where has the world’s population increased?
TRANSCRIPT
Chapter 2: Population 53
To understand the relationship between population andresources in a country, geographers examine a country’s physi-ological and agricultural densities together. As shown in Table2-1, the physiological densities of both Bangladesh and theNetherlands are high, but the Dutch have a much lower agri-cultural density than the Bangladeshi. Geographers concludethat both the Dutch and Bangladeshi put heavy pressure on theland to produce food, but the Dutch agricultural system utilizesfewer farmers than does the Bangladeshi system.
Similarly, the Netherlands has a much higher physiologicaldensity than does India but a much lower agricultural density.This difference demonstrates that, compared with India, theDutch have extremely limited arable land to meet the needs oftheir population.
Recall from Chapter 1 how the Dutch have built dikes andcreated polders, areas of land made usable by draining waterfrom them. The highly efficient Dutch farmers can generate alarge food supply from a limited resource.
KEY ISSUE 2
Where Has the World’sPopulation Increased?
■ Natural Increase■ Fertility■ Mortality
After identifying where people are distributed acrossEarth’s surface, we can describe the locations where thenumbers of people are increasing. Population increasesrapidly in places where many more people are born thandie, increases slowly in places where the number of birthsexceeds the number of deaths by only a small margin,and declines in places where deaths outnumber births.The population of a place also increases when peoplemove in and decreases when people move out. This ele-ment of population change—migration—is discussed inChapter 3. ■
Natural IncreaseGeographers most frequently measure population change in acountry or the world as a whole through three measures—crude birth rate, crude death rate, and natural increase rate.
• Crude birth rate (CBR) is the total number of live births ina year for every 1,000 people alive in the society. A CBR of20 means that for every 1,000 people in a country, 20 babiesare born over a 1-year period.
• Crude death rate (CDR) is the total number of deaths ina year for every 1,000 people alive in the society. Compara-ble to the CBR, the CDR is expressed as the annual numberof deaths per 1,000 population.
• Natural increase rate (NIR) is the percentage by which apopulation grows in a year. It is computed by subtractingCDR from CBR, after first converting the two measures fromnumbers per 1,000 to percentages (numbers per 100). Thusif the CBR is 20 and the CDR is 5 (both per 1,000), then theNIR is 15 per 1,000, or 1.5 percent. The term natural meansthat a country’s growth rate excludes migration.
The world NIR during the early twenty-first century has been1.2, meaning that the population of the world had been growingeach year by 1.2 percent. The world NIR is lower today than itsall-time peak of 2.2 percent in 1963, and it has declined sharplysince the 1990s. However, the NIR during the second half of thetwentieth century was high by historical standards.
About 80 million people are being added to the population ofthe world annually (Figure 2-8). That number represents a declinefrom the historic high of 87 million in 1989. The number of peo-ple added each year has dropped much more slowly than the NIRbecause the population base is much higher now than in the past.
World population increased from 3 to 4 billion in 14 years,from 4 to 5 billion in 13 years, and from 5 to 6 billion in12 years. As the base continues to grow in the twenty-first cen-tury, a change of only one-tenth of 1 percent can produce verylarge swings in population growth.
The rate of natural increase affects the doubling time,which is the number of years needed to double a population,assuming a constant rate of natural increase. At the earlytwenty-first-century rate of 1.2 percent per year, world popu-lation would double in about 54 years. Should the same NIRcontinue through the twenty-first century, global population
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FIGURE 2-8 World population growth, 1950–2010.The percentage by which the population grew (that is, thenatural increase rate [NIR]) declined during the latetwentieth century from its historic peak in the early1960s, but the number of people added each year did notdecline very much, because with world populationincreasing from 2.5 billion to nearly 7 billion peopleduring the period, the percentage was applied to an everlarger base.
