Population Growth and Malnutrition
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Chapter 1.2
Population Growth
and Malnutrition
31
Michael J Klag Parul Christian
Dean, Johns Hopkins Senior Program Officer,
Bloomberg School of Public Women’s Nutrition, Bill &
Health, Baltimore, MD, USA Melinda Gates Foundation,
Seattle, WA, USA; Professor,
Department of International
Health, Johns Hopkins
Bloomberg School of Public
Health, Baltimore, MD, USA
“Population growth is an important driver of economic progress. Every
stomach comes with two hands attached. Every mouth is backed by a
creative human intelligence. We can solve the problems that are caused
by our growing numbers. In fact, we have been doing so for many
centuries now.” 32
Steven W Mosher (born 1948), American social scientist and President of the Population Research Institute
The magnitude of global
Key messages population growth
The world’s population reached 7 billion on October 31, 2011
• The speed at which the world’s according to the United Nations Population Fund; according
population is increasing is without to the United States Census Bureau, this milestone was
precedent and poses a wide range of attained on March 12, 2012.1 In the 1970s, it had been at
approximately half this figure. The speed at which the world’s
complex challenges for nutritionists,
population is increasing is entirely without precedent (Figure
agriculturalists and public health 1). It places enormous strain on the planet’s resources, and
professionals alike. poses a wide range of complex challenges for nutritionists,
agriculturalists and public health professionals alike.
• Life expectancy has also increased rapidly,
A little over two centuries ago, the world’s population was
especially in the developed world.
1 billion (Table 1). It was to grow sevenfold in the ensuing
• At the same time as the world’s two centuries. It took just 123 years to double, under the
influence of the Industrial Revolution and the accompanying
population has been rapidly growing,
advances in science and medicine. It took 46 years to double
childhood mortality rates have seen a from 2 to 4 billion, but only 39 years to double from 3 to 6
dramatic decline. million; and an additional 1 billion was added 12 years later.
• There will be a third more mouths to In part, this dramatic increase occurred due to a
feed by 2050. Food production will phenomenon called the “population momentum,” as a larger
percent of the population was in its reproductive years
have to rise considerably to meet this
during the period in question. The World Bank defines
demand, and Sub-Saharan Africa will population momentum as: “The tendency for population
require special attention. growth to continue beyond the time that replacement-level
fertility has been achieved because of a relatively high
• Overall population growth will fuel the concentration of people in the childbearing years.”2 Even as
growth of urban areas, and the rise of fertility rates began to decline around the 1970–80s due to
urban populations will have wide- the effect of family planning programs, the previously high
ranging health implications. fertility rates resulted in continuing accelerated population
growth. The rate of change in the world population was the
highest during the 50-year period from 1925 to 1975, at 100
to 200 percent (Table 1).
“The scale, severity and duration of the
Assuming a medium fertility variant or at replacement levels,
world food problem are so great that a
by 2050 the world population will be 9 billion and by 2100,
massive, long-range, innovative effort
10 billion (Figure 2). Much of this increase will occur in
unprecedented in human history will be
developing countries, with the population of high-income
required to master it.”
countries remaining relatively constant (Figure 3).
US PRESIDENT’S SCIENCE ADVISORY COMMITTEE, 1967
Figure 1: World population since 10,000 BCE
Chapter 1.2 | Population Growth and Malnutrition
33 Figure 1 | World population since 10,000 BCE
7
6
5
Billion People
4
3
2
1
0
-10000 -8000 -6000 -4000 -2000 0 2015
Source: https://ourworldindata.org/world-population-growth/, accessed July 8, 2016
Figure
Figure 2 |2:Estimated
Estimated and
and projected
projected world
world population,
population, billions,
billions, 1950–2100
1950–2100
28
Contant fertility variant
High fertility varient
Medium fertility varient
24
Instant replacement fertility variant
Low fertility varient
20
16
12
8
4
0
1950
1960
1970
1980
1990
2000
2010
2020
2030
2040
2050
2060
2070
2080
2090
2100
Source: https://ourworldindata.org/world-population-growth/, accessed July 8, 2016
Source: United Nations, Department of Economic and Social Affairs, Population Division (2011): World Population Prospects: The 2010 Revision. New York.
