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SECTION TEST - ACADEMIC READING
(Time: 60 minutes)

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Passage 1

The Gulf Stream and Global Warming

Labrador and London lie at about the same latitude, but Labrador is frigid and has only 30 miles of paved roads while London is one of the major centers of civilization. Why do two places, equidistant from the Arctic Circle, have such disparate climates? The Gulf Stream that flows by the British Isles makes all the difference: Its warm waters make northwestern Europe so abundant with life that palm trees can actually grow on the southern shores of England.

This life-giving Gulf Stream is warm, salty water, which travels along the surface of the Atlantic Ocean from the Caribbean, along the east coast of the United States, and then veers toward Europe. In the tropics, this water is warmed by the sun and becomes saltier because of the higher rate of evaporation in the heat. The Gulf Stream divides as it travels, but the majority of the stream moves north and east. As it travels past Europe, the Gulf Stream warms the atmosphere, and the prevailing westerly winds bring the warmed air to all of northwestern Europe, making the area suitable for intense agriculture. The Gulf Stream makes it possible for Europe to feed an increasingly large population.

After the Gulf Stream reaches southeast Greenland and western Iceland, much of the heat of the stream is gone, and the colder, denser water then sinks. The bulk of the Gulf Stream is carried down toward the ocean floor into as many as seven large vortices, called chimneys. They suck the Gulf Stream waters down over a mile deep, where the water is then drawn into another dynamic ocean current. Almost 2 miles below the surface, this cold water current flows in reverse, from the north southward. When this cold water nears the equator, it is again pulled up from the bottom of the ocean as the surface water is heated and starts its journey north. This upwelling brings with it minerals and food from the detritus at the bottom of the ocean to refresh food supplies for fish and other marine creatures.

This stream of water—the warm water traveling north along the surface and the cold water traveling south along the floor—has become known as the Great Ocean Conveyor Belt. This flow of ocean currents has been extremely important in regulating the temperature of the globe and in making life possible. These currents in the North Atlantic are part of the Great Conveyor Belt that flows through all the oceans of the world. The least stable section of this global current is in the North Atlantic. The Gulf Stream is the most unstable of all.

Predictions of the effects of global warming on the Gulf Stream are based on computer models, which differ to some extent. But several important facts are known. South of Greenland, there used to be as many as seven chimneys that pulled water from the Gulf Stream down toward the ocean floor. In the last several years, only one remained, and then, in 2007, that one disappeared. The causes for the demise of the chimneys may include the increase in fresh water from glacial melt. In recent winters, glacial melt has released record amounts of fresh water into the oceans. As the North Atlantic waters, including fresh water from rivers as well as the increased amount of glacial melt, mix with the Gulf Stream, the salt water is diluted. Because fresh water is not as dense as salt water, it does not sink, which impairs the natural mechanism for forming the chimneys. As the chimneys have disappeared, the Gulf Stream has slowed. About 30 percent of the water from the Gulf Stream that used to reach Europe travels elsewhere or is lost in the disintegration of the current, a loss of over six million tons of water flow every second. Without a strong Gulf Stream, the slow, cold water of the lower part of the conveyor belt fails to rise, which reduces the circulation of nutrients for marine life. The problem of warming then worsens: As less surface water, which is full of carbon dioxide from the atmosphere, siphons into the depths of the ocean, less carbon dioxide is removed from the atmosphere, thus increasing global warming.

Ocean sediments and glacial cores show that there have been global swings in temperature in the past. The last Ice Age, when much of North America and northern Europe were covered in glaciers 2 miles thick, occurred when the average Temperture dropped about 5 degrees Celsius. That ice age ended about 20,000 years ago. The last “Little Ice Age,” when the average temperature dropped only 1 to 2 degrees Celsius, occurred in the sixteenth and seventeenth centuries, hitting Europe hardest. At that time, the Gulf Stream had slowed to about half its usual rate.

Core samples also show that the changes in temperature have been abrupt, not gradual. There would be little time to prepare for the devastating changes resulting from the weakening of the Gulf Stream. The good news is that in the winters of 2008 and 2009, one of the chimneys off southeastern Greenland suddenly burst into action again, bringing the Gulf Stream waters down deep enough to be caught in the conveyor and to keep the ocean currents in the North Atlantic flowing.

The flow chart below shows a possible effect of global warming on the Gulf Stream. Complete the flow chart using the list of words below.

less salty	colder	warmer
sink	rise	weakened
strengthened	heated	food
thaw	air	form

sink less salty thaw weakened food rise

(1).
(2).
(3).
(4).
(5).
(6).

