Download 21 Diagnostic Test Read “World Is Skating on Thin Ice” before

Read “World Is Skating on Thin Ice” before answering Numbers 28 through 36.
World Is Skating on
THIN ICE
From National Life Magazine
I
f any explorers had been hiking to the North
Pole this summer, they would have had to
swim the last few miles. The recent discovery
of open water at the Pole by an icebreaker
cruise ship has surprised many in the scientific
community.
This finding, combined with two recent
scientific studies, confirms that the Earth’s ice
cover is melting at an accelerating rate. A study by
two Norwegian scientists projects that within 50
years the Arctic Ocean could be ice-free during the
summer. The other study, by a team of four U.S.
scientists, reports that the vast Greenland ice sheet
is melting.
An earlier study reported that the thickness of
the ice sheet has been reduced by 42 percent over
the last four decades. The area of the ice sheet has
also shrunk by six percent. This thinning and
shrinkage has reduced the Arctic Ocean ice mass
by nearly half.
Meanwhile, Greenland is gaining some ice in
the higher altitudes, but it is losing much more at
lower elevations, particularly along its southern
and eastern coasts. The huge island of 2.2 million
square kilometers is experiencing a net loss of
some 51 billion cubic metres of water each year, an
amount equal to the annual flow of the Nile River.
The Antarctic is also losing ice. In contrast
to the North Pole, which is covered by the Arctic
Sea, the South Pole is covered by the Antarctic
continent, a land mass roughly the size of the
United States. Its continent-sized ice sheet, which
is on average 2.3 kilometers thick, is relatively
stable. But the ice shelves, the portions of the ice
sheet that extend into the surrounding seas, are
fast disappearing.
A team of American and British scientists
reported in 1999 that the ice shelves on either side
of the Antarctic Peninsula are in full retreat. From
roughly mid-century through 1997, these areas
lost 7,000 square kilometers. Huge icebergs that
have broken off are threatening ships in the area.
Scientists attribute the accelerated ice melting to
a regional temperature rise of some 2.5 degrees
Celsius since 1940.
These are not the only examples of melting.
Lester Brown of the Worldwatch Institute, in an
Issue Alert released today says, “My colleague,
Lisa Mastny, who has reviewed some 30 studies
on this topic, reports that ice is melting almost
everywhere—and at an accelerating rate. The
snow/ice mass is shrinking in the world’s major
mountain ranges: the Rocky Mountains, the
Andes, the Alps, and the Himalayas. In Glacier
National Park in Montana, the number of glaciers
has dwindled from 150 in 1850 to fewer than 50
today. The U.S. Geological Survey projects that
the remaining glaciers will disappear within 30
years.”
Scientists studying the Quelccaya glacier in
the Peruvian Andes report that its retreat has
accelerated from 3 meters a year between roughly
1970 and 1990 to 30 meters a year since 1990.
In Europe’s Alps, the shrinkage of the glacial
area by 35 to 40 percent since 1850 is expected
to continue. These ancient glaciers could largely
disappear over the next half-century.
Brown notes that shrinkage of ice masses in
the Himalayas has also accelerated alarmingly. In
eastern India, the Dokriani Bamak glacier, which
retreated by 16 meters between 1992 and 1997,
drew back by a further 20 meters in 1998 alone.
The Worldwatch Institute
warns that if the massive snow/ice
mass in the Himalayas—which is
the third largest in the world after
the Greenlandic and Antarctic
ice sheets—continues to melt,
it will affect the water supply of
much of Asia. All of the region’s
major rivers—the Indus, Ganges,
Mekong, Yangtze, and Yellow—
originate in the Himalayas. The
melting in the Himalayas could
alter the hydrology of several
Asian countries, including
Pakistan, India, Bangladesh,
Thailand, Vietnam, and China.
Antarctica landscape with icebergs that have broken off due to accelerated
Less snowmelt in the summer
ice melting. They are a threat to ships in the area.
dry season to feed rivers could
exacerbate the hydrological poverty
This melting and shrinkage of snow/ice masses
should not come as a total surprise. Swedish
already affecting so many in the region.
scientist Svente Arrhenius warned at the beginning
As the ice on land melts and flows to the sea,
of the last century that burning fossil fuels could
sea level rises. Over the last century, sea level
rose by 20 to 30 centimeters. During this century,
raise atmospheric levels of carbon dioxide (CO2),
creating a greenhouse effect. Atmospheric CO2
the existing climate models indicate it could
rise by as much as one meter. If the Greenland
levels, estimated at 280 parts per million (ppm)
ice sheet, which is up to 3.2 kilometers thick in
before the Industrial Revolution, have climbed
places, were to melt entirely, sea level would rise
from 317 ppm in 1960 to 368 ppm in 1999—a gain
of 16 percent in only four decades.
by 7 meters.
Even a much more modest rise would affect
As CO2 concentrations have risen, so too has
the low-lying river floodplains of Asia, where
Earth’s temperature. Between 1975 and 1999, the
much of the region’s rice is produced. According to
average temperature increased from 13.94 degrees,
a gain of 0.41 degrees in 24 years. The warmest 23
World Bank analysis, a one-meter rise in sea level
years since record keeping began in 1866 have all
would cost low-lying Bangladesh half its Riceland.
occurred since 1975.
