Cement: Emissions
Calculating cement's enormous share of industrial CO2
Calculating cement's enormous share of industrial CO2 What this tab covers The greenhouse-gas footprint of the commodity at a global level, split by lifecycle phase: extraction (or farming), refining and processing, movement, usage, and recycling or end of life. Intensities are per unit of product; the global total combines intensity with world output. Also covers other environmental impacts and the main levers to cut emissions. Emission intensity 0.63 t CO2e per t range 0.5-0.8 (UltraTech 0.60 scope 1 per t cementitious FY2025; US 0.73 in 2023) · cradle-to-gate, global average, including kiln fuel and grinding electricity Global emissions per year 2,400 Mt CO2e per year 2025 · 0.63 t/t x 3.8 billion t (derived). Process (limestone) CO2 alone was 1.57 Gt in 2023Per t of cement (global average blend), cradle-to-gate at the plant. Intensity: Columbia Business School CKI, 'Decarbonizing Cement', 2026 (indicative); UltraTech SLB report FY2025; EPA 2024. Global total: Columbia CKI 2026; USGS MCS 2026; Global Carbon Atlas 2024.
Share of footprint by lifecycle phase
Extraction 1% Refining / processing 94% Movement 5%Footprint by lifecycle phase
| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| Extraction | about 0.005 t CO2e/t cement | 1% | diesel for drilling, blasting and hauling about 1.2-1.5 t of limestone and clay per t of cement | quarry is usually next to the kiln | derived from 4.3 kg CO2/t for crushed rock (MPA 2009 via BGS 2010), indicative |
| Refining / processing | about 0.59 t CO2e/t cement | 94% | limestone calcination (CaCO3 to CaO) about 50-60% of total; kiln fuel, mostly coal and petcoke, 30-40%; grinding electricity about 5% | clinker makes up 80-90% of emissions, so the clinker ratio is the main swing factor | Columbia CKI 2026; Conway (2023) gives a 60:40 process-to-fuel split |
| Movement | about 0.03 t CO2e/t | 5% | trucks to ready-mix plants and sites; ships for traded cement and clinker | concrete mixing and transport together are about 5% of sector emissions | Columbia CKI 2026 |
| Usage | net uptake: concrete reabsorbs 12-23% of process CO2 over its life | – | carbonation of hardened concrete | no combustion; Conway cites about 17% reabsorption. Uptake is slow and often not counted in inventories | Columbia CKI 2026; Conway (2023) |
| Recycling / end of life | cement is not recycled; crushed concrete reused as aggregate at about 3.7 kg CO2e/t | – | crushing demolition waste | recycling saves virgin aggregate, not clinker; fresh fracture surfaces add some carbonation | USGS MCS 2026; Environment Agency calculator via ERM for The Crown Estate, 2010 |
Other environmental impacts
Concrete uses about a tenth of the world's industrial water (Conway 2023). Kilns emit NOx, SO2 and dust; US plants are cutting output to meet new particulate standards (USGS 2026). Quarry permits are a local constraint, as in Sweden's 2021 shortage.
Levers to cut emissions
- Cut the clinker ratio from 0.76 today towards the IEA's 0.57 by 2050 using fly ash, slag, limestone and calcined clay (Columbia CKI 2026)
- Alternative fuels: global use is 12.8 times the 1990 level and CO2 per t of cementitious is down 25% since 1990 (GCCA GNR 2024)
- Waste heat recovery and renewable power: UltraTech has 351 MW of WHRS and 1,020 MW of renewables, with green power at 31.5% in Q4 FY2025, targeting 85% by 2030
- Carbon capture for the 50-60% process CO2 that fuel switching cannot touch; works in theory but is costly for a low-margin product (Conway 2023)
- Heidelberg Materials reported net 512 kg CO2 per t of cementitious in 2025, down 3%, showing what best-practice European plants achieve
India
India's high blending (470 Mt of cement from 400 Mt of clinker capacity) keeps intensity below the US: UltraTech's scope 1 was 595 kg CO2 per t cementitious in FY2025, down 17% from 716 in FY2017. At about 0.6 t/t, India's 470 Mt implies roughly 280 Mt CO2 a year (derived, indicative), and coal-heavy grid power (about 0.72 t CO2/MWh, CEA) raises grinding emissions.
Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.