Concrete: the most destructive material on Earth

Limestone quarries and cement factories are often sources of air
pollution. Photograph: Zoonar GmbH/Alamy

After water, concrete is the most widely used substance on the planet.
But its benefits mask enormous dangers to the planet, to human health –
and to culture itself
* [65]A brief history of concrete: from 10,000BC to 3D printed houses
* Editor’s pick: best of 2019. We’re bringing back some of our
favorite stories of the past year. [66]Support the Guardian’s
journalism in 2020

by [67]Jonathan Watts
Mon 25 Feb 2019 01.00 EST [ ]


In the time it takes you to read this sentence, the global building
industry will have poured more than 19,000 bathtubs of concrete. By the
time you are halfway through this article, the volume would fill the
Albert Hall and spill out into Hyde Park. In a day it would be almost
the size of China’s Three Gorges Dam. In a single year, there is enough
to patio over every hill, dale, nook and cranny in England.
[68]Concrete: the most destructive material on Earth – podcast
Read more

After water, concrete is the most widely used substance on Earth. If
the cement industry were a country, it would be the third largest
carbon dioxide emitter in the world with up to 2.8bn tonnes, surpassed
only by China and the US.

The material is the foundation of modern development, putting roofs
over the heads of billions, fortifying our defences against natural
disaster and providing a structure for healthcare, education,
transport, energy and industry.

Concrete is how we try to tame nature. Our slabs protect us from the
elements. They keep the rain from our heads, the cold from our bones
and the mud from our feet. But they also entomb vast tracts of fertile
soil, constipate rivers, choke habitats and – acting as a rock-hard
second skin – desensitise us from what is happening outside our urban
fortresses.

Our blue and green world is becoming greyer by the second. By [69]one
calculation, we may have already passed the point where concrete
outweighs the combined carbon mass of every tree, bush and shrub on the
planet. Our built environment is, in these terms, outgrowing the
natural one. Unlike the natural world, however, it does not actually
grow. Instead, its chief quality is to harden and then degrade,
extremely slowly.
Q&A

What is Guardian concrete week?

Show

This week Guardian Cities investigates the shocking impact of concrete
on the planet, to learn what we can do to bring about a less grey
world.

Our species is addicted to concrete. We use more of it than anything
else except water. Like that other manmade wonder material, plastic,
concrete transformed construction and advanced human health. But, as
with plastic, we are only now waking up to its dangers.

Concrete causes up to 8% of global CO2 emissions; if it were a country
it would be the world's worst culprit after the US and China. It fills
our rubbish dumps, overheats our cities, causes floods that kills
thousands of people – and fundamentally changes our relationship to the
planet.

Can we kick our addiction, when it's so hard to imagine modern life
without it? In this series of articles, [70]Concrete Week will explore
the impact of the material on our environment and us, and look at
alternative options for the future.

Chris Michael, Cities editor
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All the plastic produced over the past 60 years amounts to 8bn tonnes.
The cement industry pumps out more than that every two years. But
though the problem is bigger than plastic, it is generally seen as less
severe. Concrete is not derived from fossil fuels. It is not being
found in the stomachs of whales and seagulls. Doctors aren’t
discovering traces of it in our blood. Nor do we see it tangled in oak
trees or contributing to subterranean fatbergs. We know where we are
with concrete. Or to be more precise, we know where it is going:
nowhere. Which is exactly why we have come to rely on it.

This solidity, of course, is what humankind yearns for. Concrete is
beloved for its weight and endurance. That is why it serves as the
foundation of modern life, holding time, nature, the elements and
entropy at bay. When combined with steel, it is the material that
ensures our dams don’t burst, our tower blocks don’t fall, our roads
don’t buckle and our electricity grid remains connected.

Solidity is a particularly attractive quality at a time of
disorientating change. But – like any good thing in excess – it can
create more problems than it solves.

At times an unyielding ally, at times a false friend, concrete can
resist nature for decades and then suddenly amplify its impact. Take
the floods in New Orleans after Hurricane Katrina and Houston after
Harvey, which were more severe because urban and suburban streets could
not soak up the rain like a floodplain, and storm drains proved
[71]woefully inadequate for the new extremes of a disrupted climate.
The levee of the 17th Street Canal, New Orleans, after it was breached
during Hurricane Katrina.
When the levee breaks ... The levee of the 17th Street canal, New
Orleans, after it was breached during Hurricane Katrina. Photograph:
Nati Harnik/AP

It also magnifies the extreme weather it shelters us from. Taking in
all stages of production, concrete is said to be responsible for
[72]4-8% of the world’s CO2. Among materials, only coal, oil and gas
are a greater source of greenhouse gases. Half of concrete’s CO2
emissions are created during the manufacture of clinker, the
most-energy intensive part of the cement-making process.

