jon@CSVAX.CALTECH.EDU (03/10/86)
> From: hplabs!sdcrdcf!oberon!smeagol!earle@ucbvax.berkeley.edu (Greg Earle) > ... > Do you live in a cave? It IS a bad thing - most (if not all) of the > world's ecosystem problems can be directly traced to humankind multiplying > like flies and devouring all available space!!!! > > I don't think a 2% growth rate is 'multiplying like flies', and I > don't think 10 acres per person is 'devouring all available space'. > This message seems quite hysterical. Do you hate mankind? Do you > hate yourself? How long should we keep up this 2% growth rate? Area of Earth ~ 2.01062e+08 sq. miles (all land assumed). Current population ~ 4*10^9 (actually substantially greater). Year Population Area (sq. mi) Area needed / Area of the Earth needed @ 10 acres/person ----- ------------- --------------- ------------------------------- 0 4e+09 6.25e+07 0.310849 100 2.89786e+10 4.5279e+08 2.25199 200 2.0994e+11 3.28031e+09 16.3149 300 1.52094e+12 2.37647e+10 118.196 400 1.10187e+13 1.72167e+11 856.286 500 7.98263e+13 1.24729e+12 6203.49 600 5.78313e+14 9.03614e+12 44942.1 700 4.18967e+15 6.54637e+13 325590 800 3.03527e+16 4.74261e+14 2.35878e+06 900 2.19895e+17 3.43585e+15 1.70885e+07 1000 1.59306e+18 2.48915e+16 1.238e+08 OK, so I might be off by a constant here or there (the only way I could find out how big an acre was in square miles was the 'units' program). The end result doesn't matter, just wait a few more centuries. The message you were responding to may have been overstated, but no more (if that much). Clearly we CANNOT continue to expand at an exponential rate for long (on a historical timescale). This is not hysteria but fact supported by your own numbers. Which does not imply in any way that we have to start killing people to prevent it (unless you think that contraception == killing people, which I doubt most of us agree with). And no, I neither hate mankind nor myself. I like both of us enough to want a future in which everyone has resources and energy to spare. -- Jon Leech (jon@csvax.caltech.edu) __@/
mcgeer%ji@UCBVAX.BERKELEY.EDU (Rick McGeer) (03/11/86)
"For food grows like 1,2,3, and man liek 2,4,8..." Malthus had fun extrapolating exponential growth curves, too. So did Forrester and Ehrlich. Doomsday hasn't hit yet, and it doesn't look any more likely to me than when Malthus wrote, or Forrester. Exponential growth curves *always* flatten, for one reason or another. Populations either get seriously whacked (a plague, war) or get rich and thus stop breeding. [True enough -- as Lady Jackson used to point out, on a national scale the only *sure* method of birth control is national wealth. The United States would currently be suffering a population *decline* if it were not for immigration. Try that the next time some character flames away about breeding like flies in East LA!] For this reason, space may well be the solution to our future population problems, not because a significant percentage of humanity will emigrate, but because space is gonna make us all stinking rich. -- Rick.