(reposted with original error corrected)
RICS have published an infographic comparing the Embodied Carbon and Production of various construction materials . In my view, an uninformed viewer might assume that the problem materials in relation to Embodied Carbon and Construction are Aluminium and Concrete .
My issues are as follows:
Firstly, the production figures are global, although this is not specified and no source is given for the figures.
Secondly, timber and brick have been excluded from the assessment. ICE gives the typical fossil CO2 emission from production of the UK consumption mixture of timber products as 0.31 kg CO2e/kg, and global production of timber is estimated at 3.5 billion m3 (source UNECE). For brick, global consumption is estimated at 1,300 billion bricks a year (source CATF) and I have estimated the average brick to be 2.5 kg. ICE gives the average CO2e per kg of brick at 0.24 kg/kg but I have doubled this as most brick production occurs in emerging economies with much less efficient means of production than the UK.
Thirdly, the graph doesn’t show the resulting total Embodied CO2 resulting from global production of each product – the global carbon footprint, and also doesn’t take account of the fact that not all global production is used in construction and infrastructure – the percentages vary widely between products.
- 25% of aluminium used for construction
- 36% of copper used in construction and infrastructure
- 3.6% of lead used in construction
- 50% of steel is used in construction and infrastructure
- I estimate 100% of concrete and brick is used in construction and infrastructure
- Approximate 16% of 3.5 billion m3 wood harvested is used in construction.
Using this data, the graphs look very different, and we should be much more concerned by the embodied carbon of copper, and much less concerned by aluminium. Steel, concrete and brick impacts globally also look much more comparable, and significant at a global level than in the RICS graph.
Finally, I would note that the Embodied Carbon figures used by RICS, taken from the ICE Database, are per kg of global production for Aluminium, per kg of European production for Copper (global ECO2 is expected to be higher according to ICE), per kg of UK production for concrete, per kg of UK production for Steel (with a European recycled content) (the global figure is 1.95 kg CO2e/kg from ICE), and the geographic scope is unclear from ICE for Iron and Lead. I have used the timber figure from ICE based on UK consumption and assumed a density of 400 kg/m3, and for brick a figure double the UK figure with an assumed mass of 2.5 kg/brick.