# Maize: Emissions

Counting the climate cost of a billion tonnes of grain

Source page: https://www.materialinsights.org/commodities/maize/emissions/

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 1.70 kg CO2e per kg range wide by farm and region · cradle-to-retail, global mean of 2010 data; phase shares not shown here, but the farm stage is largest Global emissions per year 2,300 Mt CO2e per year 2025/26 · 1.7 kg/kg times 1,331 Mt; an upper bound, since feed maize skips milling, packaging and retail

Per kg of maize product (maize meal), cradle-to-retail including land-use change, global mean. Intensity: Poore and Nemecek (2018), Science, via Our World in Data. Global total: Derived from Poore and Nemecek (2018) and USDA (indicative).

#### Footprint by lifecycle phase

| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| **Extraction** | N-fertiliser supply chain alone about 0.15 t CO2e per t grain (derived) | – | N fertiliser manufacture and field N2O, land clearing in Brazil, diesel, grain drying | Derived: maize takes about 16-17% of world N fertiliser (Heffer et al. 2017, indicative), about 15 kg N per t, times 10.5 t CO2e per t N | Menegat et al. (2022); IFA (indicative) |
| **Refining / processing** | small for feed; ethanol plants use gas for heat | – | wet and dry milling, ethanol distillation | US corn ethanol has about 44% lower lifecycle emissions than petrol (Argonne GREET, Lee et al. 2021, indicative) | Lee et al. (2021) (indicative) |
| **Movement** | about 0.02-0.1 t CO2/t (indicative) | – | barge, rail and bulk shipping; bulk carriers emit roughly 3-10 g CO2 per tonne-km depending on size (IMO Fourth GHG Study 2020, indicative) | US Gulf to East Asia is among the longest routes | IMO Fourth GHG Study 2020 (indicative) |
| **Usage** | most maize is fed to animals, whose own emissions are counted under livestock | – | cooking for food maize; feed conversion | About 62.5% of world maize is feed (USDA 2025/26) | USDA WASDE (Oct 2026) |
| **Recycling / end of life** | losses and waste carry the full footprint without use | – | storage losses, mycotoxin rejections, food waste | Food loss and waste is about 8-10% of global GHG emissions (UNEP Food Waste Index 2024, indicative) | UNEP (2024) (indicative) |

#### Other environmental impacts

Nitrate leaching from the US Corn Belt feeds the Gulf of Mexico dead zone. Soy-maize expansion in Brazil's Cerrado drives land clearing. Irrigated maize draws on aquifers.

#### Levers to cut emissions

- Cut N rates and use inhibitors; better nutrient management can cut N2O sharply (Menegat et al. 2022)
- Avoid land conversion for second-crop expansion
- Use heat pumps or biomass for grain drying
- Carbon capture on ethanol fermentation CO2, which is nearly pure

#### India

India grows about 40 Mt at 3.54 t/ha (FAOSTAT 2024), so emissions per tonne are raised by low yields even with lower inputs; maize's new role in ethanol shifts some of its footprint into fuel (content tile; indicative).
 Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.

## Other sections

- [Summary](https://www.materialinsights.org/commodities/maize/index.md)
- [Overview](https://www.materialinsights.org/commodities/maize/overview/index.md)
- [Correlation](https://www.materialinsights.org/commodities/maize/correlation/index.md)
- [Extraction](https://www.materialinsights.org/commodities/maize/extraction/index.md)
- [Production](https://www.materialinsights.org/commodities/maize/production/index.md)
- [Stocks](https://www.materialinsights.org/commodities/maize/stocks/index.md)
- [Cycles](https://www.materialinsights.org/commodities/maize/cycles/index.md)
- [Trading](https://www.materialinsights.org/commodities/maize/trading/index.md)
- [Movement](https://www.materialinsights.org/commodities/maize/movement/index.md)
- [Criticality](https://www.materialinsights.org/commodities/maize/criticality/index.md)
- [Characteristics](https://www.materialinsights.org/commodities/maize/characteristics/index.md)
- [Relationships](https://www.materialinsights.org/commodities/maize/links/index.md)