(Updated: April 15, 2011)
34
Mexico City, one of the world’s megacities
Table 1 | World population milestones
Year World Population Interval
1804 1 billion
1927 2 billion 123 years later
1960 3 billion 33 years later
1974 4 billion 14 years later
1987 5 billion 13 years later
1999 6 billion 12 years later
2011 7 billion 12 years later
Change in population profiles over time
In many European countries, the total fertility rate – the countries in Africa and Asia have a high total fertility rate.
average number of children a woman will have during her Family planning strategies are urgently needed in these
lifetime if she experienced the current age-specific fertility countries, both to limit the number of children born and to
rates and if she survived through the end of her childbearing ensure appropriate intervals between births.
years – is below the level of 2.0 which is required to replace
Meanwhile, life expectancy has grown rapidly, especially in
the population without increasing it. In Germany, for
the developed world. In the USA, for example, it increased
instance, it is only 1.4. In the USA, it stands at just above
by 56% for males and 63% for females between 1900 and
this figure, at 2.1. China, with its policy of one child per
2000. The proportion of the population aged over 65 is
family, had a total fertility rate of 1.7 in 2014, according to
projected to more than treble from 7% (111 million people)
the World Bank, whereas India scored a higher than
to 23% (450 million) by 2050. By 2050, the Western Pacific
replacement level at 2.5. Countries in Africa, by contrast,
Region will have the second oldest population of all WHO
demonstrate a very high total fertility rate, with Niger
regions – just below Europe where 25% of the population
scoring highest of all at 7.2. With certain exceptions, most
Chapter 1.2 | Population Growth and Malnutrition
35
will be aged over 65. With a projected population of 450 32.9 million), Shanghai (China, 28.4 million), Mumbai (India,
million older people by 2050 globally, the Western Pacific 26.6 million), Ciudad de México (Mexico, 24.6), São Paulo
Region will have far more older people than any other world (Brazil, 23.2 million), Dhaka (Bangladesh, 22.9 million),
region. At the same time as the population growth has been Beijing (China, 22.6 million) and Karachi (Pakistan,
occurring and fertility rates have been declining, childhood 20.2 million). Tokyo’s population will grow from its 1970
mortality has been dramatically declining globally. It is figure of 23.3 to 38.7 million, and New York-Newark’s from
projected to continue to do so across different regions, 16.2 to 23.6. London, the first great metropolis of the
although the decline has slowed somewhat in recent years in Industrial Revolution, will occupy only 36th place, with a
Sub-Saharan Africa. population of 10.3 million. Despite the massive increase in
the size of existing megacities, more and more of the population
Overall population growth will fuel the growth of urban
will be residing in smaller urban areas, as these get built in
areas, which may become home to 50% of the world’s
response to overall population growth (Figure 4). After 2050,
population by 2050. The number of megacities is expected to
rural populations are predicted to remain stable, while the
grow to 36 by 2025, from a baseline of two in 1970 (Tokyo
urban population of the planet will continue to grow.
[Japan] and New York-Newark [USA]). These two cities are
predicted to be accompanied in the top ten by Delhi (India,
Figure 3 | Growth in developing v. developed countries 1965–2050
Figure 3: Growth in developing v. developed countries 1965–2050
10
Developing countries
Developed countries
8
6
Billion People
4
2
0
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
2015
2020
2025
2030
2035
2040
2045
2050
Source: Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat (2007)
Chapter 1.2 | Population Growth and Malnutrition
Figure 4: Urban and rural populations by development area, 1950–2050
Figure 4 | Urban and rural populations by development area, 1950–2050 36
6
More developed regions
urban populations
More developed regions
rural population
5
Less developed regions
urban populations
Less developed regions
rural population
4
Billion People
3
2
1
0
Source: UN, World Urbanization Prospects: The 2011 Revision
Aerial view of Shibuya in Tokyo, Japan –
the world’s most populous city.
Sub-Saharan Africa
Sub-Saharan Africa in particular will require special
attention. Although the rate of population growth in this
region is declining rapidly, it will continue to increase from
770 million in 2005 to 2 billion by 2050. Chronic hunger
and malnutrition are already high in Sub-Saharan Africa,
and so this region will face a special challenge in the years
to come. Vulnerability to climate and dependence on
rainwater for irrigation makes the agricultural economy of
Sub-Saharan Africa as a whole extremely fragile, and this
tendency has been accentuated by lack of appropriate
investment in agriculture in recent decades. The
development of smallholder farming may be key to the
region’s success in the future. There is cause for hope,
however, when one reflects that Asia had only two staple
crops during the “Green Revolution” masterminded by
Norman Borlaug in the 1960s and ’70s: Africa has no fewer
than eight. Borlaug, who developed high-yielding, disease-
resistant, semi-dwarf varieties of wheat, was credited at the
time with saving a billion lives.
