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Why might the World face an overpopulation problem?Chapter 2 Key Issue 4Malthus Theory of Population GrowthIn 1798 Thomas Malthus published his views on the effect of population on food supply. His theory has two basic principles:Population grows at a geometric rate i.e. 1, 2, 4, 16, 32, etc. Food production increases at an arithmetic rate i.e. 1, 2, 3, 4, etc.

Malthus (cont.)The consequence of these two principles is that eventually, population will exceed the capacity of agriculture to support the new population numbers. Population would rise until a limit to growth was reached. Further growth would be limited when: preventive checks - postponement of marriage (lowering of fertility rate), increased cost of food etc.positive checks - famine, war, disease, would increase the death rate. Malthus (cont.)

Population grows geometrically.Population exceeds carrying capacityPopulation is kept in check preventative and/or positive checks2. The Malthusian CrisisThe Malthusian crisisAvailable agricultural spaces are limited.Technical progresses (machinery, irrigation, fertilizers, and new types of crops) are slow to occur.Increasing incapability to support the population.If this persists, the population will eventually surpass the available resources.The outcomes are Malthusian crises:Food shortages.Famines.War and epidemics.Fix the population in accordance with available resources.Necessity of a moral restraint on reproduction. Dr. Jean-Paul Rodrigue5Overexploitation2. The Malthusian CrisisPopulationResourcesTechnological InnovationTimeQuantityt2t3t1 Dr. Jean-Paul Rodrigue62. The Malthusian CrisisThe Malthusian Crisis has not occurredMalthus has been criticized on several accounts during the last 200 years.Religious view (Protestantism), racist and elitist.Did not foresee the demographic transition:Changes in the economy that changed the role of children in the industrializing societies.Failed to account for improvements in technology:Enabled food production to increase at rates greater than arithmetic, often at rates exceeding those of population growth.Enabled to access larger amounts of resources.Enabled forms of contraception. Dr. Jean-Paul Rodrigue7Global Growth in Population and Grain (Wheat and Rice) Production, 1961-2005

Dr. Jean-Paul Rodrigue8Source: FAOEsther Boserups Theory of Population GrowthIn contrast to Malthus, instead of too many mouths to feed, Boserup emphasized the positive aspects of a large population;In simple terms, Boserup suggested that the more people there are, the more hands there are to work;She argued that as population increases, more pressure is placed on the existing agricultural system, which stimulates invention;The changes in technology allow for improved crop strains and increased yields.

Anti-populationists vs. pronatalistsMalthus anti-populationistEchoed in recent debates by Paul Ehrlich, author of The Population Bomb;Ehrlich believed that the earths carrying capacity would quickly be exceeded, resulting in widespread famine and population reductions;Boserup pronatalist (cornucopian)Echoed in recent debates by Julian Simon, who opposed Ehrlich by using economic theories; ie. Resources needed to support populations are becoming more abundant, not scarcer;

Possible Stage 5: DeclineLow CBRIncreasing CDRNegative NIR

Large Elderly PopulationLess Young Women having Children High Dependency Ratio---pensions, elder care

The Epidemiologic Character of Population Phenomenaepi, upon; demos, people; logos, study

Epidemiology is the study of what comes upon groups of people.

Epidemiology is concerned with the distribution of disease and death, and with their determinants and consequences in population groups.

1. Epidemiological transitionConceptFocuses on changes over time in the causes of mortality affecting certain populations:Health conditions.Disease patterns.Result in a decline in death rates and an increase of life expectancy.The society goes through a transition from communicative diseases to degenerative diseases.171. Epidemiological TransitionTimeShare of mortalityCommunicative diseasesDegenerative diseasesAge of communicative diseasesAge of receding pandemicsAge of degenerative and man-made diseasesHigh FertilityHigh MortalityHigh FertilityDecreasing MortalityLow FertilityLow MortalityLI=70 yearsLI=50 yearsLI=30 years18The Epidemiologic Transition

The Epidemiologic TransitionStage 1: Pestilence and Famine

Infectious and parasitic diseasesEpidemicsExample Black Plague

High CDRThe Epidemiologic TransitionStage 2: Receding PandemicsImproved sanitation, nutrition, & medicine during Industrial RevolutionRapidly Declining CDR

Fig. 2-23: By mapping the distribution of cholera cases and water pumps in Soho, London, Dr. John Snow identified the source of the water-borne epidemic.Cholera in London, 1854The Epidemiological TransitionStage 3 Degenerative & human-created diseases

Chronic Disorders associated with agingCardiovascular diseases (hear attacks) & cancerModerately Declining CDR

The Epidemological TransitionStage 4: Delayed degenerative diseases

Cardiovascular diseases and cancersBUT life expectancy of older people extended through medical advancesCancer growth retarded or removedBypass to repair cardiovascular systemHigh Obesity ratesNon-nutritious food/sedentary lifestyleLow but increasing CDR

Sprawl & Obesity

Sprawl and Health Concerns

Because this study is ecologic and cross-sectional in nature, it is premature to imply that sprawl causes obesity, hypertension, or any other health condition. Our study simply indicates that sprawl is associated with certain outcomes. Future research using quasi-experimental designs is needed to tackle the more difficult job of testing for causality.

Relationship Between Urban Sprawl and Physical Activity, Obesity, and Morbidity by Reid Ewing, Tom Schmid, Richard Killingsworth, Amy Zlot, Stephen Raudenbush in the American Journal of Health Promotion, Inc., September/October 2003, Vol. 18, No. 1The Epidemiological TransitionStage 5 Reemergence of infectious & parasitic diseases

EvolutionAntibiotics and genetic engineeringEmergence of new strains of viruses and bacteriaPovertyUnsanitary conditions in developing countriesIncreased ConnectionsSpreads from Developing to developed countries

HIV/AIDS Prevalence Rates, 2005Fig. The highest HIV infection rates are in sub-Saharan Africa. India and China have large numbers of cases, but lower infection rates at present.Health CareIndicators of HealthInfant Mortality rateLife ExpectancyProvision of Health CareHealth Care expendituresAvailable Medical Services Fig. 2-10: The infant mortality rate is the number of infant deaths per 1000 live births per year. The highest infant mortality rates are found in some of the poorest countries of Africa and Asia.Infant Mortality RatesFig. 2-11: Life expectancy at birth is the average number of years a newborn infant can expect to live. The highest life expectancies are generally in the wealthiest countries, and the lowest in the poorest countries. Life Expectancy at birthHealth Care per Capita

Government Expenditures on Health Care