Showing posts from category demography.
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Iran’s Surprising and Shortsighted Shift on Family Planning
›August 8, 2012 // By Elizabeth Leahy Madsen
In late July, Iran’s government announced that it would no longer fund family planning programs, a dramatic reversal following 20 years of support. The change is especially abrupt for a country that has been lauded as a family planning success story, with thorough rural health services and an educated female population contributing to one of the swiftest demographic transitions in history.
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A Roundup of the ‘Global Trends 2030’ Series on Population Aging
›The National Intelligence Council is trying something new for this year’s Global Trends report: keeping a blog. So far, there have been postings from analysts and contributors on everything from migration and urbanization to international banking and precision strike capabilities, but over the past week, one of the most extensive series yet went up on demography. Though youth bulge theories have often dominated population-related security discussions, 11 posts highlight the newest and least understood of all demographic conditions: advanced population aging.
In parts of the world, mainly Europe and several countries in East Asia, populations are set to become “extremely mature” because of sustained declines in average fertility to very low levels and steady increases in lifespan. Demographers measure maturity by a population’s median age – the age of the person for whom precisely half of the population is younger and half older. Japan and Germany currently have the most mature populations; both are reported to have a median age slightly over 45 years. By 2030, UN Population Division and U.S. Census Bureau projections suggest that there may be between 19 and 29 countries that pass this benchmark. In Japan, the median age is projected to be 51.
If 5 out of 10 people in a country over 50 years old sounds unprecedented, that’s because it is. In this series, titled “Population Aging to 2030,” a group of political demographers, economic demographers, political scientists, and historians discuss the implications of this never-before-experienced set of age structures.
In his introductory essay, “Population Aging: A Demographic and Geographic Overview” (cross-posted here on New Security Beat), Richard Cincotta outlines the upcoming demographic trend, identifying the particulars of these novel age structures and indicating the regions that are expected to mature into economically and politically advantageous and disadvantageous demographic profiles.
In “Population Aging – More Security or Less?,” Jack Goldstone examines the effects on the U.S. military of a maturing developed world. With the United States and their traditional allies having proportionally fewer young people, will this impact limit their ability to put “boots on the ground?” Can new partnerships be developed in order to make up for this shortfall in man power?
In “China: the Problem of Premature Aging,” Richard Jackson focuses on China’s unique set of aging issues. Due to strict immigration laws and the one-child policy, China is experiencing the most rapid aging of the major powers. The favorable age structure which has enabled huge economic growth will soon shift to being a major burden on a relatively smaller working-age population, having potential political and societal consequences beyond that.
“The Sun Has Yet to Set on China” provides a different interpretation of the challenges China faces. Jennifer Dabbs Sciubba argues that although there will be changes in age structure, the problems may be overstated and the United States may still face a challenge to its status as sole global superpower.
In “Population Aging and the Welfare State in Europe,” Ronald Lee and Andrew Mason emphasize the stresses aging will exert on the extensive social welfare programs of many European states. The combination of longer life expectancy and declining fertility rates has led to a large and increasing funding gap in the welfare system, leaving questions as to the future viability of these programs.
In “Population Aging and the Future of NATO,” Mark Haas foresees that the welfare funding gap could have far-reaching international security consequences. With European governments diverting more and more resources away from military spending to fund welfare programs, the current U.S. irritation with NATO is likely to continue, as European allies “free ride” on the back of U.S. military supremacy in order to cut their defense budgets.
In “The Beginning of History: Advanced Aging and the Liberalness of Democracies,” Richard Cincotta examines the future of the liberal democratic political systems across aging countries. With increasing pressure on resources and a large disparity likely between the native born and migrant populations, it may become challenging for these states to remain liberal and democratic.
For Toshi Yoshihara, author of “The Strategic Implications of Japan’s Demographic Decline,” the aging process will pose a question of priorities for the leaders of Japan. The decreasing number of personnel available to the military, the effects of which were highlighted by the recent tsunami, will force a strategic decision between a defense force that is prepared primarily to address immediate and local security threats or one that is trained primarily for broader humanitarian interests.
“A Demographic Sketch of a Reunified Korea” provides interesting insights into the hypothetical demography of a single, unified Korea. Putting aside the two very distinct social paths that evolved during the past 60 year, Elizabeth Hervey Stephen uses demographic projections to envisage the challenges and opportunities that could arise from reunification.
