Greenhouse gas mitigation in agriculture

Area of Science:

• Agricultural Science
• Environmental Science
• Climate Change Mitigation

Background:

• Agriculture covers 37% of Earth's land, contributing significantly to global greenhouse gas (GHG) emissions, including 52% of methane and 84% of nitrous oxide.
• Agricultural soils' role in carbon dioxide (CO2) flux is minor, acting as both a sink and source.
• Anthropogenic GHG emissions from agriculture present a critical area for climate change mitigation strategies.

Purpose of the Study:

• To assess the mitigation potential of various agricultural practices on greenhouse gas (GHG) emissions.
• To quantify the technical and economic potential for GHG mitigation in agriculture by 2030.
• To evaluate the role of agricultural feedstocks in substituting fossil fuels for energy production.

Main Methods:

• Review and synthesis of existing data on agricultural GHG emissions and mitigation potentials.
• Estimation of technical and economic mitigation potentials under different carbon price scenarios.
• Analysis of GHG reduction potential through biomass energy production from agricultural feedstocks.

Main Results:

• Global technical mitigation potential from agriculture (excluding biomass energy) is estimated at 5500-6000 Mt CO2-eq.yr-1 by 2030.
• Economic mitigation potentials range from 1500-1600 Mt CO2-eq.yr-1 (at $20 t CO2-eq.-1) to 4000-4300 Mt CO2-eq.yr-1 (at $100 t CO2-eq.-1).
• Biomass energy from agricultural feedstocks shows significant economic potential, ranging from 640 to 16,000 Mt CO2-eq.yr-1 across different carbon prices.

Conclusions:

• Improved cropland and grazing land management, along with degraded land restoration, offer the most significant GHG mitigation opportunities in agriculture.
• Practices like water management, land use change, agroforestry, and livestock/manure management provide lower but still important mitigation potential.
• Agriculture holds substantial potential for GHG mitigation through direct emissions reduction and indirect benefits via biomass energy production, with economic viability increasing at higher carbon prices.