Discussion 1 we will discuss population questions. This will – worth up to 15 points. Everyone...
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Transcript of Discussion 1 we will discuss population questions. This will – worth up to 15 points. Everyone...
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!
Human Population Growth
How will demographic, economic and cultural
changes interact with Earth's physical, chemical and
biological environment?
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
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
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?
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.
1. Pre industrial-high birth & death
2. Industrial-births drop
3. Post industrial-low birth & death
Ages 0-14Ages 0-14 Ages 15-44Ages 15-44 Ages 45-85+Ages 45-85+
Rapid GrowthGuatemala
NigeriaSaudi Arabia
Rapid GrowthGuatemala
NigeriaSaudi Arabia
Slow GrowthUnited States
AustraliaCanada
Slow GrowthUnited States
AustraliaCanada
MaleMale FemaleFemale
Zero GrowthSpainAustriaGreece
Zero GrowthSpainAustriaGreece
Negative GrowthGermanyBulgariaSweden
Negative GrowthGermanyBulgariaSweden
Population Age StructurePopulation Age Structure
Fig. 11.16a, p. 247
Age-Sex Structure
• Population Momentum
• Past children 0-14 outnmumbered
• 2002 – children 30% of population
• Near future expected to decline to 20%
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
• Everything is connected
Managing population growth
Managing population growth
<1%1-1.9%2-2.9%3+%Data notavailable
Annual worldpopulation growth
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).
1. Energy – US 5% of pop with 26% energy consumption. Leads to global warming
2. Natural resources – industrial countries 20% of pop with roughly 80% consumption of timber, aluminum, iron
5 problems associated with population growth –
most to do with RESOURCES
5 problems associated with population growth –
most to do with RESOURCES
3. Land use – US in 200 yrs lost 70% topsoil, 50% wetlands, 90% old growth, 99% prairies
4. Water pollution – US 40% of surface waters unfit
5. Waste – • New York (4#garbage)• Paris(2.4#)• Cairo(1.1#)
Human population problemsHuman population problems
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?
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
Factors affecting human population sizeFactors affecting human population size
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
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
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.
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
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.
Ag & Food
• http://www.fao.org/docrep/005/y4252e/y4252e00.htm
• World Agriculture (2003 summary)– Crops– Livestock– Forestry– Fisheries
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
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
Forestry & Fisheries
• later
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).
• 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.
Food ShortagesFood Shortages
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/
Industrialized agricultureIndustrialized agriculture
Shifting cultivationShifting cultivation
Plantation agriculturePlantation agriculture
Nomadic herdingNomadic herding
Intensive traditional agricultureIntensive traditional agriculture
No agricultureNo agriculture
World Food Production
Fig. 12.2, p. 263
Food ProductionFood Production
Rapidly increasingRapidly increasing
Prices decreasingPrices decreasing
Shortages in developing countriesShortages in developing countries
Approaching limits on meat productionApproaching limits on meat production
Producing Food by “Green”-Revolution Techniques (this is not organic)
Producing Food by “Green”-Revolution Techniques (this is not organic)
High-input monoculture High-input monoculture
Selectively bred or genetically-engineered crops
Selectively bred or genetically-engineered crops
High inputs of fertilizer High inputs of fertilizer
Extensive use of pesticidesExtensive use of pesticides
High inputs of water High inputs of water
Increased intensity and frequency of cropping
Increased intensity and frequency of cropping
Early Green Revolutions
First green revolution(developed countries)First green revolution(developed countries)
Second green revolution(developing countries)
Second green revolution(developing countries)
Major International agricultural research centers and seed banksMajor International agricultural research centers and seed banks
Fig. 12.4, p. 265
Green Revolution
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
Environmental Effects of Food Production
Biodiversity loss:Tropical forest loss to marginal agBiodiversity loss:Tropical forest loss to marginal ag
Soil: 40% of ag soil is degraded (erosion, tilling damageNutrient depletion, poor irrigation
Soil: 40% of ag soil is degraded (erosion, tilling damageNutrient depletion, poor irrigation
Air pollution: airborne pesticides, methane gasesAir pollution: airborne pesticides, methane gases
Water: runoff from fertilizers, depletion of water resources
Water: runoff from fertilizers, depletion of water resources
Human health:workers exposure to pesticides, Endocrine disruptors, Availability of nutrient rich foods
Human health:workers exposure to pesticides, Endocrine disruptors, Availability of nutrient rich foods
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)
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 erosionArroyo/USGS
In Summary
• Growth is happening
• It affects earth’s resources– Sustainable use of resources is key
Solutions: Influencing Population Size
Solutions: Influencing Population Size
MigrationMigrationEnvironmental refugeesEnvironmental refugees
Reducing birthsReducing birthsFamily planningFamily planning
Empowerment of womenEmpowerment of women
Economic rewards and penaltiesEconomic rewards and penalties
Solutions: Sustainable AgricultureSolutions: Sustainable Agriculture
Low-input agricultureLow-input agriculture
Organic farmingOrganic farming
More benefits to the poorMore benefits to the poor
Increasing funding for research in sustainable techniques
Increasing funding for research in sustainable techniques