significantly more productive per unit of human labor input and significantly less efficient per unit of energy input. But there seemed no downside to the trade, as the fossil energy was so near to “free” that the reduction in efficiency made little difference. However, as we will discover, there is a downside, and a significant one at that. Consider driving a car as opposed to walking – the car and its fuel use over 33 times the energy you would need to merely walk from Point A to Point B but gets you there about ten times faster 118 (this doesn’t include all the embodied energy costs in roads and infrastructure and various other savings e.g. if it’s a long distance, you don’t have to find somewhere to spend the night). The downside of using much less human energy (labor) is that we use more total energy (from fossils) – substantially more . We’re willing to use fossil energy lavishly to replace even small amounts of expensive human labor. Consider another example: milking cows. Using a stool and a bucket, a human worker spends 20 minutes per day hand milking one cow. Early mechanical milkers reduced this to 8-13 minutes, and with current technology, only 3-6 minutes are required. The very latest in dairy farming technology, the Automated Milking System (AMS), decreases this to two minutes. However, while less and less human labor is required per cow, the mechanized process consumes more and more energy per gallon of milk: hand milking requires about 14 kWh of electric work per cow per year – the AMS uses about 400-600 kWh of electricity per cow per year, and counting the energy embedded in the system itself (manufacturing the machines and so on), this increases to a whopping 5000 kWh per cow per year. The increasing productivity of human labor is bought with a “comparatively huge” increas e in energy intensity that exceeds it by orders of magnitude. 119 Because our energy has been so inexpensive, a vast increase in productivity per human effort allows for any combination of: higher profits to the farmer, higher wages for the employees, lower prices for milk to consumers, and, more indirectly, more people in existence at one time (via more and cheaper food being available). In the above graph, mechanizing with cheap energy increased profits per hour four- or five-fold. Just about everything in modern economies is an example of this “trade” – the substitution of what humans used to do themselves, with technology underpinned by cheap fossil energy. This has resulted in huge economic benefits (from which emanate cultural stories about our own cleverness and ingenuity). TaaL: There is a story, perhaps apocryphal, that the island of Manhattan was sold by its original residents to the Dutch for a few dollars’ worth of tools, cloth, and glass beads. While in retrospect this may seem like a one -
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