37
0
1
2
3
4
5
6
7
8
China, Hong Kong, SAR
Lagos,
Slovakia
Figure
Malta
Portugal
Slovenia
the capital
Lithuania
Germany 1.36
Russian Federation
5: Total
TFYR Macedonia
Barbados
of Nigeria,
Serbia
Trinidad and Tobago
fertility
Armenia
Belgium
seen by
Denmark
Brazil
Bahamas
Australia
Dem. People’s Rep. of Korea
fromcountry,
Myanmar
USA 2.07
Uruguay
Turkey
New Caledonia
Figure 5 | Total fertility by country, 2005–2010
Guyana
Source: UN Department of Economic and Social Affairs – Population Division.
Bangladesh
the air. The 2005–2010
Réunion
Uzbekistan
Guam
Panama
Bhutan
Western Sahara
Fiji
Botswana
Laos
French Guiana
Gabon
Zimbabwe
city’s population currently stands at 21 million.
Micronesia
Samoa
Guatemala
Solomon Islands
Côte d’lvoire
Eritrea
Central African Republic
Gambia
Equatorial Guinea
Niger 7.19
Benin
Angola
Chad
MaliChapter 1.2 | Population Growth and Malnutrition
Figure 6: Gains in US life expectancy: 1900–2050
Figure 6 | Gains in US life expectancy: 1900–2050 38
90
80
70
Female 0
Male 0
60
Age
Female 65
Male 65
50
40
30
1900 1920 1940 1960 1980 2000 2020 2040
Source: Courtesy of Agree, 2011.
Figure 7: Childhood mortality, 1950–2050
Figure 7 | Childhood mortality, 1950–2050
330
280
230
Deaths per 1,000 births
180
130
Sub-Saharan Africa
South-central Asia
80 World
30
Source: WHO World Population Prospects: The 2004 Revision.Street scene in India.
39
Urbanization and health
The growth of populations living in urban environments has Urban environments also tend to discourage physical activity
wide-ranging health implications. One in three urban dwellers and promote consumption of unhealthy, calorie-dense diets
lives in slums, where nutrition, sanitation, and air and water that are high in refined carbohydrates such as white flour and
quality are usually very poor. This amounts to 1 billion white rice. The process of refining a food not only removes the
people worldwide. Urban air pollution kills approximately fiber; it also removes much of the food's nutritional value,
1.2 million people each year around the world, mainly due including B-complex vitamins, healthy oils and fat-soluble
to cardiovascular and respiratory diseases. Much of this vitamins. The consumption of the many processed foods that
pollution, although not all of it, is attributable to emissions characterize the modern Western diet results in higher
from motor vehicles. The incidence of tuberculosis is also much prevalence of obesity, diabetes and related non-communicable
higher in big cities. In the Democratic Republic of Congo, for diseases, which account for 63% of deaths worldwide.
example, 83% of people with tuberculosis live in cities. Countering these factors, the provision of health services is
more efficient in cities; but the growth of urban populationsChapter 1.2 | Population Growth and Malnutrition
40
will create a host of practical, logistical and financial with greater disparities observable in urban than in rural
challenges, placing huge burdens on public health systems in areas. In absolute terms, however, large swathes of the
general and healthcare budgets in particular (Table 2). world’s population will still rise out of extreme poverty.
Global poverty has declined in the past two decades, and A recent USDA report predicts an improvement in the
the global poverty ratio is predicted to fall from its 2005 global food insecurity situation, projecting that only 6% of
figure of 21% to 2.5% in 2050. 3 Economic growth has the world population will have inadequate access to food by
occurred, but is highly variable within countries, and over 2026, compared to 17% at present. Decreased food prices
time will even lead to higher income inequality within and increasing incomes, especially in Asia, may be linked to
individual countries. In India, for example, the top 20% of this decline. 5
earners in rural settings can only match the incomes made
Population growth is contributing to climate change, which
by middle and upper middle earners in cities. The lowest
is putting pressure on food systems and will impact
earners in urban settings are far ahead of the rural poor,
agricultural yields. Food systems themselves contribute
who account for 80% of rural populations, and the urban
19–29% of greenhouse gas emissions, and agricultural
top 20% of earners far outstrip all other categories.4
production accounts for 80–85% of total food systems
Disturbingly, the GINI Index – a measurement of the
emissions, although significant variation by country exists.
