Concrete is not derived from fossil fuels. But though the problem is bigger than plastic, it is generally seen as less severe. The cement industry pumps out more than that every two years. Instead, its chief quality is to harden and then degrade, extremely slowly.Īll the plastic produced over the past 60 years amounts to 8bn tonnes. Unlike the natural world, however, it does not actually grow. Our built environment is, in these terms, outgrowing the natural one. By one calculation, we may have already passed the point where concrete outweighs the combined carbon mass of every tree, bush and shrub on the planet. Our blue and green world is becoming greyer by the second. But they also entomb vast tracts of fertile soil, constipate rivers, choke habitats and – acting as a rock-hard second skin – desensitise us from what is happening outside our urban fortresses. They keep the rain from our heads, the cold from our bones and the mud from our feet. The material is the foundation of modern development, putting roofs over the heads of billions, fortifying our defences against natural disaster and providing a structure for healthcare, education, transport, energy and industry.Ĭoncrete is how we try to tame nature. If the cement industry were a country, it would be the third largest carbon dioxide emitter in the world with up to 2.8bn tonnes, surpassed only by China and the US. After water, concrete is the most widely used substance on Earth.
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