Transcript Chapter 2 Key Issue 4 - Mounds View Public Schools

Thomas Malthus on Overpopulation
-Malthus was an English economist who lived from 1766—1834
-he was the first to argue that population growth was far
outnumbering the development of food supplies
“An Essay on the Principle of Population” (1798)
-in this, his most famous work, Malthus theorized that while
population increases geometrically (1,2,4,8,16,32,64,128…) food
supply increases arithmetically (1,2,3,4,5,6,7,8,9,10)
Today
1 person
1 unit of food
25 years
2 persons
2 units
50 years
4 persons
3 units
75 years
8 persons
4 units
100 years
16 persons
5 units
125 years
32 persons
6 units
150 years
64 persons
7 units
Malthus said “moral restraint” was needed to reduce CBR or
disease, war, famine, or other disasters increased CDR
Neo-Malthusians:
Some geographers are reexamining Malthus’s theory because of Earth’s high
NIR during late 1900s
Two Reasons to Reconsider Malthus’s Theory:
1. The gap between population growth and resources is wider than even
Malthus anticipated
-he failed to anticipate that the greatest population growth would occur in the
poorest countries because the transfer of medical technology but not
wealth will affect the LDCs differently--it will extend time spent in Stage II
(high growth)
-in East African countries, population growth has outpaced economic growth
-income is rising 2% each year, but population increasing 3% annually
The result is that most people in these countries are economically worse off
than they were 10, 20, or 30 years ago
2. World population growth is stripping Earth of many resources
-can see this through growing number of wars and civil violence
-people need to start fighting for resources
Some human populations have already exceeded the carrying capacity of
their area
Malthus’s Critics:
Malthus’s theory is based on a fixed supply of world resources
-critics feel that humans have some ability to choose courses that
can expand food supply and other resources
-new technology can offset scarcity of minerals and arable land by
using existing resources more efficiently and substituting new
resources for scarce ones
Esther Boserup and Simon Kuznets—feel higher human population
may stimulate economic growth and therefore produce more food
-can the Earth produce more food than it does now?
Julian Simon—says that more people means more brains to invent
new ideas which will improve life
Marxist Friedrich Engels argued that the Earth has sufficient
resources to eliminate global hunger and poverty
-believes that capitalism causes hunger and poverty because
workers do not have enough food because they do not
control the production and distribution of food and they are
not paid sufficient wages
Many argue that a larger population creates more consumers that
can create greater demand for goods which can result in more
jobs
Many African political leaders feel that increased population means
more power as more young people are able to serve in the armed
forces
Malthus Theory and Reality
Vaclav Smil—geographer who has found that food production has
consistently grown at a faster rate than the natural increase rate
since 1950
Reasons Why Food Production Has Grown Faster Than Malthus
Theorized:
1. Better growing techniques
2. Higher yielding seeds
3. Cultivation of more land
Many people around the world cannot afford food or they do not
have access to food sources, but these are in reality problems of
wealth distribution rather than insufficient global production of
food
Population has not grown as fast as Malthus predicted
-he expected population to hit 10 billion by 2000, but it has
reached only 6 billion
-he did not see cultural, economic, or technological
advancements that helped more countries enter Stages III
and IV of the demographic transition
During the 1990s, the world NIR dropped from 1.8% to 1.3%
-from 2.1 to 1.6% in LDCs
-from .5 to .1% in MDCs
Despite a lower NIR during the 1990s, the population base was
broader, so overall population continues to rise
Reasons for Declining Birth Rates:
Two Ways NIR can Decline:
1. Lower CBR
2. Lower CDR
Lower NIR has been a result of lower CBR, but in some sub-Saharan
African countries higher CDRs have lowered NIR (AIDS)
Two Ways Used to Help Reduce Birth Rates:
1. Economic Development
2. Distribution of Contraceptives
Varied economic and cultural conditions cause variations among
countries
Economic Development:
A wealthier community has more money to spend on education and
health-care programs that would promote lower birth rates
-get more women to attend school and remain in school later
-more likely to learn employment skills
-gain more economic control over their lives
Help to make more informed choices about reproduction
Improved health-care programs will improve infant mortality rates
-improved pre-natal care
-education about sexually transmitted diseases
-child immunization
More children surviving will likely cause women to have fewer
overall children
Angola is a country in sub-Saharan Africa which is typical of LDCs and
is an area of concern for high population growth
Angola’s population pyramid shows typical
Stage II high growth
Longer life expectancy shows that although
birth rates remain high, people are living
longer (likely due to introduction of new
medicines)
Angola Total Fertility Rate
TFR seems to be leveling
Demographers project that
Angola will move into Stage III
(Moderate Growth) as TFR
begins to lower
People will continue to live
longer
More babies will survive
Less babies will be born
Distribution of Contraceptives—can cause a rapid decline in CBR
