The impact of concrete on the environment

    If you’re reading this, chances are you’re touching concrete right now or touching something that’s touching concrete. By weight, the material makes up 46 percent of everything humans make. But for most of us, concrete remains hidden in plain sight: we live and work in it, step on it and ride it, but we walk through the concrete world like a city kid walks through a forest for the first time. We see shape and color but don’t stop to think how it all relates.

    Where people are, concrete is almost ubiquitous. Where there are few or no people, the impact of concrete is also ubiquitous, as concrete and cement together are the two largest emitters of atmospheric carbon, the most abundant greenhouse gas. Most estimates count emissions from the materials as 6 to 8 percent of the world’s total, though some estimates are as high as double.

    The huge production scale plays a major role. Global Cement, a monthly report that is one of the bibles of the industry, estimates that the world produces enough concrete and cement to build a city the size of Paris every week – about 33 billion tons per year. Population growth drives part of the huge volume, but a bigger driver is that modern life demands more and more concretely per person. In 1980, the per capita use of concrete was a third of what it is today, and the UN expects increased urbanization and population growth to be enough to double the world’s total floor space by 2060. Each ton of concrete produced yields 0.93. tons of CO2 emissions.

    Concrete may help protect us from combustible forests and provide a bulwark against the rising seas, but the climate impacts are also driving wildfires and melting ice caps, leaving us in a vicious circle: the best material for resilience requires more resilience against the impacts of it. The recently concluded COP27 climate denials pressured wealthy countries to provide $100 billion a year to help poorer countries adapt to the impacts of climate change. Should the money flow, expect thousands of miles of new concrete seawalls and other concrete strongholds in endangered zones.

    An aerial view of the Jayne Byrne interchange under construction. [Photo: Nisian Hughes/Getty Images]

    One of Chicago’s most prolific concrete yards is on South Lumber Street, less than six miles from where I live. It is the turnkey batch plant where the Ozinga Bros. mountains of raw material combine to create the finished roads and buildings that climb around the center of the city and fill the iconic high-rise skyline visible in the distance. The city’s recent super-tall construction boom has literally pushed the company’s concrete into the clouds. I see the plant almost daily as I drive along the elevated stretch of I-55 that encircles it. It opens onto the Jane Byrne interchange, a concrete monster that connects four major highways and requires drivers to use each synapse to safely merge. This means that every time I drive it, I risk starring as the next collision on Waze. But I can’t help but look down on the Ozinga factory. It is most enchanting in the early morning twilight – those luminous white towers, full of sand, gravel and cement, the pack of about 40 large, red-striped, spinning concrete mixers lined up like circus elephants. It’s fascinating: a photograph of Margaret Bourke-White comes to life.

    On this day in mid-November I go to the factory. I will see the road from below. A nine-year, $800 million highway rehabilitation should end in 10 days, and the rush to complete will send nearly every truck in the yard to the construction site to pour away the rough equivalent of a square mile. That is almost equivalent to 250 foundations for single-family homes. At 6 o’clock I meet the first team. Men hang out in the break room. The work has been canceled for the time being due to rain and ice. The ice causes large trucks to slip and the rain weakens the concrete. The drivers wait and share stories, such as the one about a job where the ground collapsed under a truck.

    Andre Calhoun, one of the plant managers, uses the downtime to show me the inside of the towers where the raw materials are mixed and the suspended hoppers that unload mixed concrete into the drums of trucks passing underneath. The installation runs 24 hours a day. Mechanics are always on hand to prevent the conveyor belts, rotating buckets and dosers from collapsing under the destructive force of the sand, rocks and water that flows through them. The gray river of wet concrete rarely stops moving. The plant also backs on the south branch of the Chicago River. In the nineteenth century, nearly every forest in the Midwest was cleared to build Chicago, and the lumber came into the city raw and ground by barge. In 1871, the Great Chicago Fire ended the wooden era as the city was rebuilt with sturdier materials.

    The Ozinga Concrete Factory. [Photo: stevegeer/iStock Editorial/Getty Images Plus]

    Now cement, stones and sand are unloaded from the river into barges at Lumber Street. Ozinga’s plant in Chicago’s Chinatown is one of America’s top producing urban plants. It’s also the headquarters of a dozen dispatchers with headsets who stare at large monitors and guide the company’s trucks through the often-choked urban maze. A wall of screens gives the control room feel like a war room, though the dispatchers are quiet, calm and focused, even when arguing with drivers who don’t like their routes.

