Decarbonizing Agriculture Part 2: How to Reduce Agricultural GHG Emissions
In Part 1, we examined the major sources of agricultural greenhouse gas emissions — from enteric fermentation and manure management to fertilizer use and soil carbon loss. Now we turn to solutions: what can actually be done to reduce these emissions?
The good news is that proven mitigation strategies exist for every major emission source. The challenge lies in adoption, scale, and the complex economics of farming.
Reducing Methane from Livestock
Feed Additives
One of the most promising near-term strategies for reducing enteric methane is the use of feed additives. Research has shown that certain compounds — including 3-nitrooxypropanol (3-NOP, marketed as Bovaer) and red seaweed (Asparagopsis) — can reduce methane emissions from cattle by 20–80% depending on the additive, dosage, and animal.
These additives work by inhibiting the methanogenic archaea in the rumen that produce methane during digestion. While regulatory approval and cost remain barriers to widespread adoption, several commercial products are now entering the market.
Improved Breeding and Genetics
Selective breeding for feed efficiency can indirectly reduce methane emissions per unit of output. Animals that convert feed more efficiently produce the same amount of milk or meat with less feed — and therefore less methane per unit of production.
Herd Management
Reducing herd size while maintaining productivity through improved genetics, nutrition, and health management can achieve absolute emission reductions. In dairy, the trend toward fewer but more productive cows has already contributed to declining per-unit emissions in many developed countries.
Better Manure Management
Anaerobic Digestion
Anaerobic digesters capture methane from liquid manure and convert it into biogas, which can be used for electricity generation or upgraded to renewable natural gas. While capital costs are significant, digesters provide both emission reductions and a revenue stream from energy production.
Composting and Solid Storage
Converting from liquid to solid manure management systems can significantly reduce methane emissions. Composting, when properly managed, produces primarily CO₂ rather than methane — a meaningful improvement given methane's higher warming potential.
Reducing Nitrous Oxide from Fertilizers
Precision Application
Applying the right amount of nitrogen, at the right time, in the right place, and from the right source — known as the "4R" framework — can reduce N₂O emissions by minimizing excess nitrogen available for conversion. Variable-rate technology and soil testing enable more precise application.
Nitrification Inhibitors
Chemical nitrification inhibitors slow the conversion of ammonium to nitrate in the soil, reducing the pool of nitrogen available for denitrification (the primary N₂O production pathway). These are commercially available and can reduce N₂O emissions by 30–50% when used correctly.
Enhanced Efficiency Fertilizers
Controlled-release and polymer-coated fertilizers release nitrogen gradually, better matching plant uptake patterns and reducing the peak nitrogen concentrations that drive N₂O production.
Soil Carbon Sequestration
Regenerative Agriculture
Practices including cover cropping, reduced tillage, diverse rotations, and integration of livestock on cropland can increase soil organic carbon over time. While the permanence and scalability of soil carbon sequestration are debated, the co-benefits — improved soil health, water retention, and biodiversity — are well-established.
Agroforestry
Integrating trees into agricultural landscapes (silvopasture, alley cropping, riparian buffers) can sequester significant amounts of carbon in both biomass and soil. Agroforestry systems also provide shade, windbreaks, and habitat — making them a multi-benefit strategy.
Biochar
Applying biochar — charcoal produced from biomass pyrolysis — to agricultural soils can sequester carbon in a highly stable form while improving soil properties. Biochar-based carbon removal is increasingly recognized in voluntary carbon markets as a durable CDR pathway.
The Path Forward
Decarbonizing agriculture will not come from any single strategy. It requires a portfolio approach: reducing methane from livestock, managing nitrogen more precisely, rebuilding soil carbon, and transforming the systems that connect farms to consumers.
The technical knowledge exists. The challenge now is implementation at scale — requiring supportive policy, market incentives, and accessible technical assistance for farmers and food companies.
Written by Patrick Pelegri-O'Day · November 17, 2023
