The Inestimable Challenge

Abstract

As those across both the industry and border community know, concrete is one of the most essential and versatile materials of modern society, and its importance is beyond doubt. Present in countless infrastructure projects of the ages, and into the future, its durability, strength, and versatility as a modern building material—and its indispensability—are unquestioned. Concrete structures can last for decades or even, under the right conditions and designs, centuries! Resistant to weathering, erosion, and fire makes concrete a remarkable material for structures that need to withstand extreme conditions. A versatile material that can be used for a wide range of applications, from pavements, buildings, and infrastructure to decorative elements. However, this widely used material of ours also has its darker side, and that is in its sustainable usage. The importance of understanding the implications of this material to ensure that concrete production and usage do not cause harm to the environment, and society, is a paramount discussion and debate for experts across conferences, public debates, and journals such as this journal, which informs and influences policy makers. According to the United Nations Climate Action, G20 countries are responsible for about 75 per cent of the world's CO2-eq emissions. To keep global warming below 1.5 degrees Celsius, we need to reduce greenhouse emissions to −45 per cent of 2010 levels by 2030; however, we are currently tracking to +10 per cent. The use of concrete has significant implications for sustainability, primarily due to its environmental impact. It is widely quoted that concrete is second only to water as the most consumed material, with about four tonnes per year used for every woman, man, and child on the planet. It is also widely cited that cement production accounts for around 8 per cent of global greenhouse gas emissions, which was a figure first presented in the 2000s, before accurate emissions data were available, and repeatedly requoted since and leading to dramatized headlines such as “Concrete: the most destructive material on Earth.” It is time that was corrected. According to IPCC AR6 WPIII report, with process improvements, cement production accounts for 2.6% of global greenhouse gas emissions (1.5 Gt CO2-eq of a global total of 59 Gt CO2-eq) and if these make up 40% of total cement-related emissions, this figure goes to about 4%. This is not by any means to understate the challenges ahead, just to best reflect where cement and concrete production, more broadly, sit in the hierarchical challenges. According to the September 2022 tracking report by the International Energy Agency, the cement subsector is currently not on course to achieve a net zero emissions scenario by 2050, and significant efforts and investments are required if progress is to be made. This involves investing in all aspects of abatement, including dematerialization, substitution, capture, and storage, as well as natural and industrial sequestration. Furthermore, it necessitates the critical development of design codes and standards to facilitate these efforts. This requires significant commitment and investment in research and low-carbon industries and products, clear policy direction by governments, and speedy rollouts of new codes and standards—and starts with all of us!