4 ms·

"Considering the declining birth rates throughout the world..." where did you get that statistic from?

by hnriot 13y ago

rdl 13y ago
Birth rates have been declining and sub-replacement-level in Japan, "rich" Europe, and parts of the US for years (decades, I think) -- Japan and Singapore are particular far along on this. Plus of course the great Chinese experiment of the "one child policy", and Russia's collapse in birthrate in the late 1980s/1990s (largely due to the fall of the USSR). Even in high-fertility countries, it's been dropping from 5 to more like 2-3, largely correlated with female education and opportunities other than (early, exclusive) motherhood. (The US would have a negative growth rate if it weren't for immigration, largely from Spanish-speaking nations in the Western hemisphere.) Population of the earth as a whole is still increasing, but that's largely due to a few parts of the world which have had huge birthrates in the past and a large population under-30 (and under-18, so it will continue for a while.). It's a mean vs. median problem.
- hnriot 13y ago
  thanks for the explaining why you suggested the world's birth rate is dropping. As you say, population of the earth as a whole is still increasing, and the birth rate is not in decline. It's not a mean vs. median problem at all. If it were in decline we wouldn't be facing one of the biggest global issues of over population.
  - rdl 13y ago
    Population is one number. Birth rate is a derivative of that. A rate of change in birth rate is the second derivative of population. Population'' is clearly negative -- the global birth rate IS in decline, and has been since 1950 according to the UN (I don't see earlier stats). Population is still increasing because Population' is positive. (well, actually Birth rate > death rate). Per country, it actually is a median vs. mean problem; most countries (hence, median) have below-replacement birth rates; there are a limited number of countries with substantially above replacement birth rates, due to both fertility and the demographic composition (lots of young people).
    - dragonwriter 13y ago
      > Population is one number. Birth rate is a derivative of that. No, its not. For several reasons. Firstly, because the derivative of population is the rate of population growth (persons/unit time) which is not just the rate of births per unit time, but births minus deaths. Secondly, because "birth rate" isn't the rate of births per unit time, but the rate of births per unit time per unit population. > Population'' -- the global birth rate IS in decline, and has been since 1950 according to the UN Those statements are only distantly related and only the latter is clearly true. While the birth rate (births/person/year) has been dropping for quite a long time, the second derivative of population with respect to time was around 0 from the late 1980s to recently, with the first derivative hovering at around 1 gigaperson / 12 years, though projections are that that rate of increase is slowing somewhat now. The second derivative of population with respect to time was actually positive for most of the 20th century, with each successive billion people added in a shorter period of time until it leveled off around at the 12 years / billion level. [1] http://en.wikipedia.org/wiki/Population_growth http://en.wikipedia.org/wiki/Population_growth
ThePhysicist 13y ago
e.g. here (links to Gapminder): http://bit.ly/1jN1Xqc http://bit.ly/1jN1Xqc Use the slider to move the time axis. Birth rates have declined in most of the world during the last 100 years, with a strong inverse correlation between life expectancy / wealth and birth rate. The US still withstands this trend somewhat with a birth rate just above 2.0, whereas most European countries range between 1.3 - 1.7 births / woman (which is not enough to sustain population). This Wikipedia article is also interesting: http://en.wikipedia.org/wiki/Birth_rate http://en.wikipedia.org/wiki/Birth_rate

"Considering the declining birth rates throughout the world..." where did you get that statistic from?

by hnriot 13y ago

"Considering the declining birth rates throughout the world..." where did you get that statistic from?

rdl 13y ago

Birth rates have been declining and sub-replacement-level in Japan, "rich" Europe, and parts of the US for years (decades, I think) -- Japan and Singapore are particular far along on this. Plus of course the great Chinese experiment of the "one child policy", and Russia's collapse in birthrate in the late 1980s/1990s (largely due to the fall of the USSR). Even in high-fertility countries, it's been dropping from 5 to more like 2-3, largely correlated with female education and opportunities other than (early, exclusive) motherhood. (The US would have a negative growth rate if it weren't for immigration, largely from Spanish-speaking nations in the Western hemisphere.) Population of the earth as a whole is still increasing, but that's largely due to a few parts of the world which have had huge birthrates in the past and a large population under-30 (and under-18, so it will continue for a while.). It's a mean vs. median problem.

hnriot 13y ago
thanks for the explaining why you suggested the world's birth rate is dropping. As you say, population of the earth as a whole is still increasing, and the birth rate is not in decline. It's not a mean vs. median problem at all. If it were in decline we wouldn't be facing one of the biggest global issues of over population.
- rdl 13y ago
  Population is one number. Birth rate is a derivative of that. A rate of change in birth rate is the second derivative of population. Population'' is clearly negative -- the global birth rate IS in decline, and has been since 1950 according to the UN (I don't see earlier stats). Population is still increasing because Population' is positive. (well, actually Birth rate > death rate). Per country, it actually is a median vs. mean problem; most countries (hence, median) have below-replacement birth rates; there are a limited number of countries with substantially above replacement birth rates, due to both fertility and the demographic composition (lots of young people).
  - dragonwriter 13y ago
    > Population is one number. Birth rate is a derivative of that. No, its not. For several reasons. Firstly, because the derivative of population is the rate of population growth (persons/unit time) which is not just the rate of births per unit time, but births minus deaths. Secondly, because "birth rate" isn't the rate of births per unit time, but the rate of births per unit time per unit population. > Population'' -- the global birth rate IS in decline, and has been since 1950 according to the UN Those statements are only distantly related and only the latter is clearly true. While the birth rate (births/person/year) has been dropping for quite a long time, the second derivative of population with respect to time was around 0 from the late 1980s to recently, with the first derivative hovering at around 1 gigaperson / 12 years, though projections are that that rate of increase is slowing somewhat now. The second derivative of population with respect to time was actually positive for most of the 20th century, with each successive billion people added in a shorter period of time until it leveled off around at the 12 years / billion level. [1] http://en.wikipedia.org/wiki/Population_growth http://en.wikipedia.org/wiki/Population_growth

ThePhysicist 13y ago

e.g. here (links to Gapminder): http://bit.ly/1jN1Xqc http://bit.ly/1jN1Xqc Use the slider to move the time axis. Birth rates have declined in most of the world during the last 100 years, with a strong inverse correlation between life expectancy / wealth and birth rate. The US still withstands this trend somewhat with a birth rate just above 2.0, whereas most European countries range between 1.3 - 1.7 births / woman (which is not enough to sustain population). This Wikipedia article is also interesting: http://en.wikipedia.org/wiki/Birth_rate http://en.wikipedia.org/wiki/Birth_rate