Cement is the largest single source of industrial emissions on the planet, responsible for 7% of global carbon emissions. If cement were a country, only the US and China would emit more.
These astronomical emissions – 2.8 gigatonnes of CO2 per year – are driven by demand. Cement is the primary ingredient in concrete, of which the world consumes 30 billion tonnes a year. That is enough to fill five million Olympic swimming pools.
So, is the world faced with a choice between using more concrete, and reaching net zero emissions in line with global climate goals?
“I certainly think we will continue to use concrete after we have reached net zero, but not in the way we do today, and not to the same extent,” says Tim Gudmand-Høyer. He is a chief consultant at Ramboll and holds a PhD in civil and structural engineering with a specialty in concrete structures.
“Concrete is a major source of emissions, and we need to find solutions for that. But in many parts of the world, which are in, or expecting, building booms, concrete is a cheap, reliable material, and here it is hard to see the alternative,” he adds.
Experiments in low carbon concrete
Tim Gudmand-Høyer is part of a team at Ramboll that experiments with new ways to reduce the carbon intensity of concrete buildings. Using computational design, they have designed a model community centre in the Kanalbyen project in Fredericia, Denmark, with a carbon footprint of less than 5 kg CO2e/m2 per year.