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How Did We Arrive at 7 Billion – and Where Do We Go From Here? [Part One]
›October 26, 2011 // By Elizabeth Leahy MadsenThe United Nations Population Division has estimated world population will reach seven billion on Monday. Which changes in demographic trends led us to this milestone? What do the past and present tell us about how human numbers will change in the future?
The “Day of Seven Billion” was announced this spring following the release of the latest revision of UN population projections. Although the seven billionth person will not be precisely identified, this estimate is based on careful demographic modeling. Every two years, the UN revises its projections to incorporate the latest trend data and modify its assumptions, as seemingly small changes can make a huge difference demographically.The UN estimates that the seven billionth person alive today will be born on October 31. Demographer Elizabeth Leahy Madsen explains how we got to that number, its significance, and where our demographic path might take us from here. Read part two here.
The United Nations Population Division has estimated world population will reach seven billion on Monday. Which changes in demographic trends led us to this milestone? What do the past and present tell us about how human numbers will change in the future?
The “Day of Seven Billion” was announced this spring following the release of the latest revision of UN population projections. Although the seven billionth person will not be precisely identified, this estimate is based on careful demographic modeling. Every two years, the UN revises its projections to incorporate the latest trend data and modify its assumptions, as seemingly small changes can make a huge difference demographically.
Demography Is Driven by Fertility and Population Momentum
Since world population reached three billion in 1959, the rate of growth has increased, peaked, and begun to slow. Each succeeding milestone was reached more quickly than the last: It took 15 years to reach four billion, 13 years to hit five billion, and only 11 years to get to six billion at the end of 1998. The interval leading to seven billion was slightly longer, at 13 years, as the global rate of population growth has slowed.
Although mortality and migration also affect population trends, the factor with the greatest influence by far is fertility – the average number of children born to each woman. The decline in the global fertility rate from an average of nearly 5 children per woman in the early 1960s to 2.5 children today has in turn slowed the pace of world population growth. However, demographic momentum from previous generations of high fertility can drive population growth for decades to come. Even if Nigeria reached replacement-level fertility today, its population would still grow by one-third by 2050 as the number of births continued to exceed the number of deaths.
Assumptions Matter
Population projections consider: 1) current data about fertility and 2) assumptions about the ways fertility will change in the future. These assumptions vary depending on the source, so how much of a difference do they make? As it turns out, quite a lot.
Projections of world population in 2050 range from 8.1 billion (if fertility rates fall to a global average of 1.7 children per woman) to 10.9 billion (if they remain unchanged). The gap of nearly three billion between those possibilities is greater than the combined populations of China and India today.
Estimates vary even more widely for the end of the century, with the UN projecting that by 2100 world population could total anywhere between 6 billion (if total fertility falls to an average of 1.55 children per woman) and 27 billion (if every country’s fertility rates remain constant at today’s levels).
While demographers parse the details of the projections, policymakers would like to know which of these scenarios is more likely. After all, the economic, environmental, and political consequences of a population of 8 or 11 billion two generations hence are not the same, and a world of 27 billion is difficult for anyone to fathom.
If we simply projected past trends into the future at a steady rate, the population estimates on the low end of the fertility spectrum seem more likely. The global fertility rate has fallen from 4.5 children per woman in the early 1970s to 2.5 today, a decline of 43 percent, so the 14 percent decline projected in the medium-fertility variant between now and 2050 seems reasonable at first glance, perhaps even conservative. The medium-fertility variant assumes that all countries’ fertility rates will begin moving towards replacement level, around 2.1 children per woman, regardless of whether they are currently above or below that number.
However, even a 14 percent decline in fertility assumes that areas where fertility rates remain stalled at high levels will soon begin rapid declines, paralleling the past experience of other regions. As Population Reference Bureau demographer Carl Haub writes, “the assumption that the developing world will necessarily follow the path of the industrialized world…is far from a sure bet.”
In the last 40 years, fertility rates in the Caribbean, northern and southern Africa, Latin America, and all of Asia declined by 50 percent or more. The pace of decline in sub-Saharan Africa, while still notable, was much slower, at 23 percent. In order to meet the UN medium-variant projections, the region’s fertility rate would need to fall by nearly 40 percent by mid-century.