income distribution of a country's residents that helps define
The relationship between climate change and nutrition is
the gap between the rich and the poor – is increasing in
discussed in detail elsewhere in this book.
countries with high economic growth and high populations,
An escalator in a crowded shopping mall. Economic growth is likely to lead to higher income
inequality not just between nations but also within individual countries.Chapter 1.2 | Population Growth and Malnutrition
41 Table 2 | Implications of change for global health The nutrition transition
Confidence Modernization, urbanization, economic development and
Health effect level
increased wealth are also leading to predictable shifts in diet
Increase in malnutrition and consequent High referred to as the “nutrition transition”. This is broadly
disorders, including child growth and
development.
classified into five patterns (Table 3).
Increase in death, disease, and injury from heat High Most low-and middle-income countries are currently moving
waves, floods, storms, fire and drought. from pattern 3 (end of famine) to pattern 4 (consuming more
Mixed effects on malaria, with some Very high energy-dense diets). This shift from traditional diets to
contractions balanced by expanded Western-style diets has been a key contributor to the obesity
geographic range and change in seasonality.
epidemic in low- and middle-income countries. Meanwhile,
Change in the range of some vectors of High childhood stunting (low height for a given age), an indicator of
infectious diseases.
undernutrition in the earliest years of life, and which results in
Increase in diarrheal diseases. Moderate increased mortality and cognitive deficits, is still at unacceptably
Increase in number of people exposed to Low high levels. Although declines in stunting are observed
dengue fever.
worldwide, and the MDG target of halving the incidence of
Decrease in cereal crop productivity in low Moderate stunting worldwide by 2015 was nearly achieved, 162 million
latitudes for even small temperature increases.
children were stunted in 2012, with particularly high levels of
Source: IPCC Fourth Assessment Report Climate, 2007.
Table 3 | The five patterns of the nutrition transition
Pattern Description Commentary
1 Hunter-gatherer Individuals live highly active lifestyles, hunting and foraging for food. Diets typically are rich in
fibrous plants and high in protein from lean wild animals.
2 Early agriculture Famine is common, slowing individuals’ growth and decreasing their body fat.
3 End of famine Famine recedes as income rises and nutrition improves.
4 Overeating, As income continues to rise, individuals have access to an abundance of high-calorie foods, and
obesity-related they become less active, leading to increases in obesity and obesity-related chronic diseases,
diseases such as diabetes and heart disease.
5 Behavior change In response to increasing rates of obesity and obesity-related chronic diseases, individuals change
their behavior – and communities promote behavior changes – to prevent these conditions.
Source: IPCC Fourth Assessment Report Climate, Behavior change
prevalence in south Asia, Sub-Saharan Africa, the Caribbean, nutrition transition. This will place considerable demands on
and Oceania. Appropriate breastfeeding and complementary the world’s food production systems, and alternative sources
feeding practices are key to the prevention of stunting, as are of food, such as fisheries and aquaculture, should be explored.
adequate levels of sanitation and hygiene.
Outlook
Meat consumption, which is important for meeting
requirements for intake of animal protein as well as the According to the FAO, there will be a third more mouths to
micronutrients iron, zinc and vitamin A, is growing feed by 2050, despite an anticipated decline in fertility rates
worldwide. There are, however, vast regional discrepancies across the globe.7 Food production will have to rise by 70% to
in levels of meat consumption, with citizens of Bangladesh, meet this need, which will place huge demands both on the
Nigeria, Ethiopia, the Democratic Republic of Congo and environment and on the world’s agricultural systems.
