‘It’s almost carbon-negative’: how hemp became a surprise building material

By Edward Helmore
The Guardian
February 15, 2024
Category: Wood, Paper & Green Building
Region: International

©Laszlo Kovacs

Cannabis sativa – or specifically its non-psychoactive variant, hemp – is being touted for building blocks for housing that may avoid some of the environmental, logistic and economic downsides of concrete. The cement industry is responsible for about 8% of carbon dioxide emissions, alongside problems created by unyielding surfaces and low R-value properties. The search for large-scale alternatives has so far yielded few results, but on a small scale there are intriguing possibilities, including the use of hemp mixed with lime to create low-carbon, more climate healthy building materials. …Recently hemp’s ability to capture more than twice its own weight in carbon – twice as fast as traditional forestry – has come into focus. By some estimates, hemp can capture up to 15 tonnes of CO2 per hectare, through photosynthesis. Hemp cultivation taking up only 25% of the world’s agricultural land used for dairy and livestock would close the UN emissions gap of 23 gigatons of CO2 annually.

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