Some of the largest, fastest-growing populations in the developing world would need to experience a major acceleration from recent trends. In Nigeria, fertility edged down by 15 percent between 1970 and 2010, but the medium variant projection depends on a decline of 37 percent over the next four decades; Ethiopia’s fertility rate will need to fall by half.
Gender Matters, Too
The great irony of fertility trends is that gender inequities play an important role at both ends of the scale. In countries with the highest fertility rates, women tend to have less education than men and less autonomy. Their fertility choices may be greatly affected by the preferences of their husbands or other family members. In Niger, which has the highest fertility rate in the world, married men would, on average, like three more children than married women. In Uganda, where women average more than six children each, 60 percent of men report that domestic violence is justified.
By contrast, in countries with the lowest fertility rates, women have achieved equal access to education and the labor market, with more autonomy about how to earn income and what to do with it. Yet cultural expectations that place the burden for child and elder care and housework almost entirely on women can make marriage an unappealing option. In Japan, which is among the 10 lowest fertility countries in the world, more women are choosing to stay single: The marriage rate has fallen by almost half since the 1970s. Japanese women who do marry are waiting until their late 20s and tend not to give birth until they are 30, both of which result in lower average family size.
Even at this end of the demographic spectrum, the assumptions embedded within population projections seem optimistic. Japan’s fertility rate was last above replacement level in the early 1970s; it has fallen steadily to 1.3 children per woman today. The UN projections assume that fertility will immediately reverse track and begin rising to over 1.8 children per woman in 2050, rebounding above two children per woman before the end of the century.
The stalled high fertility rates in much of sub-Saharan Africa and parts of the Middle East, together with unprecedented low fertility in Eastern Europe and parts of East Asia, indicate that we are currently in an era of remarkable demographic diversity, despite the UN’s projection of future convergence.
Continue reading part two here.
Elizabeth Leahy Madsen is a consultant on political demography for the Wilson Center’s Environmental Change and Security Program and former senior research associate at Population Action International.
Sources: Boling (2008), Haub (2011), Japan Statistics Bureau, Measure DHS, UN Population Division, UN Population Fund, Washington Post.
Image Credit: Chart data from UN Population Division, arranged by Elizabeth Leahy Madsen. -
Watch: Understanding Peak Water Can Help Us “Avoid the Worst Disasters,” Says Peter Gleick
›October 26, 2011 // By Kate Diamond“The advantage of the idea of peak water is that it lets us think differently about the limits that face us,” said MacArthur “Genius” Fellow and Pacific Institute President Peter Gleick in this short interview with ECSP. Gleick, who launched the latest edition of The World’s Water at the Wilson Center last week, has been talking about peak water since 2009 when he and Pacific Institute colleague Meena Palaniappan first wrote about the concept in that year’s water report (see our interview from then too).
Renewable vs. Non-Renewable
Peak water is “the idea that we are effectively running into constraints and limits on our water use,” said Gleick, in part because of population growth. “It lets us think differently about the limits to the water that’s available for us to use, and about the water that it’s appropriate for us to use, and about the policies to put in place to avoid the bad things that happen when we reach or exceed peak constraints.”
Gleick breaks the concept into three categories:- Peak renewable water: “Where we can no longer increase the amount of water we’re taking out of rivers – when we take all of it.”
- Peak nonrenewable water: “Where, very much like oil, we’re over-pumping a non-renewable ground water supply – a nonrenewable aquifer – and it becomes more and more expensive and more and more damaging and more and more difficult to pump ground water.”
- Peak ecological water: “Where the use of additional water causes more ecological harm than it provides economic benefit.”
Across all three categories, said Gleick, we are very bad at understanding limits. “We don’t measure peak water carefully, we don’t collect the data necessary to understand when we’re approaching or exceeding peak water limits.”
“But without a doubt we are exceeding peak water limits in more and more regions of the world,” he said. “And that’s going to have implications for our economies. It’s going to have implications for our environment.”
“Understanding and applying the idea of peak water is the first step toward developing strategies and institutions to avoid the worst disasters associated with overuse and inappropriate use of our water resources.” -
Robert Draper, National Geographic
People and Wildlife Compete in East Africa’s Albertine Rift
›The original version of this article, by Robert Draper, appeared on National Geographic.
