Lesson 2: Population Dynamics April 6, 2006 ENV H 311: Intro. to Environmental Health 1 ENV H 311: Lesson 2 1 Lesson 2. Population Dynamics Or . . . Health, Disease & Population Growth Chuck Treser Chuck Treser University of Washington University of Washington Dept. of Environmental & Dept. of Environmental & Occupational Health Sciences Occupational Health Sciences Thursday, April 6, 2006 Thursday, April 6, 2006 ENV H 311: Lesson 2 2 Lesson 2 Overview Human population growth Limiting Factors Is Disease a limiting factor? Who is responsible for disease? Consequences of human population growth ENV H 311: Lesson 2 3 World Population Trend
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Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 1
ENV H 311: Lesson 2 1
Lesson 2. Population Dynamics
Or . . .Health, Disease &
Population Growth
Chuck TreserChuck TreserUniversity of WashingtonUniversity of Washington
Dept. of Environmental &Dept. of Environmental &
Occupational Health SciencesOccupational Health Sciences
Thursday, April 6, 2006Thursday, April 6, 2006
ENV H 311: Lesson 2 2
Lesson 2 Overview
Human population growth
Limiting Factors
Is Disease a limiting factor?
Who is responsible for disease?
Consequences of human populationgrowth
ENV H 311: Lesson 2 3
World Population Trend
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 2
ENV H 311: Lesson 2 4
Human life requires:
Air
Food
Water
Habitat
Needs for Survival
ENV H 311: Lesson 2 5
Early Humans
Hunting & gatheringlifestyle provides:
A limited diet
For small bands
Use of a limited range
But, the range couldchange due toenvironmental orother pressures
ENV H 311: Lesson 2 6
Advent of Agriculture
Supported largerpopulations
Farmers are stationary
Motive for Trade
Stockpiling foodsupplies
Vulnerability of foodsupplies
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 3
ENV H 311: Lesson 2 7
Consequences
Water supplies
Source(s)
Contamination
Sewage disposal
Solid wastedisposal
Rodent food
ENV H 311: Lesson 2 8
Animal Husbandry
Close relationship
Proximity tozoonotic (animal)diseases
Food preparationand storagebecomes an issue
ENV H 311: Lesson 2 9
Human DiseaseAnimal with most closely
related pathogen
Measles Cattle (Rinderpest)
Tuberculosis Cattle
Smallpox Cattle (cowpox), Etc.
Influenza Pigs and Ducks
Pertusis Pigs and Dogs
Malaria (falciparum) Birds (Chickens & Ducks?)
Source: Diamond J. Guns, Germs and Steel, 1997
Table 3.1 Examples of Diseases that Human Populations ProbablyContracted from Domesticated Animals
Zoonotic Diseases
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 4
ENV H 311: Lesson 2 10
Poultry 26
Rodents 32
Horse 35
Pig 42
Sheep/Goats 46
Cattle 50
Dog 65
Table 3.2 Number of Diseases that Human PopulationsShare with Domesticated Animals
Source: McNeil WH. Plagues and People, 1977
Zoonotic Diseases
ENV H 311: Lesson 2 11
Cooperative Labor
An assured foodsupply leads to:
Larger populationspossible
Specialization
Organization of
society
In turn leads to . . .
ENV H 311: Lesson 2 12
Development of Cities
New Problems with
Food Supplies
Water Supplies
Wastewater
treatment/disposal
Garbage disposal
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 5
ENV H 311: Lesson 2 13
Trade
Links previouslyunlinked peoples
Leads to Trade Routes
Roads
River and Ocean travel
Speeds and Facilitatesspread of pathogens
ENV H 311: Lesson 2 14
War
Large concentrationsof men
Tends to follow TradeRoutes
Roads
River and Ocean travel
Speeds and Facilitatesspread of pathogens
ENV H 311: Lesson 2 15
Völkerwanderungen
Movement of largepeople groups
Europe from thecollapse of the RomanEmpire to the MiddleAges
Contact withpreviously unknown
Peoples, and
Their pathogens
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 6
ENV H 311: Lesson 2 16
Personal Actions
ClothingProtects skin againstthe elements andsome vectors
Provides harboragefor other vectors
Religous RitesConcentrates people
May encourageunsanitary practices
Pilgrimages
ENV H 311: Lesson 2 17
Urbanization
Concentrates People
Public Works
More people = Moreprojects
Seasonal migration ofworkers
Facilitates spread ofpathogens
ENV H 311: Lesson 2 18
World Population
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 7
ENV H 311: Lesson 2 19
Combat
Vectorborne Diseases
Periodic Famine
Nutritional Deficiencies
Contagious (Crowd) Diseases
Industrial Chemical Toxins
Over-nutrition
Homosapiens
appear
Towns &
Citiesappear
Industrial
Revolution
Source: McMichael AJ. Planetary Overload, 1993
Population Hazards
ENV H 311: Lesson 2 20
Population Constraints
Food Supply (Agriculture)
Water
Security (War or Conflict)
Fertility
Disease
ENV H 311: Lesson 2 21
Two Theses
Disease is an important populationconstraint.
