Steel: Emissions
Scrap versus blast furnace: a nearly fourfold carbon gap
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 2.18 t CO2e per t range 0.7-3.5 · cradle-to-gate, world average 2024; scrap-EAF 0.71, DRI-EAF 1.66, BF-BOF 2.66 t CO2e/t; up to about 3.5 t for Indian coal-based routes. CO2-only intensity is 1.92 t/t Global emissions per year 4,100 Mt CO2e per year 2025 · 2.18 t CO2e/t x 1.90 Bt crude steel (derived); about 3,650 Mt on the CO2-only 1.92 t/t, roughly 7-9% of world CO2Per t of crude steel cast (cradle-to-gate, worldsteel boundary incl. upstream mining and CH4/N2O). Intensity: worldsteel Sustainability Indicators 2025; Smil 2016 for India. Global total: worldsteel 2025; USGS MCS 2026; McKinsey 2014 via Smil (8% share).
Share of footprint by lifecycle phase
Extraction 12% Refining / processing 85% Movement 3%Footprint by lifecycle phase
| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| Extraction | about 0.26 t CO2e/t steel | 12% | mining and shipping inputs upstream of the mill: iron ore, coking coal (incl. coal-mine methane), limestone | Estimated as the gap between worldsteel's expanded GHG figure (2.18) and its direct-plus-power CO2 figure (1.92), so it also includes CH4 and N2O | worldsteel 2025 (derived) |
| Refining / processing | about 1.85 t CO2e/t (BF-BOF ironmaking about 1.5-1.9; BOF about 0.07; hot rolling about 0.09) | 85% | coke making, sintering, hot stoves and blast furnace reduction; electricity for EAFs and rolling | About 70% of BF-BOF emissions come from preparing the furnace charge and running the blast furnace. IEA component values: sinter about 290 kg, coke 285 kg, hot stoves 330 kg, BF gas about 1,255 kg CO2 per t | Smil 2016 citing IEA 2012 and Pardo et al. 2012 |
| Movement | about 0.05-0.1 t CO2/t steel (indicative) | 3% | Capesize shipping of about 1.5 t of ore and 0.5 t of coal per t of BF steel | Derived from ore freight factors of 0.02-0.06 t CO2 per t ore; delivery of finished steel adds a little more | derived (see Iron ore tile; indicative) |
| Usage | not applicable (no direct emissions) | – | steel in buildings, vehicles and machines emits nothing in use | Enabling effects: lighter high-strength steel cuts vehicle fuel use, and steel in wind turbines and grids enables low-carbon power; Smil notes wind turbines save about six times the CO2 emitted making their steel | Smil 2016 |
| Recycling / end of life | scrap-EAF about 0.71 t CO2e/t, about 73% below BF-BOF | – | electricity to melt scrap (under 350 kWh/t), electrodes, natural gas | Steel is the world's most recycled material: US recycling rates are 80-90%, with 97% for structural steel and near 100% for cars. Each tonne recycled saves 1.1 t of ore and 0.6 t of coking coal | worldsteel 2025; USGS MCS 2026; Smil 2016 |
Other environmental impacts
Coke ovens and sinter plants emit particulates, SO2, NOx and benzene; the US gave a 2-year relief from 2024 coke-oven air rules in November 2025 (USGS). Steelmaking also uses large volumes of water, and slag (about 0.25-0.3 t per t of iron, indicative) is mostly reused in cement and roads.
Levers to cut emissions
- Shift to scrap-EAF where scrap is available: 0.71 vs 2.66 t CO2e/t for BF-BOF (worldsteel 2025)
- Gas-based DRI-EAF today (1.66 t CO2e/t) and hydrogen DRI later, which can cut CO2 by more than 90% with clean hydrogen (indicative)
- Blast furnace efficiency: pulverised coal injection, top-gas recovery and waste-heat power; best BF energy rates fell to about 13 GJ/t of hot metal (Smil)
- Carbon capture on blast furnace gas, at costs of at least $50 per t CO2 (Smil 2016)
- Material efficiency: higher-strength grades and longer building life cut tonnes needed
India
India's steel is among the most carbon-intensive: integrated mills emit up to about 3.5 t CO2/t and coal-based DRI up to 3.3 t (Smil 2016, citing IEA), and 84% of India's 55.8 Mt of sponge iron in FY2025 was coal-based (Ministry of Steel). The Ministry of Steel's 2024 green steel taxonomy rates steel below 2.2 t CO2e per t of finished steel as green (indicative).
Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.