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Global Environmental & Human Health Issues. Molly Kile, ScD ENVRE-115 Fall 2009. Announcements. More features added to the course website http://isites.harvard.edu/icb/icb.do?keyword=k64179&pageid=icb.page286023 - PowerPoint PPT Presentation
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Global Environmental & Global Environmental & Human Health IssuesHuman Health Issues
Molly Kile, ScDENVRE-115
Fall 2009
AnnouncementsAnnouncements
• More features added to the course website
http://isites.harvard.edu/icb/icb.do?keyword=k64179&pageid=icb.page286023
• Assessment of class participation will depend on in-class participation, live chat sessions, blog entries, and personal communications with teaching staff
• For book report can select texts from “Additional Books To Consider” in syllabus or one of your own choosing if given instructor approval.
• Pedagogical goal of assignments is to foster critical thinking which involves comparing, contrasting and synthesizing what one has learned which requires being open to new knowledge and actively reflecting on its meaning.– Homework #2 is due September 22– Use the drop box to submit your assignments. If you emailed in your
assignment you should go back and put it in the drop box.
Logistics of Distance EducationLogistics of Distance Education• Lecture is available as a live streaming feed during class period
and are also archived after processing (< 48 hrs)
• Chat room is monitored during class
• If you live outside of the New England area you must arrange for proctored midterm and final exam a minimum of two weeks prior to scheduled exam dates– http://www.extension.harvard.edu/2009-10/DistanceEd/how-it-
works/policy.jsp
Economic LiteracyEconomic Literacy
• There is no formal (only suggested) economics prerequisite for this course
• Check your economic literacy and review concepts by taking the “Economic Literacy Self Assessment” on the course website. You should be familiar with these terms and concepts before the lecture on October 13.
• If you need or want to review economic terminology you can use any undergraduate economics textbook or the “Guidelines for Preparing Economic Analyses” by the US EPA.– http://yosemite.epa.gov/ee/epa/eed.nsf/webpages/Guidelines.ht
ml
Agenda For TodayAgenda For Today
• Drivers of environmental issues
• Underlying Ecological Principles
• Demographic and Epidemiological Transition
• Linkage between human health and development
• Demographic dividend
Ecological Footprint ResultsEcological Footprint ResultsQuestion 5 If everyone lived like you, how many planets would we need?A. 1B. 2C. 3D. 4E. 5F. 6G. more than 6
Total
0% 5% 10% 15% 20% 25% 30%
G. F. E. D. C. B. A.
This means it takes 36 more months for the Earth’s ecosystems to regenerate what we are using in a single year.
Global Human FootprintGlobal Human FootprintAs of 2003, exceeded the Earth’s biocapacity by ~25% As of 2003, exceeded the Earth’s biocapacity by ~25%
(WWF)(WWF)
For how long can this go on?• Humanity’s demand will be twice the biosphere’s productive
capacity in 2050• A moderate business-as-usual scenario, based on United Nations
projections of slow, steady growth of economies and populations
Drivers of environmental Drivers of environmental issuesissues
POPULATION DRIVERPOPULATION DRIVERIn the past 200 years, the global population has increased exponentially
Math Behind Exponential Math Behind Exponential GrowthGrowth
Consider a country with 100 people, growing at 7% per year. In 10 years, the population will double to 200 people, in another 10 years it will double again to 400 people, etc (see graph)
How long will it take this country to reach 1 million?