But other environmental impacts are far less well understood. Concrete
is a thirsty behemoth, sucking up almost a 10th of the world’s
industrial water use. This often strains supplies for drinking and
irrigation, because [73]75% of this consumption is in drought and
water-stressed regions. In cities, concrete also adds to the
heat-island effect by absorbing the warmth of the sun and trapping
gases from car exhausts and air-conditioner units – though it is, at
least, better than darker asphalt.

It also worsens the problem of silicosis and other respiratory
diseases. The dust from wind-blown stocks and mixers contributes as
much as 10% of the coarse particulate matter that chokes Delhi, where
researchers [74]found in 2015 that the air pollution index at all of
the 19 biggest construction sites exceeded safe levels by at least
three times. Limestone quarries and cement factories are also often
pollution sources, along with the trucks that ferry materials between
them and building sites. At this scale, even the acquisition of sand
can be catastrophic – [75]destroying so many of the world’s beaches and
river courses that this form of mining is now [76]increasingly run by
organised crime gangs and associated with [77]murderous violence.
[78]Concrete is tipping us into climate catastrophe. It's payback time
Read more

This touches on the most severe, but least understood, impact of
concrete, which is that it destroys natural infrastructure without
replacing the ecological functions that humanity depends on for
fertilisation, pollination, flood control, oxygen production and water
purification.

Concrete can take our civilisation upwards, up to 163 storeys high in
the case of the Burj Khalifa skyscraper in Dubai, creating living space
out of the air. But it also pushes the human footprint outwards,
sprawling across fertile topsoil and choking habitats. The biodiversity
crisis – which many scientists believe to be [79]as much of a threat as
climate chaos – is driven primarily by the conversion of wilderness to
agriculture, industrial estates and residential blocks.

For hundreds of years, humanity has been willing to accept this
environmental downside in return for the undoubted benefits of
concrete. But the balance may now be tilting in the other direction.
__________________________________________________________________

The Pantheon and Colosseum in Rome are testament to the durability of
concrete, which is a composite of sand, aggregate (usually gravel or
stones) and water mixed with a lime-based, kiln-baked binder. The
modern industrialised form of the binder – Portland cement – was
patented as a form of “artificial stone” in 1824 by Joseph Aspdin in
Leeds. This was later combined with steel rods or mesh to create
reinforced concrete, the basis for art deco skyscrapers such as the
Empire State Building.

Rivers of it were poured after the second world war, when concrete
offered an inexpensive and simple way to rebuild cities devastated by
bombing. This was the period of brutalist architects [80]such as Le
Corbusier, followed by the futuristic, [81]free-flowing curves of Oscar
Niemeyer and the elegant lines of [82]Tadao Ando – not to mention an
ever-growing legion of dams, bridges, ports, city halls, university
campuses, shopping centres and uniformly grim car parks. In 1950,
cement production was equal to that of steel; in the years since, it
has increased 25-fold, more than three times as fast as its metallic
construction partner.

Debate about the aesthetics has tended to polarise between
traditionalists like Prince Charles, who condemned Owen Luder’s
brutalist Tricorn Centre as a “mildewed lump of elephant droppings”,
and modernists who saw concrete as a means of making style, size and
strength affordable for the masses.

The politics of concrete are less divisive, but more corrosive. The
main problem here is inertia. Once this material binds politicians,
bureaucrats and construction companies, the resulting nexus is almost
impossible to budge. Party leaders need the donations and kickbacks
from building firms to get elected, state planners need more projects
to maintain economic growth, and construction bosses need more
contracts to keep money rolling in, staff employed and political
influence high. Hence the self-perpetuating political enthusiasm for
environmentally and socially dubious infrastructure projects and
cement-fests like the Olympics, the World Cup and international
exhibitions.