Burma consuming an average of just 0–10 g meat per day and According to the best-case scenario, 4.5% of the world’s
those of the USA, France and The Netherlands consuming population will be malnourished in 2050 (as opposed to 12.4%
70–80 g daily. If the consumption of milk is included, over in 2005); the worst-case scenario puts this figure at 5.9%
70% of the world’s population consumes less than 30 g of (Tables 4 and 5). Approaches to making agriculture more
animal protein per day.6 Nevertheless the consumption of innovative, efficient and sustainable, and to ensuring that it
meat, vegetable oils, sugar and pulses is projected to increase delivers not just more calories but also improved nutritional
in developing countries, many of which are undergoing a content, are discussed in chapters 3 and 4 of this book.Chapter 1.2 | Population Growth and Malnutrition
Table 4 | World food supply and demand projections: best-case scenario 42
WORLD FOOD SUPPLY AND DEMAND IN MARKET FIRST SCENARIO
World crop production Crop land Yield Crop loss ratio
(million metric tons) (million hectares) (tonnes/hectare) (percent)
2005 4,190 1,544 2.71 30.3%
2050 6,584 1,617 4.07 22.3%
percentage change 57.1% 4.7% 50.0%
avg ann. percentage change 1.0% 0.1% 0.9%
CALORIES AVAILABLE PER PERSON
World OECD Non-OCED Sub-Saharan Africa
2005 2,800 3,421 2,662 2,256
2050 3,207 3,635 3,135 2,588
percentage change 14.5% 6.3% 17.8% 14.7%
avg ann. percentage change 0.3% 0.1% 0.4% 0.3%
PERCENTAGE OF POPULATION MALNOURISHED
World OECD Non-OCED Sub-Saharan Africa
2005 12.4% 1.9% 14.8% 30.7%
2050 4.5% 0.0% 5.3% 18.5%
Source: Hillebrand E, White Paper, Expert Meeting on how to feed the world in 2050, FAO 2010.
Table 5 | World food supply and demand projections: conservative estimates
WORLD FOOD SUPPLY AND DEMAND IN TREND SCENARIO
World crop production Crop land Yield Crop loss ratio
(million metric tons) (million hectares) (tonnes/hectare) (percent)
2005 4,190 1,544 271 30.3%
2050 6,150 1,620 3.8 24.1%
percentage change 46.8% 4.9% 39.9%
avg ann. percentage change 0.9% 0.1% 0.1%
CALORIES AVAILABLE PER PERSON
World OECD Non-OCED Sub-Saharan Africa
2005 2,800 3,421 2,662 2,256
2050 3,099 3,648 3,013 2,507
percentage change 10.7% 6.6% 13.2% 11.1%
avg ann. percentage change 0.2% 0.1% 0.3% 0.2%
PERCENTAGE OF POPULATION MALNOURISHED
World OECD Non-OCED Sub-Saharan Africa
2005 12.4% 1.9% 14.8% 30.7%
2050 5.9% 0.0% 6.8% 21.4%
Source: Hillebrand E, White Paper, Expert Meeting on how to feed the world in 2050, FAO 2010.Rice terraces in Longsheng
County, Guangxi, China. Feeding
the world’s burgeoning
population will require
innovations in agriculture.
43Chapter 1.2 | Population Growth and Malnutrition
My personal view here. FP2020 is a global partnership that supports the 44
rights of women and girls to decide, freely, and for
Michael J Klag themselves, whether, when, and how many children they
want to have. FP2020 works with governments, civil
Population growth underlies many of the most important society, multilateral organizations, donors, the private
challenges facing the world today. In the future, the world sector, and the research and development community to
will be more populous, especially in low- and middle- enable 120 million more women and girls to use
income countries, more urban, and with an older and contraceptives by 2020. FP2020 is an outcome of the 2012
more obese population which will be characterized by London Summit on Family Planning where more than 20
even greater economic disparities than is the case today. governments made commitments to address the policy,
All these trends will impact poor countries more severely financing, delivery and sociocultural barriers to women
than wealthy ones. accessing contraceptive information, services and supplies.
Donors also pledged an additional US$2.6 billion in
Family planning is essential to curb population growth,
funding. It is very important that this goal be achieved.
and Family Planning 2020 (FP2020) has a key role to play
References
Further reading 1 http://www.worldometers.info/world-population/, accessed December 14, 2015.
Rosen S, Thome K, Meade B. International Food Security 2 http://www.worldbank.org/depweb/english/modules/glossary.
Assessment, 2016–2026. A report summary from the Economic html#momentum, accessed July 8, 2016.
Research Service. USDA June 2016. http://www.ers.usda.gov/ 3 Hillebrand, E. Poverty, growth and inequality over the next 50 years. FAO, 2010.
media/2109786/gfa27.pdf, accessed July 22, 2016. 4 Sen, A (mimeo, 2004) based on NSS data.
Vermeulen SJ, Bruce M, Campbell BM. Climate Change and Food 5 Rosen S, Thome K, Meade B. International Food Security Assessment,
Systems. Annu. Rev. Environ. Resour. 2012. 37:195–222. http:// 2016–2026. A report summary from the Economic Research Service. USDA
www.annualreviews.org/doi/abs/10.1146/annurev- June 2016. http://www.ers.usda.gov/media/2109786/gfa27.pdf
environ-020411-130608, accessed July 22, 2016. 6 FAOSTAT 2001.
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