David Coleman points to immigration as a possibly-mitigating force to aging in the developed world. In “The Impact of Immigration on the Populations of the Developed World and Their Ethnic Composition,” Coleman concludes that the developed world is likely to become “super diverse” by 2030. But this trend can be volatile. International migration is subject to many political and economic factors, bringing into question whether the developed world can rely on migration to supplement their native growth rates.
In “The Ethnic Future of Western Europe to 2030,” which wraps up the series, Eric Kaufmann examines the ethnic make-up of Western Europe in the coming decades. While the size of ethnic minority populations may be smaller than in the United States, the speed of growth in these minorities is likely to be much more rapid in Western Europe. This unprecedented increase in migrant populations could exacerbate ethnic social tensions, particularly in urban areas.
The broad nature of these essays suggests that advanced population aging will emerge within the context of many types of policy debates in the coming decades. While these 11 brief essays only scratch the surface of their respective areas of research, they provide a broad introduction to the politics of advanced population aging.
Jonathan Potton is a student at the University of Aberdeen and currently interning at the Stimson Center for demographer Richard Cincotta.
Sources: UN Population Division, U.S. Census Bureau.
Image Credit: Courtesy of Richard Cincotta. Data from U.S. Census Bureau’s international database. -
From Youth Bulge to Food and Family Planning, Los Angeles Times’ ‘Beyond 7 Billion’ Series Synthesizes Population Challenges
›Over the next 40 years, the world is set to add 2.3 billion people. Millions more will join the middle class, pushing consumption upwards and further straining the world’s natural resources. Variables like climate change and political instability will exacerbate that strain and complicate efforts to bolster peaceful and stable development. Los Angeles Times correspondent Kenneth Weiss and photographer Rick Loomis examine these numerous and interconnected challenges in a five-part series on population growth and consumption dynamics.
Speaking to demographic and health experts (including a number of New Security Beat regulars, like Richard Cincotta, Jon Foley, and Dr. Joan Castro), Weiss provides a thorough, astute, and compelling assessment of population dynamics in a rapidly changing world. The series starts with a basic introduction to population, climate, and consumption dynamics and progresses through to discuss political demography, global food security, and detailed looks at two important case studies, China and the Philippines.
Part One: A Population Primer
Population growth alone poses a number of challenges as cities become more crowded and demand for basic resources like water and food outpaces supply. Climate change and the unpredictable and sometimes extreme weather that is its hallmark “will make all of these challenges more daunting,” writes Weiss. And “population will rise most rapidly in places least able to handle it.” Africa, the Middle East, and South Asia, already expected to bear the brunt of climate change with rising sea levels, shorter growing seasons, and increasingly variable weather patterns, will also have to support the bulk of the world’s population growth by mid-century. Populations in Europe, North America, and East Asia are expected to stay stable or decline in numbers.
The magnitude of growth in Africa, the Middle East, and South Asia, however, is uncertain. What happens from here “hinges on the cumulative decisions of hundreds of millions of young people around the globe,” Weiss writes. And yet, “population growth has all but vanished from public discourse.” Family planning in particular remains hamstrung by “erratic funding and unpredictable crosscurrents.” The result, he writes, is that even “under the best conditions, it’s hard to get contraceptives into the hands of impoverished women who want them.”
Part Two: The Arc of Instability
Drawing on work from demographer Richard Cincotta, George Mason University’s Jack Goldstone, Population Action International, and others, part two of Weiss’ series examines youth bulges and the so-called “arc of instability,” stretching across the disproportionately youthful countries of Africa, the Middle East, and South Asia.
When a large youth population is mixed with other societal conditions, like “religious and ethnic friction, political rivalries, economic disparities, or food shortages,” youth can be “the kindling” for a spark that ignites simmering tensions, writes Weiss. Afghanistan is a case in point, where unemployed young men are often turning to the Taliban not out of extremist fervor, but out of a desperate need to support themselves and their families. “It’s too hard to employ this many people and too easy to recruit them into violence,” Cincotta told Weiss.
And Afghanistan is just the beginning, according to Goldstone. “We are literally going to see one billion young people come into the populations in the arc of instability over the next two decades,” he said. “We can’t fight them. We have to figure a better way to help them.”
