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Discussion 1

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  1. Discussion 1 • we will discuss population questions. • This will – worth up to 15 points. Everyone will begin with a C and move up or down depending on their contribution to the discussion. • I will track • Participation, • Facts with references • Information from chapters 7, 8, 9 • Points of view • Other elements of thought • Feel free to bring in good tasting visuals!

  2. Human Population Growth How will demographic, economic and cultural changes interact with Earth's physical, chemical and biological environment?

  3. The Human Population: Growth and Distribution Today ???? 1999 World Population at 6 Billion 1960 ~3 Billion http://www.ibiblio.org/lunarbin/worldpop World POPClock from US Bureau of the Census http://www.census.gov/cgi-bin/ipc/popclockw National POPClock from US Bureau of the Census http://www.census.gov/cgi-bin/popclock

  4. The Human Population: Growth and Distribution Today ???? 1999 World Population at 6 Billion 1960 ~3 Billion http://www.ibiblio.org/lunarbin/worldpop World POPClock from US Bureau of the Census http://www.census.gov/cgi-bin/ipc/popclockw National POPClock from US Bureau of the Census http://www.census.gov/cgi-bin/popclock

  5. Questions • As we go through the information today jot down a question that comes to mind. Write your name on it and hand these in at the end of class. • What question(s) would you ask the experts regarding the Earth’s population growth?

  6. Demographic Transistion • Theoretical model of economic & cultural change that explains the trend of declining death rates & birth rates that occurs when a nation experiences industrialization. • Pre industrial-high birth & death • Industrial-births drop • Post industrial-low birth & death

  7. Male Female Rapid Growth Guatemala Nigeria Saudi Arabia Slow Growth United States Australia Canada Zero Growth Spain Austria Greece Negative Growth Germany Bulgaria Sweden Ages 0-14 Ages 15-44 Ages 45-85+ Population Age Structure Fig. 11.16a, p. 247

  8. Age-Sex Structure • Population Momentum • Past children 0-14 outnmumbered • 2002 – children 30% of population • Near future expected to decline to 20%

  9. Why Do Scientists think we will reach carrying capacity? • Carrying capacity – maximum number that the environment will support • Haiti, Rwanda and Somalia, share a high and rapidly increasing density of population, extreme poverty, and a shortage of essential environmental resources, in particular a drop in per capita food production. • These are the 1st examples of the consequences of exceeding the environmental capacity of a country or region • The increase in environmental refugees who leave their homes because local resources can no longer support them is another symptom of this problem. http://earthwatch.unep.net/data/wri.php

  10. Annual world population growth <1% 1-1.9% 2-2.9% 3+% Data not available Managing population growth • Everything is connected

  11. I = PAT • The impact (I) of any population can be expressed as a product of three characteristics: • the population's size (P), • its affluence or per-capita consumption (A), • the environmental damage (T) inflicted by the technologies used to supply each unit of consumption (Ehrlich and Ehrlich 1990, Ehrlich and Holdren 1971, Holdren and Ehrlich 1974).

  12. 5 problems associated with population growth –most to do with RESOURCES • Energy – US 5% of pop with 26% energy consumption. Leads to global warming • Natural resources – industrial countries 20% of pop with roughly 80% consumption of timber, aluminum, iron

  13. Human population problems • Land use – US in 200 yrs lost 70% topsoil, 50% wetlands, 90% old growth, 99% prairies • Water pollution – US 40% of surface waters unfit • Waste – • New York (4#garbage) • Paris(2.4#) • Cairo(1.1#)

  14. A look at the evidence for are we headed to Carrying Capacity? Or are we there? • A comparison of factors in 3 countries • Haiti – at or over K for that country • China – most populous country • US – how do we measure up?

  15. Factors affecting human population size 1. Momentum from Age Structure i.e.continued movement in the same direction based on how many people are of child-bearing age • So many young people that even replacement level births will cause the population to continue growing 2. How well the land supports human life

  16. Assessing It • TEMPORAL TRENDS IN POPULATION, ENVIRONMENT AND DEVELOPMENT • GOVERNMENT VIEWS AND POLICIES • POPULATION SIZE AND GROWTH, AND DEVELOPMENT • RURAL & URBAN MIGRATION, POPULATION CHANGE AND THE ENVIRONMENT • HEALTH, MORTALITY, FERTILITY AND THE ENVIRONMENT

  17. Assessing It • THE ENVIRONMENT (note these are the remaining chapters in the text!) • AGRICULTURE & FOOD • HEALTH & WELL BEING • CLIMATE & ATMOSPHERE • COASTAL & MARINE ECOSYSTEMS • FRESHWATER SYSTEMS • BIODIVERSITY • FOREST & LAND MANAGEMENT • ENERGY RESOURCES • ECONOMICS & SUSTAINABILITY

  18. Urbanization How well the land supports human life • Urbanization. • In 1950, 30 per cent of the world were urban-dwellers, • 2000 the proportion had risen to 47 per cent. • The urban population is projected to equal the rural population by 2007.

