Buzz
Just over a century ago, figures like Scott, Shackleton, and Mawson faced Antarctica’s blizzards, cold, and deprivation. In the name of Empire and in an era of heroic exploits, they crafted an impression of Antarctica that persisted well into the 20th century – a vision of remoteness, adversity, desolation, and solitude reserved for only the bravest. It was portrayed as a place detached from everyday reality, devoid of apparent value to anyone.
B
Entering the 21st century, our perception of Antarctica has evolved. While physically Antarctica remains distant and likely just as cold, and spending time there still requires a commitment uncommon in everyday life, the continent and its surrounding ocean are increasingly recognized as integral parts of Planet Earth and crucial components of the Earth System. Is this because the world seems smaller these days, compressed by media and tourism, or because Antarctica truly holds a central position in the Earth’s ecosystem? Scientific research over the past five decades has revealed – and continues to reveal – that Antarctica’s vast mass and frigid temperatures exert significant influence on climate and ocean currents, impacting millions of lives worldwide.
C
Antarctica wasn't always cold. The gradual breakup of the supercontinent Gondwana, coupled with the northward drift of Africa, South America, India, and Australia, eventually created sufficient space around Antarctica for the formation of an Antarctic Circumpolar Current (ACC) flowing west to east under the prevailing westerly winds. Antarctica cooled, its flora vanished, glaciation began, and the continent assumed its current appearance. Today, the ice covering the bedrock reaches thicknesses of up to 4 km, with surface temperatures plunging as low as –89.2°C. The chilling gusts sweeping over the ice cap and out to sea – known as katabatic winds – can reach speeds of up to 300 km/h, resulting in formidable wind-chill effects.
D
From this extreme environment emerge potent forces that resonate globally. The Earth's rotation, combined with the creation of low-pressure cells off Antarctica's coast, offers astronauts a view of Antarctica that is as breathtaking as it is magnificent. These cells move northeastward, intensifying and deepening, churning the Southern Ocean into turbulent seas revered by sailors. Recent studies indicate that ocean temperatures may better predict rainfall in Australia than the pressure difference between Darwin and Tahiti – the Southern Oscillation Index. With more accurate predictions, graziers in northern Queensland can avoid overstocking during dry years, reducing losses and preventing serious pasture degradation that could take decades to rectify. CSIRO is developing this as a prototype forecasting system, and as our knowledge of Antarctica and the Southern Ocean grows, so too will our ability to enhance and extend predictive capabilities.
E
The ocean's surface temperature results from the interplay between deep-water temperature, air temperature, and ice cover. Each winter, between 4 and 19 million square kilometers of sea ice form, trapping vast amounts of heat near the continent. Only now are we beginning to understand the influence of sea ice on southern Australia's weather patterns. Sea ice also extends its influence beyond Antarctica. Antarctic krill – small shrimp-like crustaceans that are the staple diet for baleen whales, penguins, some seals, flighted seabirds, and many fish – thrive in years with extensive sea ice and struggle when ice cover is sparse. Many species of baleen whales and flighted seabirds migrate between hemispheres, thriving when krill populations are plentiful.
F
The global ocean circulation system functions like a vast conveyor belt, transporting water, minerals, and nutrients between hemispheres and from the deep ocean to the surface. The Antarctic Circumpolar Current (ACC) is the world's longest current with the greatest flow rate. It connects the deep waters of the Atlantic, Indian, and Pacific Oceans, contributing to the global thermohaline circulation. During winter, fierce katabatic winds sometimes clear ice from patches of the sea surface, forming expansive ice-covered lagoons known as 'polynyas'. Recent research reveals that as fresh sea ice forms, it is swiftly swept away by the wind, sometimes traveling up to 90 kilometers in a single day. Because only freshwater freezes into ice, the remaining water becomes saltier and denser, sinking until it spills over the continental shelf. Cold water holds more oxygen than warm water, so as it rises in the northern hemisphere, it replenishes and revitalizes the ocean. The condition and productivity of northern hemisphere oceans owe much to Antarctic processes.
Questions 1-5
The reading passage consists of seven paragraphs labeled A-F
Which paragraph contains the following information?
Indicate the correct letter A-F in boxes 1-5 on your answer sheet.
