Techniques For Removing Carbon Dioxide From The Atmosphere - IELTS Listening Answers & Explanations
From IELTS Recent Actual Test 6 Academic Listening Test 6 · Part 4 · Questions 31–40
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Questions
Questions 31–33 Multiple Choice (One Answer)
Choose the correct letter, A, B, or C.
Questions 34–40 Table Completion
Complete the table.
Write NO MORE THAN TWO WORDS OR A NUMBER for each answer.
| Three Problems of Geosequestration | ||
|---|---|---|
| Risk of leaks | Cost | 34 still not proven |
| Gas would become 35 | expensive, particularly the 36 | Require the plant to burn 37 of its coal |
| ↓ | ↓ | ↓ |
| risk of widespread 38 | Price of electricity could 39 | release of more Sulphur, ash, and 40 |
Answers & Explanations Summary
| # | Answer | Evidence | Explanation |
|---|---|---|---|
| Q31 | B | This gas comes from the burning of fossil fuels, such as coal and oil, and it is virtually impossible for society to prevent, or even limit such activity | Excerpt/Transcript Explanation: The transcript says that it is almost impossible for people to stop or reduce the burning of fuel which releases the gas because the need for power is so high. Answer Explanation: The answer says that people cannot lower the amount of CO2 gas that is produced or sent into the air. Reason For Correctness: The correct answer is B because the speaker mentions that society burns coal and oil for energy, and it is "virtually impossible" to stop or even "limit" (lessen/reduce) this. Since burning these fuels produces CO2, society cannot effectively reduce the creation of this waste gas, even though it causes global warming. |
| Q32 | B | Even when enhancing this process through high temperature and pressure, or pre-treatment of the mineral, it is still far too slow to be economical | Excerpt/Transcript Explanation: The transcript explains that even when we try to make the process better or faster using heat and pressure, it is still not fast enough to be a good way to save money while cleaning the air. Answer Explanation: The answer means that we are able to speed up the process of changing carbon dioxide gas into a hard material. Reason For Correctness: The correct answer is B because the lecturer explains that scientists can use special methods like high heat, high pressure, or treating the minerals first to help this change happen. Even though the lecturer says the process is still not fast enough to be cheap to use (economical), these methods are intended to 'enhance' or improve the speed of the natural reaction. |
| Q33 | B | The CO2 may be removed from the atmosphere, but the high oceanic acidity which would result raises its own set of problems, mostly with all the delicate life and the intricate food chains in the seawater, some on which we ourselves depend -- and that's something which no one wants to experiment with | Excerpt/Transcript Explanation: The transcript explains that dumping carbon dioxide into the sea would create high acid levels. This is dangerous because it would hurt the sensitive animals and the complex webs of life (food chains) that exist in the water. Answer Explanation: The answer B means that the ocean contains many different living things that rely on each other in a complex way. Reason For Correctness: The correct answer is chosen because the lecturer mentions that the ocean has 'intricate food chains.' In simple English, an 'intricate food chain' refers to a system where many different types of life are closely connected because they eat or depend on one another. The lecturer warns that changing the ocean's chemistry would harm these connected lives. |
| Q34 | effectiveness | This carries, however, three serious disadvantages, namely: the risk of leaks, the considerable costs involved, and finally, the unproven effectiveness | Excerpt/Transcript Explanation: The transcript says that there are three big problems with this method. It lists the last problem as the "unproven effectiveness," which means we do not know for sure if it really works. Answer Explanation: The answer "effectiveness" means how well a method works to solve a problem. Reason For Correctness: The correct answer is "effectiveness" because the lecturer lists three specific problems with the technique of putting gas underground. These problems are leaks, costs, and "unproven effectiveness." The table asks for what thing is "still not proven," which matches the speaker's use of the word "unproven." |
| Q35 | a liquid / liquid | Although the gas would be deep and sealed over by masses of rock and earth, the huge pressures in these spaces would turn the gas into a liquid state, capable of moving through rock fissures or faults | Excerpt/Transcript Explanation: The transcript explains that deep underground, the very strong pressure turns the gas into a liquid. This liquid form is dangerous because it can move through small cracks in the rocks and leak out. Answer Explanation: The answer explains that the carbon dioxide gas changes from a gas into a liquid form when it is put into spaces deep underground. Reason For Correctness: The correct answer is based on the section of the talk discussing the 'risk of leaks.' The speaker notes that when carbon dioxide gas is pumped into deep underground spaces, the very high pressure (huge pressures) causes the gas to change its state. Instead of staying as a gas, it becomes a liquid, which allows it to flow through cracks (fissures) in the rocks. |
