About one million people inhabited the world twelve thousand years ago at the beginning of civilization, and were consuming just barely enough natural resources to increase the population by a paltry few hundred per year.
Five of every six people believed that humanity's destiny was to take over the world, while the rest respected Nature and wanted to consume as much as was safe for them and the other creatures in the world. The vast majority in each group preferred to maximize the number of people without improving their lifestyle, with the minority preferring to maximize their lifestyle without increasing the number of people.
Mathematically, the history of global population consumption appears to have unfolded as a result of the activities of these groups which grew proportionately with population. Each has succeeded according to their size and natural constraints, and together forming a spectrum that is a composite of all of them.
The group that respected Nature achieved its goal in the 1920s, when (on average) about one-fourth of renewable resources were being consumed by humanity, leaving half to other creatures and the remaining quarter as a surplus for use in hard times. With nearly two billion people in the world, the minorities had grown so that more than one million people wanting maximum happiness were in this group. In the other group, seven thousand people were working for happiness and world domination.
By 2015 we were three years from achieving the goal of using the maximum amount of resources that would keep the world habitable, but it was snatched away due to an unintended consequence of the pursuit of that goal: global warming. Our use of fossil fuels had unleashed the equivalent of a competing species, effectively consuming a growing share of the remaining resources, depriving us of their use, and then forcing us to consume less.
As long as the group that prefers population over happiness is dominant, we can expect population to stay constant while per-capita consumption drops to the minimum required to maintain a healthy population with food security, which is what it was about 1500 years ago (and what I've been calling "minimum footprint"). That level will be reached by 2040. The preceding decrease in consumption would have kept up with the removal of resources due to global warming.
After 2040 our consumption decrease will slow; but, as it drops, our population will drop with it. Even worse, our collective decrease in consumption will not keep pace with global warming. By 2063 our population will reach zero just as global warming "consumes" all of the resources needed by us and the species we have depended upon.
This narrative tracks with updates to my population-consumption model utilizing new data and insights. It includes the results of a "backcasting" exercise that reproduced basic features of past population and consumption, lending credibility to its projections. My narrative of the future is based on an observed correlation between average global temperature and humanity's global ecological footprint, and assumes that self-sustained global warming will have its own global footprint, independent of ours after 2015 (which is when it is calculated to impose a limit to growth of our own global footprint). As my Twitter feed will attest, I have been monitoring related news and have become convinced that global warming is currently self-sustaining and is having a significant impact on other species, especially those near the bottom of the food chain that will directly impact our survival.
Given our proximity to the limits my model postulates with and without global warming, the model is now making clearly observable predictions of the behavior of familiar global variables in the very near-term: global population, economy (Gross World Product), and wealth. Perhaps the most obvious of these predictions is a rapid decrease in growth rates for these variables over the next two years, beginning soon this year, and an unstoppable contraction of the economy and wealth beginning in 2017.
I likely won't live to test the most critical of the predictions, around 2040, when population either begins to fall because humanity has reduced consumption too far, or we will have already gone extinct after finding a way to survive while killing the rest of the species that historically kept us alive. If some people are alive when my projections show there will be none under any circumstances, then my model will be a glorious failure, glorious because I wish more than anything that the hideous future it projects never comes true.