Cementing our future with a concrete plan

22 October 2025 - Faizaan Karani

Faizaan Karani is the second-place prize holder in the 2025 Climate Change and Me essay competition

In this essay, Faizaan talks about how concrete is responsible for 8% of global greenhouse gas emissions, but there is research that points to solutions.

If I were to ask you about the key drivers of climate change, you’d probably roll your eyes at me. This is textbook. We’ve all been taught about the glaring impacts caused by our cars, plastics and coal power plants, yet most of us are blissfully unaware of the silent killer right beneath our feet. Pavements… well, not actually pavements, but the concrete which it is made of. Yes, the dull, grey and ordinary material that makes up every building and highway you can see is actually the climate villain of our world. When I first learnt that concrete was responsible for 8% of global greenhouse gas emissions (Purton 2024.), the city skylines and bridges I used to admire began to crumble before me. It felt different. Ironic. The material we associate with safety, stability and advancement is actually just cementing our destruction. Your cursor may be hovering over the “X” button as you read this, but I implore you to cement yourself in reality. If we want to tackle climate change, we first need to focus on the very ground we stand on.

You are probably still sceptical but let me answer your question as to how a mixture of miscellaneous stones can be a carbon emitter. I apologise to my fellow readers who thought that they escaped chemistry in high school, but it is time to put on our lab coats. Cement is a mixture of various materials such as silicon, aluminium, etc., but most importantly, limestone (CaCO3). During the synthesis of cement, limestone undergoes the process of calcination, decomposing CaCO3 into CaO (Calcium Oxide) and…you guessed it…CO2. According to the principle of conservation of matter (and my Grade 10 knowledge), 44% of this limestone is converted to CO2. Effective? No. Destructive? Yes.

Our problems don’t end there. After calcination, the mixture has to be heated at extremely high temperatures (between 1300*C and 1500*C) in huge kilns to form clinker. This heating process contributes to even more CO2 being released into the atmosphere, leading to an absolutely horrifying statistic. The Intergovernmental Panel on Climate Change (IPCC) has stated that for every ton of concrete produced, 0,9 tons of CO2 is simultaneously released into the atmosphere. To put the statistic into perspective, the World Economic Forum has stated that concrete production has released up to 1,6 billion metric tons of carbon dioxide in 2022 alone (Purton 2024.). Now that is a scary number.

I was just as shocked as you when I learnt that. Unlike aeroplanes (fun fact: cement production releases more carbon dioxide than the whole aviation industry) and power stations, we can’t visibly see carbon dioxide (CO2) being emitted from our homes or construction sites. This emission is invisible and quiet. And that is exactly what created the narrative of obliviousness in our minds. However, now that we can see through the grey façade, shouldn’t we start to demand action? Why has the media ignored this when reporting on climate considerations? That’s where it gets complicated.

Concrete isn’t a luxury; it’s a fundamental part of modern society. We can’t just get rid of it. I’d go as far to say it is an essential need for humans. In fact, after water, concrete is the most consumed material globally. But why? Concrete is essential in the construction of infrastructure, hospitals, schools, roads, water and sanitation systems, EVERYTHING! With urbanisation increasing at an exponential rate, especially in under-developed regions such as Africa (the region is expected to see a 90% increase in urban populations by 2050 (Riley 2025.)), demand for concrete will certainly increase, resulting in extremely high carbon emissions. Replacing concrete is not feasible- there are no better alternatives.

This is exactly why the media ignores it. Why fight a battle which can’t be won? However, battles aren’t won by sitting back and watching, they are won by taking action. And we can. Thankfully, we have innovative and promising solutions ready to fight on the frontlines. Just recently, a US-based company called Brimestone discovered a method to replace limestone with highly abundant carbon-free silicate stones, reducing carbon emissions by over 40% (Purton 2024.). Other research suggests that changing the composition of clinker (by using alternate materials) can maintain the quality of concrete whilst reducing emissions by 60% (Bandera 2024.). Using renewable energy practices to heat kilns alongside utilising carbon capture technology can offer slightly more expensive yet proven effective solutions. Furthermore, governments can provide incentives for factories to comply with new sustainable regulations. The list goes on and on…

These solutions have sparked hope in me that we won’t cement our destruction, but rather our future (I deeply apologise for the terrible puns). We have an ocean of promising solutions; however, they can never reach the daylight if this lack of awareness and support continues. Cement has always been our silent killer; constantly overshadowed by media emphasis on plastics, transport and energy production. The time has arrived to break the silence and make the unseen seen.  Only through our voices can we convince the world to act in implementing these ideas. Schools, social media platforms, newspapers and governments need to start giving attention to this invisible threat so that our children can be around to admire the same skylines we once did. Concrete has already been the catalyst of the modern world and only we can make it the catalyst of a sustainable world.  

Reference List:

1. Purton M. (2024). Cement is a big problem for the environment. Here's how to make it more sustainable. World Economic Forum. Available at: https://www.weforum.org/stories/2024/09/cement-production-sustainable-concrete-co2-emissions/ . (Accessed: 14 July 2025).
2. Fischetti M., Bockelman N., Srubar W. (2023). Solving Cement’s Massive Carbon Problem. Available at: https://www.scientificamerican.com/article/solving-cements-massive-carbon-problem . (Accessed: 14 July 2025).
3. Bandera, G. (2024). Why is concrete so damaging to the environment?. Fair Planet. Available at: https://www.fairplanet.org/story/concrete-climate-change-environmental-injustice/ . (Accessed: 14 July 2025).
4. Riley, I. (2025). Cement Demand Forecast 2050. World Cement Association. Available at: https://www.globalcement.com/magazine/articles/1368-cement-demand-forecast-2050?. (Accessed: 14 July 2025).
5. How Much Carbon Dioxide Does Concrete Produce? Understanding Its Environmental Impact. Concrete Captain. Available at: https://concretecaptain.com/how-much-carbon-dioxide-does-concrete-produce/ . (Accessed: 14 July 2025).
6. Belaid, F. (2022). How does concrete and cement industry transformation contribute to mitigating climate change challenges?. Science Direct. Available at: https://www.sciencedirect.com/science/article/pii/S2667378922000220 . (Accessed: 14 July 2025).
7. Ghoneim, R., Mete, G., Hobley, A. (2022). Steel and cement can drive the decade of action on climate change. This is how. Available at: https://iap.unido.org/articles/steel-and-cement-can-drive-decade-action-climate-change-how. IAP. (Accessed: 14 July 2025).