Well, according to an article on a creationist website, the world is dangerously close to becoming underpopulated. The guy espewing this bullshit (in a Frankfurterian sense) is actually a Ph.D! Not quite sure as to what, because as opposed to serious Ph.D.'s, he's not very forthcoming with his credentials and delving into the roots of his publication costs money - in the true spirit of knowledge sharing and Christian values of sharing knowledge.
I do not have a Ph.D. in whatever he has, but I do have a masters (an MBA, lol) and a bit of research experience, as well as a functioning brain and strong google-fu, which apparently is all that is needed to pick him apart.
So to refute his argument:
"A million births every four days sounds like quite a lot. Most people in our innumerate society won’t think about it as a proportion of the total human population and whether it means galloping population growth. Being the pest I am, I did.
I calculated how many births that makes every year: 365 / 4 = 91.25, so this birth rate means 91.25 million people are born every year. That sounds like a lot. But a ballpark figure for total human population today is 6.7 billion, which, divided by 91.25 million, yields 73.4.
In other words, at a birth rate of 1 million every 4 days, it would take 73.4 years to replace the world’s population. With the world’s average life expectancy hovering around 67, that means 1 million births every 4 days is below replacement rate, which would entail that population is shrinking now, not growing."
Well, dear Mr. Ph.D., life expectancy is calculated by a mortality index, essentially how old the people who died in the given year were. It means that if a person leads his life in an instant it is valid, otherwise it is a historical index of the deceased unrelated to expected life span of a newborn (not to be confused with life expectancy index). In addition, life expectancy varies depending on how long you have lived. If you have survived to 5, the chances of reaching 6 is infinitely higher than if you have not, and your probability of reaching 80 increases every year you are alive. And so on.
What is the expected lifespan of a newborn today? Well, it depends on a number of factors such as the life table, age group mortality rate, unknown future fertility rates, unnown scientific advancements etc. If we invent a medicine tomorrow that increases life expectancy by 10 years (and for some reason, we seem to invent life extending treatments on a regular basis, it could be, perhaps, by science he doesn't know or understand), then it ultimately leads to a conclusion that it is impossible to completely accurate determine population growth.
However, and of course, some people with actual intellectual capacity are attempting to calculate this based on extensions of past oberservations and presumptions of future developments, and their median conclusion is about 9b people (or 1/3 more than today) as a plateau in a couple of hundred years. This will not happen before replacement rates per women approaces 2, expected to occur in another 50-100 years.
In addition, the facts are wrong. Accoring to evidence, there are about 140m births per year, or about 1.54m per 4 day (?) period. Using correct data, the equation it yields 6.9b/140m, which yields 49.2 years.
The remained of the article depends wholly on this faulty premise based on bad math.
This is not my field or anything close to what I'm actually knowledgable about. If someone can pick apart the errors in mine and his argumentation further, I would be delighted.
The facts in general seem about right and maybe we do not need a one child policy. Enough people are having no children which compensates for those having more than 2 children. The population is expected to start dropping after the year 2050 but it is a stretch to say that after 2100 we will have a population in the hundreds of millions. You can assume that as the population gets around 1 billion maybe people might have more children. It is all a guess anyway.
His main problem is that he does not account for population cohorts - there are much more people of child rearing age than an average would show. We have a large group of people 15 to 35 which will continue to mean a population increase until 2050.
Hasn't that PhD (or BS D..) dude ever seen any statistics of population growth on this planet?
Like the UN charts of the historic population growth charts (and most population growth projections too)? While wikipedia isn't the best source to quote anything, at least those charts should talk for themselves http://en.wikipedia.org/wiki/World_population
Even if suddenly the whole world would switch to have a Chinese population control policy (one offspring per couple allowed), it would still take a long time to get the population growth to actually stop, unless of course there are enough natural disasters etc.