The mwami remembers when he was a king of sorts. His judgment was sovereign, his power unassailable. Since 1954 he, like his father and grandfather before him, has been the head of the Bashali chiefdom in the Masisi District, an undulating pastoral region in eastern Democratic Republic of the Congo (DRC). Though his name is Sylvestre Bashali Mokoto, the other chiefs address him as simply doyen – seniormost. For much of his adult life, the mwami received newcomers to his district. They brought him livestock or other gifts. He in turn parceled out land as he saw fit.
Today the chief sits on a dirty couch in a squalid hovel in Goma, a Congolese city several hours south of Masisi. His domain is now the epicenter of a humanitarian crisis that has lasted for more than a decade yet has largely eluded the world’s attention. Eastern Congo has been overtaken by thousands of Tutsi and Hutu and Hunde fighting over what they claim is their lawful property, by militias aiming to acquire land by force, by cattlemen searching for less cluttered pastures, by hordes of refugees from all over this fertile and dangerously overpopulated region of East Africa seeking somewhere, anywhere, to eke out a living. Some years ago a member of a rebel army seized the mwami’s 200-acre estate, forcing him, humiliated and fearing for his safety, to retreat to this shack in Goma.
The city is a hornet’s nest. As recently as two decades ago Goma’s population was perhaps 50,000. Now it is at least 20 times that number. Armed males in uniform stalk its raggedy, unlit streets with no one to answer to. Streaming out of the outlying forests and into the city market is a 24/7 procession of people ferrying immense sacks of charcoal on bicycles or wooden, scooter-like chukudus. North of the city limits seethes Nyiragongo volcano, which last erupted in 2002, when its lava roared through town and wiped out Goma’s commercial district. At the city’s southern edge lies the silver cauldron of Lake Kivu – so choked with carbon dioxide and methane that some scientists predict a gas eruption in the lake could one day kill everyone in and around Goma.
The mwami, like so many far less privileged people, has run out of options. His stare is one of regal aloofness. Yet despite his cuff links and trimmed gray beard, he is not a chief here in Goma. He is only Sylvestre Mokoto, a man swept into the hornet’s nest, with no land left for him to parcel out. As his guest, a journalist from the West, I have brought no gifts, only demeaning questions. “Yes, of course my power has been affected greatly,” the mwami snaps at me. “When others back up their claims with guns, there is nothing I can do.”
Continue reading on National Geographic.
Photo Credit: “Aerial View of Goma,” courtesy of UN Photo/Marie Frechon. -
Peter Gleick: Population Dynamics Key to Sustainable Water Solutions
›October 21, 2011 // By Theresa Polk“Water is tied to everything we care about,” said MacArthur “Genius” Fellow and President of the Pacific Institute Peter Gleick in an interview with ECSP. However, “we cannot talk about water or any other resource issue…without also understanding the enormously important role of population dynamics and population growth.”
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Water and Poverty in a World of 9 Billion, Vulnerable Agriculture in the Niger Basin
›In a two–part Water International special report on water, food, and poverty, examining 10 of the world’s major river basins, a team of researchers say that instead of worrying about having enough water to sustain the world’s growing demand, policymakers should be concerned with understanding how to manage what they already have.Introducing the special report, Simon Cook, Myles Fisher, Tassilo Tiemann, and Alain Vidal note in “Water, Food and Poverty: Global- and Basin-Scale Analysis” that the vast majority of population growth over the next few decades is expected to happen in developing countries, “where the disjunct between poverty, water and food is particularly acute.” Gaining a better understanding of water – how much we have, who uses it, and how best to use it – is essential to improving development results in the face of this demographic explosion. Water is linked with poverty and development through issues like scarcity, access, and water-related hazards (like drought, flood, and disease). But the authors conclude that water productivity – the ease or difficulty in getting water from its source to agriculture – “is by far the most important water-related constraint to improved food, income and environmental security.”In “Water, Agriculture and Poverty in the Niger River Basin,” Andrew Ogilvie et al., paint a bleak picture of life in one of West Africa’s most important basins, writing that “[m]uch of the population in the basin suffers from extreme, chronic poverty and remains vulnerable to droughts and malnutrition.” Many of the Niger basin’s 94 million residents rely on subsistence agriculture, and most of that agriculture relies on rainwater rather than groundwater irrigation systems. Over time, the authors write, “there is little doubt that climate change will increase the strain on already-vulnerable agriculture.” Population growth will exacerbate this strain; the basin’s population is expected to increase as much as fourfold by 2050. In spite of this bleak picture, the authors conclude that “[i]mprovements in rainfed agriculture can have an important impact on poverty reduction and food security due to the large population dependent on it.” -
Roger-Mark De Souza, RH Reality Check
Sex and Sustainability: Reflections For My Son Nick
›October 20, 2011 // By Wilson Center StaffThe original version of this article, by Roger-Mark De Souza, appeared on RH Reality Check.