Passage 2

DISAPPEARING DELTA

(A) The fertile land of the Nile delta is being eroded along Egypt's Mediterranean coast at an astounding rate, in some parts estimated at 100 metres per year. In the past, land scoured away from the coastline by the currents of the Mediterranean Sea used to be replaced by sediment brought down to the delta by the River Nile, but this is no longer happening.

(B) Up to now, people have blamed this loss of delta land on the two large dams at Aswan in the south of Egypt, which hold back virtually all of the sediment that used to flow down the river. Before the dams were built, the Nile flowed freely, carrying huge quantities of sediment north from Africa's interior to be deposited on the Nile delta. This continued for 7,000 years, eventually covering a region of over 22,000 square kilometres with layers of fertile silt. Annual flooding brought in new, nutrient-rich soil to the delta region, replacing what had been washed away by the sea, and dispensing with the need for fertilizers in Egypt's richest food-growing area But when the Aswan dams were constructed in the 20th century to provide electricity and irrigation, and to protect the huge population centre of Cairo and its surrounding areas from annual flooding and drought, most of the sediment with its natural fertilizer accumulated up above the dam in the southern, upstream half of Lake Nasser, instead of passing down to the delta.

(C) Now, however, there turns out to be more to the story. It appears that the sediment-free water emerging from the Aswan dams picks up silt and sand as it erodes the river bed and banks on the 800-kilometre trip to Cairo. Daniel Jean Stanley of the Smithsonian Institute noticed that water samples taken in Cairo, just before the river enters the delta, indicated that the river sometimes carries more than 850 grams of sediment per cubic metre of water - almost half of what it carried before the dams were built.

'I'm ashamed to say that the significance of this didn't strike me until after I had read 50 or 60 studies,' says Stanley in Marine Geology. 'There is still a lot of sediment coming into the delta, but virtually no sediment comes out into the Mediterranean to replenish the coastline. So this sediment must be trapped on the delta Itself.'

(D) Once north of Cairo, most of the Nile water is diverted into more than 10,000 kilometres of irrigation canals and only a small proportion reaches the sea directly through the rivers in the delta. The water in the irrigation canals is still or very slow-moving and thus cannot carry sediment, Stanley explains. The sediment sinks to the bottom of the canals and then is added to fields by farmers or pumped with the water into the four large freshwater lagoons that are located near the outer edges of the delta. So very little of it actually reaches the coastline to replace what is being washed away by the Mediterranean currents.

(E) The farms on the delta plains and fishing and aquaculture in the lagoons account for much of Egypt's food supply. But by the lime the sediment has come to rest in the fields and lagoons it is laden with municipal, industrial and agricultural waste from the Cairo region, which is home to more than 40 million people. 'Pollutants are building up faster and faster,' says Stanley.

Based on his investigations of sediment from the delta lagoons, Frederic Siegel of George Washington University concurs. 'In Manzalah Lagoon, for example, the increase in mercury, lead, copper and zinc coincided with the building of the High Dam at Aswan, the availability of cheap electricity, and the development of major power-based industries/ he says. Since that time the concentration of mercury has increased significantly. Lead from engines that use leaded fuels and from other industrial sources has also increased dramatically. These poisons can easily enter the food chain, affecting the productivity of fishing and farming. Another problem is that agricultural wastes include fertilizers which stimulate increases in plant growth in the lagoons and upset the ecology of the area, with serious effects on the fishing industry.

(F) According to Siegel, international environmental organisations are beginning to pay closer attention to the region, partly because of the problems of erosion and pollution of the Nile delta, but principally because they fear the impact this situation could have on the whole Mediterranean coastal ecosystem. But there are no easy solutions. In the immediate future, Stanley believes that one solution would be to make artificial floods to flush out the delta waterways, in the same way that natural floods did before the construction of the dams. He says, however, that in the long term an alternative process such as desalination may have to be used to increase the amount of water available. 'In my view, Egypt must devise a way to have more water running through the river and the delta/ says Stanley. Easier said than done in a desert region with a rapidly growing population.

Complete the summary of paragraphs E and F with the list of words below.

artificial floods	desalination	delta waterways	natural floods
nutrients	pollutants	population control	sediment

artificial floods desalination pollutants

In addition to the problem of coastal erosion, there has been a marked increase in the level of contained in the silt deposited in the Nile delta. To deal with this, Stanley suggests the use of in the short term, and increasing the amount of water available through in the longer term.

