by Deborah Blum
We do not often hear about this reproductive revolution, says Lewis—even though many environmentalists argue that future population trends are absolutely critical to the future sustainability of humans on the planet. “It almost seems as though we have collectively decided to ignore this momentous transformation of human behavior.”
Perhaps the disconnect comes from how we think about the problem. Understanding the current human population equation requires us to hold two opposing ideas in our heads at the same time. First, birthrates globally are falling almost everywhere. As John R. Wilmoth, the new head of the United Nations Department of Economic and Social Affairs Population Division, noted earlier this year: “Fertility levels have fallen substantially in most regions, far beyond what most observers expected fifty years ago.” Half the world now lives in countries with fertility at or below the long-term replacement level of 2.3. That includes some devoutly Muslim countries, such as Iran, as well as many primarily rural countries where girls get a meager education and are often forced into marriage at a very young age. The average woman of the world today has 2.5 children, half what her mother and grandmother had.
The second fact is that despite falling fertility, there is a considerable increase in overall human numbers still to come. The UN’s statisticians this year raised their estimate of the likely increase in the world’s population in this century. They predict that rather than growing from today’s 7.2 billion to 10.1 billion, the population will increase to almost 11 billion people by century’s end. One reason for the apparent paradox of fast-falling fertility and continuing high population projections is that today’s mothers were born at a time when women still had four or five children—most of whom, for the first time in history, grew to adulthood. As in India, this baby-boom generation is so numerous that, even with small families, they will inflate the numbers substantially before ceasing to be fertile. Also, to a lesser extent, rising life expectancy will increase the population.
But the rate of worldwide population increase is declining, from 2.1 percent in the 1960s to today’s 1.2 percent. And demographers recently noted that we have reached what they call “peak child.” The number of children younger than fifteen has stopped rising and is likely to start falling in the future.
Some countries, notably in southern and eastern Europe and in East Asia, have seen their fertility rates fall well below replacement level for a generation now. From Italy and Greece to Russia, Japan, and South Korea, this figure is at or below 1.5. Many argue that modern women in such countries are, in effect, on childbirth strike because their male partners, employers, and governments make it hard for them to combine parenthood with a career.
Will fertility rates in these countries recover to replacement levels? The UN currently believes they will, though no country has yet done so fully. Women may not do what the demographers think they will.
At the other end of the spectrum are questions about the fate of sub-Saharan Africa; here, despite some decline, fertility rates are often still above three children per woman. The rates reach seven children per woman in Niger and Mali in West Africa. Poor peasant farmers still often see children as a good investment in labor on the farm as well as an insurance policy for their old age.
If things go badly, Africa could end the century with as many as 3 billion people, compared to 1 billion today. The UN is currently of that view. It regards numerous African nations as being stuck in a poverty trap that is also a fertility trap. Recently it upped its estimates of both Africa’s current fertility rates and its likely future rates. It reckons, for instance, that Africa’s most populous nation, Nigeria, will surge from around 175 million today to more than 800 million before the century is out.
But others think that Africa in the twenty-first century could follow the Asian example from the late twentieth century, with fertility falling dramatically to replacement levels or below.
Who’s right? Optimists point out that poverty no longer dooms countries to high fertility, as shown by examples such as Burma and Bangladesh. But pessimists say it is unlikely that hard-pressed African governments will be delivering either wealth or Asian-style education systems to their fast-growing citizenry anytime soon.
However, it may be a mistake to think that governments are key to reducing fertility. Evidence from both Asia and Latin America indicates that wider social forces are at work: women are making their own choices. Female emancipation is key.
This could happen in Africa, too. Time and again, surveys show that most African women also want smaller families. Even in the poorest countries, advances in health care and campaigns against major killer diseases mean that most kids grow to adulthood. Women do not need to produce large families in order to deliver the next generation. But they still must take charge of their lives sufficiently to achieve small families; this requires cultural change. And as we have seen, in much of the poor world these cultural drivers come not from books, schoolteachers, tribal chiefs, or even the words of priests and mullahs. As in the villages of India and Brazil, the most dynamic force in changing social mores in villages and slum communities is a box in the corner of the living room: the TV.
Television’s spread throughout the world is extraordinary. There are today something like 1.4 billion TV sets worldwide, or roughly one for every five people. In Asia and Latin America, even the poorest are glued to the box. In India, states where the average daily income is below two dollars per person still have TV sets in more than half of households, say Jensen and Oster.
In Africa, however, the spread has been slower. Across the continent, a billion people have only around 50 million TV sets. Government television broadcasting is mostly amateurish and unattractive. Satellite dishes to access other stations remain rare outside southern Africa. Most people still listen primarily to the radio.
But growing evidence suggests that TV could be the catalyst for change. In Kenya, Makutano Junction, a TV soap funded by the British government’s Department for International Development (DFID) together with the family planning agency Marie Stopes International, is now in its twelfth series. The Sunday evening prime-time staple has 7 million viewers in Kenya and many more in neighboring Tanzania and Uganda. It addresses a range of social issues, with family planning at the forefront.
