Let’s face it: the earth has too many humans, using natural resources up too quickly, and the population will be forced to decline to a sustainable level sooner or later. Achieving a sustainable situation will require that there be a lot less humans, especially when fossil fuels become scarce. That means the human birthrate must decline. For population to be reduced without a birthrate reduction would mean that average lifespans would have to decline to near the minimum childbearing age, which I think is highly unlikely. Before sustainability is reached, however, there will be a long period of change, of probably 70 to 200 or more years. How will population most likely be reduced during that period?
Natural disasters are unlikely to be a major factor. Examining the natural disasters of the past few decades, in which increasing population has combined with concentration of people along coastlines and in major cities to create huge losses, we can see that in most major disasters the dead number in the thousands or tens of thousands, and a large proportion of the victims have already borne children or are past childbearing age, and thus are already past having much impact on the birthrate. Compared with a world population of over 6.5 billion, these disasters have no impact at all.
Mega-disasters such as will likely occur if the oceans rise will not make much difference, either. If the oceans were to rise by, say, three feet, it would probably cause more than a billion people to move inland, and the major ocean-related disasters – cyclones and tsunamis – would have much higher potential death tolls. Even if the deaths from such huge disasters were to be in the millions, however, the impact on the total population would be quite small, and the impact on the birthrate would be even smaller.
A worst-case rise in sea levels could be bad, but probably not bad enough to significantly lower the population. Of course, if it occurred quickly enough, the rise of the oceans would shut down many refineries, shipping ports, and power generation plants, and could potentially cause serious food shortages in even the most developed countries such as the United States, after which the resulting famine could cause many more deaths than any tsunami or hurricane. Besides the current projections that it will take at least decades to see a meaningful change in sea level, I can only guess that the population reductions resulting from a more rapid rise would still have small, if any, lasting effect on world population in the long term, and even less impact on the birthrate. Once the infrastructure was restored, the adjustment would be made within a decade and little change in world population would be measurable a decade after that. As a result I have to think that, short of an asteroid striking the earth, natural disasters are unlikely to reduce population significantly.
Could war reduce world population significantly? When one examines the biggest wars, and the trends in losses over the centuries, even the worst, World War II, cost the world less than 73 million people. In addition, war casualties since then have fallen significantly. The one exception would be an all-out nuclear war, but, so far, world powers seem to all be pretty much aware of the terrifying dangers of such an event, and that M.A.D. (mutually assured destruction, a cold war term) means nobody wins … nobody.
Epidemics could be serious, but this situation appears to be getting a lot of appropriate attention. Once natural disasters and wars are eliminated, major population reductions could still be caused by famine or epidemic. The question is still open on possible epidemics such as bird flu, so I will continue to watch the situation and see how people are responding to it – scientists are keeping a close eye on the situation, and the only significant problem I see is the usual one of getting governments to work together and do the right things to reduce the risk.
That leaves two possibilities in my mind – famine and voluntary birth control. Obviously, famine is the real threat. Underdeveloped and undeveloped countries have the highest birth rates these days. I recently learned that, in many cases, this is due to the wish of parents to be sure they will have children to look out for them in their old age in the face of high mortality rates (infant and other). The only way the very poor can be sure they will be cared for in their old age, especially in a country with variable political and economic factors and no “social safety net”, is to have a lot of kids and hope that a few will still be around when they need them. This points quite clearly to the solution to overpopulation: help the underdeveloped countries with aid in the areas of education, economic assistance, and family planning.
We in the developed world NEED to provide economic, education, and family planning assistance to the underdeveloped countries. It has been shown over and over that, when people are eating better, finding jobs, and feeling more secure the birth rate goes down. If we don’t help the fast-growing countries of the world lower their birth rates, not only will pollution, climate change, political unrest, and food and energy shortages get worse, but rapidly increasing numbers of people will be pulling up stakes and moving, by any means necessary, to where life is better – Europe, North America, Japan, Australia, New Zealand, and anywhere else that looks good. The illegal immigration we see today could be like nothing compared to what will happen in the future if we don’t help those people have better lives (and lower birthrates) where they are. It is unlikely that voluntary birth rate reduction will occur on its own.
That’s my take on it. I appreciate your comments as always.