HUMAN POPULATION& SUSTAINABILITY

HUMAN POPULATION - HISTORY

Homo sapien sapien “wise man”

250,000 – 500,000 years ago

Hunter-gather populations considered stable at 3 million prior to the development of agriculture(35,000 – 40,000 years ago)

HUMAN POPULATION - HISTORYAgricultural Revolution – the development and domestication of traditional farming techniques (Mesopotamia ~10,000 years ago)

Led to the development of civilizations and could support larger populations.

Human population growth is exponential 2, 4, 8, 16, 32, 64, 128, 256, 512

HUMAN POPULATION - GROWTHPopulation still regulated by limiting factors due to environmental conditions• Water• Food• Arable land• Space• Disease

HUMAN POPULATION - GROWTHAdvancements in medicine, industrial manufacturing, and commercial large scale farms increased the population growth rate.

More people = more resources = more water, air, food, shelter, clothing, energy, minerals, medicine, space.

Has the human population already passed the carry capacity of Earth?

HUMAN POPULATION - RESOURCES

A supply that benefits humans–water, land, air, ore, life

Natural resources: the resources the Earth provides• 2 Types of Natural Resources–Renewable –Nonrenewable

HUMAN POPULATION - RESOURCES

RENEWABLE• Natural resources that can be used indefinitely, reused, or

recycled • Sun, water, fertile soil, nitrogen, carbon, living things

NONRENEWABLE• A resource that exists in a fixed amount• Can be replaced but the process takes hundreds of

millions of years• fossil fuels, gemstones, silver, uranium, biodiversity

RESOURCES - SUSTAINABILITY• Renewable resources are replaced through

natural processes

• Humans must not use the resources faster than they can be replaced

• Sustainable yield: the replacement of renewable resources at the same rate they are consumed

RESOURCES - AGRICULTURESustainable Agriculture / Aquaculture• Farming using principles of ecology, natural• Does not abuse or overuse available resources• Efficient use of resources; space, water, nutrients• Limits environmental impact• Ensure long term use of land and productivity• Economical profit

RESOURCES - AGRICULTURESustainable Methods• Fuel efficient / man powered machines• Organic pesticides and herbicides• Crop rotation, cycling different crops• Organic fertilizers, composting• Biocontrols, natural predators• Crop integration, polycultures• Drip irrigation or native food crops

RESOURCES - AGRICULTURE

Commercial / Industrial Agriculture• Machines, equipment, transportation• Pesticides and herbicides• Large areas clear cut for farms• Monoculture • Irrigation systems• GMOs

RESOURCES - AGRICULTUREProblems with Commercial / Industrial • Excessive tilling, erosion• Nutrient depletion, no more nutrients in soil• Clear cutting large areas, slash’n’burn• Poor irrigation, waste of water• Salinization or desertification – “dead” soil• GMOs weak against disease• Chemical herbicides/pesticides hurt

ecosystem

RESOURCES – FOSSIL FUELSChemicals formed by heat and pressure from dead plants & organisms– Primary source of energy for the U.S.• Coal, oil, and natural gas

– Takes millions of years to form – Non-renewable– Produce pollution • CO2, NOx, SOx, Mercury, etc

RESOURCES - NUCLEARUses the energy released in the process of nuclear fission, where a radioactive atom is split or decays into two smaller atoms.

Advantages• High Energy outputs• Large supply• Emits 1/16 amount of Carbon Dioxide as coal• Moderate land use

Disadvantages• High cost• Thermal pollution from the nuclear power plants• Accidents (Chernobyl and 3 mile Island)• Radioactive waste

RESOURCES - SOLARSolar Energy

– Passive Solar Heating: Capturing sunlight directly and converting it to heat

– Active Solar Heating: using solar panels to collect heat

– Photovoltaic Cells (PV cells): solar energy is converted into electrical energy, silicia

– Problems: expensive to buy

RESOURCES – GEOTHERM / HYDRO

Geothermal Energy– Energy produced by naturally occurring steam and

hot water– Only available in geologically active areas

Water Energy– Hydroelectric Power: the power of falling water

turns turbines that produce electrical energy – Hydrotidal Power: power of the rising and receding

tides moves turbines producing electrical energy

RESOURCES - WINDWind Energy

–Wind turbines convert mechanical energy of the wind to electrical energy

– A large portion of the US’s energy could be supplied by wind farms in Texas, North and South Dakota

– Problems: Must have constant wind, unattractive and kills birds, transportation

– FASTEST growing market

RESOURCES - BIOMASSBiomass– Renewable resource

– Includes wood, dried crops and dried fecal matter from animals

– Wood is a primary source of energy for 50% of the world

– Biogas: mix of methane and CO2 from animal waste that is used for cooking fuel

– Gasohol: mix of gasoline and ethanol that can be used as fuel