In a recent series, the female hero, Anna, loses her twins in childbirth after failing to attend a clinic. She leaves the hospital with her abject partner, Josiah, who declares, “You are right. I should have come with you for checks at the clinic. Now we’ll go to family planning like you wanted.”
Since Makutano Junction went on air in 2001, Kenya’s fertility rate has fallen from 5.0 to 3.8. DFID makes no great claim that Makutano Junction caused this drop. “The extent to which MJ is able to contribute to actual changes in behaviour is difficult to establish,” it says. But audience research shows that viewers appreciate and act on “very specific and practical information” that MJ provides—for instance, how to find Marie Stopes clinics.
Similarly, Ethiopia’s Amharic-language radio show Yeken Kignit (“Looking Over One’s Daily Life”), broadcast from 2002 to 2004, coincided with an estimated fall in fertility rates in Amharic-speaking areas from 5.4 to 4.3. That also coincided with a big increase in demand for contraceptives in those areas, says the Population Media Center’s Ryerson.
We should not think the power of soaps is purely a developing-world phenomenon. Many argue that soaps have played a role in triggering changes in attitudes toward homosexuality and gay marriage in Europe and North America, for instance. And even Sabido-style programs are being tried in rich nations. Witness the arrival of online soaps with overt messages, such as East Los High at hulu.com. Launched in June 2013, the soap—funded by the Population Media Center with help from the California Family Health Council—targets Latino teens with tales of a girl from a single-parent household who struggles against temptation.
Looking back, it’s ironic that many of the same activists warning of the population bomb back in
the 1960s were also telling people to “kill your TV.” They saw TV as a socially damaging technology, bringing in its wake violence, destructive consumer desires, and social dislocation. But TV can also be a force for good, giving isolated and underprivileged people—especially women—a window on different worlds and a sense that they can change their lives. It empowers and increases aspirations—and even delivers lower fertility rates. Could the humble soap save the world? Stay tuned.
COREY S. POWELL
The Madness of the Planets
FROM Nautilus
I AM A STAUNCH BELIEVER in leading with the bad news, so let me get straight to the point. Earth, our anchor and our solitary haven in a hostile universe, is in a precarious situation. The solar system around us is rife with instability.
Residents of Chelyabinsk, Russia, experienced this firsthand at 9:20 A.M. local time last February 15, when a 50-foot-wide asteroid slammed into Earth’s atmosphere and exploded above the town, shattering windows, collapsing the roof of a local zinc factory, and sending more than a thousand people to the hospital with glass cuts and other injuries. Millions of people saw the videos of Comet ISON meeting a different but related cataclysmic fate as it took a swan dive past the sun on Thanksgiving Day. In the space of a few hours, the 4.5-billion-year-old comet was reduced to a cloud of sputtering rubble.
But these incidents are mere pixels in the sweeping picture emerging from the latest theories of how our solar system formed and evolved. Collisions and dislocations are not occasional anomalies; they are a fundamental cosmic condition.
“Things are not as simple as they were supposed to be, with the planets staying quiet forever,” says Alessandro Morbidelli, a planetary dynamics expert at the Nice Observatory in France. “When the planets form, they don’t know they have to form on good orbits to be stable for billions of years! So they are stable temporarily but are not stable for the lifetime of the star.”
Translation: Earth was forged in chaos, lives in chaos, and may well end in chaos.
While Morbidelli is explaining all this to me in a cheery Italian accent, I cannot help fixating on the grim connotations of his last name. He and his scientific compatriots are amplifying a recent realization about our celestial home: instability is our natural state. For centuries, Isaac Newton and his followers envisioned a solar system that runs like divine clockwork. Only in the past decade have high-precision mathematical simulations shown just how wrong he was. Carl Sagan famously declared that “we’re made of star stuff.” Morbidelli has an equally profound message: we are made of cosmic chaos.
“You might take a trip around the galaxy, come back in 5 billion years, and say, hey, there is no Mercury anymore, and Earth is now on an eccentric orbit that is catastrophic for life,” Morbidelli continues in his musical voice. It’s easy to be cheery when talking about events that nobody alive will ever experience, I suppose, but his tone doesn’t change a bit as he starts ticking off the parts of the solar system in flux.
“There are unstable populations in the asteroid belt, Kuiper Belt, and Oort Cloud,” Morbidelli says. These instabilities are relics of the chaos in which Earth and the other planets formed. The Chelyabinsk meteor emerged from the asteroid belt, perhaps from a smashup that took place about 30,000 years ago. The Kuiper Belt, just beyond Neptune, and the Oort Cloud, a vast hive of dormant comets extending halfway out to the next star, can also send objects careening our way. That is where Comet ISON came from.
After the Chelyabinsk disaster, Morbidelli and a group of colleagues huddled to figure out the implications of all that instability. Meteor impacts seemed to be happening a lot more often than their models predicted. When they presented their updated results last month, they concluded that the true rate of Chelyabinsk-scale events is probably ten times as high as they had previously estimated. There is no clean separation between the unsettled past and the present.
