The cement industry is a major producer of carbon dioxide, a potent greenhouse gas. Concrete damages the most fertile layer of soil, topsoil. Concrete is used to create hard surfaces that contribute to surface runoff that can cause soil erosion, water pollution and flooding. If the cement industry were a country, it would be the third largest emitter in the world, behind China and the United States.
It contributes more CO2 than aviation fuel (2.5%) and is not far behind the global agricultural business (12%). When we think about climate change and how to contribute to slowing it down, we naturally think about how we travel, the products we use at home, how we heat our homes, and so on. We don't tend to look at the four walls around us and think that they might be contributing to the problem. When, in fact, concrete is said to be responsible for about 4-8 of the world's CO2 emissions.
Coal, oil and gas are the only materials that emit higher levels of greenhouse gases. Like that other man-made miracle material, plastic, concrete transformed construction and advanced human health. We could look to other materials to displace the use of concrete, such as more wood or biomass materials. Engineers claim that these 12-metre-high concrete walls will stop, or at least slow down, future tsunamis, but locals have heard such promises before.
The Sydney Opera House, Delhi's Lotus Temple, Dubai's Burj Khalifa and Rome's magnificent Pantheon - which boasts the world's largest unsupported concrete dome - all owe their shape to the material. The classic example is Japan, which embraced concrete in the second half of the 20th century with such enthusiasm that the country's government structure was often described as the doken kokka (state of construction). In the time it takes you to read this sentence, the world's construction industry will have poured more than 19,000 concrete bathtubs. But the concrete used in our modern built environment owes much of its composition to a process patented in the early 19th century by Leeds mason Joseph Aspdin.
Because concrete is so widespread, the amount of CO2 released in the industry is growing all the time. Brazilian operators boast that the 12.3 million cubic metres of concrete would be enough to fill 210 Maracana stadiums. This was a time when extraordinarily expensive bridges were built to sparsely inhabited regions, multi-lane roads were built between tiny rural communities, the few remaining natural riverbanks were cemented, and ever-increasing volumes of concrete were poured into the dikes that were to protect Japan's 40th coastline. There are countless companies and organisations that have designed specific solutions to improve the environmental impact of the concrete industry.
Of course, it is much easier to mobilise a nation to do something that improves people's lives, but either way concrete is likely to be part of the deal. It is these unique attributes of concrete that have helped drive global cement production since the 1950s, with Asia and China being the fastest growing countries since the 1990s.