Population fluctuation in humans ?

[fredjacksonsan]

Every animal in the world has a natural population fluctuation. For example, as rabbits multiply in the wild, the fox/coyote/other predator population also increases due to the increased food supply. When the rabbits start to decline in population, so do the predators.

In several areas of the US, deer populations are suffering from starvation due to their own prolific reproduction.

Another very well known example is the lemmings, which periodically run themselves off cliffs, killing millions. (Urban Legend, but useful for illustration)


Now the question in the title: What is the normal population fluctuation in humans?

If you consider the plague, then there was a huge dip in the European population in the middle ages. Then in 1918-19, the influenza pandemic killed many many people. There may have been others in the distant past, but none (or few) were recorded.

Since those times, there has been a continuous upswing in the human population of the planet. Many diseases have been cured by modern science, and other advances in things like safety of food, quality of that food, and good nutrition have helped to maintain a healthy population.

But are we headed for a population downturn? Most diseases are easily thwarted nowadays, but AIDS remains one example that has so far eluded efforts at vaccination. There have been severe losses of life in many African nations due to the AIDS virus, and it continues to spread. Could AIDS be the new plague, or is there another disease on the horizon?

Every population curve I've seen always shows the population continuing to climb. Is this merely confidence that science can stay ahead of mother nature? Or could it be that scientists realize that the time will come when the planet can no longer maintain the growing population, but are insulating the masses from that information?

So will the population continue to grow, or are we on a population bubble that will eventually burst?

[turtlecrxsi]

First, I'd like to say that this is a very interesting topic. I think you bring up some valid points about diseases being cured and and the quality of food, nourishment etc. improving, essentially prolonging the longevity of the human lifespan. Obviously, it is still up to people themselves to live a healthy lifestyle. Cancer still kills millions every year as well as aids.

I think that humanity naturally as well as politically deals with its own issues of demography. In China, there are laws about the number of children conceived etc. Humans die from accidents and murders every day which would probably be considered part of the natural demographic chart. Mother nature also plays a huge part in this... for example, earthquakes.

But what about wars? Wars kill more people than a murder or accidental death except for maybe a natural disaster like maybe an earthquake or tsunami. But what if two war-waging countries were fighting and an earthquake killed everybody. Anyway, not to sound too pessimistic, I just think that wars are one way in which the human population is somewhat controlled in the modern era...

[dirtydx]

the next pandemic is definitely coming, SARS was just a small example of how quickly we can lose control. There's nothing we can do except cope with it when the time comes. Science is helpfull to us, but nature is in control.

[fredjacksonsan]

Originally Posted by turtlecrxsi

....

But what about wars? Wars kill more people than a murder or accidental death except for maybe a natural disaster like maybe an earthquake or tsunami. But what if two war-waging countries were fighting and an earthquake killed everybody. Anyway, not to sound too pessimistic, I just think that wars are one way in which the human population is somewhat controlled in the modern era...

Agreed; Man is the only animal that routinely kills his own species in conflict. The genocide in Rwanda was especially bad.

Originally Posted by dirtydx

the next pandemic is definitely coming, SARS was just a small example of how quickly we can lose control. There's nothing we can do except cope with it when the time comes. Science is helpfull to us, but nature is in control.

My thoughts exactly. Sooner or later, there will be a bug (germ) that takes a couple weeks to show any signs of illness(or has no outward signs), kills 80% of victims in a couple more weeks, has no treatment and is transmitted easily. [It might even be man made, but that's another thread]. The CDC and its counterparts overseas do a fantastic job, but they have their limitations.

[eversio11]

Originally Posted by fredjacksonsan

Another very well known example is the lemmings, which periodically run themselves off cliffs, killing millions.

That's actually a very well known urban legend

[AlmostStock]

This reminds me of the thread "The future of mankind". It seems fairly obvious that human population can't continue to climb forever. I think resource depletion and the wars that follow, along with environmental degradation, will drive the next downward fluctuation. With peak oil now in our sights many don't think we're that far away.

[fredjacksonsan]

Originally Posted by eversio11

That's actually a very well known urban legend

Agreed and true;

http://www.snopes.com/disney/films/lemmings.htm

The legend was useful for illustration and I've edited the original post.

[MagicRat]

Originally Posted by AlmostStock

This reminds me of the thread "The future of mankind". It seems fairly obvious that human population can't continue to climb forever. I think resource depletion and the wars that follow, along with environmental degradation, will drive the next downward fluctuation. With peak oil now in our sights many don't think we're that far away.

True.
Stastistically, the rate of human population growth has been declining. This means the human population is still growing, but more slowly than in most of the 20th century.
The population will level off at about 11 billion people in about 45 years or so, as I recall.
Most weathier industrialised nations have negative population growth and rely on immigration for growth.
Only the poor nations still have population growth. Therefore, as living standards improve, the growth rate declines.

However, our modern, Western living standards are simply not sustainable. At some point we all will have to consume far less resources and/or drastically reduce the population, as resources become more scarce.

[Muscletang]

The U.S. is climbing some but not really big in population. Europe is slowly dying. Africa and Asia are exploding because they don't have birth control.

The thing is if a virus breaks out, Africa and Asian will probably be hit first.

Watch the movie "Outbreak" though and that'll open your eyes. Seriously it's one of the only movies that scares the shit out of me.

[MagicRat]

Originally Posted by Muscletang

Africa and Asia are exploding because they don't have birth control.

Yes, but its more than that.
Families there have lots of kids because it's traditional, and people believe that children are an asset, kids can work and support the family, especially when the parents get a bit older.

Therefore, as people become wealther and have better paying jobs, as in Europe, they are less dependent on needing kids for support.

Also, the parents are expected to actually send the kids to school instead of sending them to work, as is done so often in poor regions of the world, which is a financial disincentive to have lots of kids.