The classic example is [83]Japan, which embraced concrete in the second
half of the 20th century with such enthusiasm that the country’s
governance structure was often described as the doken kokka
(construction state).
The pressure-controlled water tank at the Metropolitan Area Outer
Underground Discharge Channel in Kusakabe, Japan.
A pressure-controlled water tank in Kusakabe, Japan, constructed to
protect Tokyo against floodwaters and overflow of the city’s major
waterways and rivers during heavy rain and typhoon seasons. Photograph:
Ho New/Reuters

At first it was a cheap material to rebuild cities ravaged by fire
bombs and nuclear warheads in the second world war. Then it provided
the foundations for a new model of super-rapid economic development:
new railway tracks for Shinkansen bullet trains, new bridges and
tunnels for elevated expressways, new runways for airports, new
stadiums for the 1964 Olympics and the Osaka Expo, and new city halls,
schools and sports facilities.

This kept the economy racing along at near double-digit growth rates
until the late 1980s, ensuring employment remained high and giving the
ruling Liberal Democratic party a stranglehold on power. The political
heavyweights of the era – men such as Kakuei Tanaka, Yasuhiro Nakasone
and Noboru Takeshita – were judged by their ability to bring hefty
projects to their hometowns. Huge kickbacks were the norm. Yakuza
gangsters, who served as go-betweens and enforcers, also got their cut.
Bid-rigging and near monopolies by the big six building firms (Shimizu,
Taisei, Kajima, Takenaka, Obayashi, Kumagai) ensured contracts were
lucrative enough to provide hefty kickbacks to the politicians. The
doken kokka was a racket on a national scale.

But there is only so much concrete you can usefully lay without ruining
the environment. The ever-diminishing returns were made apparent in the
1990s, when even the most creative politicians struggled to justify the
government’s stimulus spending packages. This was a period of
[84]extraordinarily expensive bridges to sparsely inhabited regions,
multi-lane roads between tiny rural communities, cementing over the few
remaining natural riverbanks, and pouring ever greater volumes of
concrete into the sea walls that were supposed to protect 40% of the
Japanese coastline.

In his book Dogs and Demons, the author and longtime Japanese resident
Alex Kerr laments the cementing over of riverbanks and hillsides in the
name of flood and mudslide prevention. Runaway government-subsidised
construction projects, he told an [85]interviewer, “have wreaked untold
damage on mountains, rivers, streams, lakes, wetlands, everywhere — and
it goes on at a heightened pace. That is the reality of modern Japan,
and the numbers are staggering.”

He said the amount of concrete laid per square metre in Japan is 30
times the amount in America, and that the volume is almost exactly the
same. “So we’re talking about a country the size of California laying
the same amount of concrete [as the entire US]. Multiply America’s
strip malls and urban sprawl by 30 to get a sense of what’s going on in
Japan.”

Traditionalists and environmentalists were horrified – and ignored. The
cementation of Japan ran contrary to classic aesthetic ideals of
harmony with nature and an appreciation of mujo (impermanence), but was
understandable given the ever-present fear of earthquakes and tsunamis
in one of the world’s most seismically active nations. Everyone knew
the grey banked rivers and shorelines were ugly, but nobody cared as
long as they could keep their homes from being flooded.

Which made the devastating [86]2011 Tohoku earthquake and tsunami all
the more shocking. At coastal towns such as Ishinomaki, Kamaishi and
Kitakami, huge sea walls that had been built over decades were swamped
in minutes. Almost 16,000 people died, a million buildings were
destroyed or damaged, town streets were blocked with beached ships and
port waters were filled with floating cars. It was a still more
alarming story at Fukushima, where the ocean surge engulfed the outer
defences of the Fukushima Daiichi nuclear plant and caused a level 7
meltdown.

Briefly, it seemed this might become a King Canute moment for Japan –
when the folly of human hubris was exposed by the power of nature. But
the concrete lobby was just too strong. The Liberal Democratic party
returned to power a year later with a promise to spend 200tn yen
(£1.4tn) on public works over the next decade, equivalent to about 40%
of Japan’s economic output.
A bus drives past a seawall in Yamada, Iwate prefecture, Japan, in
2018.
‘It feels like we’re in jail, even though we haven’t done anything bad’
... A seawall in Yamada, Iwate prefecture, Japan, 2018. Photograph: Kim
Kyung-Hoon/Reuters

Construction firms were once again ordered to hold back the sea, this
time with even taller, thicker barriers. Their value is contested.
Engineers claim these 12-metre-high walls of concrete will stop or at
least slow future tsunamis, but locals have heard such promises before.
The area these defences protect is also of lower human worth now the
land has been largely depopulated and filled with paddy fields and fish
farms. Environmentalists say mangrove forests could provide a far
cheaper buffer. Tellingly, even many tsunami-scarred locals hate the
concrete between them and the ocean.

