The seven billion mark:
The best guess is that a little over a year ago the number of people in the world exceeded seven billion. (Jeff Tollefson Seven Billion and Counting NATURE vol. 478 no. 7369 October 20, 2011 page 300) Those who concern themselves with such matters seem to see this as an unmitigated disaster. Well I am certainly with them on the number. Two billion is said to be about as many as the world can support with traditional agriculture. Anything above that is ultimately unsustainable.
They are predicting that the developed world over the rest of the century will be about stable with actually a rise in North America, with that rise leveling off toward the end of the century. Only in Africa are the numbers high and rising. Managing to get Africa more prosperous is the best bet for keeping the population under some sort of control; richer people have fewer children.
Of course there are two basic ways to reduce the fertility of a population: reversible and irreversible. To my observation as a planet we are taking the irreversible approach.
The urban population of the world is rising rapidly and expected to continue to rise at least until 2025. The rural population has been in actual decline and is expected to continue to decline. Since cities never actually produce enough children to survive, must therefore rely on immigration, the decline in the worlds rural population should be a source of hope or panic depending on whether one believes the process if reversible.
Ideally populations should be stable. And they should be stable at a sustainable level. By the calculations of the professionals, if the birth rate is only .5 children than what is expected over the course of this century, the population should decline to six billion by that time, after having risen to eight billion. A similar error in the opposite direction would raise the population to sixteen billion over the same period of time. I think that would not be good. Even my own wildest ideas for technical growth (and I can be pretty wild when I put my mind to it) would not permit universal prosperity in that event.
Yes, there are too many of us. No, I don’t trust the published predictions. Yes I think our only hope for a nice future is to understand what drives fertility and make rational choices.
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