By Steve Austin, JD | ASLA | Clinical Associate Professor of Landscape Architecture, Washington State University
The enormous carbon emissions associated with concrete are now forcing us to reckon with our urban future. For 100 years we have used concrete to reshape the planet to suit the immediate needs of rapid urbanization. Its use is so prevalent that it is, after water, the second most used substance on earth. Concrete is so ubiquitous that it also seems that our imaginations have been encased in it as well, for few can imagine life without it. Yet we must, because concrete is incompatible with the zero emission era.
Over the last 100 years global urban population rose from under 10% to over 56%. It is projected to grow to nearly 70% of humanity by 2050. In the past, concrete was like magic in accommodating this explosive urban growth; there was almost nothing it couldn’t do. It is not an overstatement to say that concrete made the modern world. Without concrete, there would be few significant bridges, dams, large buildings, storm drainage, floodwalls, ports, and so much else. As Jonathan Watts has written in The Guardian, concrete puts “roofs over the heads of billions, fortifying our defenses against natural disaster and providing a structure for healthcare, education, transport, energy and industry.”
But this has come at a great climate cost. If cement – concrete’s prime ingredient – production were a country, it would be the world’s third largest CO2 emitter after China and the U.S., accounting for as much as 8% of annual global emissions. There is no way for this number to improve much and it certainly cannot get to zero. While there are some tweaks to lower emission intensity, cement cannot be made without carbon emissions. There is nothing– no technology, new material, or chemistry – that will miraculously appear and enable us to replace anywhere near the amount of concrete we use today.
Cement emissions must end because the climate crisis is rapidly accelerating. An April 2020 study found that, without massive changes to our current emissions trajectory, 2°C of global warming is likely to be reached sometime around 2040. According to climate scientist Joëlle Gergis, “the implications of this are unimaginable – we may witness planetary collapse far sooner than we once thought.” Climate science is absolutely clear as to how to avoid this fate: we must end all CO2 emissions from fossil fuels, land use change, ruminant animals and cement. And further, we must rapidly draw down excess CO2 in the atmosphere.
Obviously, we have a significant conundrum.
Our civilization can decide that we cannot live without the benefits that concrete confers and that the devastating impacts of increasing global heating might be ameliorated somewhat by using more concrete in defensive infrastructures. There is also a hope that we can offset cement emissions with as yet undeveloped technologies. This appears to be our current path.
Alternatively, we could decide that continued use of concrete is incompatible with what science says is the most vital action to stop the climate crisis – ending all emissions. This will be unbelievably difficult but it is the path to justice, as climate change is the greatest human rights violation in history.
However, in a desire for equity, many well-meaning climate leaders object to the immediate phase out of cement emissions as concrete can provide “undeveloped” nations an ability to build infrastructures to match those in developed nations. The belief is that these infrastructures can help increase standards of living similar to those in developed nations.
Yet even with this proposed allocation, it is clearly understood that at some point all cement emissions must go to zero, including this proposed short term overhead for infrastructure development.
This continued allowance for concrete is misguided. If we are to pursue actual justice, we should not continue to build cement-rich infrastructure anywhere. It is not equitable but inequitable to allow continued emissions for cement. Since increasing CO2 emissions intensifies the crisis, what is the logic of adding more for any reason? More emissions will simply increase climate violence, especially among the world’s poorest inhabitants. Plus, since all excess atmospheric carbon will need to be sequestered in an attempt to restore a livable climate, why make that more difficult than it will already be by adding more emissions, even if well intended?
Continuing to allow emissions is like a dog chasing its tail: emit more, suffer more, use more concrete to protect and defend, repeat. This would be nearly comical if it wasn’t so deadly.
This is also a colonialist approach, where only cement-rich infrastructures like those in “advanced” societies are deemed appropriate for development in poorer countries, negative externalities be damned. This is likely to reinforce centuries of oppression where a few will benefit and many will suffer.
Ultimately, it is inequitable to tie any nation to cement-rich infrastructures, because the lifespan of most of them is less than 50 years. Since cement cannot be created without enormous CO2 emissions, all existing and new concrete infrastructures will not be able to be maintained or replaced in the later part of this century. We will still need to be in an emissions lockdown and we’ll have to be focused on drawing down excess CO2. Building more cement-rich infrastructures without this ability is insanity and only dooms our children to deal with an even greater problem than we have.
(It is true that not using concrete might limit renewable energy deployment. My response is: is there a crisis or not? If there is a crisis, then ending it is all that matters.)
So, if we can’t use concrete what are we to do? The needs won’t go away. Our emerging zero emission civilization can learn much from the discipline of Permaculture, which professes a powerful precept: “turn problems into solutions.” To meet future needs, the key thing to change is our minds. This change can be achieved through our use of language and through a widening of perspectives.
We can unshackle imagination from self-limiting language to find solutions that provide victories from multiple viewpoints. This is the opposite of using concrete to physically “fix” something, which often causes unintended consequences which then must also be “fixed.”
A zero emission civilization based along permacultural ideals will be regenerative. Concrete is not regenerative. Its use destroys natural infrastructures without replacing the ecological functions that humans depends on for life support like fertilization, pollination, oxygen production and water purification.
We have so much concrete-caused damage to undo. In its place, we must enable life to flourish and reclaim life support functions. We’ll have to do more than that however. We also must practice abstinence by not building new or repairing cement rich infrastructure, even though it means an end to many components of current life. This in turn will require new conversations on what is truly essential and will spur us to find ways to turn problems into regenerative solutions. If we can’t find a way to do this with a perceived essential need without emissions, then maybe it wasn’t essential in the first place. It will be good to experience humility in our approach to the future.
We must end all carbon emissions very soon if we are to have any chance at maintaining a livable climate. Concrete is not compatible with that reality.
We might as well get started on figuring out the way forward.
Lead Image: © Steve Austin (used with permission)