Part Three: Feeding a Growing Population
As the world’s population continues to grow, and as more families join the middle class, world food production will have to double by mid-century in order to meet future demand. “What that actually means,” says World Wildlife Fund’s Jason Clay, an agriculture specialist, “is that in the next 40 years we need to produce as much food as we have in the last 8,000.”Jon Foley on how to feed nine billion and keep the planet
Weiss presents the Horn of Africa and Punjab as microcosms of the problems facing global food production in the 21st century. Desertification and urbanization are eating away at potential cropland, while harmful farming techniques leech essential nutrients from soil, rendering it useless for future use. Insufficient infrastructure means that food spoils as it’s shipped from where it’s produced to where it’s needed, while extreme and widespread poverty means that those most in need can’t afford enough to feed their families.
Stuck between growing demand and restricted supply, the University of Minnesota’s Jonathan Foley said the challenge of the century is straightforward: “How will we feed nine billion people without destroying the planet?”
Part Four: Population and Consumption in China
China has “a greater collective appetite – and a greater ecological impact – than any other country,” writes Weiss, making it a prime example of “how rising consumption and even modest rates of population growth magnify each other’s impact on the planet.”
The country’s one-child policy slowed population growth rapidly, cutting fertility almost in half in less than a decade. Over time, a large working-age cohort with few dependents emerged, and helped China reap a demographic dividend. The resulting economic prosperity has come at a cost, however, as rising incomes and increasing consumption, spread across 1.3 billion people, have wreaked havoc on the country’s environment on a scale not seen anywhere else in the world.
Because of that scale, what happens in China will have global repercussions. Climate scientists “say that in order to avoid a potentially catastrophic rise in global temperatures, worldwide carbon dioxide emissions must be cut in half by 2050,” Weiss writes. “For that to happen, China’s emissions would have to peak by 2020” – 15 years earlier than official government projections. The government remains opposed to further limits on emissions, arguing that such limits would “cripple” economic growth – an unfair impediment considering that developed countries were able to “pollute their way to prosperity, their argument goes.”
Part Five: Family Planning in the Philippines
Weiss ends the series with an in-depth look at family planning in the Philippines – a country at the forefront of the global debate over access to contraception. Lawmakers in the 80-percent-Catholic country have steadfastly refused to fund family planning services, while support from the international community all but vanished when USAID, “the major donor of contraceptives to the Philippines,” said in 2008 that it would end its contraceptive program.
Today, half of all pregnancies in the Philippines are unintended. Lawmakers are considering a “reproductive health bill…call[ing] for public education about contraceptives and government subsidies to make them available to everyone,” but a powerful opposition, including Church leadership, has stalled the bill for 14 years, Weiss writes.Joan Castro on population-environment programing in the Philippines
Public officials, including the former Manila mayor who ended the city’s contraceptive program 12 years ago, portray unbridled population growth as an economic asset, saying that “when you have more people, you have a bigger labor force.” For the millions of Filipinos who live in poverty, however, the lack of affordable family planning services leaves them with little control over family size and puts the Philippines on track to grow from 96.4 million people today to 154.9 million by mid-century. At that rate, the Philippines would be Asia’s third fastest growing country, behind Timor Leste and Afghanistan.
Not everything in the series is dire – there are side columns highlighting population, health, and environment programming in Uganda, Iran’s successful family planning program, and Dr. Joan Castro’s family planning and marine conservation work in the Philippines. But Weiss is not naïve about the challenges ahead. Under any of the United Nation’s population projections, “living conditions are likely to be bleak for much of humanity,” he writes. “Water, food, and arable land will be more scarce, cities more crowded, and hunger more widespread.”
“Even under optimistic assumptions, the toll on people and the planet will be severe.”
But while the population challenges facing the world are many, Weiss, like many before him, makes one argument clear: providing family planning services to the 222 million women who want to control the number of children they have but cannot would go a long way towards minimizing future strain.
Be sure to check out the photo and video features accompanying the “Beyond 7 Billion” series on the feature site.
Note: The sentence beginning with “When a large youth population…” was corrected.
Sources: Los Angeles Times, UN Population Division.
Video Credit: “The Challenge Ahead,” used with permission courtesy of the Los Angeles Times; Photo: “Dharavi,” used with permission courtesy of Rick Loomis/Los Angeles Times; Jon Foley video: TEDx. -
Population Aging: A Demographic and Geographic Overview
›The original version of this article, by Richard Cincotta, appeared on the National Intelligence Council’s Global Trends 2030 Blog. It is the first post in a series on population aging, featuring Jack Goldstone, Richard Jackson, Jennifer Dabbs Sciubba, Ronald Lee, Andrew Mason, Toshi Yoshihara, Elizabeth H Stephen, David Coleman, and Eric Kaufmann.
