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For the last four decades, we’ve been worrying about the global population soaring past sustainable levels in just another century and a half, and predicting that our numbers would peak at around 10 billion or so since a human population that numerous would overwhelm almost all the available resources we have, and facing constant war, starvation, and an increase in poverty, just as steps are being made to ease the latter two. But thanks to global industrialization and a cross-pollination of cultures and ideas, the real worry isn’t a continued climb in our population to its absolute possible peak into the mid 2100s, but the halving of it in the same time frame. Why? In a nutshell, the world is getting older and birth rates are down in 59 nations as baby boomer generations start heading into their twilight years while the rest of us are having fewer and fewer children. And as the aging generations live out their last days, there will be plenty of major problems as the world adjusts.

future metropolis

As fewer and fewer workers refill government coffers for pensions and safety nets for the elderly, it costs more and more to run retirement programs. In the United States, healthcare costs are projected to keep soaring as the baby boomers enter old age, and it’s very likely that austerity measures will have to be put in place to keep the government from going bankrupt. Nations across Europe, Asia, and parts of the Middle East will face very similar situations. This is what happens when the population grows not so much because of childbirths, but because our medical and technological advances are keeping people alive longer. As new generations grow, the older ones are still around, so the overall tally goes up. Decades of fewer children, whether by choice and new economic opportunities that place restrictions on having children, or by strict government measures like the population controls imposed by China, have created a world in which the elderly are going to dictate what will happen to future economies and societies. Call it the coming indirect economic gerontocracy if you’re big on sociopolitical buzzwords, or the gerontopocalypse if you’re a fan of sensationalistic ones.

So, you may ask, why not simply entice fertile couples to have children who’ll replace all those aging workers and keep the status quo? This way, retirees are being supported on an almost one to one basis, right? While that my sound good in theory, the reality is far more complex. Younger workers today often face extremely high unemployment rates and senior workers in stable, reliable jobs aren’t in a big hurry to relinquish them, since they’re putting the finishing touches on the nest eggs they’ve set up for their retirement. And the cost of typical retirements is rising, giving them even more incentive to hold on to their jobs. Likewise, as technology keeps on advancing, the skills and knowledge of elderly workers becomes obsolete, relegated to highly specialized teams which are supposed to be experts in legacy tools and design patterns to support future concepts. And while there are skills that are never obsolete, at some point, the elderly workers become sages instead of an archive of practical, easily implemented advice for future cultures and new ways of doing things, which means that it will be difficult to justify employing more of them longer and longer, even in part-time role.

On the younger side of the spectrum, we have couples whose financial commitments limit them to one or two children at most. Unable to take enough time off to tend to their progeny, and in dire need to keep working for nearly two decades to provide their growing kids with food, clothes, and education (not to mention making the time for just being with their children and being able to take them on vacations or give them presents), they’re not going to suddenly start trying to meet government fertility quotas. In other words, even though we’ve finally realized what’s going to happen to the future of our population, there really isn’t much we can do but manage the coming financial and demographic problems as best we can over the next century. When generation Y is headed for retirement, the world could well be populated by less than 5 billion people. After that point, how the societies of the future will adjust to the changing demographics will depend on the state of global economies and labor markets. And if trends stay the same, the next point of equilibrium may be 3.5 billion people instead of the 10 billion predicted by the UN at the beginning of the next century…

[ illustration from a work by Ryan Quackenbush ]

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A while ago, I wrote a post about some of the evolutionary mysteries presented to us by women’s breasts, pointing out how sexual selection doesn’t completely explain their sizes and shapes. Today, we’ll take a look at another possible product of sexual selection, one that seems to be a little more clear cut. I’m talking about the penis of the human male, the biggest in length, girth, absolute size and in proportion to the body when put up against that of all other ape species. But how did it get that way? Well, if evolutionary psychologist Carole Jahme is right, then the blame rests with you ladies. Thanks to your preferences in mates, the human penis grew in size to become more flexible, loosing the small bone of its evolutionary relatives. There weren’t many advantages to this change in physiology other than pleasing the female eye, among other things, but that’s all that matters from an evolutionary standpoint since without a shot at reproduction, your line will go extinct…

