(Highly) recommended (for repeated) viewing, or better *studying*: Dr. Albert A. Bartlett's (brilliant!) presentation on "Arithmetic, Population, and Energy"
How to find this answer?
for example, according to the poodwaddle-worldclock, there were 146 M births
and 59 M deaths in 2010. That's Births/Deaths = 146/59 =
247 / 100.
Seems high, doesn't it? So I looked up a number for the death-rate. Wikipedia gives 0.837 % (for 2009)
or, even simpler, we take (numbers for 2009, rounded) from wikipedia:
Actully, death-rate of < 1% seems low to me; but several sources agree on this figure.
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we assume population = 7 G, growth-rate = 1.18%, and we calculate:
Deaths: D = 0.84 % of 7 G = 58.8 M
Births/Deaths = B/D = 141/82.6 = (rounded:) 240 / 100.
Growth: G = 1.18 % of 7 G = 82.6 M; with G = B - D, of course, and
Births: B = D + G = 141 M; and we get
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Birth_rate = 2.00 %
Death_rate = 0.84 % and we get:
B/D = 2/0.84 = 238 / 100
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My first estimate was D = 2%, G = 1.2%, thus B = 3.2% and B/D =
160/100.
But the estimate of D=2% is based on a
serious/dumb/huge mistake. It would be a reasonable estimate for
the death-rate for a STABLE population with an average
life-span of 50 years. But it does not take population-growth
into account! For a population doubling in veryroughly 50 years,
D=1% is more reasonable approximation.
----
Note:
some numbers are rounded; and "%" should maybe more
precisely be written "% p.a." (i.e. percent per year);
and M = mio, G = bio, of course.
Any corrections or suggestions-for-improvement would be welcome; please send to [email protected]
Anwers to my simple question --so far, without exception-- seem to indicate that noone, that's NOT ONE, has really grasped (the gravity of) the problem.