What do global warming, world population and human survival have to do with the age of women when they first have children?
When I first got married (a bad mistake), the two of us were only slightly older than the average ages of people getting married in those days: 24 and 27. Now, I suspect, it is higher: the average age a mother gives birth in the US is 25, and that includes teen pregnancies.
The average age a woman gives birth has risen, especially in developed countries. Among developed countries, the US average age of 25 is the lowest, because of the high rate of teen pregnancies (others average 29). Americans (except for the teens) are more like Europeans and Japanese in delaying pregnancies than those figures appear. And (almost) everyone is trying to prevent teen pregnancies. But biology will out, especially when people are repressed about sexuality. Sexuality is powerful even if you've been prepared for it and know about it. When you are unprepared: repression can lead to explosion.
Biologically it might be ideal for a woman to have babies in her early 20's, but if she also wants an independent life, or a career, then early 20's could be the worst time. Biology is inexorable, however. Women in their 30's have more difficulties conceiving, and as they pass 40, fewer and fewer women are fertile. So, there may be a tradeoff.
On the other hand, perhaps this is a trend that aligns with the needs of our planet; it will reduce population growth; ultimately it may even reduce global population.
The Biblical literalists will fume that we must "be fruitful and multiply," but really, does this make sense when world population is 6.77 billion, and rising? When I was born, there were 2.3 billion people in the world; population has tripled. Before it stops growing, it's predicted to reach 9 billion in 2050. When men first repeated the phrase, 'be fruitful"' there were probably only a few hundred million people in the world!
Fundamentalism requires rigid thinking, but it also represents the cultural lag that Anthropologists note in most societies: beliefs change after social conditions make it increasingly uncomfortable for the believer: their reality does not match their ideology. If women demand autonomous lives, and want child-raising and family sustaining to be only one of their roles--or none at all--then beliefs will have to change.
It seems, if population trends continue, that they must change. The Earth won't sustain a population of 9 billion people for very long. Projections are that population will start to decline after 2050. Why? Because: women all over the world will be delaying childbearing and having fewer and fewer children. I won't be around, and neither will most of you, but those projections assume that most people will survive and (moderately) multiply up until 2050.
With increasingly wild weather and out of control global warming, perhaps those projections will be dramatically off.
The only time when world population declined by the amount it could now, if global warming goes out of control, was the Black Death in the 1340's, which swept the whole Eurasian continent, and reduced population by a third. As awful as this sounds, it may be what the planet needs--unless human beings can finally learn to live together and cooperate, and live in ways that stabilize the Earth's climate.
The global warming bills in Congress are pale shadows of what is needed, and even they may not pass, because of all the heated rhetoric and money thrown at opposing them.
What are the chances that people will finally work together? Humans are entirely adaptable, but they will only rally together when they all feel threatened by a common danger. Because we are so adaptable, we will adapt to the danger. One adaptation might be by moving to environments where there is enough to eat. You think we have an immigration problem now! Then, we'll have an in-migration problem, too: I don't want everyone to come to the uplands of the Northeast US, where we'll probably have water, at least--as opposed to desertification, earthquakes, tsunamis and rising seas. If we have wild weather, even the Northeast could have tornadoes.
Things may have to get a whole lot worse before people band together, but by then it might be too late; we might have done too much damage; the climate may have built up too much instability in self-sustaining and reinforcing loops. That doesn't mean a new ice age, or a completely tropical earth; it means all bets are off: no species has ever destabilized the Earth's climate before
So, only a small fraction of humanity might survive. I wonder if they'll learn from our mistakes.