Numerous low-lying island countries would have
Researchers are discovering that a modest rise
to be evacuated. The residents of densely populated
in temperature of only one or two degrees Celsius
river valleys of Asia would be forced inland into
in mountainous regions can dramatically increase
already crowded interiors. Rising sea level could
create climate refugees by the millions in countries
the share of precipitation falling as rain while
decreasing the share coming down as snow. The
such as China, India, Bangladesh, Indonesia,
Vietnam, and the Philippines.
result is more flooding during the rainy season, a
Even more disturbing, ice melting itself can
shrinking snow/ice mass, and less snowmelt to feed
rivers during the dry season.
accelerate temperature rise. As snow/ice masses
These “reservoirs in the sky,” where nature
shrink, less sunlight is reflected back into space.
With more sunlight absorbed by less reflective
stores fresh water for use in the summer as
surfaces, temperature rises even faster and melting
the snow melts, are shrinking and some could
disappear entirely. This will affect the water supply
accelerates.
Brown says that we don’t have to sit idly by as
for cities and for irrigation in areas dependent on
this scenario unfolds. He says there may still be
snowmelt to feed rivers.
Diagnostic Test
time to stabilize atmospheric CO2 levels before
continuing carbon emissions cause climate change
to spiral out of control. “We have more than
enough wind, solar, and geothermal energy that
can be economically harnessed to power the world
economy. If we were to incorporate the cost of
climate disruption in the price of fossil fuels in the
form of a carbon tax, investment would quickly
shift from fossil fuels to these climate-benign
energy sources.”
Now answer Numbers 28 through 36. Base your answers on “World Is Skating on Thin Ice.”
28. What information led scientists to discover that the Earth’s ice cover is diminishing rapidly?
F. the discovery of the greenhouse effect by a Swedish scientist about 30 years ago
G. the fact that mountainous areas of the world are experiencing more precipitation
H. the discovery by the British that the ice shelf in Antarctic is stable and predictable
I. a discovery of open water at the North Pole and evidence from two scientific studies
29. What effects would the rising sea level have on Bangladesh?
A. The rainfall would increase and the ice mass would diminish.
B. Mountainous areas would see less rainfall, depleting summer water reserves.
C. The country would lose much of its farmland forcing residents to move inland.
D. Temperatures of low-lying areas would rise, forcing people to move to cooler coastal areas.
30. What evidence best supports the author’s claim that people have been aware of the changes in the
earth’s climate for a very long time?
F.
G.
H.
I.
Over the last century, sea levels rose significantly in all parts of the world.
The glaciers in the Alps have shrunk about 40 percent in the last fifty years.
The warmest 23 years have all taken place in approximately the last 30 years.
In the early 20th century, a scientist warned of the risks of increased CO2 levels.
31. What is most likely the author’s purpose in writing this article?
A. to explain how scientists became aware of the reduction of the polar ice cover
B. to convince readers to help fund research to learn the causes of the melting ice cap
C. to illustrate effects of global warming on the world, especially the Asian population
D. to convince readers that the melting ice cap illustrates a need for alternate sources of power
32. What evidence supports the idea that the glaciers in Europe’s Alps may disappear over the next fifty
years?
F.
G.
H.
I.
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The shrinkage of ice masses always follows a consistent pattern.
In the past 150 years, glaciers have shrunk to almost one half their original size.
The shrinking ice mass in the Himalayas has advanced by 36 meters since 1992.
The U.S. Geological Survey projects that the remaining glaciers will disappear soon.
33. How will the melting snow/ice masses in the Himalayas affect the water supply of Asia?
A. The floodplains will overflow and people will need to learn flood control farming.
B. As the snowmelt that feeds rivers diminishes, many countries will become even drier.
C. The amount of precipitation will increase, causing more flooding during the dry season.
D. As the snowmelt decreases, area rivers will change course, no longer flowing into countries that
need water the most.
Diagnostic Test
34. According to the article, how is the Antarctic different from the
North Pole?
F. It is covered by solid ground.
G. It is surrounded by ice shelves.
H. It is studied by climate scientists.
I. It is unaffected by rising CO2 levels.
35. The author organizes the article by
A. explaining the effects of global warming and then listing its causes.
B. presenting a theory about melting ice and then supporting it with examples.
C. describing an arctic hike and then showing how it relates to global warming.
D. describing evidence of melting ice and then giving explanations and solutions.
36. Read this sentence from the article.
The thinning and shrinkage has reduced the Arctic Ocean ice mass by nearly half.
Which of the following sentences uses the word mass with the same meaning as in the
sentence above?
F.
G.
H.
I.
A mass of excited fans crowded around the movie star’s limousine.
Weighted down by its enormous mass, the ocean liner sank rapidly.
Hearing news of the sale, shoppers began to mass outside the store at 5 A.M.
Scientists claimed the mass of the unexplored planet and divided it into colonies.
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