“Are we going to talk about sex again?!” screamed my 12-year old son, Nick, as he ran down the stairs, away from me. That was five years ago and I had just sat down with him to have one of our father-son talks, this time about sex and sustainability.
Now Nick, a rising senior, is preparing for college at the same time as the global community is preparing for an important landmark of its own: the United Nations predicts that by October 31, world population will reach 7 billion.
The confluence of these two events gives me reason to think about the world Nick is inheriting from my generation, and makes me consider what I can say to him as he heads off to college.
This World of 7 Billion
I try to get my head around it. It’s a world of 7 billion people. With greater connectivity than I could have ever dreamed possible. A world of widening disparities and growing environmental degradation. A world with a changing climate. A world of crashing economic markets and changing debt ceilings.
It’s also a world of finite resources and growing demand.
Continue reading on RH Reality Check.
Photo Credit: David Hawxhurst/Wilson Center. -
Watch: Scott Wallace on the Amazon’s Last Uncontacted Tribes and the Intersection Between Human Rights and Conservation
›October 19, 2011 // By Wilson Center StaffIn the far west of the Amazon, some of the last uncontacted indigenous tribes on Earth live untouched by modern society. Scott Wallace, frequent contributor to National Geographic and former public policy scholar at the Wilson Center, spoke to New Security Beat about his new book, The Unconquered: In Search of the Amazon’s Last Uncontacted Tribes, which chronicles his harrowing trip through the Javari Valley Indigenous Land. Wallace accompanies former sertanista (“agent of contact”)-turned-native rights advocate Sydney Possuelo as he attempts to map and protect the territory of the flecheiros, or Arrow People, named for the poison-tipped arrows they use.
The Brazilian government and activists are trying to protect the areas where these native groups live and allow them to choose for themselves if they want contact. “It’s not that hard to find us,” Wallace said. For the moment, however, “it’s clear that they do not want that contact.”
By protecting these people, the government is also protecting thousands, if not millions, of acres of virgin rainforest, said Wallace, creating a mutually beneficial intersection between human rights and environmental conservation.
“The assumption is that there is now a global village, everyone’s connected…no one of us is separated from anyone else on the planet by more than six degrees of separation,” said Wallace. But that assumption breaks down in the face of these people who live in complete isolation from the rest of the world.
We have to decide whether to leave them alone and let them live their lives or try to make lasting contact, said Wallace. Contact would open up the tribe’s land and resources to development but come at great risk to their society, their lives (due to vulnerability to disease), and the Amazonian ecosystem, as the example of India’s Adavasi tribes demonstrates. -
Health and Harmony: Population, Health, and Environment in Indonesia
›Borneo’s Gunung Palung National Park is a microcosm of both the island’s ecological wealth and vulnerability. More than half of the park is undisturbed forest; the remainder, however, “is being torn down day after day” at an alarming rate, said Health in Harmony’s Nichol Simpson at an event on integrated approaches to population, health, and environment (PHE) programs in Indonesia. Alene Gelbard of the Public Health Institute’s Company-Community Partnerships for Health Indonesia (CCPHI) program joined Simpson on September 29 at the Wilson Center. Both speakers emphasized that no matter what issue a group works on, engaging local communities is essential for success.
