Basic principles of population growth
r (growth rate) = b (births) – d (deaths)
- r > 0, population grows
- r < 0, population declines
- r = 0, population stable
Two factors for maximum growth rates:
- Remove all barriers (there are no limiting factors)
- Intrinsic rate of increase (exponential growth)
Two types of growth
- Exponential: No or few limiting factors
- Logistic: Limiting Factors
Something or things that limit further population growth.
Intrinsic rate of increase
A population is growing at a maximum rate
Maximum population density a species under study can achieve based on limiting factors present at a study site.
Grand Canyon National Park Deer Management
- Predators removed
- Herbivores removed
- Population explosion of deer: (1918: ~40k; 1924: ~100k)
- The crash: Winter of 1924 (~60k deer die)
- Modern Management
Population growth varies inversely with population density
Factors independent of population density control population growth
Study of population change over time
First person to realize that populations cannot grow forever.
Population growth in the United States
- Fastest-growing developed nation
- Due primarily to immigration, but also high reproductive rate (fastest growing subgroup are Latinos)
- Soon to be a “majority minority” country
Demography of Nations
- Developed Countries: Some have achieved 0 population growth or close to it.
- Moderately Developed Countries: Increase in population because birth rates stay current while death rates drop.
- Less Developed Countries: 0 population growth because of high birth and high death rates.
4 Stages of Population Growth
- STAGE 1: Preindustrial – High birth and high death rates.
- STAGE 2: Transitional – High birth rates, but death rates drop.
- STAGE 3: Industrial – Birth rates come down and eventually reach zero population growth.
- STAGE 4: Postindustrial – Populations eventually decline.
- Used to allow someone to get into the free market system and begin making money.
- Usually offered by international banks, given to people in various developing countries.
Overpopulation leads to instability
- Economic: Low income in overpopulated countries (Civil unrest, warfare, banditry)
- Refugees: Economic, political, and ecological (Refugees migrate to escape untenable situations)
- Illegal immigration: To richer countries (Straining the economy of host countries)
Carrying capacity: Limiting factors
- Space: Overpopulation
- Food: Food insecurity and famine
- Climate and Weather: Climate Change
- Soils/Minerals: Erosion
- Disease: Avian flu (H5H1), H1N1, and other “emerging diseases”
- Human Activity: Pollution and other damage to the ecosystem
Degradation of Quality of Life
- Chronic Hunger
- Water Shortage: Must be high quality
- Economic: Collapsing infrastructure and social systems
Four way to eliminate chronic hunger
- Reduce population growth rate
- Increase economic development: A better economy allows more people to buy adequate food
- Increase food supply
- Better distribution of food supply
World Bank and IMF
- Loan money to developing nations to develop things that are sometimes not environmentally friendly.
- Example: Aswan High Damn, Egypt
- The other problem with the loans is that they will loan massive amounts of money to these countries which doesn't help them to stimulate the economy enough so they become buried in debt.
Why is fertility rate high?
- Higher mortality of children
- Children as workers
TFR among religions
- Highest: Catholic
- Moderate: Protestants and Jews
- Lowest: No religious affiliation
Why women tend to live in poverty (4)
- Income inequality
- No legal rights
- Poor education
- Reduced political participation
TFR Policies by Country
- China: Penalties for >1 child. 1.6 births/woman.
- India: “aggressive” approach to bringing TFR down
- Mexico: 32% of population is <15yrs old
- Nigeria: 5.9 births/woman; 45% of population <15yrs old
- Europe: Stabilizing or declining
Energy Sources and Issues
- Nuclear: Few ghg issues; high storage risk
- Oil: Versatile energy source; many ghg issues
- Wind and Solar: Major infrastructure and availability issues (As-yet-unrecognized habitat destruction issues)
- Coal: Important source of energy, but major ghg and pollutant issues
- Biofuels: Major habitat destruction issues, uses more energy than it replaces, and is subsidized
Why have a policy?