Of course there’s a bit more to it than that. Sexual selection is the same reason why peacocks have giant fans for tails, making them a potential target for fast predators. While it would seem that males with an extravagant plumage are easier to find, chase, and catch would branch off into something less conspicuous and far more subtle to avoid predation, the peahens prefer a male who can keep his outrageous plumage safe from both predators and competitors. Same applies to male lions whose dark, thick manes attract more females, and a giant deer which went extinct at the end of the Ice Age, the Irish Elk, which had a pair of titanic antlers to attract potential mates and intimidate rivals. Human penises followed the same selective pressures, as we see with typically male contests in which penis size serves to establish the perception of fertility and sexual athleticism in a bid to attract women and intimidate other men. Likewise, since human sperm compete to fertilize eggs, a larger set of testicles and higher sperm production would help fertilize more eggs and produce more offspring who inherit the sexual characteristics that should give them at least as good of a shot at reproducing as their parents, assuming they’ll get to puberty; which at one time was no guarantee.

So what about the often heard male question regarding whether he’s adequately endowed to attract women’s attention? If sexual selection can explain why humans have the genitals they do today, could it provide at least a couple of clues there? Well, as a matter of fact, it can. While for many young men the idea of adequate size comes from adult entertainment, porn is really a bad source of information here because it portrays a narrow slice of the population based on very subjective criteria. Instead, we can look at the distribution of penis sizes as measured by condom maker Ansell, which shows that nearly 25% of males have a penis which measures between 5.5 and 6 inches. After the 6 inch mark, there’s a rapid drop-off in sizes and males endowed with 7 or more inches make up just 5% of the population compared to the 70% of males with a length between 5.5 and 7 inches. What does that tell us? If women preferred very large penises, we would expect to see either a more even distribution of male endowments between 5.5 and 9 inches (the largest size recorded by the survey, just under 0.1% of the group), or a skew towards the larger end of the scale. This indicates that the preferred size for human females is in the 5.5 to 7 inch range, primarily between 5.5. and 6.5 inches. Seven inches and over is more of an oddity, the likes of which we tend to see in porn.

On a side note though, it might be interesting to look back after a number of generations to note if penis sizes increased in any meaningful way thanks to the influence of pop culture. My guess would be that constraints on the male anatomy will stay in place for quite a while since there’s more to sex than just a certain penis size. A male at the top 1% of the size distribution chart might actually cause a lot more pain than pleasure. After all, in this case of sexual selection it’s about what women want, not necessarily what males think will intimidate the competition and make a statement to a potential mate, and the size distribution shows that quite well…

[ illustration from a Thai contraceptive ad ]

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Today, there are more than 6.8 billion humans on our planet living in almost every corner of the world, making us one of the most successful species of macroscopic animals of all time. And we’re still growing in number by approximately 1.15% every year, giving quite a few scientists and politicians good reasons to start worrying about the potential impact that a runaway population explosion will have on the environment, infrastructure, and energy demands around the world. Since the vast majority of future growth will come from areas affected by poverty and with highly underdeveloped infrastructures, some are even saying that we need to put a freeze on advanced research projects until we can put nearly 80% of the species firmly on its feet. Others, myself included, advocate the exact opposite, that we need to boost global R&D to find new and better ways to build efficient, reliable power grids and critical infrastructure where it’s needed most. And yet others are saying that we need to push into space in the next few decades or we’ll run out of room on Earth.

But maybe, we shouldn’t really be worried about global population growth. Maybe, this problem will solve itself by the end of the century and our real concern should be runaway consumption of wealthy nations? That’s the question posed in a recent column for The Prospect by British science journalist Fred Pearce, and this idea is backed by sound facts from a demographic and statistical standpoint. As noted in the first link, we might be reaching the limit of how much our species can expand and the rate of growth has been steadily slowing over the last few decades from its peak of 2.19% in 1963, something on which Pearce expands with his examples of falling birth rates across the world thanks to modern medicine and today’s industrial lifestyle. With farming being treated as a corporate enterprise and higher survival rates for newborns, even in rural areas of nations still struggling with providing the basics, less and less kids have to be born to keep the family going. And that means longer lifespans for more people will eventually be offset by lower birth rates and the world population will eventually decline, reaching an equilibrium.