This series, Population Aging to 2030, begins with an introductory essay aimed at familiarizing readers with some of the demographic and geographic particulars of this phenomenon, and with several key demographic terms. The term most in need of definition is, of course, “population aging.” -
Nine Strategies to Stop Short of Nine Billion
›Although most analysts assume that the world’s population will rise from today’s seven billion to nine billion by 2050, it is quite possible that humanity will never reach this population size.
My chapter in this year’s State of the World 2012: Moving Toward Sustainable Prosperity, “Nine Population Strategies to Stop Short of 9 Billion,” outlines a series of strategies that would prompt significant declines in birth rates. Based purely on the intention of women around the world to have small families or no children at all, these initiatives, policies, and changes in attitude could end population growth before mid-century at fewer than nine billion people.
Examples from around the world demonstrate effective policies that not only reduce birth rates, but also respect the reproductive aspirations of parents and support an educated and economically active society that promotes the health of women and girls. Most of these reproduction policies are relatively inexpensive to implement, yet in many places they are opposed on the basis of cultural resistance and political infeasibility.
In creating this list, I sought to eschew the language and approaches of “population control” or the idea that anyone should pressure women and their partner on reproduction. Instead, I hoped to highlight strategies that could put human population on an environmentally sustainable path:- Provide universal access to safe and effective contraceptive options for both sexes. With two in five pregnancies reported as mistimed or never wanted, lack of access to good family planning services is among the biggest gaps in assuring that each baby will be wanted and welcomed in advance by its parents.
- Guarantee education through secondary school for all, especially girls. In every culture surveyed to date, women who have completed at least some secondary school have fewer children on average, and have children later in life, than do women who have less education.
- Eradicate gender bias from law, economic opportunity, health, and culture. Women who can own, inherit, and manage property; divorce; obtain credit; and participate in civic and political affairs on equal terms with men are more likely to postpone childbearing and to have fewer children compared to women who are deprived of these rights.
- Offer age-appropriate sexuality education for all students. Data from the United States indicates that exposure to comprehensive programs that detail puberty, intercourse, options of abstinence and birth control, and respecting the sexual rights and decisions of individuals can help prevent unwanted pregnancies and hence reduce birth rates.
- End all policies that reward parents financially based on the number of children they have. Governments can preserve and even increase tax and other financial benefits aimed at helping parents by linking these not to the number of children they have, but to parenthood status itself.
- Integrate lessons on population, environment, and development into school curricula at multiple levels. Refraining from advocacy or propaganda, schools should educate students to make well-informed choices about the impacts of their behavior, including childbearing, on the environment.
- Put prices on environmental costs and impacts. In quantifying the cost of an additional family member by calculating taxes and increased food costs, couples may decide that the cost of having an additional child is too high. Such decisions, freely made by women and couples, can decrease birth rates without any involvement by non-parents in reproduction.
- Adjust to an aging population instead of boosting childbearing through government incentives and programs. Population aging must be met with the needed societal adjustments, such as increased labor participation, rather than by offering incentives to women to have more children.
- Convince leaders to commit to stabilizing population through the exercise of human rights and human development. By educating themselves on rights-based population policies, policymakers can ethically and effectively address population-related challenges by empowering women to make their own reproductive choices.
Kathleen Mogelgaard assisted with research for this piece.
Robert Engelman is the president of the Worldwatch Institute and contributing author to State of the World 2012: Moving Toward Sustainable Prosperity.
Sources: Bloom et al. (2011), Guttmacher Institute, Kohler et al. (2008), Population Reference Bureau, UN, UNFPA, The Wall Street Journal, Yadava and Yadava (1999).
Image Credit: Worldwatch Institute, State of the World 2012: Moving Toward Sustainable Prosperity. -
World Population Day 2012: Looking Beyond Reproductive Health
›How should the seven billion or so of us on Earth mark World Population Day? Today, major global players are focusing on increasing access to family planning around the world. But there are other important aspects to population that also deserve our sustained attention.
The links between demography and development have come into the limelight over the last few months, first as advocates decried the last minute removal of reproductive rights language from the Rio+20 outcome document and now as the Bill and Melinda Gates Foundation prepares a massive funding push for reproductive health (starting today, not coincidentally).