0.00200,000.00400,000.00600,000.00800,000.00
1,000,000.001,200,000.001,400,000.001,600,000.001,800,000.00
0 20 40 60 80 100 120 140
Years
Pop
ulat
ion
t = ln [N(t)/N(0)] / r
t = ln (1,000,000/100)/0.07t = ln (10,000)/0.07t = 9.2103/0.07t = 131.5 years
Doubling Time (The Rule of 70)Doubling Time (The Rule of 70)
• The basic differential equation for exponential growth: dN/dt = rN, over the period from t=0 to t = the time period in question, where N is the quantity growing and r is the growth rate
• The integral of this equation is Nt = N0 x ert where N(t) is the size of a quantity after t intervals have elapsed, N(0) is the initial value of the quantity, e is the base of the natural logarithm, r is the average growth rate over the interval in question, and t is the number of intervals
• If one knows the final and initial values of N and the average growth rate, one can find the time it takes at that average growth rate for the quantity to grow from its initial value to the final value
t = ln [ N(t)/N(0) ] / r
• A special case is the doubling time, which is the time when N(t)/N(0) = 2. At that point rt = ln 2 = 0.69. If one knows the growth rate as a decimal fraction, then the Doubling Time = 0.69 / r.– This can be further simplified…the Rule of 70If the growth rate is given in percent, then 0.69 must be multiplied by
100, and the doubling time = 69/r. This can then be rounded up to 70. This simplifies to:
Amount of time for population to double = 70/rate expressed as a percentage
ExamplesExamples
1. How long would it take for a population to double if the growth rate is 3.5%?
Doubling Time
Time = 70/3.5 = 20 years
2. In a country where the GDP is growing at 4.5% per annum and the population is growing at 1.0 % per annum, how long will it take for the per capita GDP to double?
Doubling time = 70/(4.5%-1% ) = 70/3.5 = 20 years
3. In 1971, global population was 3.8 million and it is currently 6.8 million. What was the global population growth rate during this time frame?
Doubling Time
Time= 70/rate(%)36 years = 70/raterate = 70/36rate= 1.9%
AFFLUENCE & TECHNOLOGY AFFLUENCE & TECHNOLOGY DRIVERSDRIVERS
Global Income Distribution
Global distribution of income by economic Global distribution of income by economic classclass
Source: Sutcliffe, 2005. Department of Economic and Social Affairs.WP 2. United Nations
Influence of economic status on resource use
Consumer Preferences
• Increasing wealth changes pattern of demand and ability to afford reducing externalities
• Kuznets curve illustrates the relationship between economic development and environmental degradation
Economics & Environmental Economics & Environmental Degradation Degradation (Kuznet’s Curve)(Kuznet’s Curve)
Stage 1 Stage 2
Start ofindustrialdevelopment
Initiation ofemissionscontrol
Stabilizationof air quality
Stage 3 Stage 4
Improvement of air quality
High Technology applied
Low Level of development High
Development of air pollutionproblems in cities according to development status
WHO Guideline ornational standard
Stage 0
Relationship between air pollution problems in cities and the level of development. As a city experiences development, the air pollution problems in the city increase rapidly, before stabilizing and declining as air pollution controls are implemented (Source: Based on Haq et al, 2002; Peters 2003)
Examples of Kuznet’s CurveExamples of Kuznet’s Curve
Ehrlich Identity: I=PATEhrlich Identity: I=PAT
• Environmental Impact is a multiplicative product from small changes in Population, Affluence and Technology
• Mathematically represented as:
(I + ΔI) = (P + ΔP)(A + ΔA)(T + ΔT)
Divide through by the identity (1 + ΔI/I) = (1 + ΔP/P)(1 + ΔA/A)(1 + ΔT/T)
Where ΔI/I, ΔP/P, and ΔT/T is the percentage increase in impact, affluence and technology
Quantifying ImpactQuantifying Impact
• Example: Lead in gasoline from 1946 to 1968 in the US– Pop. increased 42%– Vehicle mile per capita doubled– Amount of lead per vehicle mile increased 81%
(I + ΔI/I) = (P + ΔP/P)(A + ΔA/A)(T + ΔT/T)
(1 + ΔI/I) = (1 + 0.42)(1 + 1.0)(1 + 0.81)
(1 + ΔI/I) = 5.14
ΔI/I = 5.14 – 1
=4.14
Or 414% increase in lead
Population Impact Depends on Underlying Distribution
6.0 millionMentally Deficient
6.0 millionMentally Gifted
Population Impact of Subclinical Lead Toxicity
9.4 millionMentally Deficient
2.4 millionMentally Gifted
57% Increase inMentally Deficient
Population
Underlying Ecological Underlying Ecological PrinciplesPrinciples
Carrying CapacityCarrying Capacity
• Ecological definition:– the number of individuals in a population that the
resource of a habitat can support
• Other definitions:– Point at which the birth rate equals the death rate– The number of individuals an environment can support
without significant negative impacts– The population size is constrained by whatever resource
is in shortest supply (Malthus)
Tragedy of the [Unregulated] Tragedy of the [Unregulated] CommonsCommons
Garrett HardinGarrett Hardin
“Picture a pasture open to all. It is to be expected that each herdsman will try to keep as many cattle as possible on the commons. Such an arrangement may work reasonably satisfactorily for centuries because tribal wars, poaching, and disease keep the numbers of both man and beast well below the carrying capacity of the land.”
