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Unformatted text preview: 11 Estimates of Human Carrying Capacity: A Survey: of Four Centuries The earliest known estimates of how many people the Earth could support formed part of the intellectual explosion of the seventeenth century. William Harvey proved the existence of the circulation of blood in De Motu Cordis (1628), John Graunt began demography and modern statistics in Natural and political observations made upon the bills of mortality ( 1662), Gottfried Leibniz published Ars combinatoria ( 1666) and discovered the fundamental theorem of the infinitesimal calculus ( 1672-76), Antoni van Leeuwenhoek published the first of his letters on microscopy to the Royal Society in the Philosophical Transactions ( 1673), Isaac Newton explained why heavenly bodies move in their orbits in the Principia ( 1687) and John Locke published his Essay on Human Understanding ( 1690). On 25 April 1679, in Delft, Leeuwenhoek wrote down what may be the first estimate of the maximum number of people the Earth can support. Around 1695, Gregory King in London estimated the population that the Earth's "Land If fully Peopled would sustain", in a manuscript notebook first published in 1973. At first a trickling and then a steady stream of estimates of how many people the Earth could support followed these early calculations. More than 65 estimates are summarized briefly in chronological order in Appendix 3. You are encouraged to read Appendix 3 whenever you feel the urge to learn more details about these estimates. ESTIMATES OF GLOBAL HUMAN CARRYING CAPACITY: LEVELS The estimates of how many people the Earth can support vary from less than one billion to more than 1,000 billion. The low estimates indicate that -212- more people are already on the Earth than can be supported (for some time period, usually not stated, in some mode of life considered plausible or desirable by the estimator). Low estimates imply that a decline in human numbers below the present 5.7 billion is inevitable. The intermediate estimates indicate that human numbers are on the verge of exceeding what the Earth can support (again, for some time period, usually not stated, in some mode of life considered plausible or desirable by the estimator). Since the Earth's population would exceed 8.4 billion by 2150 if fertility had fallen to the replacement level in 1990 (Chapter 8), the intermediate estimates of the Earth's maximum supportable human population could range from 5.7 billion toany choice is bound to be arbitraryperhaps 10 billion or 15 billion. The high estimates indicate that the Earth could sustain substantially more than 10 billion or 15 billion people, even as many as 10 or 100 times more (once again, for some unstated time period in some mode of life considered plausible or desirable by the estimator)....
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This note was uploaded on 06/20/2011 for the course EHJ EHJ351 taught by Professor Peterabrams during the Spring '11 term at University of Toronto- Toronto.
- Spring '11
- The Land