Passage 3

Painters of time

‘The world's fascination with the mystique of Australian Aboriginal art.'

Emmanuel de Roux

A The works of Aboriginal artists are now much in demand throughout the world and not just in Australia, where they are already fully recognised: the National Museum of Australia, which opened in Canberra in 2001, designated 40% of its exhibition space to works by Aborigines. In Europe their art is being exhibited at a museum in Lyon, France, while the future Quai Branly museum in Paris -which will be devoted to arts and civilisations of Africa, Asia, Oceania and the Americas - plans to commission frescoes by artists from Australia.

B Their artistic movement began about 30 years ago, but its roots go back to time immemorial. All the works refer to the founding myth of the Aboriginal culture, ‘the Dreaming’. That internal geography, which is rendered with a brush and colours, is also the expression of the Aborigines' long quest to regain the land which was stolen from them when Europeans arrived in the nineteenth century. ‘Painting is nothing without history,' says one such artist, Michael Nelson Tjakamarra.

C There are now fewer than 400.000 Aborigines living in Australia. They have been swamped by the country's 17.5 million immigrants. These original ‘natives' have been living in Australia for 50.000 years, but they were undoubtedly maltreated by the newcomers. Driven back to the most barren lands or crammed into slums on the outskirts of cities, the Aborigines were subjected to a policy of ‘assimilation’, which involved kidnapping children to make them better ‘integrated’ into European society, and herding the nomadic Aborigines by force into settled communities.

D It was in one such community, Papunya, near Alice Springs, in the central desert, that Aboriginal painting first came into its own. In 1971, a white schoolteacher, Geoffrey Bardon, suggested to a group of Aborigines that they should decorate the school walls with ritual motifs, so as to pass on to the younger generation the myths that were starting to fade from their collective memory, lie gave them brushes, colours and surfaces to paint on cardboard and canvases. He was astounded by the result. But their art did not come like a bolt from the blue: for thousands of years Aborigines had been ‘painting’ on the ground using sands of different colours, and on rock faces. They had also been decorating their bodies for ceremonial purposes. So there existed a formal vocabulary.

E This had already been noted by Europeans. In the early twentieth century, Aboriginal communities brought together by missionaries in northern Australia had been encouraged to reproduce on tree bark the motifs found on rock faces. Artists turned out a steady stream of works, supported by the churches, which helped to sell them to the public, and between 1950 and I960 Aboriginal paintings began to reach overseas museums. Painting on bark persisted in the north, whereas the communities in the central desert increasingly used acrylic paint, and elsewhere in Western Australia women explored the possibilities of wax painting and dyeing processes, known as ‘batik’.

F What Aborigines depict are always elements of the Dreaming, the collective history that each community is both part of and guardian of, The Dreaming is the story of their origins, of their ‘Great Ancestors’, who passed on their knowledge, their art and their skills (hunting, medicine, painting, music and dance) to man. ‘The Dreaming is not synonymous with the moment when the world was created.' says Stephane Jacob, one of the organisers of the Lyon exhibition. ‘For Aborigines, that moment has never ceased to exist. It is perpetuated by the cycle of the seasons and the religious ceremonies which the Aborigines organise. Indeed the aim of those ceremonies is also to ensure the permanence of that golden age. The central function of Aboriginal painting, even in its contemporary manifestations, is to guarantee the survival of this world. The Dreaming is both past, present and future.’

G Each work is created individually, with a form peculiar to each artist, but it is created within and on behalf of a community who must approve it. An artist cannot use a ‘dream’ that does not belong to his or her community, since each community is the owner of its dreams, just as it is anchored to a territory marked out by its ancestors, so each painting can be interpreted as a kind of spiritual road map for that community.

H Nowadays, each community is organised as a cooperative and draws on the services of an art adviser, a government-employed agent who provides the artists with materials, deals with galleries and museums and redistributes the proceeds from sales among the artists.

Today, Aboriginal painting has become a great success. Some works sell for more than $25,000, and exceptional items may fetch as much as $180,000 in Australia.

I 'By exporting their paintings as though they were surfaces of their territory', by accompanying them to the temples of western art, the Aborigines have redrawn the map of their country, into whose depths they were exiled,’ says Yves Le Fur, of the Quai Branly museum. ‘Masterpieces have been created. Their undeniable power prompts a dialogue that has proved all too rare in the history of contacts between the two cultures’.

Complete the flow chart below. Choose NO MORE THAN THREE WORDS from the passage for each answer.

overseas museums thousands of years tree bark/bark school walls

(1)
(2)
(3)
(4)

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