tractor with a fertiliser bowser

We eat and drink fossil fuels | How energy subsidy shapes modern agriculture

Do you know what happens on farms to grow the vast quantities of food needed to feed everyone? No? Start with a massive use of energy.

We eat and drink fossil fuel, a lot of it. 

Not literally, of course, but so much of our agricultural production relies on fossil fuel energy subsidy that we could be consuming the stuff directly, cutting out the farmer altogether.

The reason is a little convoluted but ultimately simple enough — the current human population spike is a result of fossil fuel energy subsidies applied to agriculture over the last 100 years.

large crowd on the street
Photo by Joseph Chan on Unsplash

Large crowd on the street in Hing Kong.

Global agriculture is a weird combination of ancient ways, and science fiction made real. 

Most farms worldwide are small, single or family-operator enterprises that rely on old but trusted crop and livestock production techniques with minimum input. Many of these are subsistence farming systems that feed just the family with a little over to exchange for cash. These small-scale farmers manage three-quarters of the agricultural land in the world.

Then there are the commercial operators, the big farms. 

These are relatively few but farm a quarter of the global agricultural land with intensive, input-dominated systems that are increasing hi-tech operations. They use machinery, fertilisers, pesticides and mechanical harvesters. Thanks to the energy subsidy from fossil fuels, they produce vast volumes of food per hectare sold into the local and global food supply chains.

Farming is both the old low-input and the new intensive, high-input forms of production.

And both methods are very recent. 

Modern intensive agriculture only started when coal provided power to the first steam-driven tractors and the machines that could manufacture fertiliser. The first factories to make synthetic fertiliser appeared in the UK in the 1850s, and by 1871 there were about 80 factories. But it wasn’t until the early 1900s and the invention of the Haber-Bosch process to convert nitrogen onto ammonia that industrial-scale fertiliser use was possible.

The first coal-fired tractors were too heavy to be helpful. The invention of the internal combustion engine and mass production of the Fordster by Henry Ford in 1917 was when tractors became practical. Fordsters sold like hotcakes.

All this energy subsidy began just a smidge over 100 years ago.

If we compare the 280 years for fertilisers and 100 years for tractors to the time since agriculture was invented 12,000 years ago, we get an idea of the newness of modern agriculture. 

At a 24-hour rave that started at midnight, intensive agriculture overslept, forgot about the pre-drinks, and arrived at the party during the last mega track,10 minutes before everyone went home.

Synthetic fertilisers arrived around 11.30 and quickly threw down a few expensive tequila shots, but the tractors from Henry Ford’s production lines found the bar closed. The barman had already called for the last orders.

But when fertilisers arrived, there were few buyers. It took until the 1950s before the world’s farmers, especially in North America, Europe and parts of Asia, got stuck into modern farming with an exponential increase in fertiliser use, cropping area, crop yield, and energy consumption on farms.

graphic showing the rapid rise in fertiliser consumption since the early 1900s, fertilisers that are part of the energy subsidy

Image Source: By Owengaffney – International Geosphere-Biosphere Programme (IGBP) synthesis: Global Change and the Earth System, Steffen et al 2004, Public Domain,

Sorry, what happened exactly?

Plant growth requires light, water, nutrients and a substrate for the roots, typically soil.

How fast plants grow and how big they get is determined by the ability of the plant to capture available energy (light) and obtain the various nutrients (nitrogen, phosphorus, trace elements) it needs to make cells. 

The plant also needs a water supply to get the nutrient to the leaves, where the critical chemistry happens.

In natural systems, light and available nutrients are constrained to some degree. Nutrients and water are held by the soil and released according to the soil structure and the biology that goes on within it. Plants compete for the best access to this constrained supply and are adapted by evolution with particular tactics to give them the best chance of survival, growth and reproduction.

Hundreds of plant species in a natural forest or grassland capture their share of the light, water and nutrients in a given space at a given time. 

Left undisturbed, this becomes a patchy but relatively stable and efficient use of resources under the prevailing climate and weather conditions with the efficient conversion of the sun’s energy to plant biomass (primary production) which is food for animals (secondary production).

Agriculture commandeers the same processes but concentrates plant growth into the parts of plants that humans use for food — corn kernels, wheat grain, sugar beet, or grass stems eaten by livestock.

What happens is that agriculture refocuses natural processes to produce what humans need. And to make this happen, humans add lots of external energy.

And for the last 100 years, this energy subsidy has come from fossil fuels, directly to power machines and industrial processes for fertilisers and pesticides and indirectly in creating the infrastructure and technology to deliver the inputs to the crops and the livestock.

Photo by James Baltz on Unsplash

Combine harvesters can operate at night thanks to GPS tracking systems. But they ride over increasingly degraded soils.

What sustainably FED suggests about energy subsidy

A challenging reality is that we eat fossil fuels because they form an energy subsidy to intensive agricultural production.

Our heterotroph biology means we have to ingest biomass (stored energy), which must come from somewhere. It is created on farms through the help of energy inputs.

Billions of people who shop for food in supermarkets cannot avoid eating this fossil fuel energy subsidy. Global food security depends on long supply chains that run from the paddock to the plate, and at every link in the chain, there is an energy cost.

This reality has many consequences—most of the posts on sustainably FED look into one or more of them.

The big one to highlight here is that this energy subsidy is critical to human survival. Contrary to the wishes of some in the environmental movements; we cannot just turn it off. There are too many people alive to feed by letting nature do its thing unmolested. We have to channel ecological processes into food production, which requires energy and nutrient inputs.

Why must we do this?

Think about it.

Hero image from photo by Etienne Girardet on Unsplash


Mark is an ecology nerd who was cursed with an entrepreneurial gene and a big picture view making him a rare beast, uncomfortable in the ivory towers and the disconnected silos of the public service. Despite this he has made it through a 40+ year career as a scientist and for some unknown reason still likes to read scientific papers.

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