“It feels like we’re in jail, even though we haven’t done anything
bad,” an oyster fisherman, Atsushi Fujita, [87]told Reuters. “We can no
longer see the sea,” said the Tokyo-born photographer [88]Tadashi Ono,
who took some of the most powerful images of these massive new
structures. He described them as an abandonment of Japanese history and
culture. “Our richness as a civilisation is because of our contact with
the ocean,” he said. “Japan has always lived with the sea, and we were
protected by the sea. And now the Japanese government has decided to
shut out the sea.”
__________________________________________________________________

There was an inevitability about this. Across the world, concrete has
become synonymous with development. In theory, the laudable goal of
human progress is measured by a series of economic and social
indicators, such as life-expectancy, infant mortality and education
levels. But to political leaders, by far the most important metric is
gross domestic product, a measure of economic activity that, more often
than not, is treated as a calculation of economic size. GDP is how
governments assess their weight in the world. And nothing bulks up a
country like concrete.

That is true of all countries at some stage. During their early stages
of development, heavyweight construction projects are beneficial like a
boxer putting on muscle. But for already mature economies, it is
harmful like an aged athlete pumping ever stronger steroids to ever
less effect. During the 1997-98 Asian financial crisis, Keynesian
economic advisers told the Japanese government the best way to
stimulate GDP growth was to dig a hole in the ground and fill it.
Preferably with cement. The bigger the hole, the better. This meant
profits and jobs. Of course, it is much easier to mobilise a nation to
do something that improves people’s lives, but either way concrete is
likely to be part of the arrangement. This was the thinking behind
Roosevelt’s New Deal in the 1930s, which is celebrated in the US as a
recession-busting national project but might also be described as the
biggest ever concrete-pouring exercise up until that point. The Hoover
Dam alone [89]required 3.3m cubic metres, then a world record.
Construction firms claimed it would outlast human civilisation.

But that was lightweight compared to what is now happening in China,
the concrete superpower of the 21st century and the greatest
illustration of how the material transforms a culture (a civilisation
intertwined with nature) into an economy (a production unit obsessed by
GDP statistics). Beijing’s extraordinarily rapid rise from developing
nation to superpower-in-waiting has required mountains of cement,
beaches of sand and lakes of water. The speed at which these materials
are being mixed is perhaps the most astonishing [90]statistic of the
modern age: since 2003, China has poured more cement every three years
than the US managed in the entire 20th century.
[91]The grey wall of China: inside the world's concrete superpower
Read more

Today, China uses almost half the world’s concrete. The property sector
– roads, bridges, railways, urban development and other
cement-and-steel projects – accounted for a third of its economy’s
expansion in 2017. Every major city has a floor-sized scale model of
urban development plans that has to be constantly updated as small
white plastic models are turned into mega-malls, housing complexes and
concrete towers.

But, like the US, Japan, South Korea and every other country that
“developed” before it, China is reaching the point where simply pouring
concrete does more harm than good. Ghost malls, half-empty towns and
white elephant stadiums are a growing sign of wasteful spending. Take
the huge new airport in Luliang, which opened with barely five flights
a day, or the Olympic Bird’s Nest stadium, so underused that it is now
[92]more a monument than a venue. Although the adage “build and the
people will come” has often proved correct in the past, the Chinese
government is worried. After the National Bureau of Statistics found
450 sq km of [93]unsold residential floor space, the country’s
president, Xi Jinping, called for the “annihilation” of excess
developments.
The Three Gorges Dam on the Yangtze River, China is the largest
concrete structure in the world.
The Three Gorges Dam on the Yangtze River, China, is the largest
concrete structure in the world. Photograph: Laoma/Alamy

Empty, crumbling structures are not just an eyesore, but a drain on the
economy and a waste of productive land. Ever greater construction
requires ever more cement and steel factories, discharging ever more
pollution and carbon dioxide. As the Chinese landscape architect Yu
Kongjian has pointed out, it also suffocates the ecosystems – fertile
soil, self-cleansing streams, storm-resisting mangrove swamps,
flood-preventing forests – on which human beings ultimately depend. It
is a threat to what he calls “eco-security”.

