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