2015-would put the total population at 4.90 billion in 2000, an increase of only 2.1 percent, and a modest price to pay for a much healthier population.
At this point in the demographic transition, the biggest population changes are likely to come from drops in the fertility rate. The UN projections assume an annual decline of .07; a 50 percent greater de- cline would mean an 18.8 percent decrease in the projected population 2100. In fact, the most effective techniques for extending life expec-...