Empirical Study of Embodied Carbon in Nigerian Construction Industry Supply Chains

Embodied carbon in the building materials supply chain is an increasingly critical component of the construction industry's total carbon footprint, and Nigeria's rapidly growing construction sector represents both a significant emission source and a major opportunity for low-carbon transition through material substitution and supply chain reform. This study empirically investigates the embodied carbon of primary building materials in the Nigerian construction industry supply chain, collecting primary data on production processes, energy inputs, and transport distances for cement, fired clay brick, steel reinforcement, aluminium products, and ceramic tiles sourced and manufactured in Nigeria. Life cycle assessment methodology following ISO 14044 was applied to quantify the embodied carbon of each material from cradle to construction site gate in kilograms of carbon dioxide equivalent per tonne. Data were collected from fourteen manufacturers across South West, South South, North Central, and North West zones through facility visits and energy consumption record analysis. Results demonstrate that Nigerian-produced Portland cement has an embodied carbon of 847 kg CO2e per tonne, twelve percent above the international industry average, attributable to older kiln technology and higher clinker ratios in domestic production formulations. Nigerian recycled steel has significantly lower embodied carbon than imported virgin steel (410 versus 1,850 kg CO2e per tonne), creating a strong environmental case for domestic steel scrap utilisation. Compressed stabilised earth blocks show the lowest embodied carbon of all assessed wall materials at 28 kg CO2e per tonne. The study recommends a Nigerian construction industry embodied carbon policy framework and clinker reduction targets for the cement industry. Keywords: embodied carbon, building materials, life cycle assessment, Nigerian construction, supply chain.