Increasing Human Population

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Increasing Human Population

• The Greatest Environmental Problem
• Spring 2012, Lecture 2

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US Census Bureau Population Estimate
Click link below to see Latest Census Bureau
Estimate of U.S. and World Populations
United State Population Clock
World Population Clock
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United Nations Population Division 2012
Estimates
Year Population Year Population
1950 2 529 229 2005 6 506 649
1955 2 772 982 2010 6 895 889
1960 3 038 413 2015 7 284 296
1965 3 331 007 2020 7 656 528
1970 3 696 186 2025 8 002 978
1975 4 076 419 2030 8 321 380
1980 4 453 007 2035 8 611 867
1985 4 863 290 2040 8 874 041
1990 5 306 425 2045 9 106 022
1995 5 726 239 2050 9 306 128
2000 6 122 770
In thousands
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2050 Population Estimates
Year of Estimate Low variant Medium variant High variant Constant fertility variant
2002 7 408 573 8 918 724 10 633 442 12 753 513
2005 7 679 714 9 075 903 10 646 311 11 657 999
2008 7 958 779 9 149 984 10 461 086 11 030 273
2012 8 112 191 9 306 128 10 614 318 10 942 544
In thousands
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Thomas Malthus (1798) An Essay on the
Principle of Population

• Populations grow geometrically while supporting
  resources grow arithmetically
• Population, if not purposefully checked
  (preventative checks), would outpace resources
  and lead to unplanned positive checks that
  would return population to sustainable levels

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Significant Developments and Human Population
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Recent Population Explosion

• Detailed look at the last thousand years

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Crop Yield and Fertilizer Input

• Green revolution
• high-yielding crop varieties
• chemical fertilizers
• pesticides
• irrigation
• mechanization

Global Fertilizer use
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Humans Have

• Transformed or degraded 39-50 of the Earth's
  land surface
• Increased atmospheric CO2 concentration by 40
• Overexploited or depleted 22 of marine fisheries
  
• 44 more are at the limit of exploitation

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New South Wales, Australia
Figure shows the trend in the total catch for
marine fisheries in NSW since 198485.
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Changes Due to Man

• About 20 of bird species have become extinct in
  the past 200 years, almost all of them because of
  human activity
• Man uses more than half of the accessible surface
  fresh water
• On many islands, more than half of plant species
  have been introduced by man
• On continental areas, man has introduced 20 or
  more of the plant species present

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Human Activities

• Over 50 of terrestrial nitrogen fixation is
  caused by human activity
• Use 8 of the primary productivity of the oceans
  (25 for upwelling areas and 35 for temperate
  continental shelf areas)

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Changes Due To Man
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Population and Availability of Renewable
Resources
Total
Per Capita
1990
2010
Change ()
Change ()
Population (millions)
5,290
7,030
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Fish Catch (million tons)
85
102
20
-10
Irrigated Land
237
277
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-12
(million hectares)
Cropland (million hectares)
1,444
1,516
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-21
Rangeland and Pasture
3,402
3,540
4
-22
(million hectares)
Forests (million hectares)
3,413
3,165
-7
-30
Source Postel, S. "Carrying capacity Earth's
bottom line." State of the World, 1994.
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Regional population patterns Population density
Consortium for International Earth Science
Information Network.
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Doubling Times
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Doubling Time Map - 2000
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Worldwide Fertility, 2005

• Children per woman

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Reduction in Childhood Death Rates

• DDT used against mosquitoes that transmit malaria
• Childhood immunization used against cholera,
  diphtheria, etc.
• Antibiotics used against bacterial infections

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Demographic Transitions

• When a country moves from stage 1 of the
  demographic model to stage 2, a population
  explosion occurs
• This transition occurs when technology and
  medical care improvements decrease a countries
  death rate dramatically while the birth rate
  stays the same this causes the natural rate of
  increase to increase rapidly

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Demographic Transition -Sweden
Rate of Natural Increase
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Demographic Transition -Mexico
Rate of Natural Increase
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National Age Structures

• The proportion of individuals in different age
  groups has a significant impact on the potential
  for future population growth
• Mexico large fraction of young people likely to
  reproduce in the near future
• Sweden even distribution of population through
  all age groups, and many people beyond prime
  reproductive years
• United States even distribution except for
  bulge due to post WWII baby boom

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Age Structures

• Each horizontal bar is a five-year cohort
• Blue pre-reproductive, yellow reproductive,
  and orange post-reproductive

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People over 100 years old in U.S.
4,000 in 1970
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People over 100 years old in U.S.

