[MUSIC] Hi, welcome back to the lesson on the metabolic pattern of industrial society. In this session, we will look at the changes that took place in the metabolic pattern of social-ecological system when we move from endosomatic to exosomatic conversions. These will imply going back to the analysis of the component of the metabolic pattern. And to see what are the factors they are being crucial in determining the massive move away from endosomatic energy. If you remember, endosomatic energy is the energy converted inside the human body, so the muscle, the human activity energy. And then how this has been replaced by basically machine and fossil energy. So the critical element determining the characteristic of the endosomatic metabolic pattern were three. You must have an energy input, in this case, it was food. A power capacity, in this case where power of the muscles of human being. And the control, of course, was the brain that was controlling human activity. So the combination of food, muscle and brain controlling the activity was needed to carry out that specific activity. We saw that that solution had a few important problem. One, they have a low density in supply. If you remember, if you want to have more food you need more land. And then especially, if you have more food per capita, you have to exploit more land per capital. And this was problematic. Then there is a low level of power capacity because we saw the humans are not expressing a big power level, 01 horsepower and there is not big difference between men, women. So basically, it doesn't matter the combination that you are using. And then that the endosomatic metabolic pattern is generating a too low surplus, so basically plain the society could not afford to have education and then, a large part of activity dedicated at handling information. What happened with exosomatic metabolic pattern? The factor determining human activities are different. The energy input at the moment is given by fossil energy. The power capacity is given by machines, exosomatic converter. And still we need control, human activity brain control on what is happening to carrying out task. Then the difference here are really, really enormous. The density in supply is huge. You remember, we had an example of how different is the energy density per hectare over oil field compared with the biomass. Then the power capacity is extremely, extremely high. This is something we will see in this session. And, of course, this make possible to generate enough surplus to have a large fraction of the workforce processing information in the service sector. So, if you remember this is something that we already saw in the previous lessons on endosomatic energy. The realization between how much energy you can use in terms of food, and how much land you can exploit. If you want to increase the yield per hectare that this solution is limited, you can add nutrient, but this require labor. Ultimately, the more energy you want to get, the more work you have to employ to get this energy. So, this without fossil energy plain as the society and the problem in increasing dramatically at the level of energy, the only things you can do is predate energy of someone else. Just to give you an example, if you would like to replace today the power of American tractors, only tractors, we are not discussing about airplanes or trains or other with real horses. We would need at least 250 million horses which would require 300 million hectares for producing the feed. That is, more than twice the total US arable land. You have to calculate the horsepower for tractors is irrelevant in relation to the power that is used by American society. But I mean this, what I would like to focus on in this session is that the oil and energy is not the only problem. The problem is the special nature of power capacity given by exosomatic device. In fact, oil has been around for a long period of time. Marco Polo described this as an entertaining burning water. And Rockefeller started the business of cars, because gasoline was a pollutant. They had to, was a byproduct of making lamp fuel. So what is important that power capacity solve an enormous quantity of problem and for this reason is what, together with fossil energy, made possible the jump that we had with industrialization. You remember we already saw this picture, this is the power level when we are using endosomatic power, muscle power. The difference between a group of people, only men, only adult and so on, is not that impressive, move from 90 watt to 43 watt. But if we put it against this, the power level of a tractor, you will get a 147,000 watts. So you can really see that a machine is something completely different from humans when coming to the ability of delivering useful energy. And this 200 horsepower machine is not even a big machine, it's just a medium, small example of power capacity. Let's see another problem. It's when you have 33 horsepower, this is on the top, you can see that. At the time before the Industrial Revolution, those who are doing monoculture, they had to do this kind of harvesting. And you compare it with a regular machine. You can see that there are several difference to be considered. First of all, much more people like you have five people here just for running this and then they have to take care of these horses for the rest of the day, for the rest of the year. There are other important difference, when a tractor runs out of fuel, it stops working. If a horse runs out of hay, it just die and then when you get back the fuel in the tractor, the tractor runs again. Again, if the horse passed away [LAUGH] it doesn't matter, if you'll start bringing in hay when it's too late. So what happened is that basically you remember we already saw this that the one big problem with the low power capacity is having a work that have big power. And this is classic in agriculture when you have to harvest and you have to harvest in one week or two weeks all you can. Then if you are keeping the 30 horses that we saw before for harvesting, then for the rest of the year they will be just eating without doing anything. So basically, the cost of power capacity of horses is much, much higher than the cost of power capacity of tractor. So just to give you an example what happened, as soon as tractor were available in the United States, this is the number of horses and the number of tractor. And how this changed between 1912 and 1960 in United States. You can really see that millions of horses went away quite quickly compared with the tractors. There is another important point is that if you are concentrating power capacity. This is an example, in the city, this was New York City in 1893. Then, if you are concentrating power capacity, you are concentrating as well the device they are using for power capacity. And this device are horses then the horses are having some side effect. Like in this case was the accumulation of manure in the streets. Finally, the last point that we discuss before is that when you have a society which is operating on exosomatic energy. I don't know if you remember, we already saw this. This is how the different input consumed by society, energy, human activity, power capacity, are used in a society, this is Spain 2007. You can see other than these total of energy was a human activity of power capacity are divided across different compartment of the society. And you can see that in modern society, the vast majority of the hours of paid work, 64%, are allocated in service and government, why is that? Because exosomatic device make possible to produce things by using only a limited amount of hours. You see that for energy of mining here, for agriculture, we are using a very limited amount of hours or labor. Eight hours per year to produce all the energy constituent in one year in 2007. And you will see that you will go down in the future after 2007. So if we go back, you remember we saw this and we will see in the next session with EROI. That this is the amount of energy entering at one particles in the derivative part and one particles in energy mining that is the hyper-cycle generating energy for the rest of the society. Very small parts of the energy, electricity and thermal energy, goes into the energy of mining. So if we are looking at the fraction of the total that is used by the energy of mining sector, this fraction is very negligible. Only 8% of the electricity, 6% of the thermal energy carriers, only 1000th of the human activity. And only 3% of the power capacity of a society is used to generate the exosomatic energy. So this is really the winner what made possible to start doing something, a complete difference in the modern societies.