Morbidelli’s view replaces Newtonian clockwork with something more akin to quantum uncertainty, with everything defined by probabilities of survival. Over time, every object in the solar system that can be destroyed, scattered, or ejected will eventually be destroyed, scattered, or ejected. That is how Earth came to be. That is how it exists today.
The belief that Earth and the rest of the solar system were born in largely their present form—the arrangement and characteristics of the planets almost preordained—has deep, clinging roots in the history of science. It extends further than Newton, back to the influential writings of the thirteenth-century monk Johannes de Sacrobosco, who described the universe in terms of clean, geometric patterns. You could plausibly draw a line all the way to the perfect heavenly spheres of Aristotle. Amazingly, the same basic philosophy (built atop a very different scientific foundation) persisted well into the space age.
In retrospect, that simple and comforting view had begun to unravel long before most scientists recognized what was happening. As far back as the 1970s, theoretical models trying to simulate the formation of the solar system kept coming up with an unwanted result: the planets migrated wildly, toward and away from the sun, making a royal mess of things in the process. “It would come out of pen-and-paper theory work, but it was immediately ignored,” says Kevin Walsh, a leading researcher in solar system dynamics at Southwest Research Institute in Boulder, Colorado. “It showed up as throwaway comments in some papers, but no one seriously proposed that planetary migration was an important process.”
The idea languished for a couple decades until a series of scene-shifting discoveries forced the theorists to reconsider. In 1995 two Swiss astronomers detected 51 Pegasi b, a planet orbiting a dim yellow star located 50 light-years away in the constellation Pegasus. It was the first world found orbiting another star similar to the sun. The planet is a gassy, Jupiter-size giant, the kind of world that theoretically can form only in the cool regions far from its parent star. But there was 51 Pegasi b, hugging close in a searing-hot orbit. The only sensible explanation astronomers could come up with was that the planet had formed far out and then somehow shifted sharply inward. They dubbed this puzzling world a “hot Jupiter” and waited to see if it was a fluke.
It was not. Within a year, a competing American team discovered two more hot Jupiters; several dozen similar worlds are now catalogued. As astronomers got better at searching, they started to find a number of other improbable planets. Some were in highly oval orbits; some revolved around their stars at a steep angle, or even backward. Such arrangements did not seem physically possible unless the planets had migrated dramatically at some point. If that process happened around other stars, it could have happened here as well. “And that’s when it really started to kick off,” Walsh says.
In 2009 Walsh was a postdoctoral fellow at the Nice Observatory, where he collaborated with Morbidelli. Walsh was already an expert in solar system dynamics; now he became fascinated by the concept of migrating planets and buried himself in the details of how the process would work. He focused on the earliest stages of solar system formation while Morbidelli tackled a later, secondary instability.
Getting planets to move is extremely easy in mathematical models of a newborn solar system. The challenge—as those pen-and-paper theorists of the 1970s had discovered—was finding ways for planets not to move. Data from the Hubble Space Telescope and other great observatories show that in the big picture infant planets emerge from a swirling disk of gas and dust around a just-formed star, known as a protoplanetary nebula. For the first few million years, planets are little more than debris bobbing on the waves in the disk.
“That nebula outweighs the planets about a thousand to one, so the gas can push the planets around really dramatically,” Walsh says. As a result, he realized, the early solar system must have been more like bumper cars than clockwork. He also saw that if he fully embraced the idea of instability and took it to its logical conclusions, he could account for many aspects of the solar system that had previously defied easy explanation: Why is Mars so small? How did the asteroid
belt form? And above all, why is Earth’s chemical makeup so different from what was predicted by the original formation models?
Walsh knit his ideas into a theory he calls the Grand Tack, which creates a startlingly new narrative of how Earth and the other planets formed. At present, Jupiter’s orbit is 5.2 times wider than Earth’s. It is also sticking to its 11.8-year orbit like a metronome.
But according to Walsh, Jupiter actually formed quite a bit farther out and then, during the solar system’s initial 5 million years, executed a series of dramatic swoops. First it spiraled inward to the place where Mars is now (about 1.5 times the Earth-sun distance), as the dense gas in the nebula dragged it toward the sun. Then it migrated out past its current location, yanked by the gravitational influence of the newly formed planet Saturn. The whole process took about 500,000 years—an eternity in human terms, but blazingly fast for the solar system, which is 4.6 billion years old.
So what happens, I ask, when a planet that size goes on the prowl? “Oh, it raises hell!” Walsh replies. “That’s a really big planet and it’s moving all over the place. It acts like a giant snowplow and essentially wipes out everything in its way.”
Fortunately for us, Earth had not yet formed when Jupiter was on the move; if it had, our planet might have plunged into the sun or spun off into dark oblivion. The giant planet’s influence on the inner solar system, where we live, was more indirect. Most of the action happened on the outbound track, when Jupiter rammed through thick swarms of icy comets and asteroids. That snowplow effect sent those water-rich objects raining down on Earth just as it was beginning to grow. “The bulk of the water that we see on Earth is a result of the scattering from Jupiter’s outward migration,” Walsh says. Whenever you take a swim, or just take a drink, you are benefitting from the solar system’s foundational instability.
