I have been reading some population debates online and it has caused me to reflect on it yet again.
So many people like to shout about "getting yourself fixed" or "not having children in this climate" or "stopping breeding" or how responsible it is not to reproduce.
There have also been comparisons to bacteria in a petri dish exponentially expanding their numbers blissfully uninterested in the finite nature their "sugary-gell" resources.
In that model, where we are a bacteria and the Earth is the dish of finite resources, our population is ultimately limited. It will not grow exponentially forever, as the Earth's resources are not infinite, even though one can see that human population can grow at an exponential rate (while the resources are not yet exhausted).
So, at some point the growth curve will round off. I just finished reading Carl Sagan (and Ann Druyan)'s book "Billions and Billions" from which some of my thoughts on this are derived.
The point is this: an individual deciding not to breed will never limit or reduce the potential population of the Earth. The population will march forward so long as even 2 people and their offspring breed exponentially. Their descendants will eventually fill the whole earth. So the only thing to stop it is a die off due to failing resources. We can become more efficient and try to become more just in the sharing of resources, but ultimately that upper limit is where the population cannot grow any more because of hunger, thirst and exposure.
The only decision those who choose not to reproduce are deciding is, how many of the future Earthlings will be their descendants.
To control population we must get everyone on board...EVERYONE. If we can disable reproductive powers and hand them out at a controlled rate we can then control the future balance. It's like polio, you must vaccinate everyone or you have not solved the problem.
Right now, it is a contest between you and me as to how many of the future humans will resemble me or you. The end of expansion will come in all cases, all you can do is lay hold on more resources. This is how many people are thinking who try to out-breed others.
Groups are conscientiously using Natalism to compete for the Earth's limited resources and space. The Palestinians are breeding with wreckless abandon to try to "outnumber" the already small (in a planet wide sense) group of Jews.
Mormons have a culture of pushing breeding to try to out strip the world population growth rate. Although they are noticeably failing to increase the Mormon percentage of the Earth's population. They are being strongly out done by the other groups. Making Mormons a smaller and smaller percentage of Earth's population even with their growth rates and missionary efforts.
You can't stop Central Americans from breeding at ages far closer to the onset of fertility than is culturally acceptable in the United States, so in that sense, the future will be more of them and less of us. Their time-span for a "Generation" could be half that of ours. That's a "survival of the fittest" strategy where they are winning. Not to mention the highly successful Asians.
Even if many humans die off at an alarming rate when the "sugary-gel" (Earth's life sustaining resources) vanishes, those left will resemble the current proportions of groups that had both wealth and large numbers of offspring.
So, is it irresponsible to reproduce? The upper limit is already set to stop our exponential growth. That limit is set by the finite availability of food, shelter, water, warmth and wealth. Choosing not to reproduce, even if MOST of us chose the same thing, is only a way to subtract your genetic heritage from history and quit the contest. It will not reduce the march upward, it will happen as fast as it can with or without your genes. All you are deciding is how many of the left over humans will be like you.
All it takes is one non-compliant group and over a few generations they will exponentially fill the space you leave by not having children. Self-selecting your own unfitness to propagate seems remarkably self-defeating.
If we disable reproduction and manage it, allowing a balanced mix of people to procreate, then we can control the future by our actions. Until such a freedom limiting method is instituted by an awful sounding regime, individual choice will not reduce the world population. Others will just grow more.