Types of Energy Resources

There are many types of energy available for human use, but man tends to overuse some of them which leads to environmental problems.

1. Fossil Fuels: by far the most exploited energy resource but not for much longer. (Coal, Oil, Natural gas)
2. Nuclear Energy: highly productive, but comes with hazardous issues.
3. Hydroelectric Energy: harnesses the kinetic energy of flowing water. Sounds great but what happens to the river? And what if there is no river nearby?
4. Solar energy: just like plants have been doing for millions of years! Renewable because the sun will be around for a few billion years more! But if solar energy is so great, why are we not all using it?
5. Wind: Works great! As long as there is wind. Kind of noisy though.
6. Geothermal: harnessing the thermal energy beneath the Earth’s crust! Nees to find an opening though.
7. Tidal: using the moon’s gravitational energy that the oceans convert to kinetic energy.
8. Hydrogen Fuel Cells

Energy Budget of Food Production

Farming's Energy Budget

When farming and producing food, one needs to examine the inputs, outputs, flows and storages in order to determine the energy budget.

e.g. fuels, chemicals, labor, materials, transports, wastes, energetic content of products.

Also consider that the marketable product which is produced is only a % of the total output, which may not be marketable.

For every watt of input I get ___ watts of product (dairying, cereals, etc.)

Comparing Aquatic vs. Terrestrial Food Production

Terrestrial:

• Food harvested from 1st or 2nd trophic levels thus more energetically efficient.
• Solar energy capture (GPP) more efficient.
• Energy transfers between trophic levels not as efficient.

Aquatic:

• Most food is harvested from higher trophic levels, thus not as efficient
• Solar capture (GPP) not as efficient due to absorption of sunlight by water
• Energy transfers between trophic levels fairly efficient.

Farming and Food Production

Types of Farming Systems

1. Subsistence: provision of food for family and their community; little or no surplus; mixed crops; extensive use of human labor; low use of fossil fuels, chemicals, and capital; little technology.

2. Commercial: large profit generating scale; maximized yields, monocultures; high levels of technology, energy, and chemical inputs.

Farming can also be described as:

1. Extensive: uses more land with a lower density of animals or crops; lower inputs and outputs.

2. Intensive: intensive use of land; high inputs and outputs

And as:

i. Pastoral

ii. Arable

iii. Mixed

Demographic Transition Models

A Demographic Transition Model describes the pattern of decline in mortality and natality (fertility) of a country due to social and economic development.

Can be describes as a 5-stage model:

1. Pre-industrial
2. LEDC
3. Wealthier LEDC
4. MEDC stable
5. MEDC population decline.

MEDCs vs LEDCs

• In many MEDCs, the cost of staple food items is relatively cheap.
• Most people make purchases based on taste and preference.
• Produce seasonality has mostly disappeared due to globalization. T
• his has also allowed for a greater international variety in most supermarkets.

• In LEDCs, many staple food items may not be always affordable as prices fluctuate.
• People tend to make purchases based on nutritional need and affordability.
• Political and economic agendas can affect food production (e.g. cash cropping)
• Even if food crops are not used as cash crops, food production is still impacted since arable land is being occupied all the same.
  

Population Pyramids

Population pyramids show how many individuals are alive in different age groups of a certain region in a given year. These are made up of bars, and the x-axis shows the population numbers while the y-axis shows the age group. The length of the bars shows relative proportion, shown as a percentage of the total population.

These pyramids shows population distribution and can help make predictions on population change.

Types of Pyramid Shapes
There are four stages in the population pyramids.

• Stage 1: Expanding - High CBR, rapid fall in each upwardage group due to high CDR, short life expectancy.
• Stage 2: Expanding - High CBR, fall in CDR as more individuals live to middle age, slightly longer life expectancy.
• Stage 3: Stationary - Declining CBR, low CDR, more individuals live to old age.
• Stage 4: Contracting - low CBR, low CDR, higher dependency ratio (those that cannot work), longer life expectancy.

LEDCs tend to be stage 1 or 2

MEDCs tend to be stage 3 or 4