![]() The sheer scale of manufacture is so huge, that is the issue.’ But it is the scale on which it is used that makes it high carbon. Cement is high carbon, but concrete is not. ![]() Chris Cheeseman, an engineering professor at Imperial College London, says the key thing to consider is the extent to which concrete is used around the world, and is likely to continue to be used. ![]() The problem with replacing concrete is that it is so very good at what it does. And so scientists have started innovating with other materials, in a scramble for alternatives to a universal commodity that has underpinned our modem life for many years. If concrete is the only answer to the construction of new cities, then carbon emissions will soar, aggravating global warming. The UN estimates that there will be 9.8 billion people living on the planet by mid-century. The chemical process by which cement, the key ingredient of concrete, is created results in large quantities of carbon dioxide. Materials to take us beyond concreteĬoncrete is everywhere, but it’s bad for the planet, generating large amounts of carbon dioxide – alternatives are being developedĬoncrete is the second most used substance in the global economy, after water – and one of the world’s biggest single sources of greenhouse gas emissions. You should spend about 20 minutes on Questions 1-13 which are based on Reading Passage 1 below.
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