A Comprehensive AR6?Based Climate, Land, Water, Nutritional and Supply Chain Assessment of Plant?Only vs Mixed Plant-Animal Food Systems

Sukumar Radrapu, Sneha AR

Abstract: This study evaluates the global feasibility, environmental impacts, resource requirements, and nutritional implications of replacing the entirety of global animal?source foods with plant?based crops. Using IPCC AR6 GWP100 values (CH? = 27.2; N₂O = 273), realistic global crop yields, degraded?land yield penalties, irrigation electricity, fertiliser manufacturing emissions, machinery and transport fuel use, peatland conversion risks, biogas offsets, and nutrient bioavailability constraints, this analysis produces a complete system?wide environmental model of a plant?only scenario. A nutrient?equivalent plant basket was constructed using 45% carbohydrates, 20% fat, 25% protein, and 10% micronutrient?rich foods, with soy protein limited to 10% and DIAAS adjustments applied. Based on global animal?derived digestible nutrient mass-247.3 Mt protein, 182.6 Mt fat, 1,769 Mt carbohydrate?equivalent energy, and 118 Mt micronutrient proxy-the required plant crop tonnage translates into 691.303 Mha of high?quality cropland. When adjusting for realistic degraded?land yield factors (0.525), the true requirement increases to 1,316.77 Mha, of which 996.77 Mha must be newly cultivated. New cropland outside existing rainfall?rich zones generates 4,022.96 km³/year of additional irrigation demand, requiring 2,816 TWh/year electricity and emitting 1.408 Gt CO₂/year. Fertiliser manufacturing and N?O emissions contribute a net 0.842 Gt CO?e/year after accounting for biogas offsets from crop residues and global cattle/buffalo dung (198.9 billion m³ biogas potential; IJSR 2024). Machinery, transport, and by?product processing add another 0.185 Gt CO₂/year. Combined operational emissions of a plant?only system therefore total 2.435 Gt CO?e/year-significantly higher than the 1.088 Gt CO₂e/year averaged emissions of a phased?down animal system considering only enteric methane. If 20% of new cropland follows historical expansion patterns into peat?rich regions, one?time peat emissions reach 2,192.7 Gt CO₂, dwarfing all operational emissions. Even amortised over 100 years, peat?linked emissions produce 24.36 Gt/year, exceeding total global anthropogenic emissions by more than an order of magnitude. Nutritionally, plant?only systems require large?scale industrial fortification (B12, iron, zinc, calcium, iodine, vitamin D, DHA/EPA) and heavy processing to overcome anti?nutrients and low DIAAS protein quality. This increases system fragility, energy dependence, and supply?chain vulnerability. Results show that a balanced plant?animal mixed food system is more environmentally stable, nutritionally complete, and climate?efficient than a plant?only global transition. The model highlights that practical land, water, energy, and nutrient limitations fundamentally alter the sustainability outcomes often claimed in plant?exclusive dietary narratives.

Keywords: global food systems, plant- based transition, environmental emissions, cropland expansion, nutritional limitations

How to Cite?: Sukumar Radrapu, Sneha AR, "A Comprehensive AR6?Based Climate, Land, Water, Nutritional and Supply Chain Assessment of Plant?Only vs Mixed Plant-Animal Food Systems", Volume 14 Issue 11, November 2025, International Journal of Science and Research (IJSR), Pages: 1640-1647, https://www.ijsr.net/getabstract.php?paperid=SR251124115621, DOI: https://dx.doi.org/10.21275/SR251124115621