What are the consequences of adding one more animal to my herd?
• “The population problem has no technical solution; it requires a fundamental extension in morality.”
Science 1968
OvershootOvershoot
• A rapidly growing population can exceed (overshoot) the ecological carrying capacity due to the “momentum” of its growth.
• Indicators of Overshoot– Deterioration in renewable resources – Rising levels of pollution– Growing demands by military and
industry to secure resources– Investment in human capital
postponed to meet immediate consumption demands
– Rising debt– Eroding goals for health and
environment – Growing instability in natural
ecosystems– Growing gap between rich and poor
Ecological EvidenceEcological Evidence
In 1944, 29 reindeer were introduced to St. Matthew Island.
In 1963, there were 6,000. One winter later, there were less
than 50. By 1980, there were none.
Klein, 1968
Human Population GrowthHuman Population Growth
Factors that influence human population growth:
• Fertility
• Age structure of population
• Mortality
FertilityFertility
• Birth rate is defined as the number of live births per 1,000 women aged 15-49 in a given year
• Replacement level fertility– Net reproduction rate of 1
• Every woman of childbearing age has 1 daughter
– Total fertility rate of 2.1• Every woman of childbearing age has 2.1 children
Fertility Rates Are Fertility Rates Are DecliningDeclining
Average number of children per woman
5.75.25.4
6.46.4
8.5
5.3
3.3
6.2
3.1
2.4 2.1
4.3
2.5
Egypt India Indonesia Iran Pakistan Turkey Yemen
1970-1975 2000-2005Source: United Nations, World Population Prospects: The 2004 Revision, 2005.
Four factors that influence Four factors that influence fertilityfertility
1. The proportion of women of childbearing age who are married or in a sexual union
2. The percent of women using contraception and the level of abortion
3. The proportion of women of childbearing age who currently are unable to conceive a child (usually from postpartum infecundity from breastfeeding)
4. Educational attainment of girls and women
Association Between Fertility and Association Between Fertility and Education of GirlsEducation of Girls
0
20
40
60
80
100
120
0 1 2 3 4 5 6 7 8
Percent of Girls Enrolled in Secondary School
Source: Population Reference Bureau, Population & Economic Development Linkages 2007 Data Sheet.
Total Fertility Rate
Association Between Fertility and Association Between Fertility and Female Labor Force ParticipationFemale Labor Force Participation
0
20
40
60
80
100
0 1 2 3 4 5 6 7 8
Female Labor Force Participation Rate 2004
Source: United Nations, World Population Prospects: The 2004 Revision, 2005; International Labor Organization, Yearbook of Labor Statistics 2006.
Total Fertility Rate 2000-2004
Association between fertility and Association between fertility and wealthwealth
6.4
4.9
4.1
4.9
3.2
2.42.8
2.4
1.4
Ghana 2003 Cambodia 2005 Colombia 2005
Poorest Quintile Middle Quintile Richest Quintile
Average Number of Children Born to a Woman During Her Lifetime
Source: ORC Macro, Demographic and Health Surveys.
2. Age Structure of a 2. Age Structure of a PopulationPopulation
• A large proportion of young people guarantees that population will continue to grow even with declining fertility
• Takes two or three generations (70-100 years) before each new birth is offset by a death
• Referred to as population momentum
Population MomentumPopulation MomentumThere is a growing population of women in their childbearing
years that will contribute to future world population growth even if fertility continues to decline
0.6
0.9
1.82.0 2.0
1.3
0
1
2
3
1950-1955 1970-1975 1990-1995 2010-2015 2030-2035 2045-2050
Bill
ion
s
0
1
2
3
4
5
6
Ch
ildre
n p
er
wo
ma
n
Women 15 to 49 Average number of children per woman
Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.