| Q36 | pipework | The time and effort spent on materials and construction, primarily the pipework through which the gas would travel, does not come cheaply | Excerpt/Transcript Explanation: The transcript explains that building the pipes for the gas is a main reason why this method costs so much money. Answer Explanation: The answer "pipework" refers to the system of pipes used to move the carbon dioxide gas. Reason For Correctness: The correct answer is "pipework" because the lecturer discusses the high cost of geosequestration. They explain that building the system is expensive, especially the "pipework" or pipes. This makes the overall price very high. Important words to notice are "expensive" (matching "does not come cheaply") and "pipework" (representing the specific high-cost item). |
| Q37 | a quarter / one quarter / one-quarter | In other words, the plant would have to burn one quarter more of its coal just to account for the sequestration of the carbon dioxide, and with coal producing other noxious pollutants, such as sulphur, ash, and heavy metals, the environment is hardly benefited at all | Excerpt/Transcript Explanation: The transcript states that to store the gas, the power station must use 25% (one quarter) more coal than usual. Because burning coal also creates other types of pollution, this extra coal use might not actually help the environment. Answer Explanation: The answer is the specific portion (1/4 or 25%) of the coal that a power plant would need to use just to run the machine that stores carbon dioxide. Reason For Correctness: The correct answer is identified in the transcript when discussing the third problem of geosequestration: its effectiveness. The speaker explains that the process itself uses a lot of energy. Specifically, the plant would need to use one-quarter more of its fuel (coal) just to power the system that captures the CO2. This means more coal is burned to fix the problem caused by burning coal. |
| Q38 | suffocation | Since CO2 is heavier than air, and thus pushes oxygen aside, such leaks could result in the suffocation of thousands, or tens of thousands of people — certainly not a consequence to be taken lightly | Excerpt/Transcript Explanation: The transcript explains that if the gas leaks, it replaces the oxygen in the air, which can cause thousands of people to die because they cannot breathe. Answer Explanation: The answer "suffocation" means a situation where someone dies because they cannot breathe oxygen. Reason For Correctness: The correct answer is "suffocation" because the lecturer describes it as a dangerous result of gas leaking from underground storage. Since CO2 is heavier than the air we normally breathe, a leak would push the oxygen away, making it impossible for people nearby to breathe. This leads to a risk of many people dying. |
| Q39 | almost double / double | the extra cost would have to be paid by the electricity user, whose bills would almost double as a consequence | Excerpt/Transcript Explanation: The transcript explains that the people who use electricity will have to pay the extra money for the new system, and because of that, their bills will become nearly two times larger. Answer Explanation: The answer means that the cost of electricity would increase until it is nearly twice its current price. Reason For Correctness: The correct answer is found in the section of the talk about 'The other problem of geosequestration is the cost'. The speaker explains that because building the pipework is very expensive, this cost would be passed to the people using electricity. As a result, their electricity bills would 'almost double'. In this context, 'double' is the specific word used to describe the change in price. |
| Q40 | heavy metals | In other words, the plant would have to burn one quarter more of its coal just to account for the sequestration of the carbon dioxide, and with coal producing other noxious pollutants, such as sulphur, ash, and heavy metals, the environment is hardly benefited at all | Excerpt/Transcript Explanation: The transcript explains that burning more coal to power the cleaning process actually releases other bad pollutants, including sulphur, ash, and heavy metals. Answer Explanation: The answer "heavy metals" refers to dangerous substances like lead or mercury that are released into the air when coal is burned for energy. Reason For Correctness: The correct answer is located in the final paragraph where the lecturer explains why burying carbon may not be effective. Because the machine used to bury the gas needs a lot of power, the factory has to burn more coal. This extra burning releases more harmful things besides carbon dioxide. The speaker lists these harmful pollutants as "sulphur, ash, and heavy metals." |
Transcript
You will hear a lecturer discussing techniques for removing carbon dioxide from the atmosphere.