54 The Cultural Landscape
in the year 2100 would reach 24 billion. When the NIR was2.2 percent back in 1963, doubling time was 35 years. Had the2.2 percent rate continued into the twenty-first century,Earth’s population in 2010 would be nearly 10 billion insteadof nearly 7 billion. A 2.2 percent NIR through the twenty-firstcentury would have produced a total population of more than50 billion in 2100.
More than 95 percent of the natural increase is clustered inLDCs (Figure 2-9). The NIR exceeds 2.0 percent in most coun-tries of sub-Saharan Africa and the Middle East, whereas it isnegative in Europe, meaning that in the absence of immigrants,population actually is declining. About one-third of the world’spopulation growth during the past decade has been in SouthAsia, one-fourth in sub-Saharan Africa, and the remainder
divided about equally among East Asia, Southeast Asia, LatinAmerica, and the Middle East.
Regional differences in NIRs mean that most of the world’sadditional people live in the countries that are least able tomaintain them. To explain these differences in growth rates,geographers point to regional differences in fertility and mortal-ity rates.
FertilityThe world map of crude birth rates (Figure 2-10) mirrors thedistribution of NIRs (compare with Figure 2-9). As was thecase with NIRs, the highest CBRs are in sub-Saharan Africa,
and the lowest are in Europe. Manysub-Saharan African countries have aCBR over 40, whereas many Europeancountries have a CBR below 10.
The word crude in crude birth rateand crude death rate means that we areconcerned with society as a wholerather than a refined look at particularindividuals or groups. In communitieswith an unusually large number of peo-ple of a certain age—such as a collegetown—we may study separate birthrates for women of each age. Thesenumbers are age-specific birth ratesrather than CBRs.
Geographers also use the total fer-tility rate (TFR) to measure the num-ber of births in a society (Figure 2-11).The TFR is the average number of chil-dren a woman will have throughout herchildbearing years (roughly ages 15through 49). To compute the TFR,demographers assume that a womanreaching a particular age in the futurewill be just as likely to have a child asare women of that age today. Thus, theCBR provides a picture of a society as awhole in a given year, whereas the TFRattempts to predict the future behaviorof individual women in a world of rapidcultural change.
The TFR for the world as a whole is2.6, and, again, the figures vary betweenMDCs and LDCs. The TFR exceeds 6.0in many countries of sub-SaharanAfrica, compared to less than 1.9 inmost European countries.
MortalityTwo useful measures of mortality inaddition to the CDR already defined arethe infant mortality rate and life
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FIGURE 2-9 Natural increase rate (NIR). The natural increase rate is the percentage by which thepopulation of a country grows in a year. The world average is currently about 1.2 percent. The countries withthe highest natural increase rates are concentrated in Africa and Southwest Asia.
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FIGURE 2-10 Crude birth rate (CBR). The crude birth rate is the total number of live births in a year forevery 1,000 people alive in the society. The global distribution of crude birth rates parallels that of naturalincrease rates.
Chapter 2: Population 55
expectancy. The infant mortality rate(IMR) is the annual number of deaths ofinfants under 1 year of age, comparedwith total live births (Figure 2-12). Aswas the case with the CBR and CDR, theIMR is usually expressed as the numberof deaths among infants per 1,000 birthsrather than as a percentage (per 100).
The global distribution of IMRs fol-lows the pattern that by now has becomefamiliar. The highest rates are in theLDCs of sub-Saharan Africa, whereas thelowest rates are in Europe. The IMRapproaches 100 in sub-Saharan Africa,meaning that nearly 10 percent of allbabies in the region die before reachingtheir first birthday. The IMR is less than5 percent throughout Western Europe.In general, the IMR reflects a country’shealth-care system. Lower IMRs arefound in countries with well-traineddoctors and nurses, modern hospitals,and large supplies of medicine.
Although the United States is wellendowed with medical facilities, it suf-fers from a higher IMR than Canadaand every country in Western Europe.African Americans and other minori-ties in the United States have IMRs thatare twice as high as the national aver-age, comparable to levels in LatinAmerica and Asia. Some health expertsattribute this to the fact that manypoor people in the United States, espe-cially minorities, cannot afford goodhealth care for their infants.