3. Mortality3. Mortality
• Death is the ultimate determinant of population growth
• Falling mortality precedes a decline in fertility
Death rate
Population growth rate
Birth rate
Time
Rat
e
How To Shift Causes of How To Shift Causes of MortalityMortality
• Improved sanitation and drinking water supplies
• Medical advances (vaccination, antibiotics)
• Social advances (improved nutrition, access to health care)
• Occupational Health & Safety (injury prevention, chemical safety)
• Infrastructure Improvements (roadways, housing, energy)
• Consumer Safety (injury prevention, chemical safety)
• Economic growth
Demographic TransitionDemographic Transition
Human HealthHuman HealthAnd DevelopmentAnd Development
Epidemiological TransitionEpidemiological Transitionthe study of factors affecting the health and illness of
populations • Conceptually describes the interaction
between causes of mortality, life expectancy and development
Mor
talit
y Ra
tes
Infectiousdiseases
Epidemiological Transition
Non-communicablediseases
Systematic Shift in Disease
Systematic Shift In DiseaseSystematic Shift In DiseaseM
orta
lity
Rate
s
Infectiousdiseases
Socio-Economic Development
Trauma
Type 2Diabetes
CHDCancers
PremisePremise
• Fertility has a fixed upper limit but not mortality so mortality is the fundamental factor that controls population dynamics
• Diseases and injuries control mortality
• Investment in public health shifts the causes of death (Epidemiological Transition) and this will influence population structure where women and children benefit the most
• During the late phase of the demographic transition when fertility and dependency rates fall countries can harness the demographic dividend when output per capita rises
Stages in Epidemiological Stages in Epidemiological TransitionTransition
1. The Age of Pestilence and Famine– Mortality is high and fluctuating no sustained
population growth– Life expectancy between 20-40 years
2. The Age of Receding Pandemics– Epidemics less frequent high population growth– Life expectancy between 30-50 years
3. The Age of Degenerative and Man-Made diseases– Mortality declines and stabilizes at a low level
fertility rate determines population growth– Life expectancy exceeds 50 years
Influence of Municipal Water on Influence of Municipal Water on MortalityMortality
Sewer system built & expanded
Reservoir/Aqueduct expansionsProtected watersheds
Public Health Benefits From Municipal Water Public Health Benefits From Municipal Water SupplySupply
• US from 1900-1940– Cholera and Typhoid Fever eliminated– Total mortality 140 to 20 per 100,000– Child mortality
130 to 60 per 1,000 live births – Life expectancy
16 years
• Cost-benefit analysis conducted by Cutler & Miller, 2005– 1:23 cost-benefit ratio – Every life saved cost $500* resulting in $11,500
gain* 2002 US$
The Age of Receding PandemicsThe Age of Receding Pandemics
Morbidity and mortality associated with level of developmentMorbidity and mortality associated with level of development
http://www.nytimes.com/2007/11/26/nyregion/26manhole.html
Age of Degenerative & Man-Made diseasesAge of Degenerative & Man-Made diseases
LEADING CAUSES OF DEATH, US 20021. Heart disease 28.5%2. Cancer 22.8%3. Stroke 6.7%4. COPD 5.1%5. Accidental injury 4.4%6. Diabetes
3.0%7. Influenza/Pneumonia
3.7%8. Alzheimer’s disease
2.4%9. Kidney disease 1.7%
The Changing Built Environment•Rapid population growth•Urbanization•Sprawl•Traffic•Sedentary life style•Changing diet
Less Density = More Driving Less Density = More Driving
Miles per capita– more than Miles per capita– more than doubled in one generationdoubled in one generation
Miles per Capita: 1960 to 1995 From 4000 to 9200 VMT per person
Obesity* Trends Among U.S. AdultsObesity* Trends Among U.S. AdultsBRFSS, 2003BRFSS, 2003
(*BMI ≥30, or ~ 30 lbs overweight for 5’ 4” person)
No Data <10% 10%–14% 15%–19% 20%–24% ≥25%
Case Study: People’s Case Study: People’s Republic of ChinaRepublic of China
Harnessing a Demographic DividendHarnessing a Demographic Dividend
• China began investing in social development projects including education and health care under Maoist Government
– 1952-1982: Invested in rural health through network of clinics and ‘barefoot’ doctors
• Infant mortality decreased from 200 to 34/1000 live births• Life expectancy rose from 35 years to 68 years• Fertility rates declined from 6 births/woman (1970) to 3
birth/woman(1979) to “one child” policy in 1980• Universal primary education
– 1980s saw major economic reform characterized by deregulation and liberalization opened up their economies to international trade and attracted foreign investment.
