雅思阅读 042 · The Most Material-Efficient City Design

改编自 BioEngineer / Nature Cities（2026）。题型：选择题 + T/F/NG + 填空。难度：较难（Passage 3，约 900 词）。

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🎧 课文朗读音频（约 1 分钟）

正文 Passage

Every building on the planet now has a number attached to it, and that number is its weight. In a sweeping new analysis published in the journal Nature Cities, researchers combined high-resolution satellite imagery, geospatial datasets and building material information to calculate the combined mass of 606 million structures across the globe.

The total came to 835 billion metric tons, a figure that falls just short of the estimated weight of all living plant matter on Earth, which stands at roughly 900 gigatonnes.

The work was led by Jinchao Song, a research fellow at the University of Michigan's School for Environment and Sustainability, working alongside an international team of experts from China, Denmark and the Netherlands.

Corresponding author Gang Liu, chair professor at Peking University, describes the approach as a complementary, physical angle on urbanisation. Rather than counting floor area or population alone, the team measured the sheer quantity of concrete, steel, brick, timber and other materials locked into the built environment, building by building, across every inhabited continent.

Previous efforts to quantify building materials have mostly operated at national or regional scales, aggregating statistics that smooth over the enormous diversity of urban forms. The handful of studies that did drill down to the building level tended to concentrate on high-income countries, leaving much of the Global South underrepresented.

The key finding: dense low-rise beats skyscrapers

Central to the analysis is the concept of urban form, which describes how densely buildings are packed together, how tall they rise, and how much variation exists in building heights across a city.

When the team mapped these characteristics against material-use efficiency, a clear pattern emerged. Cities with a dense coverage of uniformly short buildings maximised the amount of floor space available per person while minimising the materials required to provide it.

In other words, the most material-efficient city is not necessarily the one with glittering towers, but one where low-rise construction is packed tightly together, spreading homes, workplaces and services across a compact footprint without the structural overhead of height.

The physics behind this finding is straightforward but often overlooked in planning debates. Taller buildings demand proportionally more structural material, particularly steel and reinforced concrete, to carry their loads and resist wind and seismic forces.

The trade-off, however, is land. High-rise construction can accommodate more people within a city's existing footprint, which may be desirable or even necessary where land is scarce or protected.

Global disparities

The database also revealed stark disparities in how the world's building mass is distributed. China alone possesses roughly a quarter of the total global building weight, and together with the United States it holds the highest total building mass of any nation.

Yet when the measure shifts to a per capita basis, the leaders are the Netherlands and Norway, countries whose residents are, in a very literal sense, supported by more constructed material than almost anyone else on Earth.

High-income countries, home to about 16 percent of the world's population, account for a disproportionate 46 percent of global building material consumption.

The optimal urban form identified by the study is also unevenly distributed. More than 40 percent of the world's dense and uniformly low cities are found in high-income countries. At the opposite end of the spectrum, low-income countries host more than 80 percent of the sparse, uniformly low cities.

A fork in the road

That fork has a deadline. Of the 20 countries projected to experience the highest building material demand between now and 2050, 19 are low- or middle-income nations. The United States is the lone exception.

The implication is that the decisive choices about urban form will largely be made in places that have historically been understudied, often with limited planning capacity and under intense pressure to build quickly.

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题目 Questions

Questions 1-4: Choose the correct letter.

1. How many buildings were weighed in the study?

• A. 66 million
• B. 606 million
• C. 6.6 billion
• D. 60 billion

2. What is the most material-efficient city form?

• A. tall skyscrapers spread out
• B. dense, uniformly short buildings packed tightly
• C. single-family homes on large lots
• D. mixed high-rise and low-rise

3. Which country has the highest total building mass?

• A. China alone
• B. the United States alone
• C. China and the United States together
• D. the Netherlands

4. Of the 20 countries with highest building material demand to 2050, how many are low- or middle-income?

• A. 5
• B. 10
• C. 15
• D. 19

Questions 5-8: T/F/NG

5. The total weight of all buildings is about 835 billion metric tons.

6. Previous building material studies covered all countries equally.

7. Taller buildings need proportionally less structural material.

8. High-income countries are 16 percent of the world's population but use 46 percent of building materials.

Questions 9-13: Complete the notes. Choose NO MORE THAN TWO WORDS.

• The study was published in the journal (9) ____________.
• The total weight of all living plant matter on Earth is roughly (10) ____________ gigatonnes.
• (11) ____________ buildings demand more structural material to resist wind and seismic forces.
• Per capita, the leaders in building mass are the Netherlands and (12) ____________.
• Sparse development is the least efficient because it spreads across more land and more (13) ____________.

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答案 Answers

题号	答案
1	B
2	B
3	C
4	D
5	TRUE
6	FALSE (concentrated on high-income countries)
7	FALSE (proportionally more)
8	TRUE
9	Nature Cities
10	900
11	Taller
12	Norway
13	infrastructure

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核心词汇

urban form / building material / material efficiency / satellite imagery / concrete / steel / urbanisation / high-rise / low-rise / carbon emissions / Global South / compact city