Synthetic Fertilizer, War, and the Transgression of Planetary Boundaries

Transforming Hawaiʻi’s Food System Together (THFST) – Technical Report (2026)

With the current Gulf war disrupting a significant percentage of international oil supplies, and in the broader context of accelerating climate destabilization, we must begin reckoning with the reality of planetary boundaries and accelerating a transition away from both synthetic fertilizers and the dietary patterns that sustain a high nitrogen demand (Webb et al. 2020; Richardson et al., 2023; Rockström et al., 2025). Modern industrial agriculture remains deeply coupled to the Haber–Bosch process and the fossil-energy system that feeds it. When those systems are disrupted by conflict, the effects cascade into fertilizer markets, increased farm production costs, food price spikes and ultimately to increased global food insecurity (FAO 2026). That vulnerability reveals a deep structural problem: the global food system remains dangerously dependent on fossil energy. Equally important is that the agri-food system is a major source (~34%) of total global GHG emissions (Crippa et al. 2021).

A science-based pathway for remaining within planetary boundaries and promoting human health and nutrition therefore requires simultaneously reducing total global nitrogen demand and redesigning farming systems, rather than assuming that biological nitrogen fixation can replace synthetic fertilizer on a 1:1 basis. Recent food-system analysis associated with the The 2025 EAT-Lancet Commission on healthy, sustainable, and just food systems indicates that advances in agri-food sustainability require coordinated shifts toward plant-rich diets, reduced livestock intensity, and improved nutrient circularity. These combined strategies could reduce agricultural nitrogen demand by roughly 50% while also lowering greenhouse gas emissions (Rockström et al., 2025). This nitrogen demand reduction is key because it defines the biophysical space within which ecologically based nitrogen systems can realistically operate (Morais et al. 2021).

Within that reduced-demand context, biologically diversified farming systems provide a highly functional ecological foundation for lower external energy and nitrogen dependence while enhancing a range of globally important ecosystems and social services. Kremen and Miles (2012) showed that biologically diversified farming systems enhance a range of ecosystem services central to long-term productivity, including nutrient cycling, pest regulation, soil quality enhancement, and system resilience to shocks. Reganold and Wachter (2016) and Rosa-Schleich (2019) similarly conclude that organic and diversified farming systems perform strongly across environmental sustainability, profitability, and social well-being metrics, even where modest average yield gaps persist (when compared to conventional farming systems). More recently and at a broader empirical scale, Rasmussen et al. (2024) show across more than 2,600 study sites in 11 countries that stacked diversification strategies (cover cropping, crop rotations, polycultures, etc) generate consistent joint environmental and social benefits. Together, these and hundreds of other scientific studies and dozens meta-analyses consistently show that biologically diversified farming systems are not marginal alternatives; they are scientifically credible production systems capable of reducing dependence on fossil-fuel-based inputs (pesticides and fertilizers) while delivering a range of globally important ecosystem and social services (Raveloaritiana & Wanger (2026). 

These systems should also be understood as a critical climate adaptation strategy. Biologically diversified farming systems tend to be more resilient to climate shocks because they support greater ecological redundancy, improved soil quality, higher water-holding capacity, and more diversified production and livelihood strategies than simplified, high-input monocultures. This matters because substantial climate change inertia is already embedded in Earth’s atmosphere and ocean systems, meaning that even with aggressive mitigation, societies will face continued climatic disruption for decades (IPCC, 2022; Miles & Hoy, 2023). For that reason alone, human society should invest far more aggressively in the development, adoption, and scaling of diversified agroecological systems that are better able to withstand drought, pest pressure, extreme rainfall, heat stress, and supply-chain instability (Altieri et al., 2015; Budimir-Marjanović et al., 2026). The argument is therefore not only about mitigation; it is also about building food and farming systems capable of functioning under sustained climatic instability.

Biological nitrogen fixation, mediated by symbiotic bacteria such as rhizobia and the roots of beans, peas, lentils, and other legumes, is central to an ecological alternative to fossil-fuel-based nitrogen. Multiple bacterial genera and species support nitrogen fixation across different crops and agroecosystems, expanding the feasibility of biologically based nitrogen systems. Under favorable conditions, legume-based systems can supply substantial plant-available nitrogen. However, this supply remains below the 179+ lbs N/ac (pounds of nitrogen per acre) often used in intensive grain and animal-feed systems, creating a core tension: diversified farming systems can sustain productive agroecosystems, but not the excessive nitrogen throughput required by the current livestock-intensive, high-input global food system without reducing overall demand.

This demand-side/consumption point must be stated plainly. Food systems account for roughly one-third (34%) of total global greenhouse gas emissions (Crippa et al., 2021). Within that broader total, livestock supply chains alone account for approximately 14.5% of total human-caused emissions, equal to about 7.1 gigatonnes CO₂-eq per year (FAO, 2013). Animal-based foods also account for a disproportionate share of emissions within the food-production sector. Xu et al. (2021) estimate that they generate 57% of food-production emissions, compared with 29% from plant-based foods. This burden is driven largely by animal feed production, enteric methane, manure management, land-use change, fertilizer demand, and energy use, with meat and dairy especially significant. Because livestock systems require large upstream fertilizer inputs for feed production, a major share of synthetic nitrogen use is tied indirectly to meat- and dairy-intensive diets, especially in high-income regions. The more society reduces feed-grain demand through plant-rich dietary transitions, the more feasible it becomes for biologically based nitrogen systems to replace a meaningful share of synthetic fertilizer inputs.

This biophysical argument must also be placed in a political-economic context. DeLonge, Miles, and Carlisle (2016) show that diversified and agroecological farming systems have been systematically underinvested relative to chemically intensive systems, despite strong evidence of ecological and social benefit. Miles, DeLonge, and Carlisle (2017) further argue that research, policy, and institutional structures reinforce synthetic-input agriculture and slow agroecological transition. Rosa-Schleich et al. (2019) add that diversified systems can provide major ecological gains, but farmers still face short-term costs and transition risks that current markets rarely offset. Haber–Bosch dependence is therefore not only a technical necessity; it also reflects historical investment patterns, subsidy structures, and institutional lock-in.

The implication is clear. Continued reliance on fossil-fuel-based nitrogen ties global food security to geopolitical conflict and environmental degradation. By contrast, dietary change, diversified agroecological systems, and biologically based nitrogen fixation offer a pathway to reduce greenhouse gas emissions, nitrogen pollution, climate vulnerability, and exposure to geopolitical shocks.