Unchecked population growth,combined with increasing levels ofconsumption and technology canthreaten our environment.
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 8
ENV H 311: Lesson 2 22
“In the course of many years of pre-occupation with
infectious diseases, . . ., we have become
increasingly impressed with the importance --
almost entirely neglected by historians and
sociologists -- of the influence of these calamities
upon the fate of nations, indeed on the rise and fall
of civilizations.”Hans Zinsser, 1935
In Rats, Lice & History
Disease has played an important, but often
unrecognized role in human development
Thesis 1
ENV H 311: Lesson 2 23
Disease
Infectious diseasesevolved withhuman populations
Infectivity
Pathogenicity
Virulence
Evolution continues
ENV H 311: Lesson 2 24
Ancient Diseases
PlaguesE.g., The Ten Plagues of Egypt (~1,500 BCE)
William McNeil, Plagues & People
The Great Herbal (~3,000 BCE)
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 9
ENV H 311: Lesson 2 25
The Classical Period
1,141 BCE:Possibly firstrecord of bubonicplague(1 Samuel 4)
900 BCE: TheGreat Pestilence
430 BCE: TyphusOutbreak inGreece
ENV H 311: Lesson 2 26
The Roman Empire
1st Century BCE: Malariain the Campagna
54 CE: Major pestilence
79 CE:
Vesusvius erupts
Hun invasion
Malaria assaults Rome
100 CE: Hippocrates
125 CE: Locusts attack
165-169 CE: Smallpox?
189 CE: Reoccurrence
250 CE: Cyprian Pandemic
ENV H 311: Lesson 2 27
Europe: The Middle Ages
1250: Little Ice Age
1320s: Bubonic plagueemerges
1347 - 1352: “TheBlack Death”
1600s: Bubonic Plaguepandemic
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 10
ENV H 311: Lesson 2 28
Medieval Europe
Walled TownsWalled Towns
Little tradeLittle trade
Little learningLittle learning
Disease, hungerDisease, hunger
Primitive medicalPrimitive medical
practicespractices
ENV H 311: Lesson 2 29
The 19th Century
Age of Optimism
Industrialization
Rising Prosperity
Trade
Colonialism
ENV H 311: Lesson 2 30
19th Century (Continued)
Exploitation ofnatural resources
Waste Generation
Pollution
Occupationalhazards
Chronic diseases
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 11
ENV H 311: Lesson 2 31
Elsewhere in the World
1331: China: Bubonic Plague
~1519: Smallpox conquers Mexico
1520: Malaria arrives in NorthAmerica
1620: Pilgrims land Plymouth Rock
1630: Measles hits Massachusetts
1740: Smallpox arrives in the PacificNorthwest
ENV H 311: Lesson 2 32
The 20th Century
Increasingindustrialization
Increases tomatchpopulation/demands
Increased wasteand pollution
Global impacts
ENV H 311: Lesson 2 33
Late 20th Century Diseases
0 200 400 600 800 1000
Number of Deaths (in Thousands)
All Other Causes
Pneumonia & Influenza
Accidents
COPD
Cancers
Heart & Circulatory Disease
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 12
ENV H 311: Lesson 2 34
Thesis 2
Environmental threat results from:
1. Increased Population
2. “Modern” Technology
ENV H 311: Lesson 2 35
HumanHuman
PopulationPopulation
GrowthGrowth
““ModernModern””
TechnologyTechnology
Threats to the Environment
ENV H 311: Lesson 2 36
Environmental Threat
I = P x A x T
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 13
ENV H 311: Lesson 2 37
0.0
2.0
4.0
6.0
8.0
10.0
12.0
1750 1800 1850 1900 1950 2000 2050
Developing
Industrialized
Date
Source: World Resources 1994-1995
World P
opula
tion (
in b
illio
ns)
Population
~ 6,470,570,4609:30 a.m. Today
ENV H 311: Lesson 2 38
Production
Consumption
Affluence
ENV H 311: Lesson 2 39
Technology
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 14
ENV H 311: Lesson 2 40
The Basic Question
Are there limits to growth? . . .
