Demographics After the End

Since we have already determined that there are two potential events that would cause mass destruction that have probabilities that are high enough to think about: an asteroid hit and a deadly pandemic. 

There are too many variables to make more than very general comments about changes in population that would result from an asteroid strike, because the strike could hit anywhere on Earth and the results would be determined by the location and the size of the asteroid. The loss in life could be anything from minor to the death of nearly all humans and other creatures.  This would be the random death version of the great destruction on Earth.

On the other hand, we can make some reasonable predictions about the great pandemic, because it will hit the whole world. Whether any given individual will survive is a matter of chance, but there also would be people with natural immunity. Other relevant factors would be the disease itself, how deadly it was to start with and how immune it was to antibiotics or antivirals. There are diseases that have mortality rates that approach 100%, but the human body can throw off even a deadly disease some of the time. How much contact with the disease one would need to contract it varies widely also, but generally the more lethal the disease, the fewer germs that are necessary to produce a full-blown case. The medium for contagion is another relevant factor. Generally, airborne diseases spread more quickly. And the final factor is how long the disease takes, both incubation period and the time for it to run its course. Diseases that have long incubation periods and that take a long time to run their course are generally less lethal.

With a disease like that making the rounds, the pattern of mortality would be inversely proportional to population density. There would be areas, such as islands and sparsely populated regions, that would suffer few or no fatalities, while densely populated cities might lose ninety percent of their populations. Skin color, religion, political preference, sexual preference, and most other differences among people would make little or no difference, but health, intelligence, and knowledge in disease prevention might make the difference between life and death for some. We might find that people who went looking for help would be more likely to be infected than people who stayed home and hoped that they wouldn’t run out of food before it became safe.

A catastrophe that would kill 80% of the Earth’s human population is not difficult to imagine. If that happened now, then it would bring the population down to what it was in the late 1800’s, about one hundred thirty years ago. That would be a tremendous change, but it would be quite survivable; although things would be different. The largest cities would suffer the most. We can expect that the super-cities with populations over three million could lose more than ninety percent of their populations, and those who remained might not be able to adjust to new situation. The depopulated large cities would amount to less than 10% of the total population, but it would result in the destruction of a large part of the banking and financial industry. In some parts of the world the largest cities house the administration of government and transportation hubs.

I won't go into all of the details, but imagine eight out of every ten people you know not making it through the pandemic. Then adjust that, so that the ones afflicted with chronic diseases will be among those who don't make it. Add to that group those people who involved with public health and welfare agencies. And remember that people in the medical industry are more likely to have been exposed than other people. On the other hand, if you are a commercial fisherman or a miner, then you would have a better chance to survive. Prisons, hospitals, and universities would lose almost everyone. Farmers would do better. The two left probably were reasonably healthy and more likely tha not did not work with the public. They almost certainly are between twenty and seventy years, and they are not obese, nor are they especially slender. If you are in the group, then I may run into you afterward. 

The population would somewhat like the population of the late 1800’s in characteristics in addition to the number. The rural proportion of the population would be larger than it presently is, and it might be younger. There certainly would be few chronically ill people left; the weakest are the most likely to go in a pandemic. Some diseases attack the young, while leaving the mature alone, and others do the opposite, but there is a tendency for older people to be more likely to have a chronic disease, and people with chronic diseases would almost certainly be lost. As noted above, there probably would be a slight advantage for people who were more intelligent and better educated. Regardless of which group you are in, you probably won’t survive, but you already knew that.