• 79,086 in 2010

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People over 100 years old in U.S.
Projected 597,547 thousand in 2050
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Trends in U.S. Population
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2008 Population Projections
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Global Income Distribution, 1960 - 1989
Share of Global Income Going To Share of Global Income Going To
Year Richest 20 Poorest 20 Ratio of richest to poorest
1960 70.2 2.3 30 to 1
1970 73.2 2.3 32 to 1
1980 76.3 1.7 45 to 1
1989 82.7 1.4 59 to 1
Source United Nations Development Programme,
Human Development Program, 1992 (New York, Oxford
University Press, 1992)
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Global Income Distribution Graphic
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Global Wealth Pyramid, 2011
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Food Distribution Animation
http//vimeo.com/moogaloop.swf?clip_id8812686
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China - 20 of worlds population

• Potential for rapid population growth
• 2000 1,263,637,531

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China "one-child-per-couple" policy since 1979

• Rewards for having only one child grants,
  additional maternity leave, increased land
  allocations. Children get preferential treatment
  in education, housing, and employment.
• Couples punished for refusing to terminate
  unapproved pregnancies, for giving birth when
  under the legal marriage age, and having an
  approved second child too soon.
• Penalties include fines, loss of land grants,
  food, loans, farming supplies, benefits, jobs and
  discharge from the Communist Party.
• In many provinces sterilization is required after
  the couple has had two children.

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Chinas Population Policy Children per
woman 1970 5.01 1995 1.84 Population still
growing! Population in 2000 1.3 billion
Projected for 2025 1.5 billion
Use of abortion Forcible abortions and
sterilization Infanticide
Criticisms
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China 2025

• Approaching stabilization
• 2025 1,394,638,699

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China 2050

• Possible decline in population
• 2050 1,303,723,332

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India
2000 1,006,300,297
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India 2025

• 2025 predicted 1.396.046.308
• The base is narrower than the top

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India 2050

• 2050 predicted 1,656,553,632
• A definite baby-boom shape
• Note disparity male/female numbers

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U.N. Conference on Population (Cairo, 1994)
"Programme of Action" (182 nations)
Goal to stabilize human population at 7.8
billion by 2050
1. Provide universal access to family-planning
and reproductive health programs. 2. Recognize
that environmental protection and economic
development are not necessarily antagonistic.
Promote free trade, private investment and
development assistance. 3. Make women equal
participants in all aspects of society - by
increasing women's health, education, and
employment. 4. Increase access to education.
Provide information and services for adolescents
to prevent unwanted pregnancies, unsafe abortion,
and the spread of AIDS and sexually transmitted
diseases. 5. Ensure that men fulfill their
responsibility to ensure healthy pregnancies,
proper child care, promotion of women's worth and
dignity, prevention of unwanted pregnancies, and
prevention of the spread of AIDS and sexually
transmitted diseases.
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• United Nations Population Fund (UNFPA)
• Programs to improve
• Pre- and post-natal mother's health
• Access to voluntary family planning programs and
  contraception
• STD and HIV education and prevention
• U.S. funding withheld for many years because of
  UNFPAs support of Chinas policies
• U.S. funding restored for F.Y. 2000 at level of
  25 million

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Slowing Population Growth

• The HIV epidemic is measurably slowing population
  growth
• Nowhere is this more evident than in sub-Saharan
  Africa, a region of 800 million people, where the
  epidemic is spiraling out of control
• If a low-cost cure is not found soon, countries
  with adult HIV infection rates over 20 percent,
  such as Botswana, South Africa, and Zimbabwe,
  will lose one fifth or more of their adult
  population to AIDS within the next decade

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Slowing Population Growth

• When the United Nation's demographers did their
  biennial update of world population numbers and
  projections in October of 1998, they reduced the
  projected global population for 2050 from 9.4
  billion to 8.9 billion in 2009, it is 9.1
  billion
• Of this 500 million drop, two thirds was because
  of falling fertility - that's the good news
• The bad news is that one third of the fall was
  the result of rising mortality from AIDS