Like many students in the 1960's, my perspectives of the global picture was shaped in part by Paul Ehrlich's book, The Population Bomb, and its dire predictions of the near term consequences of not forcibly constraining world populations. While the premises and conclusions of his work were overly "enthusiastic" and did not bring about the demise of any civilization anywhere in the world in the 40 years since their publication, the conditions that he wrote about have been notched up to a
higher level of potential failure.
Ehrlich's error was in not being able to predict technological advances which would make it possible for food production to increase at a rate greater than the rate of population growth. On the other hand, he also did not account for the aging of the populations that [then] currently produced all of the Manufactured, Mined and Farmed production of the world. Population economists have not been able to devise a projection method that accurately predicts population sizes over any long period of time. One can use simple curve-fitting to show what will probably happen over a few years, but economic, environmental, and political factors act to influence the actual growth rates in was that cannot, as yet, be modeled. Cohort-component methods look at the age and gender composition of the population in sub-areas to "better" predict the population growth, with only marginal improvements in the accuracy of the predictions.
Whether or not we can make long-term projections of population size with a high degree of confidence, we can look into the near future and see what is going to happen to the composition of our population barring any massive events or social and cultural changes that might occur.
While this planet may be able to sustain a population of 8 to 10 billion of us, the question is should it be burdened with such a load. Although the damage we inflict on this planet may not look pretty, the earth has no eyes to see it. We are the ones with eyes and a consciousness to appreciate beauty and offer scorn at the damage we are doing. Our survivability is not predicated on a beautiful landscape, but it does depend on us not creating collateral toxicity that will lead to our demise. Surely, whatever we do in the next few decades there will be humans inhabiting this planet in some level of what we loosely refer to as civilization. There may be 7 or 8 billion of us or maybe only 3 or 4. It is up to us. It is our decision to make whether we exist in a comfortable world or the one Paul Ehrlich refers to as the battery-chicken world.
There is a finite quantity of fuel in the ground for us to exploit. Burning as much of it as we have to date has resulted in the environmental damage we have already seen. That damage was not just an event-based occurrence, it is a process that continues to react and continued to produce the damage. Even if we all stopped putting any carbon into the atmosphere, the degradation may not stop, because there is a multitude of natural sources of carbon dioxide, methane and other gases that result in climate alterations. Lake Lyos in Cameroon spews CO2 into the atmosphere via a man-made effervescent vent for the built-up CO2 gases in the lake water. We are not adding any CO2 to the air there that wouldn’t end up there due to periodic gas eruptions. Anhydrite deposits along the continental shelves all around the planet erratically and intermittently erupt massive quantities of methane. Other volcanoes erupt CO2 and other noxious gases. Forest fires and the clearing of rainforest plots of land all add to the greenhouse gas load of the atmosphere. Even though humans are not the sole perpetrators of carbon loading of the air, we are the only ones who can do anything about it.
It is up to us to first decide what we want the future to be, then we have to develop strategies that will move us in that direction. It is up to us to develop a Sustainable Geometry that includes all the equations and all the variables. We may only be able to address a few of them at a time, but we can use what we already know to begin the plan and start moving toward the solution.
Solar and wind power will not be a dominant source of energy in the next ten years, or even 20. But we can start now to get a few percentages on the total and by the time a new technology surfaces to take it place, we will have accomplished something.
Curitiba, Brazil made a commitment to public transportation as the dominant mode for trips to work. They started in the late 1960s and build up their systems with then existing vehicles and new ideas of how to deploy transportation. As new vehicle types and urban landscapes were built, they included the mass transportation modes as the primary one. Today, they have a 60% share of trip to work on their bus and rail systems.
In the US, we do not need to invent the most efficient wind turbine or the most efficient photo-voltaic solar panels before putting one in on the grid. We can use what we have until someone invents a better one.
The future has an annoying habit of
arriving too early. We are far from being ready to embrace the new geometry that will force us to comply. Either we shape a more sustainable future or nature will shape a more sustainable population of man. Again from the mind of Paul Ehrlich, the stabilization of population size will come from either a controlled birth rate or a higher death rate. More than likely it will be a combination of the two. Since I am moving along the age-cohort chart along with the rest of us, I would rather see a reductions in births rather than an increase in deaths.