“Multiple crises – food, fuel, and financial – have caused significant suffering and served as a wake-up call about the need to pay far more attention to the building blocks of sustainable development,” UN Secretary-General Ban Ki-moon says in an address for today. “Reproductive health is an indispensable part of the sustainable development equation.”
The sustainable development connection is fairly obvious. Environmental destruction in some of the most biodiversity-rich parts of the world has complex but significant population drivers, as Wilson Center consultant Laurie Mazur explains:Human impact on the environment is mediated by a host of factors, including culture, technology, institutions, and market forces. And inequitable socioeconomic systems mean that some human beings have far greater impact than others.
“Often, the value of biodiversity becomes apparent only when it is lost,” Mazur continues. “For example, with the global decline of honeybee populations, growers can now calculate the monetary value of pollination services that were once provided for free by nature. ‘Bee pollination is worth $190 billion,’ said Pavan Sukhdev, a Yale environmental economist, in an interview with Bloomberg. ‘But when did a bee ever send you an invoice?’”
But some generalizations can be made. We live on a planet dominated and transformed by human activity. As we have become more numerous, we have also become more adept at altering ecosystems for human use, replacing species-rich natural landscapes with simpler monocultures.
In other areas, population drivers threaten more basic scarcities: food and water, which in turn impede development and cost human lives. Some of the most successful efforts to address these relationships have combined women’s empowerment, family planning, and basic health interventions with site-based conservation and livelihood efforts.
But besides reproductive rights, there are other important aspects of population that deserve attention on this day.
The demographic dividend – a concept that marries population dynamics and development economics – requires more than just fertility decline to take effect in countries. Economic and social policies that prepare and enable young people to enter the workforce are just as important.
And the Arab Spring helps illustrate the complex relationship between population and democracy. “Among the five countries where revolt took root, those with the earliest success in ousting autocratic leaders also had the most mature age structures and the least youthful populations,” writes Wilson Center consultant and demographer Elizabeth Leahy Madsen. The work of fellow Wilson Center consulting demographer Richard Cincotta shows that countries with very young age structures are prone both to higher incidence of civil conflict and undemocratic governance. What happens next in Egypt, Libya, Yemen, and Syria will further test the connection between youth and democracy.
In South Asia, Madsen finds that as Afghanistan and Pakistan’s political circumstances have become more entwined, their demographic paths are more closely parallel than expected. “For Afghanistan, given its myriad socioeconomic, political, cultural, and geographic challenges, this is good news. But for Pakistan, where efforts to meet family planning needs have fallen short of capacity, it is not,” she writes in the first issue of the newly re-launched ECSP Report, “Afghanistan, Against the Odds: A Demographic Surprise.”
In more developed countries, population aging is a concern. At the Wilson Center last year, economists Andrew Mason and Ronald Lee explained the challenges that those on the other side of the “demographic divide” will face in the near future. From 2010 to 2015, 85 countries are projected to witness the largest absolute increase in history of their populations aged 60 and over, straining public welfare systems and reducing labor forces. It’s not the “catastrophe” that it has been portrayed to be in the media, they said, but like many demographic issues, it is a challenge that will require planning for.
These connections demonstrate the wide importance of population dynamics to understanding how the world works today. Demography is the study of us – all seven billion of us. Demography affects – and is affected by – economics, political stability, health, the environment, food security, foreign policy, development, and conflict. Let’s not overlook that breadth on this World Population Day 2012.
