Download - 5th chapter research methods
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 1/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
FUTURE
POPULATIONTRENDS
Chapter 5
Marco Savioli
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 2/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
Future population trends
Population’s age structure (fraction of the population indifferent age groups) affects income per capita
The size of world’s population is important for the amountof natural resources available to each person and world-scale environmental problems such as global warming
We can make fairly accurate guesses about populationgrowth over the next 20 or even 50 years
In the developed countries, the fraction of nonworkingelderly will rise imposing economic burden
Many developing countries will receive a «demographicgift» as population growth slows and the fraction of thepopulation made up of children falls
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 3/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
5-3
Figure 5.1 World Population, 1850 –2150
UNforecast:worldpopulationwill stabilizeat 11 billionsometimearound theyear 2200
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 4/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
5-4
Figure 5.2 Population Forecasting
Breakdown of thepopulation into thenumber of people of eachage in a particular year
To forecast the next year,we «age» the population,making an adjustment formortality
Survivorship function
gives information on thelikelihood of survival
Same calculation todetermine the number ofpeople in all other agegroups; for those agedzero, age-specific fertilityrate applied to thenumber of women ineach age group
Summing up and carryingforward year by year thisprocess gives population
forecasting (also accountfor immigration andemigration)
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 5/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
Forecasting mortality
Improvements in mortality significantly raised the net rateof reproduction (NRR)
In forecasting future changes in population growth,mortality changes are likely to have much less effect sincethe fraction of girls living through their childbearing years
is already close to 100% Potential improvements in life expectancy will have a fairly
small effect on the NRR
If the number of births does not change but people livelonger, more people are alive at any given time
Improvements in mortality less important than changes infertility in determining population growth
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 6/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
Forecasting fertility
Forecasts of fertility are made relative to replacementfertility – the level of fertility consistent with aconstant population size in the long run
Even in the most developed countries, there is some
mortality before women’s childbearing years, andslightly more boys are born than girls → TFR
consistent with zero population growth is 2.1
UN predicted in all the countries in the world TFR
would move toward replacement fertility over thenext 50 years (TFR = 2.1 by the year 2050); a sharpfall for developing and a significant rise for developed
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 7/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
5-7
Figure 5.3 Total Fertility Rate in Japan: Actual
versus Forecast
Difficultyin
forecastingfertility:pastforecastsfared notso good
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 8/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
Fertility in rich countries
2009 OECD TFR= 1.74; however, broad variation:
USA TFR = 2.05
Ita TFR = 1.41
Spa TFR = 1.40
Jap TFR = 1.37
Ger TFR = 1.36
SKr TFR = 1.28
In absence of large-scale immigration, low fertility rates
will translate into shrinking populations
Low fertility will also raise average age of the population
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 9/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
5-9
Table 5.1 Fertility in the Developing World
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 10/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
5-10
Figure 5.4 Income per Capita versus Total
Fertility Rate
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 11/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
Demographic momentum
If the number of women in their reproductive years rises(after a period of population growth), then the number ofbabies born also will rise
Even if fertility falls, the number of babies born will rise,for the simple reason that the number of women in theirreproductive years will continue to rise
Only after several generations will the effect of thisdemographic momentum wear off, at which point thegrowth rate of population will be zero
A useful measure of the demographic momentum is thefraction of the population under age 15
Over the very long run, the most important determinant ofpopulation growth will be fertility, about which we havelittle theoretical basis for speculating
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 12/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
5-12
Figure 5.5 The Great Spike in World
Population Growth (W. W. Rostow)
Rostowhasassumedthat the200 yearsafter thepopulation growthpeak willsee asymmetri
creduction
Instead ofthe greatspike, agreat stepinpopulation growthispossible
Or
negativegrowth…
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 13/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
5-13
Table 5.2 Average Annual Growth Rates
of Population by Country Group
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 14/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
The economic consequences ofdemographic change
The growth of world population over the period 2000-2050 (0.9% per year) is forecast to be only half asrapid as over the previous 50 years (1.8% per year)
What is the effect of demographic change oneconomic growth?
