Why are populations just growing by 1-2% in some nations?
Shouldn’t it grow far quicker if the average couple has 2/3 kids? Removing 25% from those who don’t want kids.
Should people “nearly double”?
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Because it takes two people to have a child, your population is only stable if the average couple has two children. And there’s enough people who only have one child, or no children at all to compensate for couples who have more than two children.
If the population is 2, and those 2 people get together and have 2 kids, now there are 4 people. Then the first 2 people die, and the population is back to 2. You’ve only doubled the population temporarily.
Generally, fertility drops as people get richer. They get better education about family planning, better access to contraceptives, and women have career alternatives that keep them in education and work in their 20s rather than marriage and having children beginning in their late teens. Much of the world has gotten richer over the recent decades, so we’re seeing many countries moving toward the fertility patterns of “rich” countries were people have just about 2 kids (often less than 2 for people born in the rich country, supplemented by higher birth rates from immigrants).
As women gain access to education they figure out they can do more with their lives than just make babies so the birth rate declines in advanced countries.
People…die?
A couple needs to have 2.1 kids just to *maintain* the population. Because that couple will die so they need to make two people simply to replace themselves.
In developed countries less than half of all couples have 3 kids. Which means less than half of all couples even manage to do more than replace themselves.
As an anecdote of the roughly 30 or so families of kids I was in grade school with only 6 of them came from a family with more then two kids. There were more families with a single child.
Population is out of control but it is slowing down and in some places, reversing. When I was a kid, there were 6 billion people on the planet. Now there are 8 billion. A thousand years abo it was about 300 million. Human population growth is becoming too much for this planet to sustain. We either have to reign it in, keep it stable, reverse it or learn how to make do with less per person.
This is a question for many religions and cultures, and economics rely on exponential growth that needs us to keep breeding. We are going to run out of land to live on and land to grow food. Earth or us will eventually say enough is enough and create some sort of slow down. In places like Asia, that is already happening because it is simply too expensive to have a kid.
In the US, the replacement rate is 2.1, in other words every woman needs to have 2.1 kids to replace the people that die. But the actual fertility rate in the US is 1.7. The only reason the US’s population isn’t decreasing is because of immigration.
In general, developed countries don’t have a lot of kids. Global population growth mostly comes from developing nations.
The growth rate is the birth rate minus the death rate. They’re pretty even, so the difference is small. The reason for that is that the number of kids born per mother is about 2.39, but not all survive to adulthood, and you divide that by 2 (so 1.195) because the rate means for all people, not just women. If couple average 1.195 babies, and the average amount of time it takes to make a new generation is 19.5 years (average age of a mom), that’s about +1% / year.
People are answering with basic math, but they still miss the basic fact that most people are not having kids in a year. Your math assumes that everyone is having 2-3 kids all at once, but a majority of people are not of age to have kids (children and the elderly), and the vast majority of reproductive-age people are not having kids in a year. A couple who has 2 kids has them over a few years, then they stop forever. The contribution of existing people to population growth is punctual and short-lived.
Birthrates are below replacement levels in many countries… many couples are choosing not to have kids, many only have 1, most have 2 at most. Replacement level is something a little over 2 kids (factoring deaths before procreation, etc) but in many countries, the average fertility rate for mothers is under 2. For some countries, their entire growth is due to people living longer and immigration.
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