    Andre walks me to the wharf and shows me a row of covered barges. The cover is a gift. It is cement, the main ingredient in concrete, that glues the mass together. It cannot get wet before using it. Andre tells me that each ship carries as much as 80 trucks, so the row of ships is equivalent to a few hundred trucks of material. I shake my head at the volumes. These ships, he says, came up the Mississippi from Holcim, the large Swiss materials company that is a major producer in the American Midwest and arguably the largest cement producer in the world (it’s hard to know because Chinese companies’ production statistics are hard to come by. to be). Verify). On other days, cement comes from China or Turkey. Most of the rock and sand is mined close to Chicago and also enters the city by barge. You can see those materials ahead, where a bucket unloader grabs loads and moves them to piles in the yard. The region’s system is a kind of highway for materials, and like cars, it starts to look congested as you approach the center. I feel a little overwhelmed.

    “You can feel the city taking shape here,” I tell Andre. “There’s all this material around us, but when you look up, you see all the bridges, roads, waterways and buildings that start somewhere like this.”

    He smiles. “A lot of people don’t see it that way,” he tells me. He says he mainly hears complaints about the noise from the trucks and the dust from the construction sites. You have to wonder, he says, whether people know where their homes, offices and roads come from.

    I’ve always known where it came from because as far back as I can remember I’ve been fascinated by things. My father, an architect, used to take me on his weekend inspections of his job sites in the Chicago area, and our family tourism often ended up at some concrete masterpiece, like the floating gardens of Xochimilco in Mexico City, where our garland-decorated boat past Félix Candela’s flimsy concrete masterpiece, the Los Manantiales Restaurant, which has sculpted the massive material into a slender, flower-like pavilion. In my early twenties I lived in developing countries in Asia. Why, I wondered, was the Indonesian cement magnate Dictator Suharto’s best friend? (Because dictators almost always keep cement and concrete tycoons around. They make dictators richer and more powerful, offer a wealth of contracts, jobs to hand out to cronies.)

    Restaurant Los Manantiales, circa 2016. [Photo: Dge/Wiki Commons]

    Later, when I was reporting on China – for my book China, Inc.–I was struck by the Chinese Communist Party’s attachment to concrete. His top leadership linked national development to large concrete projects and concrete-heavy urbanization. The country was gaining momentum on roads, dams, airports, endless high-rise districts, you name it. When the party couldn’t earn legitimacy from communist ideology, it earned it from infrastructure, and Chinese living standards skyrocketed. Prior to the pandemic and China’s current construction slowdown, the country produced and used more than half of the world’s concrete produced.

    And when I wrote a book –Shock of grey– on global demographic change, I delved deeply into the causes of the doubling of human lifespan. I came to see concrete as the world’s greatest public health asset. It is the material that provides clean water, removes dirty water and builds structures that eliminate insect-borne diseases. Parasites that reproduce in dirty floors, for example, are the world’s second most deadly hazard to children under five. And now when I buy a share or a bond, or pay my taxes, I also see concretely there. Money in it is used to build. My new city sidewalk – financed with government debt – is in my retirement portfolio. How much of my financial life, I wonder, is attached to this tangible material. I’m trying to figure that out, but I feel like it’s everywhere there too.

    The materials industries and their publicly traded peers are under intense pressure from major portfolio investors to prove their commitment to reducing their impact on the climate. In other words, meet the criteria of the ESG (environmental, social and governance) screenings now applied to tens of trillions of dollars in capital held by major investors, such as pension funds and institutional endowments. Faced with public pressure and investor reluctance, Holcim has committed to reducing its carbon emissions by 90 percent by 2050, with smaller targets. In other European countries and the US, hundreds of old and new companies are working on innovation in the construction sector.

    Leaving the factory, I follow the Interstate southwest as the highway follows another waterway, an old canal. In addition to the canal, there are more yards for building materials over several kilometers. The hills of rocks rise and fall all year round, but today they rise as high as I have seen them. An excavator on top of one of the hills looks minuscule. Most of the miles are construction debris hauled from Chicago from dismantled buildings and roads. Some of it is recycled, not as structural concrete, but as stone for gravel beds.

    I suspect most people traveling the busy road don’t see the mini mountain range, or think about its origin. The built environment can seem so static. We see a new building in a familiar place and say, “Where did that come from?” We see a vacant lot where a building we knew once stood and wonder how and when it was evacuated. Concrete may seem inert, but it is the most traveled material of all. Once you see it in motion, the built world never stands still.

    Ted Fishman, former trader and member of the Chicago Mercantile Exchange, is the author of China, Inc and Shock of Gray. His writing has appeared in The New York Times Magazine, Harper’s, Esquire and many other publications. His forthcoming book on concrete will be published by WW Norton.

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