storage "sinks", until at least 2022, and possibly much longer.

"We are seeing a significant distortion of the natural trend," said Werner Kurz, senior research scientist at the Canadian Forest Service and the leading expert on carbon cycles in the nation's forests. "Since 1999, and especially in the past five years, the forests have shifted from being a carbon sink to a carbon source."

Translation: Earth's lungs have come down with emphysema(肺气肿). Canada's forests are no longer our friends.

So serious is the problem that Canada's federal government effectively wrote off the nation's forests in 2007 as officials submitted their plans to abide by the international Kyoto Protocol, which obligates participating governments to reduce their greenhouse gas emissions.

Under the Kyoto agreement, governments are permitted to count forest lands as credits, when calculating their national carbon emissions. But Canadian officials, aware of the scientific studies showing that their forests actually are emitting excess carbon, quietly omitted the forest lands from their Kyoto compliance calculations.

"The forecast analysis prepared for the government ... indicates there is a probability that forests would constitute a net source of greenhouse gas emissions," a Canadian Environment Ministry spokesman told the Montreal Gazette.

Canadian officials say global warming is causing the crisis in their forests. Inexorably rising temperatures are slowly drying out forest lands, leaving trees more susceptible to fires, which release huge amounts of carbon into the atmosphere.

Higher temperatures also are accelerating the spread of a deadly pest known as the mountain pine beetle, which has destroyed pine forests across British Columbia and is threatening vital wood in the neighboring province of Alberta. More than 50,000 square miles of British Columbia's pine forest have been stricken so far with the markers of death: needles turn bright red before falling off the tree.

Bitter cold Canadian winters used to kill off much of the pine beetle population each year, naturally keeping it in check. But the milder winters of recent years have allowed the insect to grow rapidly. "That's what's causing some of our forests to switch from a carbon sink position to a source position," said Jim Snetsinger, British Columbia's chief forester. "Once those infested trees axe killed by the pine beetle, they are no longer taking in carbon -- they are giving it off. "

Snetsiuger noted that eventually, over the course of a generation, some of the dying forests will begin to regenerate and once again begin storing more carbon than they release. But for the foreseeable future, experts say, their models show that Canada's forests will stay stuck in a bad global-warming c

A．they balance the world temperatures

B．they are abundant to cleanse the earth's atmosphere and play an important role in cleansing the earth's atmosphere

C．they could always suck in vast quantities of carbon dioxide

D．they naturally cleanse much of the harmful heat-trapping gas

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第7题

The Melting Pot 名词解释

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第8题

The warming continues, ___ more ice.

A.melts

B.melting

C.melted

D.having melted

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第9题

How Global Warming WorksGases in the Earth's atmosphere act like glass in a greenhouse—tra

How Global Warming Works

Gases in the Earth's atmosphere act like glass in a greenhouse—trapping heat and making life on Earth possible. But there is a delicate balance. Burning coal, oil and natural gas increases atmospheric concentrations of these gases. Over the past century, increases in industry, transportation, and electricity production have increased gas concentrations in the atmosphere faster than natural processes can remove them leading to human-caused warming of the globe.

The Sources Of Global Warming

The major source of global warming is carbon dioxide pollution from power plants, automobiles, and industry. Another source is global deforestation.

Power plants are responsible for more than a third of U.S. CO2 emissions, yet there are no caps on CO2 emissions from power plants or any other industry.

Gas guzzling cars and light trucks are also responsible for a third of U.S. CO2 emissions. Current regulations allow for very inefficient vehicles which spew tons of CO2.

Trees remove carbon dioxide from the air as they grow. When they are cut and burned CO2 is released back into the atmosphere. Massive deforestation around the globe is releasing large amounts of CO2 and decreasing the forests' ability to take CO2 from the atmosphere.

Solutions

The U.S., with only four percent of the world's population, is responsible for 22 percent of the world's greenhouse gas emissions. Fortunately, solutions exist to cut our global warming emissions. Decision makers in the United States should take the following steps.

Increasing fuel efficiency standards for cars and light trucks would cut millions of tons of CO2 pollution as well as decreasing dependence on foreign oil.

Putting a cap on CO2 from power plants would cut millions of tons of CO2 pollution as well as decreasing pollution that causes acid rain, smog, and respiratory illness.

Shifting investment from fossil fuels like coal and oil to renewable energy and energy efficiency would allow cleaner, more sustainable sources of energy to take their rightful place as market leaders.

Ratification of the Kyoto Protocol would be a modest but important first step toward international emissions reductions.

The Evidence

Recently, alarming events that are consistent with scientific predictions about the effects of climate change have become more and more commonplace. The global average temperature has increased by about 0.5℃ and sea level has risen by about 10 inches(25 cm) in the past century. Official confirmation came in 1995, when the Intergovernmental Panel on Climate Change, an officially appointed international panel of over 2,500 of the world's leading scientific experts, found that evidence suggests a human influence on the global climate.

The following are events which consistent with scientists' predictions of the effects of global warming:

The past two decades have witnessed a stream of new heat and precipitation records. The 10 hottest years on record have all occurred since 1980, the hottest year ever on record is 1997, and the hottest January through July on record occurred in 1998.

Glaciers are melting around the world. Alaska's Columbia Glacier has retreated more than eight miles in the last 16 years while temperatures there have increased. A section of an Antarctic ice shelf as big as the District of Columbia broke off.

Severe floods like the devastating Midwestern floods of 1993 and 1997 are becoming more common.

Infectious diseases are moving into new areas as seen in the recent outbreaks of Dengue fever in Texas and Malaria in New Jersey.

The Opposition

The Global Climate Coalition, a powerful coalition of oil, power, and auto companies has followed the lead of tobacco companies by denyi

A．Y

B．N

C．NG

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第10题

Melting point ofAspirin is about 136°C （bath fluid is heated at 130°C previously).（)

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