Thousands of years ago, the Romans developed a revolutionary material that became the backbone of their expansive civilization. This material, praised by Pliny the Elder for its resilience against the sea, has withstood the test of time, enduring environmental forces that would easily topple modern structures. Today, we know this material as concrete, a less durable but ubiquitous component of our infrastructure, from roads and bridges to skyscrapers.
Concrete is everywhere. In fact, there are three tons of it for every person on Earth, and over the next 40 years, we will use enough to construct the equivalent of New York City every month. While concrete has undeniably shaped our skylines, it has also played a significant role in the rise of global temperatures over the last century. This trend, already altering our world, poses even greater threats for the future.
Concrete is not alone in contributing to greenhouse gas emissions; nearly every human activity does. Industrial processes, often unnoticed, are responsible for a significant portion of these emissions. For instance, refrigeration and other heating and cooling processes account for about 6% of total emissions, agriculture for 18%, and electricity for 27%. Transportation, including cars, planes, and trains, contributes 16% to greenhouse gas emissions.
However, the production of materials like concrete, steel, plastic, glass, and aluminum is responsible for 31% of emissions, with concrete alone accounting for 8% of global carbon emissions. Reducing emissions from concrete is particularly challenging due to the role of cement, one of its key ingredients.
Cement acts as the binding agent in concrete, holding together gravel, sand, and water. Unfortunately, producing cement inevitably generates carbon dioxide. The process involves extracting calcium oxide (CaO) from limestone, which is primarily composed of calcium carbonate (CaCO3). Heating limestone releases CO2, meaning that for every ton of cement produced, an equivalent ton of carbon dioxide is emitted.
Despite the challenges, concrete holds the potential to help us mitigate climate change by reducing greenhouse gas emissions. Although there is currently no completely clean concrete, promising ideas are emerging. One approach is to use clean electricity or alternative fuels to heat limestone, eliminating emissions from fossil fuels. Additionally, carbon capture technology can trap CO2 at the source, preventing it from entering the atmosphere. While such devices exist, their widespread adoption is hindered by economic factors, as transporting and storing captured carbon can be costly.
Innovators are also exploring ways to integrate captured CO2 into the concrete itself, providing a permanent storage solution. Others are experimenting with reducing the cement content in concrete or uncovering the secrets of Roman concrete. Research has shown that the Romans used volcanic ash in their cement, which, when combined with seawater, enhanced the strength and longevity of their structures.
By combining these ancient insights with modern innovations, we hope to replicate the success of Roman concrete, creating long-lasting structures that future generations can admire. As we strive to stabilize our climate, the lessons from the past may guide us toward a more sustainable future, ensuring that our descendants can marvel at our achievements thousands of years from now.
Research the composition and construction techniques of Roman concrete. Create a presentation that explains why Roman concrete has lasted so long and how it compares to modern concrete. Include visuals and examples of ancient Roman structures that still stand today.
Conduct an experiment to create different concrete mixtures using various ratios of cement, sand, gravel, and water. Test the strength and durability of each mixture by applying weight and environmental conditions. Document your findings and discuss which mixture performed best and why.
Participate in a classroom debate on the environmental impact of concrete. Divide into two groups: one arguing for the continued use of concrete due to its benefits, and the other advocating for alternative materials to reduce carbon emissions. Use data and examples from the article to support your arguments.
Work in groups to design a sustainable concrete solution that reduces carbon emissions. Consider incorporating ideas such as carbon capture technology, alternative fuels, or reducing cement content. Present your design to the class, explaining how it addresses the environmental challenges discussed in the article.
Create an infographic that illustrates the role of concrete in climate change. Include statistics on concrete production and its contribution to global carbon emissions, as well as potential solutions for reducing its environmental impact. Share your infographic with the class and discuss its key points.
Concrete – A building material made from a mixture of cement, water, sand, and gravel that hardens into a strong, solid mass – Engineers are developing new types of concrete that reduce carbon emissions during production.
Emissions – Substances, especially gases, released into the atmosphere as a result of industrial processes or human activity – Reducing vehicle emissions is crucial for improving air quality in urban areas.
Climate – The long-term pattern of weather conditions in a particular region – Scientists are studying how climate change affects biodiversity in different ecosystems.
Carbon – A chemical element that is the primary component of fossil fuels and a major contributor to greenhouse gas emissions – Efforts to capture and store carbon are essential for mitigating climate change.
Sustainability – The practice of using resources in a way that meets current needs without compromising the ability of future generations to meet theirs – Sustainability in engineering involves designing systems that minimize environmental impact.
Innovation – The introduction of new ideas, methods, or products to improve processes and solve problems – Innovation in renewable energy technologies is key to reducing our reliance on fossil fuels.
Limestone – A sedimentary rock composed mainly of calcium carbonate, used as a raw material in the production of cement – The quarrying of limestone can have significant environmental impacts if not managed properly.
Greenhouse – A structure with walls and a roof made chiefly of transparent material, such as glass, used for growing plants in regulated climatic conditions – The greenhouse effect is a natural process that warms the Earth’s surface.
Infrastructure – The basic physical and organizational structures and facilities needed for the operation of a society or enterprise – Investing in green infrastructure can help cities become more resilient to climate change.
Temperatures – The degree of heat present in a substance or object, often measured in degrees Celsius or Fahrenheit – Rising global temperatures are a clear indicator of climate change.