We can examine these economic effects by applyingthe Solow model, extended to accommodatepopulation (two points in time for a single country)
=
+
+
(−)
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 15/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
The economic consequences ofdemographic change
Case of the less developed countries (population growthrate forecast to fall from 2.1% to 0.8%) and plausiblevalues = 0.05, = 1 3.
=0.021 + 0.05
0.008 + 0.05
≈ 1.11
A slowdown in population growth, by reducing the effect ofcapital dilution, will raise the pace of economic growth
However, the level of population will continue to rise. More
people will lead to fewer natural resources per capita andthus to a negative effect on the level of output per capita
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 16/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
5-16
Figure 5.6 Changes in the Age Structure of
the Population, 1950 –2050
One of the mostimportant ongoingdemographicchanges is the agingof the world’spopulation
Over the period2000-50, themedian age of theglobal population isforecast to rise from
26.5 to 36.2 years(declining mortalityand fertility)
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 17/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
Population aging
Throughout the world there is an ongoing decline inthe fraction of population made up of children and anincrease in the fraction made up of the elderly
But the timing of this restructuring differs among thegroups of countries
in the more developed, by 2050 there will be 1.7times as many elderly people as children
in the less developed, by 2050 children will stilloutnumber the elderly
in the least developed, by 2050 the elderlyfraction of the population will still be only 7%
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 18/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
Population aging
When we think about how productive a country is, it isoften natural to focus on GDP per worker
When we ask how well off a country is, a more relevantmeasure is the output that is available for every person inthe economy, that is GDP per capita
=
=
= ×
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 19/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
5-19
Figure 5.7 Working-Age Fraction of the U.S.
Population, 1950 –2050
2000-2050
Mostdevelopedcountries:%population
15-64 from67% to 59%
Leastdevelopedcountries:
%population15-64 from54% to 65%
1950s: thepostwar babyboom raisedthe fractionof the
populationmade up ofchildren
1965-85:babyboomersentered thelabor force
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 20/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
Population aging
= income per capita, = income per worker, =fraction of the population that is of working age
= × → → = +
Decline in the fraction of the working-age population in theUS over the period 2010-30: from 0.60 to 0.54
=0.54
0.60
1 ≈ 0.5%
The demographic change will reduce the growth rate ofGDP per capita in the US by 0.5% per year
In addition, as society ages crime rates may fall, butyoung people account for much of a society’s dynamism
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 21/26
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 22/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
5-22
Figure 5.8 Distribution of the World’s
Population
Americassuffered theEuropean
«discovery»; since 1800massiveimmigrationandeconomicgrowth
Europe andAfricaexchangedtheir
positions:1900Europe’spopulation3 timesAfrica’s;2050 theopposite
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 23/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
Redrawing the world map
In addition to these intercontinental redistributions ofpopulation, there will also be changes in countries’relative populations
The countries expected to have the most populationgrowth are also the poorest. Thus, the fraction of the
population that will live in countries that are now richwill fall over time
The UN forecasts that the share of world populationliving in the currently more developed regions willdecrease from 20% to 13% (period 2000-50),whereas the fraction living in the currently leastdeveloped countries will increase from 11% to 20%
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 24/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
5-24
Table 5.4 The Composition Effect
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 25/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
Redrawing the world map
The reason that the average level of GPD per capita inthe world does not grow as quickly as the average ineach country is that the balance of population isshifting toward poorer countries (composition effect)
The fact that the fraction of the world’s populationliving in currently rich countries will fall does notmean that the fraction of the world’s population livingin rich countries will fall
More countries are becoming rich over time. Thus, the
overall balance between rich and poor people in theworld depends on which force is more powerful
8/11/2019 5th chapter research methods
http://slidepdf.com/reader/full/5th-chapter-research-methods 26/26
Copyright © 2013 Pearson Education, Inc. Publishing as Addison-Wesley
Going for the gold
Olympics may measure the outcome of internationalcompetition affected by relative population sizes
Both high income per capita and high populationshould raise a country’s medal count
In rich countries citizens have more time to devote toathletics, better facilities for training, better health
High-population countries have superior athletes
Reasonable approximation is a country’s total GDP
Also, aging population has a negative effect