- Energy needed for economic growth
- Maintaining supply requires a long-term strategy
- Managing the downsides is something only government can do
- Managing the nuclear waste is also something only the government can do
*Four core objectives in policy*
- Increasing efficiency and conservation
- Securing future fossil-fuel supplies
- Develop alternative energy sources
- Weigh costs and benefits
Something created by the industry that you do not pay for but is part of the production
Carbon Sinks (6)
- Fossil Fuels (turning from a sink to a source)
- Carbonate Rocks
Coal Ranked by Quality
- Sulfur and water content vary
- Some are better than others
- Lower sulfur content is better because leads to less acid rain
Creation of Power
- Energetic particles are given off in the decay process
- These particles carry energy
- This energy can heat water into steam
- Steam can be used to drive a turbine
- Some of the particles given off by radioisotopes may strike nearby radioisotopes, causing them to decay and give off particles
Energetic Particles given off...
- Alpha Particles (not very energetic)
- Beta Particles (more energetic)
- Gamma Particles (the most energetic)
- Contain the reaction
- Containment vessels must be cooled (this controls the reaction)
- Uncontained reaction occurs in a coolant failure (leads to a meltdown)
- U-238 bombarded with neutrons (Creates Pu-239)
- Pu-239 then used to create energy
- Safety Issues: Liquid sodium and Nuclear weapons
- Blend U-235, plutonium, oxygen
- Forms uranium and plutonium oxides
- This makes mixed-oxide, or MOX fuel
- Can be created from surplus weapons grade plutonium
- There is a lot of surplus weapons-grade plutonium
Cost of Nuclear Power
- More expensive to build than conventional fossil-fuel plants
- Heavily regulated (Regulatory cost is high)
- Protection from terrorist attack
- Results in long cost-to-recovery timeline
- Subsidies may be needed for development
Accidents: Three Mile Island
- Faulty valve sticks open (Coolant drains from reactor core)
- An uncontrolled chain reaction occurs (No coolant to slow it down)
- Partial meltdown (Minor release of radiation to the environment)
- Industry claim: A similar accident unlikely using modern plant designs
- Explosion in the building that housed the containment vessel.
- Released massive amounts of radiation into the environment.
- 20-mile radius evacuated, no one has lived there since.
- Nuclear plants can make power and bombs (Relatively easy to hide nuclear weapons programs as a result).
- Dirty bombs (Missing radioactive material).
- Selling nuclear “secrets” (How to build a bomb).
Storage of Waste
- No long-term storage
- Local political resistance (Storage / Transportation)
- Timeline (Safe storage for 1 million years)
Leader of Nucular Technology:
5 Sources of Renewable Energy
“Regionalization” of renewable energy
- Pacific Northwest: Hydropower
- Plains: Wind power
- Coastal: Tidal power and wind
- Geothermal: Highly localized
Solar power's limitations
- Cloud cover
- Seasonality (Winter/Summer; PNW Viable in summer and not in winter)
- Time of day (Sunrise, sunset)
Wind Energy / Wind Farm Downsides
- Kill a lot of bats.
- Habitat Destruction
- Localized Potential is Best
- Shore-line will not rely on it.
Water Power / Dams
- Affects Salmon runs
- Not very environmentally friendly
- Screws up flood regime.
- 2,200 dams used in the US to generate power
- Another form of hyrdo power
- Works as tide comes in and when it goes out
- Environmental impact unknown
- Enthanol Industry Subsidized in US
- Takes more corn to put in, then energy you get out of it
- Causes rising food prices
Hubbards Peak (& Normal Curve)
~30% of world’s fresh water used by people (~70% for irrigation, ~20% in industry, ~10% residential)
- Deficit is not noticeable (Deficit is made up by aquifer overpumping)
- Occurs when you do not have enough surface water for the population to drink
- Problems most serious in these countries and/or areas: China, The Indian subcontinent, The Middle East, North Africa, North America
Need 1000 m3/person/year
- Enough to satisfy drinking, hygiene and food production.
- In 18 countries, water supplies are insufficient
- By 2050, water supply insufficient in ~39 countries (~1.7 billion people will have too little water to fulfill basic needs)
Reducing flooding and damage from flooding
- Don’t remove or “reclaim” wetlands
- Don’t remove upland vegetation
- Don’t remove streamside vegetation
- Don’t channelize streams
- Don’t build in floodplains
Area that is super saturated with water, in which water can be drawn out of it.
- Rate at which aquifers are replenished. Frequently exceeded by our water use. Rates vary quite a bit, as do the amount that water is being removed.
- We draw about 2/3 of the recharge rate out of local aquifers.
Were being recharged in the past, however the weather situation has changed.
Black Hills Aquafers are the...
- Inyan Kara