Architects have been urged to reconsider their use of concrete after research found that cement – its key ingredient – was responsible for 8 % of global CO2 emissions
Research by the think tank Chatham House, underlines the need for drastic changes in the production and use of concrete, the world’s most used man-made material, because of the way in which cement is made.
More than 50 % of these emissions are intrinsically linked to the process for producing clinker, one of the main ingredients involved in the manufacture of cement, the report found.
It said important changes were needed to align with the Paris Agreement targets, which require the cement sector’s annual emissions to fall by 16 % by 2030. Yet global demand means the sector is in fact rapidly expanding.
Responding to the research, carbon emissions expert and adviser to the RIBA Stirling Prize jury Simon Sturgis called on architects and engineers to develop a ‘much better understanding of the materials they specify’.
‘There are alternatives to cement such as the waste from steel production, although this is not in huge supply,’ he added.
Sturgis pointed out that many concrete structures are ‘over-designed with a large margin for safety’ and that more lean and efficient use of concrete should be encouraged. He also noted the exploration of timber alternatives by architects including SOM.
Anthony Thistleton, director of Waugh Thistleton Architects, a pioneer and champion of the use of cross-laminated timber (CLT) on multistorey buildings, called on architects to move out of the ‘concrete age’ and into the ‘timber age’.
‘Concrete is beautiful and versatile but, unfortunately, it ticks all the boxes in terms of environmental degradation,’ he said. ’Our profession has deified the Modernists and still thinks primarily about how a building looks.
‘We have a responsibility to think about all the materials we are using and their wider impact.’
Thistleton added that concrete remained necessary in some instances but said it was essential that a building’s embodied carbon was properly considered.
‘We know from the IPCC report that we have only got 12 years left to reduce emissions,’ he said.
The Chatham House report acknowledges the difficulty in reducing concrete use with immediate effect. Much of the world’s infrastructure relies on the material to enable the provision of clean water, sanitation and transport links.
The research demands progress across several areas. By widening improvements in energy efficiency, shifting away from a dependence on fossil fuels in cement production and leveraging cement substitutions, it is hoped that considerable reductions in carbon emissions can be made.