Contributions of a mitigation measure portfolio to directing Chinese crop-livestock production system towards net-zero emissions

Abstract

Agriculture contributes over 50% of greenhouse gas (GHG) emissions within the food system and plays a key role in reaching the climate target. How and to what extent agriculture can reduce GHG emissions, and whether it can achieve net-zero emissions, remain to be further uncovered. Applying a life cycle and scenario analysis approach with the functional units defined as unit crop cultivated area and one head of livestock, we assess the residual emissions of the integrated crop-livestock production system in China after implementing a portfolio of mitigation measures. The results show that the life cycle net GHG emissions in the integrated system is 1142.19 Million tons (Mt) of carbon dioxide equivalent (CO₂-eq). In scenario 3, the combined measures targeting straw utilization achieve the greatest reduction of 270.42 Mt CO₂-eq, followed by measures implemented for manure management at 206.30 Mt CO₂-eq. The net residual emissions significantly drop to 241.35 Mt CO₂-eq, resulting from the net negative emissions achieved through bioenergy production with CO₂ capture (−398.30 Mt CO₂-eq), alongside emissions from energy and material production, and energy use (297.17 Mt CO₂-eq), as well as hard-to-abate direct emissions (342.47 Mt CO₂-eq) from enteric fermentation, manure management, and rice cultivation. Achieving further emission reductions, even net-zero and negative emissions in Chinese crop-livestock production system will strongly depend on transitioning to low-carbon energy system and expanding agricultural waste-to-energy utilization combined with CO₂ capture.