Jan 24 12 ENV222 lecture format.doc.docx

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School of Environment
Kenneth Mac Donald

ENV222 Jan. 24 Population growth Lecture format 1. The phenomenon of population growth . population growth or decline determined by ratio of birth to death rates . p. 60, Fig. 7.2; global population generally stable until Industrial Revolution of 18th c., then rapid increase; now at 7 billion, likely to add another billion in next 12 years; at current rate will double in 54 years, to be 14 billion by 2064 - however, global trend is toward declining fertility rates .populations in industrialized nations have stabilized or are falling; growth is occurring in Southern nations, in particular African . death rates are influenced by scientific knowledge, technology and public policy in areas of sanitation, food supply, medicine and disease control . birth rates are influenced by cultural attitudes toward having children and in particular to women's control of their reproduction, which is tied to education and financial status . population in any given region is also influenced by immigration into the region and emigration out; Ontario Greater Toronto Area (GTA) as a high-immigration, high-population growth region and associated environmental impacts; urban sprawl, land-use biodiversity impacts, transportation, energy-use impacts – but population growth per se is not treated as a problem in the policy discourse, but instead a benefit since associated with economic growth 2. Population as cause of the environmental problem threat to supply of global food and water . need for increased food supply means increased conversion of land to agricultural use, with consequences for biodiversity, and fossil-fuel and fertilizer, pesticide use for agriculture (growing and transporting products), with consequences for climate change, nitrogen and chemicals . as Southern nations industrialize and experience economic growth, the portion of animal protein in food supply increases, magnifying the potential environmental problem associated with food supply; in 1999, world rangelands produced 54 million tons of beef and mutton, while the land needed for that animal production could have produced 378 million tons of grain (Brown, Lester R. (2001). "Chapter 3: Eradicating Hunger: A Growing Challenge." In Worldwatch Institute, State of the World 2001. New York: W.W. Norton p. 47) - thus if humans were to eat grain directly, instead of feeding it to animals and then eating the animals, there would be that much more food available, but the trend is in the opposite direction 1 . more people means more domestic live-stock and house-hold pets with associated environmental effects, eg disease transmission from poultry, cats killing birds; plus increased strain on the global food supply (currently something like 60 million dogs in the US, 20 million dogs and cats in the UK) . in 2002, 504 million people lived in water-scarce areas, a figure expected to increase to something like 3 billion by 2025 (Engleman, Robert et al (2002). "Chapter 6: Rethinking Population, Improving Ideas." In Worldwatch Institute, State of the World 2002. New York: W.W. Norton p. 134) increased use of materials and energy . increased people means increased demand for energy and products other than food; eg, global motor-vehicle population is increasing along with population growth and, more importantly, increasing per capita income (current car population is something like 1 billion) . like food supply, the problem is compounded by economic growth (Jan. 26) which means material and energy use by each human, in both North and South, is increasing differing effects . declining population in high-consumption North aids environment; however, population growth in South is problematic because associated environmental effe
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