Adrien LUDOT
Author
As we confront the twin crisis of climate change and ecological collapse, one inconvenient truth emerges from the deep archives of agricultural history: our current uses of biomass (wood, crops, animal products, biowaste, algae etc.) are fundamentally unsustainable, largely due to their dependence on fossil fuels for energy and raw materials. Phasing out fossil fuels requires a profound transformation in how we utilize biomass. While non-food applications will need to expand to substitute petroleum-based products and molecules, a simple substitution won't be enough as biomass availability is inherently limited. The solution lies in embracing sufficiency by using biomass in ways that are equitable, ecologically sound, and restrained by planetary boundaries.
Before the Industrial Revolution, human societies relied on a solar metabolic system governed by a flow logic: energy and material cycles were primarily driven by the annual net primary production of sunlight. This system, bounded by thermodynamic limits, was fundamentally based on what nature could produce in real time. The advent of the Industrial Revolution marked a profound shift toward a stock-based metabolism. By harnessing fossil biomass, societies overcome the thermodynamic limit by accessing vast stores of solar energy accumulated over millions of years through photosynthetic activity of ancient plants and microorganisms. This mining-based metabolic system replaced the flow logic with a stock logic, enabling exponential growth and transformation (external link).
After the World War II, the term 'agricultural product' became virtually synonymous with the term 'food product'. A nutritional transition emerged, marked by a significant rise in the consumption of animal proteins at the expense of cereals (external link). This shift was driven by an energy surplus enabled by the mining metabolic regime. The dramatic increase in agricultural yields and labour productivity, as well as the decline in non-food biomass uses, was made possible through the massive injection of fossil fuels into agriculture and the chemical industry (external link). In a context where food autonomy had already been achieved and agriculture's primary outlet became food production; this dynamic generated a persistent problem of overproduction. One strategy to manage the surplus involved subsidized exports and food aid to countries in the Global South. However, it was the deliberate "organized waste" of biomass, through the expansion of intensive livestock farming and its "cerealisation" that played the most stabilizing role in cereal markets. (external link)
Today's imperative to defossilize compels a critical re-evaluation of biomass's role in industrial processes. Non-food biomass is increasingly positioned as a replacement for petroleum-derived materials across various sectors. Forests, agricultural lands, and marine ecosystems offer essential feedstocks for bio-based chemicals, materials, and energy. However, their supply cannot match the scale or energy density of fossil resources. After all, coal, oil, and gas represent the concentrated results of photosynthesis over geological timescales. It is physically impossible to harvest equivalent amounts of biomass. Any attempt at a one-to-one substitution would collapse ecosystems and undermine food security.
Recognizing this "thermodynamic wall" forces us to confront difficult choices about how we allocate the limited biomass available to us. How much should go toward biofuels? Which chemicals should be prioritized? How many cereals should be diverted to meat production? These are the real-world questions where biomass sufficiency meets political and ecological reality. To operationalize biomass sufficiency, we must establish transparent, participatory democratic processes where governments and society can jointly define a hierarchy of biomass uses at both national and local level. Institutionalizing this agreed-upon hierarchy will help navigate competing demands, resolve resource conflicts, and protect the interests of vulnerable communities.
Policies to operationalize biomass sufficiency include:
- Diet shift: The livestock sector remains the single largest consumer of global cropland. By significantly cutting meat and dairy consumption, millions of hectares could be freed up to produce materials and platform chemicals (external link).
- Development and Support Non-Food Biomass Value Chains: Farming practices should shift from input-intensive monocultures to diversified, regenerative systems that yield both food and non-food feedstock. In particular, the largely untapped potential of the algae sector deserves strategic attention.
Policymakers can advance these goals using a mix of policy instruments and through long-term strategic planning.
A review of agricultural history reveals that phasing out fossil fuels will put tremendous pressure on agroecosystems and natural ecosystems to supply industry with biomass. Biomass will be required to replace certain uses of fossil fuels, particularly in material applications for which no viable alternatives currently exist. Every ton reclaimed must be allocated wisely, with care and purpose.
Against this backdrop, today's food system, characterized by high levels of animal protein consumption, heavy reliance on ultra-processed foods, and significant waste, stands out as a historical anomaly. It is an energy-intensive and health-compromising aberration, and a temporary luxury made possible only by the extensive use of fossil fuels across all sectors of the economy. Consequently, the phase-out of fossil fuels and the resulting shifts in biomass use will usher in deep societal transformations that must be collectively debated and deliberately shaped to lead us toward a more equitable and sustainable future.