-in LDCs, demand for contraceptive devices is greater than supply
Bangladesh:
-in 2000, about 50% of women used contraceptives
-in 1975, only 6% of women used contraceptives
In areas of Africa and SW Asia, the percentage of women using
contraceptives is still very low
Women here receive less education and have fewer political rights
Women here regard having a large number of children as a measure
of higher status
Men here also regard having many children as a sign of their own
virility
Many religions also oppose some or all birth control devices
-Roman Catholics -fundamentalist Protestants -Muslims -Hindus
Government regulations (such as in China’s one-child policy) have
also rapidly lowered NIR rates
Analysts agree using both methods would be the best way to lower
CBR
World Health Threats:
Areas of sub-Saharan Africa have had declining NIR despite higher
CBR because of higher CDR (caused by AIDS)
Epidemiologic transition: focuses on distinctive causes of death in
each stage of the demographic transition
epidemiology—branch of medical science concerned with
the incidence, distribution, and control of diseases that
affect large numbers of people
EPIDEMIOLOGIC TRANSITION
Stage I—Pestilence and Famine
-principal causes of human death in this stage is infectious and
parasitic diseases, accidents, attacks by other animals and other
humans
Black Death (Bubonic Plague)—history’s most violent Stage I
epidemic
-about 25 million Europeans died between 1347 and 1350
(about half of the continent’s entire population)
The Black Death had a large effect on
human population and can be seen in large
scale population growth charts
EPIDEMIOLOGIC TRANSITION
Stage II—Receding Pandemics
Pandemic: disease that occurs over a wide geographic area and
affects a very high proportion of the population
-improved sanitation, nutrition, and medicine during the Industrial
Revolution reduced the spread of infectious diseases
Cholera: killed 500,000 in New York City in 1832
-killed 20% of the population of Cairo, Egypt in 1931
Dr. John Snow—(1813—1858)
Used geographic methods to show the spread of cholera
He mapped the deaths from cholera in 1854 in the poor London
neighborhood of Soho
Many felt the victims were being punished for sinful behavior
-being poor at this time was also considered a sin
Snow overlaid a map of the distribution of cholera victims with a
map showing the distribution of water well pumps
-these wells were being used by the poorer people for
drinking, cleaning, and cooking
Snow’s findings
showed a large
percentage of victims
were clustered near one
particular pump
Water tests from this
pump proved the water
was contaminated
Water pumps were
reconstructed to avoid
contamination
EPIDEMIOLOGIC TRANSITION
Stage III—Degenerative and human-created diseases
Characterized by less deaths from infectious diseases and an
increase in chronic disorders associated with aging
-includes cardiovascular diseases (heart) and cancers
Many countries are experiencing less deaths from infectious
diseases
-leprosy in Africa—from 483,000 (1990) to 159,000 (1993)
-worldwide polio—from 39,000 (1985) to 6000 (1994)
EPIDEMIOLOGIC TRANSITION
Stage IV—Delayed Degenerative Diseases
Cancers and heart disease spread more slowly as people age
Medical operations (i.e.—heart bypass) and improved health behavior
(i.e.—reduced tobacco use) help to delay degenerative diseases
Possible Stage V—Reemergence of Infectious and Parasitic Diseases
-would result in higher CDR, which could cause irreversible
population decline due to lower CBR and TFR and areas already in
zero population growth
Three Explanations for Possible Stage V:
1. Evolution—infectious disease microbes have evolved and
developed resistance to drugs and insecticides
Malaria: DDT helped reduce malaria from 1 million deaths in
1955 to 18 total deaths in 1963 in Sri Lanka
-now, 2 million deaths in Sri Lanka each year from
DDT resistant mosquitoes that carry malaria
2. Poverty
Tuberculosis (TB)—almost eradicated in MDCs but remains a
major cause of death in LDCs
-TB treatment is an economic strain in many LDCs
3. Improved Travel
-people travel and carry diseases whith them while also being
exposed to others’ diseases
SARS (severe acute respiratory syndrom)—originated in China in
November of 2002
-SARS diffused around the world in just days
-information about SARS was also able to distribute rapidly
-those exposed were quickly quarantined
Terrorism
Some fear that terrorists may be responsible for spreading
infectious diseases
The last smallpox outbreak was in U.S. in 1947
-began with 20 cases in Oklahoma
-within three months, over 1 million died in 25 states
The last smallpox case in U.S. was reported in 1947
-most Americans were inoculated
The last smallpox case in the world was reported in 1977 Somalia
Since the disease has been eradicated, most people have quit
receiving immunization
-makes them susceptible
AIDS—(acquired immunodeficiency syndrome)
Most lethal epidemic in recent years
HIV (human immunodeficiency virus) causes AIDS
-200,000 HIV cases in 1980
-rose to 8 million by 1990
-40 million in 2001
Since 1995, 95% of those with HIV and 99% of new HIV cases have
occurred in LDCs
Sub-Saharan Africa:
-has 11% of world’s population, but 70% of the HIV population
-40% of adults in Botswana have HIV
-5 million in South Africa have HIV
CDR rose sharply in sub-Saharan Africa during 1990s because of AIDS
-Botswana life expectancy from 55 (1980) to 39 (2000)
-Botswana and South Africa both likely to lose population
through 2050
Epidemic diseases such as AIDS will lower world population growth
projections