Most of us don't think very much about concrete. This ubiquitous substance has been with us since Roman times, providing the strength to support our houses, offices, and, in Vancouver, SkyTrain lines.
Concrete is also a common feature of our province's largest megaprojects, including the $12-billion Site C dam along the Peace River.
But a new book looking at the history of this substance, Concrete: From Ancient Origins to a Problematic Future, also demonstrates that its prime ingredient, cement, is responsible for between four to six percent of the world's carbon-dioxide emissions.
That's clear on the back cover, which states: "By one calculation, it outweighs the combined carbon mass of every plant on the planet."
Below, the book's Montreal-based author, Mary Soderstrom, shares some of what she learned while researching this subject.
Georgia Straight: What led you to decide to write a book about concrete?
Mary Soderstrom: Well, best to go back to a couple of books I've written about cities and roads. As a born-again pedestrian, I've long been interested in how to make cities livable, and walkable,. In fact, The Walkable City: From Haussmann's Boulevards to Jane Jacobs' Street (Véhicule Press, 2008) is the title of a book I wrote about 10 years ago.
One of the take-homes from that exercise was that roads are among the most enduring constructions that humans create, so I followed up with Road through Time: The Story of Humanity on the Move (University of Regina Press, 2017).
Writing about concrete is the logical next step, to make a bad pun, since concrete is essential for building modern roads and for building the cities the road serve—and shape. Of course, once I was launched on the project, I found myself fascinated by the wonders concrete can create and deeply concerned about its menace for climate change.
GS: What impact did concrete have on the rise of western civilization?
MS: "Western civilization" is a very broad term. Perhaps it would be best to divide concrete's effect into two periods.
The first covers the several centuries of Roman influence when—seemingly more or less by accident—the Romans discovered that adding a certain kind of sand to lime mortar transformed the mixture into a substance that would set in the presence of water. The result was a wave of construction that produced bridges, dams, port installations, and aqueducts as well as buildings that still wow us today.
The Pantheon in Rome is one: despite being about 1900 years old it remains gorgeous as well as being the largest unreinforced dome in the world.
The second period began in the mid-19th century after at least 1500 years during which the secrets of concrete were forgotten. Several processes for making hydraulic concrete were developed then, and when the trick of reinforcing the material with steel was perfected, the stage was set for concrete to create the world as we know it.
Modern highways, water systems, hydroelectric dams, irrigation projects, and housing for literally billions of people became possible only when concrete was widely available.
Whether this constitutes "the rise of western civilization" is a good question. Maybe a more pertinent question now is: what impact will concrete have on the end of western civilization given the climate change crisis.
GS: How realistic is it for the world to continue using concrete when its prime ingredient, cement, is responsible for a significant amount of greenhouse gas emissions?
MS: Do you mean: is it realistic to think that we collectively can change the way we do things enough to avoid climate calamity? I fear not, since the perceived threat is years away, and people have a habit of not acting until the threat is right around the corner.
And if you mean, is it "realistic" to think that were we together would we be able to avoid the climate crunch, I'd say that is also highly unlikely because even if we could undertake great mobilization the positive changes would not come fast enough to keep low land being drowned by rising seas, and to keep arid regions from becoming deserts.
Remember, too, that it's not just the carbon-dioxide emissions from making cement that are a problem: there's also the way of life that concrete makes possible. More roads mean more vehicles, more housing means more sprawl
GS: According to the Intergovernmental Panel on Climate Change, we only have a decade to take the necessary steps to prevent runaway global warming. What alternatives to concrete are there—and can they come close to meeting the needs of societies around the world?
MS: Ten years isn't very long, and I doubt whether there will be a major decrease in the use of cement in concrete before that deadline. However, there are three ways that might change that dynamic somewhat:
The first is taxing carbon, so that not using high carbon-dioxide cement becomes economically interesting. A corollary of this would be development of "green concrete" which is technically feasible but so far very expensive.
The second is using alternate materials like wood or bamboo in construction, although there are problems here, also, since where would enough to build housing come from?
The third, and probably the most effective and easiest to accomplish, is to change the way we build cities so that a premium is given on dense housing with good public transport/bike links. Unfortunately in the COVID-19 world, many governments will lack the political will to do this as people are tempted out of dense cities and into their cars to "escape" the pandemic.
C'est à suivre, as they say where I live: to be continued.
GS: What led you to break your book up into chapters entitled Earth, Fire, Water, and Air?
MS: Earlier books about concrete have usually been told chronologically. That has limitations: the writer and the reader too often get stuck in the early history of concrete, and sometimes have trouble getting past the turn of the 20th century.
I didn't want that to happen, so I looked for a way to organize the story differently. Because the s were such aces at making concrete, it seemed appropriate to consider the topic through the lens of their world view, that is a universe made up of four elements, Earth, Fire, Water and Air.
As it turns out, not only does each of these things go into making concrete, concrete is essential to their modern use.
Take water for example: concrete is composed of up of about 30 per cent water, while the material is essential for producing the pipes, canals, dams that make water available for our use.
Try to imagine a world without hydroelectricity, or drinking water piped long distances, or crops irrigated by water flowing hundreds of kilometres through concrete canals, and you get the connection.
As for earth—well, that's where all the raw materials come from. There's a reason why contractors and engineers sometimes call concrete "mud." Furthermore, the story of the various, sometimes slap dash experiments leading up to modern concrete frequently resemble a how-to journal for making mud pies.
Fire is linked to concrete in several ways. First, fire is essential for its manufacture, and secondly concrete has been and is intimately connected to war. But also, for the last century concrete has been used all over the world to build millions upon millions of dwellings that range from do-it-yourself hovels to luxury apartment towers where our home fires burn, literally or metaphorically.
Lastly, concrete has two important connections with air.
The first is as tangible, physical, and measurable: the effects on the planet’s atmosphere of making and using concrete. The second is metaphoric, and follows from the fact that the human spirit sometimes seems as insubstantial as air: it is what concrete, that wonderful, surprising material, can call forth from our souls.