Population theory

http://www. greenberg-art. com/. Toons/ http://www.greenberg-art.com/.Toons/.Toons,%20Environ/PopulationTrain.html

Demographic Transition Theory 1900 1800 1700 Stage I Stage II Stage IV Stage III Birth Rate Death Rate 2000 Demographic Growth Population

1. Epidemiological transition Concept Focuses 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.

1. Epidemiological Transition Age of communicative diseases Age of receding pandemics Age of degenerative and man-made diseases Degenerative diseases Share of mortality Low Fertility Low Mortality High Fertility High Mortality LI=70 years LI=30 years LI=50 years Communicative diseases High Fertility Decreasing Mortality Time

Malthus’ Theory of Population Growth In 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 capacity… Population is kept in “check”– preventative and/or positive checks

2. The Malthusian Crisis The “Malthusian crisis” Available 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.

2. The Malthusian Crisis Resources Population Quantity Technological Innovation t1 Resources Overexploitation Time

2. The Malthusian Crisis The Malthusian Crisis has not occurred Malthus 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.

Global Growth in Population and Grain (Wheat and Rice) Production, 1961-2005 Source: FAO

Esther Boserup’s Theory of Population Growth In 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. pronatalists Malthus– anti-populationist Echoed in recent debates by Paul Ehrlich, author of The Population Bomb; Ehrlich believed that the earth’s 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;

Singapore Population Policy http://hs-esl. ism-online

Singapore Population Policy