Life expectancy at birth measures theaverage number of years a newborninfant can expect to live at current mor-tality levels (Figure 2-13). Like everyother mortality and fertility rate dis-cussed thus far, life expectancy is mostfavorable in the wealthy countries ofWestern Europe and least favorable inthe poor countries of sub-Saharan Africa. Babies born todaycan expect to live to around 80 in Western Europe but only toaround 50 in sub-Saharan Africa.
Natural increase, crude birth, total fertility, infant mortality,life expectancy—the descriptions have become repetitiousbecause their distributions follow similar patterns. MDCs havelower rates of natural increase, crude birth, total fertility, andinfant mortality, and higher average life expectancy. Higher nat-ural increase, crude birth, total fertility rates, and IMRs andlower average life expectancy are found in LDCs.
The final world map of demographic variables—CDR—does not follow the familiar pattern (Figure 2-14). The com-bined CDR for all LDCs is actually lower than the combinedrate for all MDCs. Furthermore, the variation between the
world’s highest and lowest CDRs is much less extreme thanthe variation in CBRs. The highest CDR in the world is 23 per1,000, and the lowest is 1—a difference of 22—whereas CBRsfor individual countries range from 7 per 1,000 to 53, a spreadof 46.
Why does Denmark, one of the world’s wealthiest coun-tries, have a higher CDR than Cape Verde, one of the poor-est? Why does the United States, with its extensive system ofhospitals and physicians, have a higher CDR than Mexicoand nearly every country in Latin America? The answer isthat the populations of different countries are at variousstages in an important process known as the demographictransition, upon which we focus in the third key issue of thischapter.
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FIGURE 2-11 Total fertility rate (TFR). Total fertility rate is the number of children a woman will havethroughout her childbearing years. Again, the highest rates are in sub-Saharan Africa and the Middle East,whereas the lowest are in Europe.
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FIGURE 2-12 Infant mortality rate (IMR). The infant mortality rate is the number of deaths of infantsunder age 1 per 1,000 live births in a year. European and North American countries generally have infantmortality rates of under 10 per 1,000, whereas rates of more than 100 per 1,000 are common in Africa
56 The Cultural Landscape
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FIGURE 2-14 Crude death rate (CDR). Crude deathrate is the total number of deaths in a year for every1,000 people alive in the society. The global pattern ofcrude death rates varies from those for the otherdemographic variables already mapped in this chapter.The demographic transition helps to explain thedistinctive distribution of crude death rates.
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FIGURE 2-13 Life expectancy at birth. Lifeexpectancy at birth is the average number of years anewborn infant can expect to live. Worldwide, babiesborn this year are expected to live until their mid-sixties.Life expectancy for babies ranges from the 40s in severalAfrican countries to the 80s in some MDCs.
KEY ISSUE 3
Why Is PopulationIncreasing at DifferentRates in DifferentCountries?
■ The Demographic Transition■ Population Pyramids■ Countries in Different Stages of
Demographic Transition■ Demographic Transition and World
Population Growth
All countries have experienced some changes in naturalincrease, fertility, and mortality rates, but at different timesand at different rates. Although rates vary among countries,
a similar process of change in a society’s population,known as the demographic transition, is operating.Because of diverse local cultural and economic conditions,the demographic transition diffuses to individual countriesat different rates and produces local variations in naturalincrease, fertility, and mortality. ■
The Demographic TransitionThe demographic transition is a process with several stages,and every country is in one of them. The process has a begin-ning, middle, and end. Historically, once a country has movedfrom one stage of the process to the next, it has not reverted toan earlier stage. However, a reversal may be occurring in someAfrican countries because of the AIDS epidemic. The fourstages are shown in Figure 2-15.
Stage 1: Low GrowthMost of humanity’s several-hundred-thousand-year occupancyof Earth was characterized by stage 1 of the demographic tran-sition. Crude birth and death rates varied considerably from