We all know about the role of carbon dioxide in causing global warming. Obviously, society needs to reduce the release of carbon dioxide, otherwise known as CO2. This gas comes from the burning of fossil fuels, such as coal and oil, and it is virtually impossible for society to prevent, or even limit such activity. Our need for energy and power is just too great. Instead, a more practical idea is to collect the carbon dioxide from the burning process, for example, directly from the chimneys of power stations, and somehow prevent this gas from being released into the environment. To do that, you need to store it somehow, and that has to be essentially forever.
It is perhaps for this reason that many believe that, rather than storing the carbon dioxide as a gas, it is better to react it with metal oxides, such as magnesium or calcium, which results in the formation of a hard carbonate material. The gas is, in effect, turned into a stable and unreactive solid, which can simply be dumped anywhere. This process actually occurs naturally, although very very slowly, and is one cause of the surface limestone in the world. But this slow reaction speed is the problem. Even when enhancing this process through high temperature and pressure, or pre-treatment of the mineral, it is still far too slow to be economical.
One other technique which has been suggested is to pump the gas to the bottom of the ocean, where it would react with compounds in the seawater, forming carbonic acid. However, this alternative has now been ruled out. The CO2 may be removed from the atmosphere, but the high oceanic acidity which would result raises its own set of problems, mostly with all the delicate life and the intricate food chains in the seawater, some on which we ourselves depend -- and that's something which no one wants to experiment with.
Perhaps because of the lack of alternatives, the most commonly discussed solution to the problem of disposing of carbon dioxide is to pump the gas underground - a technique known as ‘geosequestration’. In this system, the CO2, for example, could be pumped into underground pockets within depleted oil wells, or disused coal tunnels. This carries, however, three serious disadvantages, namely: the risk of leaks, the considerable costs involved, and finally, the unproven effectiveness. Let us look at those three disadvantages in detail.
Firstly, there is the risk of leaks. Although the gas would be deep and sealed over by masses of rock and earth, the huge pressures in these spaces would turn the gas into a liquid state, capable of moving through rock fissures or faults. This could allow the gas to eventually be released to the surface. Since CO2 is heavier than air, and thus pushes oxygen aside, such leaks could result in the suffocation of thousands, or tens of thousands of people — certainly not a consequence to be taken lightly. Natural CO2 leakage from volcanic build-up has already witnessed such deadly events.
The other problem of geosequestration is the cost. The time and effort spent on materials and construction, primarily the pipework through which the gas would travel, does not come cheaply. So, if this system were to be implemented in, say, coal-fired power plants, the extra cost would have to be paid by the electricity user, whose bills would almost double as a consequence. Few people are prepared to pay this much simply to make a small dent on the effects of global warming. And this leads to the final problem.
The most basic question is whether geosequestration actually reduces global warming. The problem here is that the energy needed to create and drive the sequestration process would require approximately a quarter of a coal-fired electricity plant's output. In other words, the plant would have to burn one quarter more of its coal just to account for the sequestration of the carbon dioxide, and with coal producing other noxious pollutants, such as sulphur, ash, and heavy metals, the environment is hardly benefited at all. Nevertheless, there are many active experimental efforts underway, primarily in oil production sites. These are small but intensively monitored and analysed. All we can say now is that the jury is still out on whether underground carbon storage will one day be feasible.