I have a good friend named Julie who is self-educated, she is one of the most intelligent people I know. So when I asked her about potatoes, she replied, “perfect food...a person can live on them and nothing else.”
Turns out she is right. The potato is a complete diet consisting of 75% water and 23% starch--plus proteins and amino acids and enough vitamin C to prevent scurvy. The following analysis is derived from Walker, David, 1992. ENERGY, PLANTS AND MAN, Oxygraphics Limited.
An average sedentary male (like a webmaster) requires about 2,400 Kcal/day and can survive on roughly 7.5 pounds of potatoes/day which can be grown on 1 acre of land. Let’s look at the energy budget for a one acre crop of potatoes for a period of one year.
Energy Input MCal (from Fossil Fuels)
Fertilizer (N, P, K) 1,456
Tractor 1,050
Other Machinery 1,290
Sprays, Sundries, Irrigation 1,102
Total to Farm Gate 4,898
Transport to City 500
Total Fossil Fuel Input 5,398 MCal
Consumption of Crop by Sedentary Male (kCal/day x days x year)
2,400 x 365 x 1 = 8,760 Mcal
So the break down is
(Consumption per year-Fossil Fuel Input) = Utilization of Sunlight
8,760 – 5,398 = 3.362 (38%)
In other words, 62% of the crop was derived from “ancient photosynthesis” in the form of fossil fuels. The balance of only 38% was derived from “new photosynthesis.”
The point here is that with modern agriculture, over half of the energy harvested in today’s crops is derived from ancient photosynthesis in the form of fossil fuels that are needed to grow and deliver the crop.
If you add in the fuels needed to package, distribute, cook and dispose of the food, Walker estimates that 5 calories are expended for each calorie consumed.
In essence Walker points out that civilization as we know it today is made possible and remains entirely dependent upon ancient photosynthesis stored as fossil fuels and more disturbingly that changing the picture so that modern agriculture suddenly became entirely reliant upon contemporary photosynthesis “...would require a ten-fold reduction in population.”
Any Solutions?
When concerned people talk about “peak oil” and pumping the last barrel of crude out of the ground and fret that this might cripple the transportation industry; what they don’t get is, the scarcity of fossil fuels will surely cause a catastrophic famine of the highest magnitude to human society—which may survive, but only at much lower population levels.
Shifting to electric vehicles powered by solar charging stations will allow more ancient photosynthesis fossil fuel to be used in food production and not diverted to transportation. The big agribusiness industry could also shift to solar charged electric tractors and transport vans and solar/wind powered irrigation pumps and use solar energy to power the plants that make fertilizers and pesticides.
The consequence of you driving an electric car or choosing an electric van for your fleet might be only a small step in the right direction, or it just might stimulate the right minds in the right places to realize that electric vehicles are the future, not just for transportation, but to keep potatoes on the plate in the decades to come.
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