From Waste to Warming-Reduction: How Manure-Based Fertilisers Can Deliver Gigaton-Scale Climate Benefits Globally

Sukumar Radrapu

Abstract: Industrial synthetic fertiliser production contributes significantly to global greenhouse gas (GHG) emissions, particularly due to high-energy ammonia synthesis and the carbon-intensive processing of phosphate and potash minerals. In contrast, livestock manure is an abundant, underutilised nutrient resource capable of replacing a substantial fraction of global nitrogen (N), phosphorus (P?O?), and potassium (K?O) fertiliser demand. However, unmanaged manure is also a major source of methane (CH?), and mismanagement can reduce climate benefits. This study conducts a global scenario analysis quantifying the net climate benefits of manure-derived fertilisers under realistic management pathways. Using updated International Fertilizer Association (IFA) product-mix data, IPCC Tier-1 manure methane estimates, and a moderate anaerobic digestion (AD) adoption pathway (Scenario B: 50% AD at 80% CH? capture, 10% composting, 40% unmanaged), we find that manure can supply 144 Mt of N per year, generating 864 Mt CO?e/year in avoided synthetic fertiliser manufacture. When combined with avoided manure CH? emissions, reduced processing emissions, and energy substitution from captured biogas, the net climate benefit reaches ~1.02-1.07 Gt CO?e/year. Additionally, manure application can reduce global pesticide, herbicide, and fungicide demand by improving soil biological health, yielding an additional ~4.4 Mt CO?e/year in avoided production emissions. The findings demonstrate that manure-centred nutrient strategies offer gigaton-scale decarbonisation potential while supporting soil restoration, circular nutrient flows, and agricultural resilience.

Keywords: manure-derived fertilisers, greenhouse gas reduction, anaerobic digestion pathways, circular nutrient flows, agricultural resilience

How to Cite?: Sukumar Radrapu, "From Waste to Warming-Reduction: How Manure-Based Fertilisers Can Deliver Gigaton-Scale Climate Benefits Globally", Volume 14 Issue 11, November 2025, International Journal of Science and Research (IJSR), Pages: 1342-1344, https://www.ijsr.net/getabstract.php?paperid=MR251117102057, DOI: https://dx.doi.org/10.21275/MR251117102057