Production and distribution of food are driven by the economy. Very few of us grow our own food or find it supplied by nature. We buy almost all our food. If industrial farming fails, we can either create a new system to deliver food or we can starve.
When the economy is functioning normally, the failure of food delivery is an absurd improbability. With a failing economy, the absurd idea becomes less amusing; the improbable becomes possible.
The United States produces its annual surplus of food with less than 1% of the population working as farmers. This is very different from the age of Jeffersonian democracy, when 90% of the nation worked in agriculture and people living in cities were a small minority. The difference is industrial farming.
Even what today we call a "small family farm" is typically committed to industrial farming, a system that uses up 10 calories of fossil fuels for every calorie of food produced. (1)
In addition to being the source of diesel to power tractors in the fields and trucks hauling away the harvest, oil is the feedstock for herbicides and pesticides. Natural gas becomes the ammonia fertilizer that replaces nitrogen depleted from the soil by most crops. Some crops are processed into animal feed, and then the animal parts are processed into food. Fossil fuel energy powers processing, packaging and distribution between the farm and the grocer's shelf or the cafeteria line.
At current rates of consumption, world reserves of oil will be exhausted by approximately the middle of this century. Protestations that we should have faith in new technology to extract oil, new fossil sources to substitute for oil, fusion power, windmills on kites in the jet stream, or the imminent intervention of benevolent space aliens are smoke, mirrors and useless distractions.
Realistically, as depletion advances, it won't be possible to maintain the current rate of oil production, and the rate of consumption will necessarily drop long before the middle of the century. We're going to need a different approach to survival.
For all the plans involving possibilities for nuclear power, hydrogen, photovoltaics, alternative fuels and so on, the three fossil fuels still supply 85% of the energy we depend on.
Oil is used as the source of liquid fuel (diesel, jet fuel, gasoline) because it starts out as a liquid (easy extraction, easy transportation) and it can cheaply be turned into useful liquid fuel. Coal and natural gas can also be made into...