The Destructive Cycle: Poor Health, Poor Environment
For Simpson, “the intersection between human and environmental health” is at the heart of Health in Harmony’s work. Health in Harmony opened Clinic ASRI in 2007, aiming to provide improved healthcare to villagers throughout Gunung Palung National Park while ending their dependence on illegal logging as a means of financial survival.
The area’s inhabitants were all too easily trapped in what Simpson called “the destructive cycle.” When faced by an unexpected medical emergency, families would go into debt to pay their medical bills. Health in Harmony found that of 232 local households surveyed, 13 percent had recently experienced a major medical emergency, at an average cost of $360. Most households in the area only hold around $260 in emergency savings, so to make up the difference, about a third turned to illegal logging to pay down their debt.
By deforesting the park, illegal logging worsens the health of nearby communities. For example, Simpson said that Clinic ASRI has seen a rise in cases of malaria and tuberculosis in the surrounding communities, in part because deforestation has increased the level of mosquito activity. The link between human and environmental health is clear, said Simpson: the people ASRI serves are “living it every day. They know the cause of this. And…they want it to stop.”
Protecting Natural Resources By Improving Health
The Health in Harmony clinic located in Sukadana, a small village sandwiched between Borneo’s coast and Gunung Palung Park, helps break the destructive cycle by treating patients regardless of their ability to pay. If patients do not have cash, they can barter for their care. In one case, a girl named Yani came to ASRI after her family incurred $500 over two months of visiting hospitals and traditional healers, none of whom could treat her condition. ASRI diagnosed and treated Yani for scabies. In exchange, her mother signed a pledge to protect Gunung Palung from logging and made the clinic a floor mat to cover the $1.50 bill.
By providing affordable, high-quality healthcare that is contingent upon pledging to protect the environment, Clinic ASRI improves human and environmental health in one fell swoop, said Simpson. “Because the infant mortality rate has decreased and you’re not overcompensating,” said Simpson, families can choose to have fewer children, using free birth control provided by ASRI.
“When you have fewer and healthier children, you’re investing in your education,” said Simpson. “When you’re investing in your education, you’re investing in your country and your community. This is the virtuous cycle. I didn’t invent it, but we are proving it in Sukadana.”
The communities around the clinic have embraced ASRI’s work, partnering with them to expand their services to address additional community needs, like training farmers in more productive organic methods and providing mated pairs of goats for widows, who pay ASRI back with kid goats and manure for fertilizer.
All but one of the 23 villages that ASRI services have been consistently free of illegal logging, according to monitors who visit them on a regular basis. “We’re proving the theory that we can protect natural resources by improving health,” Simpson said.
“Health Is Key to Sustainable Development”
Gelbard took a step back to talk about CCPHI’s experience establishing multi-sector partnerships among NGOs and corporations by building trust and enabling dialogue between the communities.
With corporate responsibility becoming more popular, “everyone’s talking about partnerships these days, and everybody’s partnering with everyone,” said Gelbard. “I don’t care what they call it – I care what they’re doing” and what results they achieve, she said. A successful partnership involves “all partners doing something more than just giving money.”
Gelbard said the 2004 tsunami reinforced the notion of corporate responsibility for a lot of companies operating in Indonesia. They saw that unless they branched out beyond their own walls and “did things to help strengthen communities,” efforts at corporate responsibility simply “would not benefit them in the long-run,” she said.
Through CCPHI, companies and NGOs have partnered on a wide range of efforts, including improving access to and funding for reproductive health services, improving sanitation by increasing access to water, and combating human trafficking by empowering girls and women.
Achieving the Millennium Development Goals will require increasing access to health care in a manner that reflects the needs of communities, she said. At its core, CCPHI’s work and the partnerships it facilitates are “based on the knowledge that health is key to sustainable development,” said Gelbard.
Event Resources
Sources: Alam Sehat Lestari, American Journal of Tropical Medicine and Hygiene, Company-Community Partnerships for Health Indonesia, ExxonMobil, The Guardian, Health in Harmony, National Geographic, PBS News Hour, Public Health Institute, Republic of Indonesia Ministry of Forestry, United Nations, World Wildlife Fund
Photo Credit: Used with permission courtesy of ASRI and Nikki See, Under-told Stories.
A Publication of the Stimson Center.
