The World Without Us

The numbers resulting from such a draconian measure, fairly applied, are tricky to predict with precision: Fewer births, for example, would lower infant mortality, because resources would be devoted to protecting each precious member of the latest generation. Using the United Nations’ medium scenario for life expectancy through 2050 as a benchmark, Dr. Sergei Scherbov, who is the research group leader at the Vienna Institute of Demography of the Austrian Academy of Sciences and an analyst for the World Population Program, calculated what would happen to human population if, from now on, all fertile women have only one child (in 2004, the rate was 2.6 births per female; in the medium scenario that would lower to about two children by 2050).

If this somehow began tomorrow, our current 6.5 billion human population would drop by 1 billion by the middle of this century. (If we continue as projected, it will reach 9 billion.) At that point, keeping to one-child-per-human-mother, life on Earth for all species would change dramatically. Because of natural attrition, today’s bloated human population bubble would not be reinflated at anything near the former pace. By 2075, we would have reduced our presence by almost by half, down to 3.43 billion, and our impact by much more, because so much of what we do is magnified by chain reactions we set off through the ecosystem.

By 2100, less than a century from now, we would be at 1.6 billion: back to levels last seen in the 19th century, just before quantum advances in energy, medicine, and food production doubled our numbers and then doubled us again. At the time, those discoveries seemed like miracles. Today, like too much of any good thing, we indulge in more only at our peril.

At such far-more-manageable numbers, however, we would have the benefit of all our progress plus the wisdom to keep our presence under control. That wisdom would come partly from losses and extinctions too late to reverse, but also from the growing joy of watching the world daily become more wonderful. The evidence wouldn’t hide in statistics. It would be outside every human’s window, where refreshed air would fill each season with more birdsong.

^{Projections, Population of the World:}

^{----------- Medium UN scenario: fertility declining from 2.6 children per woman in 2004 to slightly over 2 children per woman in 2050. Source: Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat (2005).}

^{_________ Scenario assuming that all fertile women are henceforth limited to 1 child. Source: Dr. Sergei Scherbov, research group leader, Vienna Institute of Demography, Austrian Academy of Sciences.}

^{CHART BY JONATHAN BENNETT}

If we don’t, and thus let our numbers increase by half again as projected, could our technology stretch resources once more, as it did for a while back in the 20th century? We’ve already heard from the robot contingent. Relaxing on the deck of the White Holly, watching the sharks roll by, microbiologist Forest Rohwer takes a stab at another theoretical possibility:

“We could try using lasers, or some similar particle-wave beams, to actually build things remotely on other planets, or in other solar systems. That would be much faster than actually sending something there. Maybe we could code for a human, and build a human in space. The life sciences will probably provide the ability to do that. Whether physics will allow it, I don’t know. But it’s all just biochemistry, so there’s no reason why we couldn’t construct it.

“Unless,” he allows, “there really is something called a spark of life. But it’s going to take something like that, because there’s no evidence that we could actually move from here in any reasonable time frame.”