1 The example of research on weather prediction on agriculture
2 Antarctic sea ice brings life back to the world oceans’ vitality.
3 A food chain that influences the animals living pattern based on Antarctic fresh sea ice
4 The explanation of how atmosphere pressure above Antarctica can impose an effect on global climate change
5 Antarctica was once thought to be a forgotten and insignificant continent
Questions 6-8
Summary
Please match the natural phenomenon with correct determined factor
Select the correct answer from the options below:
Write the appropriate letter A-F in boxes 6-8 on your answer sheet.
6. Globally, mass Antarctica’s size and 6 … influence climate change
7. 7 … contributory to western wind
8. Southern Oscillation Index based on air pressure can predict 8 … in Australia
A Antarctic Circumpolar Current (ACC)
B katabatic winds
C rainfall
D temperature
E glaciers
F pressure
Questions 9-13
Choose the correct letter A, B, C or D.
Enter your response in boxes 22-26 on your answer sheet.
9. In paragraph B, the author wants to tell which of the following truth about the Antarctic?
A To show Antarctica has been a central topic of global warming in Mass media
B To illustrate its huge sea ice brings food to million lives to places in the world
C To show it is the heart and its significance to the global climate and current
D To illustrate it locates in the central spot on Earth geographically
10. Why do Australian farmers keep an eye on the Antarctic ocean temperature?
A Help farmers reduce their economic or ecological losses
B Retrieve grassland decreased in the overgrazing process
C Prevent animal from dying
D A cell provides fertilizer for the grassland
11. What is the final effect of katabatic winds?
A Increase the moving speed of ocean current
B Increase salt level near the ocean surface
C Bring fresh ice into southern oceans
D Pile up the mountainous ice cap respected by mariners
12. The break of the continental shelf is due to the
A Salt and density increase
B Salt and density decrease
C global warming resulting in a rising temperature
D fresh ice melting into ocean water
13. The decrease in the number of Whales and seabirds is due to
A killers whales are more active around
B Sea birds are affected by high sea level salty
C less sea ice reduces the productivity of food source
D seals fail to reproduce babies
Answers:
1. D (Đoạn D; Cho ví dụ về dự đoán nhiệt độ tại Queensland)
2. F (Đoạn F; Lượng băng mà Đại tây dương mang lại giúp đem lại sự sống cho trái đất)
3. E (Đoạn E; Bàn về chuỗi thức ăn của một số loài động vật khác nhau)
4. C (Đoạn C; Giải thích vì sao áp suất ở Đại tây dương có thể gây ra biến đổi khí hậu)
5. A (Đoạn A; Đại tây dương từng bị trôi vào quên lãng)
6. D (Đoạn B, “that Antarctica’s great mass and low temperature exert a major influence on climate and ocean circulation, factors which influence the lives of millions of people all over the globe.”
7. A (Đoạn C, “ Antarctic Circumpolar Current (ACC), that flowed from west to east under the influence of the prevailing westerly winds.”)
8. C (Đoạn D, “Recent work is showing that the temperature of the ocean may be a better predictor of rainfall in Australia than is the pressure difference between Darwin and Tahiti – the Southern Oscillation Index.”
9. C (Đoạn B, “…that Antarctica’s great mass and low temperature exert a major influence on climate and ocean circulation, factors which influence the lives of millions of people all over the globe.”)
10. A (Đoạn D, “By receiving more accurate predictions, graziers in northern Queensland are able to avoid overstocking in years when rainfall will be poor. Not only does this limit their losses but it prevents serious pasture degradation that may take decades to repair.”)
11. C (Đoạn C, “The icy blast that howls over the ice cap and out to sea – the so-called katabatic wind – can reach 300 km/hr, creating fearsome wind-chill effects.”)
12. C (Paragraph F: “Since only freshwater freezes into ice, the remaining water becomes increasingly salty and dense, sinking until it spills over the continental shelf. Cold water contains more oxygen than warm water, so when it rises, well into the northern hemisphere, it replenishes and revitalizes the ocean.”)13. C (Paragraph E: “Antarctic krill – small shrimp-like crustaceans that are the staple diet for baleen whales, penguins, some seals, flighted seabirds, and many fish – thrive in years with extensive sea ice and struggle when it is scarce.”)IELTS Practice
