When looking at the question of “What is the most important thing for humanity to do?”, it seems obvious that survival is the primary problem. I have thought of maximizing the long term total hours of human contentment as a goal, and that would require a long survival of the human species. That goal would include at least some of that living community to be content with their world at least some of the time. There are seven billion people now living, so this last year would be measured as seven billion years of human living. With that great a number of humans there is plenty of opportunity for human contentment. Contentment may be defined as complete acceptance of the world as it has been and presently is, and I grant that few people would be comfortable with that definition. However, if people did feel that way, as most creatures do most of the time, then human years would be equal to contentment years and the calculations would be identical, and easy.
Humanity must live on the resources available and in the long run that resource base will vary. For example, oil, coal and gas will not last forever, but sunshine and wind will, so in the long run we will be forced to live on renewables derived more directly from the sun’s energy. It seems more reasonable to have only a billion people consuming natural resources in the long run, because they will last longer. Also, it is easier to calculate, so we may use that number for our generalized estimates. Humanity has been agricultural, and to some degree civilized for ten thousand years, and a billion people was the world population in 1825 just before the consumption of fossil fuels took off. So that seems like a reasonable number for our human projection for population of civilized human life. That population would give us one billion people times ten thousand years, or ten trillion human years of life. If the planet Earth will not permanently support so many as a billion people, but will support population one tenth that number, or one hundred million then we would have to have humanity survive for one hundred thousand years to attain the same amount of total human life. The advantage of the smaller number is that it would be easier for the Earth to support us. If growing our population to a larger number, say ten billion, then to reach the ten trillion human years of life, it would take only a thousand years. The problem becomes how many people will the Earth support, and that is dependent on its resources and our technology for exploiting them.
This rather strange way of measuring humanity gives us a structure. It sets a goal for how we might objectively balance humanity’s goal of maximizing humanity’s survival and individual human contentment with their personal world.
If humanity and its individuals always strive to maintain its maximum short term population at its absolute maximum then there will be constant famine or near famine conditions and therefore constant strife and war. With access to modern weapons that would mean repeated atomic wars, or biological wars, and that would mean repeated population collapse, followed by maximized reproduction in a degraded world. If we as humans insist on living out this famine-style world then natural processes will reach and maintain a miserable state for nearly everyone. In those conditions the world probably wouldn’t support large numbers of people, and the world population would drop to a very low level, perhaps a few million or much less. I don’t believe humans will totally disappear in that ten thousand year time frame, because mammals survived the Chicxulub meteor impact 65 million years ago without intelligence or foreknowledge of how to protect themselves from years of privation. Humans will survive because some of them will store food in caves and survive a couple of years of really disastrous conditions.
A plan for humanity being stable at a large number, perhaps ten million to a billion, seems better than collapsing to a smaller number living in a very distressed world. To some extent humanity is already building toward that more sustainable world. Let’s hope we get there before a real disaster befalls us.
Humanity’s ultimate goal is to avoid extinction as long as possible.