• People born in the 1965 cohort with improved health care and education are now in their 40’s and in their productivity peak
• Harnessed demographic dividend due to low ratio of dependents to adults below 65
• 2005 GDP growth was 9%
• 1/3 of income growth per capita in SE Asia (about 2 percentage points) during 1965-90 is attributable to the independent influence of changes in age structure Cover from the book by David Cork and Susan Lightstone:
The Pig and the Python, How to Prosper from the Aging Baby Boom
http://www.iiasa.ac.at/Research/LUC/ChinaFood/data/anim/pop_ani.htm
Period of Potential Demographic BonusPeriod of Potential Demographic Bonus
• Countries with increasing numbers of working-age adults relative to dependent elderly and children have an opportunity to increase employment, investment, and savings
• Whether or not the demographic bonus is realized depends on economic policies and economic opportunities
1989 2011
1980 2008
1986 2050
1964 2024
1974 2047
1965 2014
1969 2037
1965 2013
2005 2050
1985 2048
2014 2050
1950 1975 2000 2025 2050
Chad
Ghana
Malawi
China
India
South Korea
Bolivia
Brazil
Guatemala
Czech Republic
Poland
Source: Population Reference Bureau, Population & Economic Development Linkages 2007 Data Sheet.
SummarySummary
• Environmental Impact is a multiplicative function of population, affluence and technology. These drivers can have a neutral, positive or negative impact on the environment.
• Population growth is a central issue in sustainable development due to concerns about ecological carrying capacity of species and it is considered a problem with a non-technical solution
• Fertility has a fixed upper limit (and is controlled effectively by education of girls/women) but not mortality so mortality ultimately controls population growth and demographics
• Causes of mortality are associated with level of development
• Investment in public health shifts the causes of death (Epidemiological Transition) and this will influence population structure (Demographic Transition) where women and children benefit the most
• When fertility and dependency rates fall countries can harness the demographic dividend when output per capita rises
Terminology and Concepts To Terminology and Concepts To ConsiderConsider
1. Erhlich Identity
2. Kuznet’s Curve
3. Tragedy of the Commons
4. Carrying Capacity
5. Overshoot and Population Momentum
6. Demographic Transition
7. How patterns of disease influence demographics (Epidemiological Transition)
8. Role of fertility, age structure and mortality in population growth
9. Population momentum can lead to demographic dividend
ResourcesResources
• “Improving the health of the world's poor” BMJ No 7107 Volume 315– http://www.bmj.com/archive/7107/7107e1.htm
• Population health in transition by John Caldwell– http://whqlibdoc.who.int/bulletin/2001/issue2/79(2)159-170.pdf
• World Health Reports– http://www.who.int/whr/en/
• Preventing disease through healthy environments: Towards an estimate of the environmental burden of disease– http://www.who.int/quantifying_ehimpacts/publications/preventingdiseas
e.pdf• Health and Economic Growth: Findings and Policy Implications.
Edited by G. López-Casasnovas, B. Rivera and L. Currais. MIT Press– http://mitpress.mit.edu/catalog/item/default.asp?ttype=2&tid=10711
• Why Has China’s Economy Taken Off Faster than India’s? David E. Bloom, David Canning, Linlin Hu, Yuanli Liu, Ajay Mahal, and Winnie Yip– http://www.hsph.harvard.edu/pgda/Bloom_Canning_China_India.pdf
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