Both in terms of:
the total number of people that can be
supported on this planet, and
the use of materials and environmental
resources necessary to sustain them.
ENV H 311: Lesson 2 41
Limits to Growth ?
Malthus & Ricardo
Club of Rome
Garret HardinTragedy of the Commons
Lester Brown World Watch
James Lovelock (Gaia)
ENV H 311: Lesson 2 42
Thomas Malthus
Lived 1766-1834
An Essay on thePrinciple ofPopulation (1798)
Population Growth isexponential
Increase in foodsupplies isarithmetic.
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 15
ENV H 311: Lesson 2 43
Population Growth
Population
Growth
Food Supplies
ENV H 311: Lesson 2 44
David Ricardo
British economist
Diminishing returns onland cultivation.
Suggested theimpossibility of a
“general glut"
an excess supply of allgoods -- in an economy.
ENV H 311: Lesson 2 45
Garret Hardin
1968 essay, Tragedy ofthe Commons
In a crowded world withless than perfect humans,free resources will beoverused.
Ruin is inevitable unlesscontrols are put in place.
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 16
ENV H 311: Lesson 2 46
The “Commons”
ENV H 311: Lesson 2 47
Lester Brown
Started theWorld WatchInstitute devotedto the analysis ofglobal environ-mental issues.
ENV H 311: Lesson 2 48
The Club of Rome
Meadows DH, Meadows
DL, Randers J, Behrens
W. The Limits to
Growth: A Report to
The Club of Rome
(1972).
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 17
ENV H 311: Lesson 2 49
Basic Concepts
The Limits to GrowthLane Co. Council of Governments, c. 1970
ENV H 311: Lesson 2 50
Questions
??
ENV H 311: Lesson 2 51
Club of Rome
Exponential Growth
Five key trendsPopulation Growth
Food Production
Resource Consumption
Industrial Production
Pollution
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 18
ENV H 311: Lesson 2 52
Conclusions of TLG Model
Within 100 years, society will run out ofnon-renewable resources leading to aprecipitous collapse of the economicsystem decreased food production andincreasing death rate.
A piecemeal approach to solving theproblem will not work
Overshoot and collapse can only beavoided by limiting population andpollution.
ENV H 311: Lesson 2 53
Criticism of theLimits to Growth
Pessimistic Assumptions
Technological Advances
Social and Political Factors
The Predictions Haven't HappenedYet
ENV H 311: Lesson 2 54
The Optimist’s View
. . . 200 years ago almost everywherehuman beings were comparatively few,poor and at the mercy of the forces ofnature, and 200 years from now, weexpect, almost every-where they will benumerous, rich and in control of theforces of nature [p. 1].
Kahn H. The Next 200 Years: A Scenario for Americaand the World, 1976.
Lesson 2: Population Dynamics April 6, 2006
ENV H 311: Intro. to Environmental Health 19
ENV H 311: Lesson 2 55
Food
Food production is climbingFood/capita is relatively steady in most of theworld
In Africa food/capita is falling
In Europe food/capita is rising
1.5 billion hectares of land undercultivation in 1990
4.0 billion possibly available
All would be needed by 2050
ENV H 311: Lesson 2 56
Water
Only 10,000 km3 out of 40,000 km3 offresh water is accessible.
3,000 km3 is polluted and undrinkable
Current use ~ 4,000 km3
In many places water tables are falling
Desalinization of sea water is possible butrequires energy