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 - HISTORY Agricultural 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 - GROWTH Population still regulated by limiting factors due to environmental conditions Water Food Arable land Space Disease

HUMAN POPULATION - GROWTH Advancements 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 - AGRICULTURE Sustainable 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 - AGRICULTURE Sustainable 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 - AGRICULTURE Problems 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 FUELS Chemicals 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 - NUCLEAR Uses 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 - SOLAR Solar 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 - WIND Wind 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 - BIOMASS Biomass – 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 CO 2 from animal waste that is used for cooking fuel – Gasohol: mix of gasoline and ethanol that can be used as fuel