In the book The Next Million Years, Charles Galton Darwin explores the basic drivers of the species we know as Homo sapiens … us. On page 151 there are three principles listed: 1. Our species obeys the laws of natural selection and thus we will change slowly in a million years. 2. We are not domesticated animals but obey the laws of wild animals. 3. We do not inherit the wisdom of our forefathers but must learn our own wisdom. In 1952 there wasn’t any directed genetic manipulation but now we have GMO (genetically modified organisms). Thus, #1 is no longer applicable even in the short run. And regarding #2, as the human DNA becomes manipulated, the possibility and long term likelihood is that our species will become as domesticated as our tame animals have been. #3, We may not inherit our ancestors’ wisdom, but because of high tech information transfer, it becomes possible to have deep wisdom much more easily if we choose to that. We already live in the early stages of Aldous Huxley’s Brave New World, and once that is stabilized for a few decades people will love it. Well, not people as we know them, but people who have been genetically perfected.
However, before basic drivers become operable, there are changes in our current human world that in many ways will revert to earlier conditions. A primary change will be in our access to physical energy. We presently get almost all the energy supplies that make our way of life possible directly, or indirectly, from coal and oil. Human population has grown from about half a billion people in 1625 to about eight billion in 2025. That is sixteen times more people alive today than when public buildings like the Vatican in Rome were already a hundred years old. When humans learned how to gather energy from natural sources like wind, then coal, and then oil, falling water, and uranium, it became possible to grow more food. A large proportion of all those forms of energy ends up being transformed into the energy in our food. That is fine and works quite well for us, but it is being consumed, there is a limited supply of it, and when it runs out it is gone forever. We will have vast amounts of energy from wind farms and solar panels, but not nearly as much as we now get in a usable form from coal and oil. We can create energy to run cars, airplanes, and tractors, and create fertilizers, but it will cost a lot more money and human effort. Much of that will be supplied by artificial means such as robots; all the same, we humans will continue to need food.
C G Darwin maintains that ultimately human population will expand to the limits of its food supply. When that limit is reached there will be a starving margin of people who because of excess reproduction will consist of a class of people who are just barely surviving when society is thriving but who actually starve to death when there is some kind of problem. When there is bad weather creating a bad harvest, or a war, or a popular new creedal system coming into being, the marginal people will starve to death. That is the natural state of all species in the long run, but in the short run that applies nearly all the time, these people will get by living at a subsistence level.
Notice in the population chart below that the world population usually took a thousand years to double, even though the total number of people was quite small. However, the massive world population present today is doubling in fifty years because we have learned to exploit the one-time-use fossil fuels. Because the land has been so overused, when the fossil energy runs out, the population may quickly drop back to 1CE levels.
The world population took off when the stored power of the earth became available for creating food but that fossil energy is almost gone.