(I'm waiting for Eagle to quote that "go forth and multiple" command...)

The world population is about 6-7 billion right now. It doubled between 1960 and 2000 (40 years) and tripled between 1927 and 2000 (73 years). There are estimates that the earth can only support 18 billion people based on the amount of arable land and so forth. The planet cannot support another tripling.

There is a good chance we will be getting close to the limit in my lifetime. I expect to live to see another doubling but probably not a tripling or reaching 18 billion.

Unless the world gets a handle on this, most children born today will experience food shortages, starvation, and wars over food and water. Everyone will experience population stress. The developed world at that time will be partly isolated from it but it is not at all obvious that the developed world will include Canada, the US, or Europe. We may very well be overrun for our food production resources. After all, the high tech superpowers of 100 years ago are no longer dominating the world.

With no plans to leave any offspring behind, I'm actually not too worried about this. But it's an obvious problem that is only going to keep getting worse until population growth is brought under control. I think it is a far more immediate threat than running out of oil or flooding from global warming!

I actually chuckled when I read that first comment.

I don't dispute the issue of overpopulation. I'm just not sure if that is a good argument for not having children in a developed or industrialized country.

Still waiting on what the proposed solution to overpopulation is.

By the way the comment that



is completely false. It was a generalization and lacked data. It also was meant in my opinion as a form of bullying the poster of the comment - Savarel. Unless a majority of countries in Europe, Japan, and S. Korea (and throw in Canada) are not considered modern. Can we agree?

And Savarel is correct if no individuals decided to have children or if there were a disaster that prevented reproduction that eventually the population would not only be unsustainable but we would in fact become extinct. Can we agree?

The issue is not in the "modern world" or industrialized countries. The issue is in the developing (India population is 1.2 billion people and there are 54 births in India a minute; while China is an exception is that what it's going to take?) and underdeveloped world (some of S. America, a majority of Africa, and parts of Asia).

No, we can't agree. Replacement rate is the rate that women would have to reproduce to produce a stable population. And it's really all about women. It depends on death rate, infant mortality, and other factors. It involves a time dimension as well so just picking a single year (or decade) isn't really relevant. And I intentionally said "about" because there are lots of ways to measure it. The more specific you get the more accurate the model. It might be 2.1 per couple, 2.05 per woman, 2.07 per woman of child bearing age, 2.071 per fertile woman of childbearing age, 2.03 per woman of child bearing age who intends to have children, etc. The point is not to split hairs but rather to point out that it is about 2. It is not 1, 3, 5, or 12. When humans evolve the ability to have fractional children it might make sense to quibble about the decimals.

I don't think the population problem is a reason not to have children in a developed country. But I do think it is a reason not to have "many" children.

As for a proposed solution, I have not proposed one. I think starvation and war will take care of the problem when it becomes severe enough. You should know by now that I am all fro free-market solutions.

So by "modern world" you mean the whole popluation of planet earth and not industrialized countries? If the whole popluation of the planet earth then sure that generalization can hold I suppose. Except I don't know how modern a good chunk of the planet really is.

My point was and is that in many of the industrialized countries populations are not being replenished. I'd still like some form of evidence (link to a credible source?)that the world average for children per set of parents is about 2. Is there such a study?

What about somehow helping people in developing and underdeveloped countries become aware of this issue? Of course I'm sure a majority of people in those countries are more concerned about such things as water, food, and making it to next week alive. Something that isn't an issue in the U.S. and therefore arguing against having more children here at least seems less valid.

As to the comment on starvation and war... That is a very sad thing. That is a bit humorous about the free-market solution comment.

It's a simple concept. A+B mate for life. They must make enough babies to replace themselves plus a slight amount extra to make up for the members of their species that die before childbearing age or otherwise don't breed. That means replacement rate is always 2 + a bit for any human population. "A bit" is bigger if more people die young or if more people choose not to reproduce.

And strictly speaking, boys don't matter. It is only replacing breeding females that matters. So unless the statistics correct for that, they are useless. And given the status of women in much of the world, the actual numbers are not very reliable.

Also, replacement rate does NOT depend on birth rate. If you think it does then you are not understanding what it represents.

I was not referring to the specific value that any particular country is replacing its population but rather an approximate value for most countries.

War and starvation are sad. But that's what happens when people are under enormous stress and can't feed themselves.

As for helping people in developing countries not have so many babies, people used to do that. They would hand out condoms. Then the religious folks got all in an uproar and most of those programs fell apart. Even programs to educate women, which has a dramatic effect on that problem and many others, often run into political problems in developing countries.

Sounds like a good argument for increasing defense spending... or at least maintaining a large stockpile of nukes and letting it be known we'll use them if attacked

Joking aside, I haven't read any of the studies on over population and potential food shortages. Do they take into account increased productivity on land? We can produce a lot more food per acre than 100 years ago. That amount will likely increase, but I have no idea if it can increase enough to meet rising demand.

This has always made me wonder why we (our government) push ethanol use so hard. To me its never seemed like a good idea to burn our food for fuel.*

*I would never say this publicly where I live. I'd be tarred and feathered by the farmers.

we're definitely into derivatives of the 4th order!

This is nothing... did you read the Obamacare thread?

Because it's getting frustrating to watch Eagle and DoingHomework misunderstand each other, I want to add:

Regarding the "replacement birth rate," it seems DoingHomework is pointing out what a theoretical replacement rate would be. He is saying that if every couple had 2.1 children, then the world population would remain constant. Eagle seems to be interpreting DH as claiming that this is what is currently happening, and I don't think DH was saying any such thing.

I think you're arguing over two different things. If I'm misunderstanding, I apologize, but if I'm right, I just wanted to clear that up so we can move past it, as it was getting a little annoying.

Nope, you got it. I know what he is saying but that has nothing to do with my initial comment that having more than ABOUT 2.1 kids is adding to world population growth.

There is a lot of irony in the situation.

I have heard the 18 billion figure many times in my life. I do not know the source and I don't really care enough to even google it right now. Whether it is 12B, 18B, or 30B based on crop yield improvements hardly matters. The point is, in the lifetime of kids born today or at the least their kids, planet earth will be full. We're going to run out of food and water long before we run out of oil. But oil is where the short term profit is so it gets all the attention.

I agree that the situation likely should have some impact on defense planning and probably even immigration policy.

Lol. Might want to have some snacks ready. It's a bit... long.