Why we must decarbonise material manufacturing to decarbonise our buildings

11 Nov 2020

The construction sector is increasingly aware of the huge carbon footprint of its material use.

The manufacturing of key construction materials (e.g. cement, steel, glass) already represents 11% of global CO2 emissions each year, and this is set to grow at an astonishing rate.

Rapid global construction rates

The total global floor area of buildings is projected to double by 2060, which is equivalent to building an area the size of Paris every week!

Meanwhile, capital investments in infrastructure are forecast to grow by 40-70% by 2040, and there are huge retrofit requirements for existing buildings.  In Europe, for example, an estimated 97% of the building stock is not efficient enough to comply with future carbon reduction targets.  While COVID-19 has caused a significant slowdown from those predictions, it may not last.  In China, for example, buildings completions in January-April 2020 decreased by 14.5% year-to-year, but picked up soon after and will likely be only 5% lower in 2020 than 2019.

Material manufacturing and embodied carbon

From a building designer’s perspective, the emissions associated with material manufacturing are a form of “embodied carbon”.  While reducing “operational carbon” of building energy use remains a significant challenge, it is being driven down in countries with building regulations.  Embodied carbon is therefore becoming increasingly critical to reducing the carbon footprint of buildings.  For example, recent estimates for three building types in the UK predicted that embodied carbon will be 67-76% of total carbon emissions.

This is increasingly recognised within the sector.  Since 2019, over 1,000 UK and global architecture and engineering practices have signed up to “Construction Declares”.  This commits them to reducing embodied as well as operational carbon. Policy is also starting to shift.  The new London Plan, for instance, will require all ‘referable planning applications’ to calculate and reduce embodied carbon [7].   At a global level, the World Green Building Council has aims for all new construction work to have 40% lower embodied carbon by 2030 and to be net zero embodied by 2050, alongside operational carbon targets.

Decarbonising our buildings thus depends on decarbonising our manufacturing industries

The message is clear: to get to net-zero carbon buildings, we must decarbonise our manufacturing industries, and do so on a global scale.  Our ongoing research in the life cycle assessment of buildings is showing that this is important not only for high-profile materials such as steel and concrete, but for the myriad of other materials and products we fix into our buildings, since these are more important than previously thought.

This is why our UKERC Industry Theme aims to research decarbonisation strategies across a wide range of industrial sub-sectors, including less energy-intensive sub-sectors that have received less historic focus.