The immediate problem with that scenario is that fewer young workers will be supporting a disproportionately large number of senior citizens, presenting a massive economic burden on the developed nations facing this scenario. In the United States, the presented solution is to allow seniors to keep working, delaying retirement as long as possible to draw less money from their government benefits and making it easier on the younger generations. However, there’s a problem with this approach because it limits the number of jobs available to those just trying to enter the workforce. Generation Y could well bear the brunt of this solution, putting up with a longer climb up the corporate ladder, more glass ceilings and depressed wages for decades. But as odd as this may seem, the dilemma of a population decline in the developed world illustrates the limits on how much our species can expand. There are only so many jobs, so many resources and so many places to live. One of these days we’ll run out of all three, especially resources which are being rapidly consumed by the developed world. As wealthy nations throw away mountains of plastic, burn through fossil fuels, and pollute the planet to their hearts’ content, they’re making fewer of our finite natural resources available to billions.

Humans, like all living things, are subject to our biological and environmental limitations. And while we’re still going to be around for the foreseeable future, evolving faster and faster as we reproduce, our numbers will eventually peak and level off. The advances of the past two centuries allowed for much better medicine, food, shelter, and necessary infrastructure which allowed for a population explosion. However, we’re running out of both the capacity and the need to keep propagating with no limits. If we do, we’ll end up with a population that we can no longer support and poverty, famine and disease will do their grim work and cull our numbers…

[ illustration by Alexandru Popescu ]

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Sometimes, you read about a certain line of research and wonder why exactly it’s being reported as a newsworthy event, and why the scientists behind it think it’s worth perusing. For example, take this quote from an article on Live Science

Many mammals have virtually no noticeable belly button. We humans, however, are left with an umbilical scar that is not only obvious but which varies dramatically…

“I propose that umbilicus, together with the surrounding skin area, is an honest signal of individual vigor,” Sinkkonen wrote in the latest issue of The FASEB Journal. “More precisely, I suggest that the symmetry, shape, and position of umbilicus can be used to estimate the reproductive potential of fertile females, including risks of certain genetically and maternally inherited fetal anomalies.”

Huh? You can tell all that by looking at a woman’s belly button based on a few studies in which people were asked to evaluate what navel shapes were most aesthetically pleasing to them? How exactly does navel shape and fertility correlate? And what would belly button shapes tell about men? Would they hint at sperm production and hormone levels? Something just doesn’t sound quite right here and the evidence is rather lacking. The only thing we have to go by is the conclusion that because humans have a very pronounced umbilical scar, it must mean something or it wouldn’t be there. That question might make sense at first, but it’s not really meaningful when we consider the random nature of evolution.

Could it be that the first humans just happened to be born with these umbilical scars and because it was entirely benign, the processes that created them carried on for hundreds of thousands of generations? Considering that randomness is how nature diversifies and organisms become more and more complex, we probably shouldn’t rush to find an explanation for how everything in our anatomy must be crucially important. In fact, that has a slight hint of the “irreducible complexity” argument of ID proponents.

Obviously, scientists should ask why we have pronounced belly buttons or exactly five fingers or toes. Some of the most profound research is often done by asking seemingly bizarre questions. But we should make sure that the explanations being given make sense in a broad context. Just ask yourself, when was the last time your partner’s belly button shape sealed the deal for you?

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when humans disappear

October 6, 2008

Call me morose, but I really enjoy watching the National Geographic show Aftermath: Population Zero which chronicles the systematic collapse of everything humans built after our species disappears from the face of the Earth. It was created during a sort of mini doomsday craze sparked by the book The World Without Us in which author Alan Wiesman lays out what would happen if humanity were to suddenly vanish. The press coverage for the book generated a flood of investigative articles and two television specials about what would happen to the planet us and Aftermath has been rerun again and again which seems to indicate good ratings for the show.

Watching Aftermath, I learned something new for myself. I never knew what would happen after nuclear reactors ran out of power. I naively assumed that they would just shut down and all the spent fuel and waste would quietly decay in concrete walls with an occasional radiation leak in a few plants here and there. Nope, no such luck as this teaser kindly explains.

So why the fascination with what will happen to the planet after were gone? All of us know that almost no trace of us will be left if any. But yet we watch how our ruins decay in graphic detail, taking in every detail of a macabre doomsday erotica. Could it be a manifestation of our unique ability to realize our own mortality and think about what will happen after were dead and gone?

After watching the show again, its final note struck me as very odd. Weve spent about 60,000 years on planet Earth as a species, but the only place capable of preserving our creative and technological legacy for millions, if not hundreds of millions of years, is the Moon. If we vanish tomorrow, our greatest legacy will be what was once deemed as a multi-billion dollar publicity stunt of the Space Race. Isnt that something?

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