  19. Land Use • Wealthy cities and countries prosper by appropriating the carrying capacity of an area vastly larger than the spaces they physically occupy. • Vancouver, BC • 1991 population of 472,000 and an area of 114 km2 (11,400 hectares). (6,000 people per yr = 635,000 in 2021) • With a per capita land consumption rate of 4.3 hectares, Vancouver's residents require 2 million hectares of land to support current consumption levels. • However, the area of the city is only 11,400 ha. Dr William Rees -University of British Colombia

  20. Per Capita Food Consumption • 2054 kcal/person/day 1965 (Developing) • 2680 kcal/person 1997 (Developing) • 3000 kcal/person in 2015 (World) • 2850 kcal/person in 2015 (Developing) • >3000 kcal/person in 2030 (World) • 3000 kcal/person in 2030 (Developing) • The bulk of the increase in consumption is in Developing countries Each day, 25,000 people die of hunger.

  21. Ag & Food • http://www.fao.org/docrep/005/y4252e/y4252e00.htm • World Agriculture (2003 summary) • Crops • Livestock • Forestry • Fisheries

  22. Crops • Higher productivity yields means growth • Area of cultivated land • Approximately 70% of all available water is used for irrigation • Environmental Impact: continued expansion into wetlands and rainforests, although this is known to be detrimental

  23. Livestock • Higher carcass weight means growth • Size of livestock herd • Most beef in the US comes from small (often part-time) farms that sell <100K/yr • Meat consumption in China went from 11.4 kg of diet in 1960s to 25kg in 1997

  24. Forestry & Fisheries • later

  25. Economics • Unprecedented pace and its uneven distribution between countries and regions. • wealthiest quarter of world population income climbed sixfold over the 20th century, • per capita income for the poorest quarter of world population grew less than threefold (International Monetary Fund, 2000).

  26. Food Shortages • WASHINGTON, DC, March 10, 2003 Over one million African refugees risk severe malnutrition and increased mortality • January 3, 2003 UN appeals for 1.4 million tons of food aid immediately • The nutritional problems of children in developing countries are considered to be associated with MORE THAN HALF of all CHILD DEATHS.

  27. Arable Land • Between now & 2030 the need for this land is projected to increase by 13% (120 million ha). • Most will come from land abundant regions of sub-sahara & South America • Deforestation is on the rise http://earthtrends.wri.org/

  28. Plantation agriculture Industrialized agriculture Nomadic herding Shifting cultivation Intensive traditional agriculture No agriculture World Food Production Fig. 12.2, p. 263

  29. Food Production • Rapidly increasing • Prices decreasing • Shortages in developing countries • Approaching limits on meat production

  30. Producing Food by “Green”-Revolution Techniques (this is not organic) • High-input monoculture • Selectively bred or genetically-engineered crops • High inputs of fertilizer • Extensive use of pesticides • High inputs of water • Increased intensity and frequency of cropping

  31. Second green revolution (developing countries) First green revolution (developed countries) Major International agricultural research centers and seed banks Early Green Revolutions Fig. 12.4, p. 265

  32. Benefit Farmers harvested more corn, wheat, rice, soybeans per hectare A way to end starvation in developing countries Harm Biodiversity Deforestation of the rainforest Mixed consequences for crop yields Declining grain production (peaked in 1980s) due to health of land Green Revolution

  33. Environmental Effects of Food Production • Biodiversity loss:Tropical forest loss to marginal ag • Soil: 40% of ag soil is degraded (erosion, tilling damage Nutrient depletion, poor irrigation • Air pollution: airborne pesticides, methane gases • Water: runoff from fertilizers, depletion of water resources • Human health:workers exposure to pesticides, Endocrine disruptors, Availability of nutrient rich foods

  34. Biodiversity Loss • Data suggest that many fruit & vegetable crops varieties have decreased in diversity by 90% in less than a century • Seed banks (Native Seeds/Search)

  35. Erosion & Depletion of Soils • Nearly vertically walled, flat floored stream channel that forms in fine, cohesive, easily eroded material • up since the mid 1800s • Climate change • Grazing • Natural erosion Arroyo/USGS

  36. In Summary • Growth is happening • It affects earth’s resources • Sustainable use of resources is key

  37. Solutions: Influencing Population Size • Migration • Environmental refugees • Reducing births • Family planning • Empowerment of women • Economic rewards and penalties

  38. Solutions: Sustainable Agriculture • Low-input agriculture • Organic farming • More benefits to the poor • Increasing funding for research in sustainable techniques