Crushed stone: Emissions
A few kilograms of CO2 per tonne, but billions of tonnes
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 0.00 t CO2e per t range 0.003-0.01 depending on rock hardness, power source and fines processing (indicative) · cradle-to-gate, UK industry average 2008 (4.32 kg CO2/t) Global emissions per year 6.50 Mt CO2e per year 2025 · US only: 4.3 kg/t x 1.5 billion t (derived); no world tonnage is publishedPer t of crushed rock aggregate at the quarry gate, cradle-to-gate (transport shown separately). Intensity: Mineral Products Association 2009 via BGS (Mitchell 2010), indicative. Global total: MPA 2009 via BGS 2010; USGS MCS 2026.
Footprint by lifecycle phase
| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| Extraction | a few kg CO2e/t | – | drilling, blasting with ammonium nitrate explosives, diesel loaders and haul trucks | the MPA average is not split by phase | MPA 2009 via BGS 2010 |
| Refining / processing | a few kg CO2e/t | – | electricity for jaw, cone and impact crushers and screens; harder granite and traprock need more energy than limestone | on India's coal-heavy grid crushing emissions are higher than the UK average | BGS 2010; CEA 2024 (indicative) |
| Movement | about 4.5 kg CO2e/t for a 25 km truck haul (derived), equal to the gate footprint | – | road 0.178, rail 0.029 and large bulk ship 0.007 kg CO2e per t-km (ERM for The Crown Estate, 2010) | seaborne stone from coastal quarries can be lower per tonne than a long road haul | ERM for The Crown Estate, 2010 (derived) |
| Usage | aggregate use: none directly; kiln use: limestone releases 0.44 t CO2 per t CaCO3 when calcined | – | 17% of US stone goes to cement and 6% to lime, where calcination emits CO2 | those emissions are counted on the cement and lime tiles | USGS MCS 2026; stoichiometry CaCO3 to CaO + CO2 |
| Recycling / end of life | recycled aggregate about 3.7 kg CO2e/t | – | crushing concrete and asphalt | the US recycled about 37 Mt into aggregate in 2025, about 2.5% of supply; EU input rate 9% | USGS MCS 2026; EU CRM 2023; EA calculator via ERM 2010 |
Other environmental impacts
Dust (respirable silica from granite and sandstone), blasting noise, groundwater drawdown and loss of hillsides are the main local impacts. Agricultural lime from crushed limestone releases CO2 in soil as it neutralises acidity.
Levers to cut emissions
- Electrify crushing and conveying, replacing diesel haul trucks with conveyors where possible
- Use rail, barge or ship for longer hauls: 0.029 or 0.007 vs 0.178 kg CO2e per t-km (ERM 2010)
- Sell quarry fines as manufactured sand rather than waste
- Raise recycled concrete and asphalt above the US 2.5% share and the EU's 9%
- Use slag and other by-products as aggregate where local (USGS substitutes list)
India
India is self-sufficient in stone from many small crushers, often diesel or grid powered at about 0.72 t CO2/MWh (CEA 2024, indicative). Dust and unregulated quarrying are bigger local issues than carbon; the CO2 that matters is from limestone burned in India's cement kilns.
Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.