Yu has led the charge against concrete, ripping it up whenever possible
to restore riverbanks and natural vegetation. In his influential book
The Art of Survival, he warns that China has moved dangerously far from
Taoist ideals of harmony with nature. “The urbanisation process we
follow today is a path to death,” he has said.

Yu has been consulted by government officials, who are increasingly
aware of the brittleness of the current Chinese model of growth. But
their scope for movement is limited. The initial momentum of a concrete
economy is always followed by inertia in concrete politics. The
president has promised a shift of economic focus away from belching
heavy industries and towards high-tech production in order to create a
“beautiful country” and an “ecological civilisation”, and the
government is now trying to wind down from the biggest construction
boom in human history, but Xi cannot let the construction sector simply
fade away, because it employs more than 55 million workers – almost the
entire population of the UK. Instead, China is doing what countless
other nations have done, exporting its environmental stress and excess
capacity overseas.

Beijing’s much-vaunted [94]Belt and Road Initiative – an overseas
infrastructure investment project many times greater than the Marshall
Plan – promises a splurge of roads in Kazakhstan, [95]at least 15 dams
in Africa, [96]railways in Brazil and ports in Pakistan, Greece and Sri
Lanka. To supply these and other projects, China National Building
Material – the country’s biggest cement producer – has announced
[97]plans to construct 100 cement factories across 50 nations.
__________________________________________________________________

This will almost certainly mean more criminal activity. As well as
being the primary vehicle for super-charged national building, the
construction industry is also the widest channel for bribes. In many
countries, the correlation is so strong, people see it as an index: the
more concrete, the more corruption.

[98]According to the watchdog group Transparency International,
construction is the world’s dirtiest business, far more prone to graft
than mining, real estate, energy or the arms market. No country is
immune, but in recent years, Brazil has revealed most clearly the
jawdropping scale of bribery in the industry.

As elsewhere, the craze for concrete in South America’s biggest nation
started benignly enough as a means of social development, then morphed
into an economic necessity, and finally metastasised into a tool for
political expediency and individual greed. The progress between these
stages was impressively rapid. The first huge national project in the
late 1950s was the construction of a new capital, Brasília, on an
almost uninhabited plateau in the interior. A million cubic metres of
concrete were poured on the highlands site in just 41 months to encase
the soil and erect new edifices for ministries and homes.
The National Museum of the Republic by Oscar Niemeyer, Brasília,
Brazil.
The National Museum of the Republic by Oscar Niemeyer, Brasília,
Brazil. Photograph: Image Broker/Rex Features

This was followed by a new highway through the Amazon rainforest – the
TransAmazonia – and then from 1970, South America’s biggest
hydroelectric power plant, the Itaipu on the Paraná river border with
Paraguay, which is almost four times bulkier than the Hoover Dam. The
Brazilian operators boast the 12.3m cubic metres of concrete would be
enough to fill 210 Maracanã stadiums. This was a world record until
China’s Three Gorges Dam choked the Yangtze with 27.2m cubic metres.

With the military in power, the press censored and no independent
judiciary, there was no way of knowing how much of the budget was
siphoned off by the generals and contractors. But the problem of
corruption has become all too apparent since 1985 in the
post-dictatorship era, with virtually no party or politician left
untainted.

For many years, the most notorious of them was Paulo Maluf, the
governor of São Paulo, who had run the city during the construction of
the giant elevated expressway known as Minhocão, which means Big Worm.
As well as taking credit for this project, which opened in 1969, he
also allegedly skimmed $1bn from public works in just four years, part
of which has been traced to secret accounts in the British Virgin
islands. Although [99]wanted by Interpol, Maluf evaded justice for
decades and was elected to a number of senior public offices. This was
thanks to a high degree of public cynicism encapsulated by the phrase
most commonly used about him: “He steals, but he gets things done” –
which could describe much of the global concrete industry.
Paulo Maluf listens to the debate over the impeachment of President
Dilma Rousseff in Brasília, 2016.
Paulo Maluf attending the debate over the impeachment of President
Dilma Rousseff in Brasília, 2016. Photograph: Ueslei Marcelino/Reuters

But his reputation as the most corrupt man in Brazil has been
overshadowed in the past five years by [100]Operation Car Wash, an
investigation into a vast network of bid-rigging and money laundering.
Giant construction firms – notably Odebrecht, Andrade Gutierrez and
Camargo Corrêa – were at the heart of this sprawling scheme, which saw
politicians, bureaucrats and middle-men receive at least $2bn worth of
kickbacks in return for hugely inflated contracts for oil refineries,
the Belo Monte dam, the 2014 World Cup, the 2016 Olympics and dozens of
other infrastructure projects throughout the region. Prosecutors said
Odebrecht alone had paid bribes to 415 politicians and 26 political
parties.

