The construction industry is a significant contributor to greenhouse gases. Cement production alone accounts for five per cent of all global carbon dioxide emissions – that is more than the entire aviation industry. And the long-term trends are upwards: by 2020 it is estimated that demand for cement will increase by 50 per cent.
One answer to this problem could lie in a field of cannabis plants in Oxfordshire in the UK. Hempcrete is an environmentally-friendly building material made using fibres from a variety of the plant which is low in THC, the psychoactive chemical in cannabis. This fast-growing crop can lock up around 1.4 tonnes of carbon per tonne of hemp, making it carbon-negative. Buildings which use hempcrete can have a carbon footprint 20 to 40 per cent lower than those constructed using conventional materials.
Joyce Ohajah follows the process from field to processing plant to building site, and meets the owner of one of the UK's first hempcrete homes.
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