For more, be sure to read some of our additional resources from the recent archives:- Food Security in a Climate-Altered Future: More Than a Supply Problem
- Taming Hunger in Ethiopia: The Role of Population Dynamics
- Uganda’s Demographic and Health Challenges Put Into Perspective With Newfound Oil
- New Surveys Generate Mixed Demographic Signals for East and Southern Africa
- In Building Resilience for a Changing World, Reproductive Health Is Key
- Demographic Security 101 (video)
- Yemen: Revisiting Demography After the Arab Spring
- Hania Zlotnik Discusses Latest Changes to UN Population Projections (audio)
- Book Review: ‘World Population Policies’
- Tunisia’s Shot at Democracy: What Demographics and Recent History Tell Us
- Joel E. Cohen on Solving the Resource-Population Equation in the Developing World (video)
Photo Credit: UN Day Secretary-General Ban Ki-moon with students in October celebrating the seven billion mark, courtesy of Eskinder Debebe/UN Photo. -
Guttmacher Updates Unmet Need Estimates, and West Africa’s Demographic Dividend Examined
›The Guttmacher Institute has updated their estimates for global contraceptive services, putting the number of women around the world who have an unmet need for modern family planning at 222 million (up from 215 million). Authors Susheela Singh and Jacqueline E. Darroch, in Adding It Up: Costs and Benefits of Contraceptive Services Estimates for 2012, also examine the estimated current costs of contraception, cost of meeting the current unmet need, and the money saved from having fewer unintended pregnancies. An estimated four billion dollars is currently spent on contraception in the developing world, and “the total cost of fully meeting the contraceptive needs of all women in the developing world with appropriate services would…be $8.1 billion per year.” Singh and Darroch note that there are substantial benefits to increasing access to contraception, including reduced infant and maternal mortality and lower education and health costs as smaller populations put less strain on existing systems. They conclude that “the gains that derive from meeting the contraceptive needs of all women in the developing world more than outweigh the financial costs.”How Can We Capitalize on the Demographic Dividend?, by Jean-Pierre Guengant of the Institute of Development Research, explores the connection between population age structure and economic growth in 12 West African countries (the West African Economic and Monetary Union plus Ghana, Guinea, Mauritania, and Nigeria). While much of Africa has recently experienced economic growth between four and six percent, Guengant notes it has been “too low to allow for any substantial increase in per capita income levels” due to continued population growth. And he suggests that projections of declining fertility in much of Africa are overly optimistic. “Contrary to popular belief,” he writes, “the demographic future of sub-Saharan Africa has not been written.” Guengant extrapolates his own fertility projection using data beginning in 1960. If fertility declines rapidly, he writes, the larger proportion of people in the labor force could increase the GDP per capita and drive up the standard of living. -
Hania Zlotnik Discusses Changes to Latest UN Population Projections
›Former UN Population Division Director Hania Zlotnik spoke recently at the Wilson Center discussing last year’s highly-publicized UN world population projections and explaining the methodology behind the figures. “The latest projections are very special,” she said, adding that “we think that this methodology is a lot better than what we had before.”
What accounts for such improvement? Zlotnik said it has a lot to do with greater availability of data. “The UN has been…mandated by governments to produce population estimates since the 1950s,” she stated, and they have refined their projections process over the years based on an increasing record of data and identification of some “patterns that can inform the future.”Former UN Population Division Director Hania Zlotnik spoke recently at the Wilson Center discussing last year’s highly-publicized UN world population projections and explaining the methodology behind the figures. “The latest projections are very special,” she said, adding that “we think that this methodology is a lot better than what we had before.”
What accounts for such improvement? Zlotnik said it has a lot to do with greater availability of data. “The UN has been…mandated by governments to produce population estimates since the 1950s,” she stated, and they have refined their projections process over the years based on an increasing record of data and identification of some “patterns that can inform the future.”
The increasingly large dataset accumulated during this process is particularly important because of what Zlotnik called “inertia” in population change. “There’s something called ‘population momentum,’ where the population changes on the basis of how many people have already been accumulated on the planet,” she explained, pointing out that many of the people included in the UN’s population projections for 2050 have already been born.
This inertia helps make population projections fairly accurate, but last year’s projections differed from previous efforts in two significant ways.
First, the UN Population Division provided projections not just to 2050 but also to 2100. These more long-term projections estimated an end-of-century population of more than 10 billion – notably higher than previous reports, which had predicted that population would stabilize mid-century at around nine billion.
Second, the underlying methodology used shifted from a deterministic to a probabilistic approach that, according to Zlotnik, does a better job capturing variability in each country’s fertility rate over the next century. “Essentially,” she explained, “a model was developed for every country that takes into account the past path of fertility change [and] also takes into account changes that have happened in other countries…Then [it] does a simulation for the future for every country, in which 100,000 paths are projected, essentially by throwing dice, and then the central path of those 100,000 is used to project the future.”
Zlotnik cautioned that projecting so far into the future is an inexact – albeit necessary – science: “Of course, as we go further into the future, the numbers are more subject to uncertainty. But [the long-term projections] help us give people a better feeling of how important it is to change trends from here to 2050, so that we ensure that, at the end of the century, the number of people on the planet is sustainable.”
“In order to make sure that the population projections made by the United Nations [are realized],” Zlotnik said, “it’s very important that fertility continues to decline, and especially that fertility decline happens in the countries that still have very high fertility.”
“Fertility decline happens in many ways,” she continued, “but the immediate reason why fertility can be reduced is that more people use modern methods of contraception.”