As a result of these revelations, one government fell, a former
president of Brazil and the vice president of Ecuador are in prison,
the president of Peru was forced to resign, and dozens of other
politicians and executives were put behind bars. The corruption scandal
also reached Europe and Africa. The US Department of Justice called it
“the largest foreign bribery case in history”. It was so huge that when
Maluf was finally arrested in 2017, nobody batted an eyelid.
__________________________________________________________________

Such corruption is not just a theft of tax revenue, it is a motivation
for environmental crime: billions of tonnes of CO2 pumped into the
atmosphere for projects of dubious social value and often pushed
through – as in the case of Belo Monte – against the opposition of
affected local residents and with deep concerns among environmental
licensing authorities.

Although the dangers are increasingly apparent, this pattern continues
to repeat itself. India and Indonesia are just entering their
high-concrete phase of development. Over the next 40 years, the newly
built floor area in the world is expected to double. Some of that will
bring health benefits. The environmental scientist Vaclav Smil
[101]estimates the replacement of mud floors with concrete in the
world’s poorest homes could cut parasitic diseases by nearly 80%. But
each wheelbarrow of concrete also tips the world closer to ecological
collapse.

Chatham House predicts urbanisation, population growth and economic
development will push global cement production from 4 to 5bn tonnes a
year. If developing countries expand their infrastructure to current
average global levels, the construction sector will emit 470 gigatonnes
of carbon dioxide by 2050, according to the Global Commission on the
Economy and Climate.

This violates the Paris agreement on climate change, under which every
government in the world agreed that annual carbon emissions from the
cement industry should fall by at least 16% by 2030 if the world is to
reach the target of staying within 1.5C to 2C of warming. It also puts
a crushing weight on the ecosystems that are essential for human
wellbeing.

The dangers are recognised. A [102]report last year by Chatham House
calls for a rethink in the way cement is produced. To reduce emissions,
it urges greater use of renewables in production, improved energy
efficiency, more substitutes for clinker and, most important, the
widespread adoption of carbon capture and storage technology – though
this is expensive and has not yet been deployed in the industry on a
commercial scale.

Architects believe the answer is to make buildings leaner and, when
possible, to use other materials, such as cross-laminated timber. It is
time to move out of the “concrete age” and stop thinking primarily
about how a building looks, said Anthony Thistleton.

“Concrete is beautiful and versatile but, unfortunately, it ticks all
the boxes in terms of environmental degradation,” he [103]told the
Architects Journal. “We have a responsibility to think about all the
materials we are using and their wider impact.”
[104]A brief history of concrete: from 10,000BC to 3D printed houses
Read more

But many engineers argue that there is no viable alternative. Steel,
asphalt and plasterboard are more energy intensive than concrete. The
world’s forests are already being depleted at an alarming rate even
without a surge in extra demand for timber.

[105]Phil Purnell, a professor of materials and structures at Leeds
University, said the world was unlikely to reach a “peak concrete”
moment.

“The raw materials are virtually limitless and it will be in demand for
as long as we build roads, bridges and anything else that needs a
foundation,” he said. “By almost any measure it’s the least
energy-hungry of all materials.”

Instead, he calls for existing structures to be better maintained and
conserved, and, when that is not possible, to enhance recycling.
Currently most concrete goes to landfill sites or is crushed and reused
as aggregate. This could be done more efficiently, Purnell said, if
slabs were embedded with identification tags that would allow the
material to be matched with demand. His colleagues at Leeds University
are also exploring alternatives to Portland cement. Different mixes can
reduce the carbon footprint of a binder by up to two-thirds, they say.

Arguably more important still is a change of mindset away from a
developmental model that replaces living landscapes with built
environments and nature-based cultures with data-driven economies. That
requires tackling power structures that have been built on concrete,
and recognising that fertility is a more reliable base for growth than
solidity.