Coking coal: Impact on nature
Gassy seams and furnaces that breathe out CO2
What this tab covers What taking energy from this source does to land, water, air and climate, wildlife and ecosystems, with life-cycle emissions and land use where measured.The impacts are those of coal mining, especially methane from deep, gassy seams, plus the very high CO2 output of blast-furnace steelmaking.
Life-cycle emissions about 341 (coking coal) and 385 (coke) g CO2/kWh of fuel heat1 Combustion CO2 only, converted from IPCC default emission factors (94.6 and 107 t CO2/TJ). Not a life-cycle electricity figure, because coking coal is used to make steel, not power.Effects on nature
| Area | Effect | Size | How it is reduced |
|---|---|---|---|
| Climate (combustion and reduction) | Carbon in coke leaves the blast furnace as CO2. The blast-furnace route is by far the most carbon-intensive way to make steel.1 | 94.6 t CO2/TJ for coking coal, 107 t CO2/TJ for coke | Scrap-based electric arc furnaces, hydrogen direct reduction, CCS on blast furnaces |
| Climate (mine methane) | Coking coal is often mined underground from gassy seams, so mine methane is a large part of its footprint.9 | Coal mining overall emitted more than 40 Mt CH4 in 2024 | Pre-drainage and use of seam gas, oxidising ventilation air |
| Steel dependence | Most of the world's steel still relies on coal, which locks in emissions.10 | About 70% (worldsteel) to 72% (Teck) of global steel relies directly on coal | Recycling scrap in electric arc furnaces |
| Substitution already achieved | Where scrap is plentiful, coal has largely left steelmaking.11 | Almost 70% of US steel and 44% of EU steel is made without coal | Scrap collection, electric arc furnaces, low-carbon electricity |
| Land | New mines and expansions take large land areas, often forest or upland.2 | One US expansion application (Warrior Met, Alabama) covers 14,040 acres for 57,500 thousand short tons | Reclamation bonds, progressive rehabilitation |
| Water and waste | Coal washing and tailings can leach nutrients and metals into rivers and groundwater.12 | Coal-mine tailings release 600 to 800 g phosphorus-equivalent per MWh of coal power (same mining phase) | Lined tailings facilities, water treatment |
Coking coal's footprint is usually counted against steel rather than energy. The reduction step itself releases CO2, so efficiency gains alone cannot remove it. Deep removal needs a different chemistry, either recycled scrap or iron reduced with hydrogen or natural gas instead of carbon.
Methane matters more for coking coal than for many steam-coal mines because the seams are often deep and gassy: IEEFA notes that metallurgical coal mines are some of Australia's most significant methane emitters. Because coking coal is harder to replace than steam coal, mine-methane capture is one of the few near-term levers.
Sources
- 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Vol. 2 Energy, Ch. 1 Introduction (Tables 1.2 and 1.4) IPCC, 2006
- Metallurgical Coal: Frequently Asked Questions (R48635) US Congressional Research Service (via EveryCRSReport), 2025
- Global Methane Tracker 2025: Understanding methane emissions IEA, 2025
- Understanding global demand for steelmaking coal Teck Resources, 2023
- Fact sheet: Metallurgical coal IEEFA, 2024
- Carbon Neutrality in the UNECE Region: Integrated Life-cycle Assessment of Electricity Sources (ECE/ENERGY/141) UNECE, 2022