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  3. (1) The cement industry is one of the world’s most polluting: it accounts fo

(1) The cement industry is one of the world’s most polluting: it accounts fo

游客2023-10-28  36
问题     (1) The cement industry is one of the world’s most polluting: it accounts for 5% of man-made carbon-dioxide emissions each year. Making this most useful of glues requires vast quantities of energy and water. Calcium carbonate (generally in the form of limestone), silica, iron oxide and alumina are partially melted by heating them to 1450°C in a special kiln. The result, clinker, is mixed with gypsum and ground to make cement, a basic ingredient of concrete. Breaking down the limestone produces about half of the emissions; almost all the rest come from the burning of fossil fuels to heat the kiln.
    (2) About 4. 3 billion tonnes of cement were consumed in 2014. The industry brings in about $250 billion a year. Cement firms have not attracted the ire of environmental campaigners in the way that oil firms have. But that could change if they shirk efforts to cut emissions in a manner consistent with keeping the world less than 2°C warmer than it was in pre-industrial times (as agreed at U.N. climate talks last year). For now, few cement companies are setting environmental targets that are tough enough.
    (3) The main reason is a lack so far of strong enough financial imperatives, but that is changing. And as is the case for many industries, going green could save firms money. Around a third of cement’s production costs come from energy bills. Retrofitting old kilns to improve thermal efficiency can lower the industry’s energy needs by two-fifths, according to the Carbon Disclosure Project, a research body. Another way to go green is to reduce the amount of clinker in cement by using waste substitutes such as fly ash from coal plants or slag from steel blast furnaces, but these are becoming scarcer and more expensive.
    (4) Capturing carbon and then sequestering it, often underground, is another method for cutting emissions. But the bother and expense of such schemes makes them a rarity. There are variations that can cut costs in rich countries. Rather than stuffing the CO2 spewed out of cement and other plants underground, Blue Planet, a carbon-capture company based in California, creates building materials from it in the form of aggregates. These can be recycled into making new concrete, avoiding the need for more limestone.
    (5) As almost all big cement firms also produce building materials such as concrete and asphalt, capturing emissions to create such products is worthwhile. It could also reduce open-pit mining for limestone, which is especially destructive. Blue Planet is providing materials for San Francisco’s new airport and has other projects across North America. Concrete is the "900-pound gorilla in the carbon footprint of any building", says its CEO, Brent Constanz.
    (6) The group of cement bosses that environmentalists need to win round is small. Just six firms— LafargeHolcim, Anhui Conch, CNBM, Cemex, Heidelberg and Italcementi—dominate the global market. The last two are set to merge this year, leaving just five behemoths. The nature of the industry helps explain its propensity for consolidation. The great weight of cement and its ingredients makes the materials tough to transport, creating localised markets. Companies prefer to serve distant markets by buying firms that are already there. Deals have multiplied as firms from the rich world have splurged on those in developing countries, and, occasionally, vice versa.
    (7) Further consolidation, bringing economies of scale, ought to help the industry to clean up. One industrial country in Asia is to introduce a national carbon-trading scheme in 2017, and the EU’s own scheme will reduce its emissions cap by 2.2% every year after 2020. The industry is becoming more vulnerable to emissions-curbing legislation, says Phil Roseberg of Sanford C. Bernstein, a research firm. Some cement giants are at last taking action. LafargeHolcim already uses an internal carbon price of $32 per tonne; Heidelberg works with one of $23. In a changing regulatory and political environment, investors may start to see nasty cracks in the business model of any firm still stuck in the industry’s old, polluting ways. [br] What does Brent Constanz mean by saying concrete is the "900-pound gorilla in the carbon footprint of any building"?
选项 A、Almost all big cement firms produce concrete.
B、Capturing emissions to create concrete is worthwhile.
C、Concrete is polluting but an essential part of construction.
D、Concrete is being provided for San Francisco’s new airport.
答案 C
解析 原文第五段提及limestone作为生产水泥的原料之一，其开采对环境有毁灭性的影响，由此可知，建筑行业必需的水泥是具有污染性的，故C项为答案。A项、B项和D项都是在第五段提及的具体内容，故排除。
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