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

Food and Food Supply

1. Define food security and food insecurity.
Food security refers to the people in an area having access each day to sufficient food with sufficient nutrients. It depends on countries having the means to produce or import enough food for its population. Also, a country must make sure that there are no harmful environmental effects that can affect its ability to produce food. Food insecurity means not being able to have either enough food or food with enough nutrients each day.

2. Distinguish between undernutrition, malnutrition, and overnutrition.
Undernutrition occurs when the food an individual eats is not enough to meet its basic energy needs. Malnutrition occurs when the food an individual eats does not contain enough proteins or key nutrients. Overnutrition occurs when the food an individual eats contains more calories or more nutrients than those that are necessary.

3. Describe the effects of diet deficiencies in Vitamin A.
A lack of Vitamin A can cause increased susceptibility to common childhood infectious diseases. Children under 6 who do not get enough Vitamin A can go blind and even die.

4. What is famine? How may it affect: societies, the environment?
Famine is a severe shortage of food in a certain area. There is mass starvation, deaths, and social disruption. Societies become chaotic and many starving people migrate to other areas and there is a frantic search for food and water. Individuals also eat their reserves of grains for future years and they will kill their breeding livestock. This will have an impact on the sustainable yield of an environment, affecting its ability to provide enough food for the population in the future.

5. What three systems provide most of the world’s food?
Wheat rice and corn provide more than half of the calories consumed by the world population.

6. Distinguish among industrialized agriculture and plantation agriculture.
Industrialized agriculture or high-input agriculture is that that uses high amounts of energy such as fossil fuels, a large amount of water, uses commercial fertilizers, pesticides and produces single crops (monocultures) and raises livestock.
Plantation agriculture is a form of industrialized agriculture used in tropical developing countries. It involves growing cash crops on large monoculture plantations that will later be sold to developing countries. Forests are cleared to make room for these plantations and biodiversity is reduced.

7. What is a green revolution? What limits could these have?
The green revolution is a process that helped increase crop yields. It involved three steps: First, monocultures would consist of selectively bred or genetically engineered key crops. Second, use of large amounts of fertilizer, pesticides and water to improve yields. Third, multiple cropping would allow an increase in the amount of crops. The green revolution limits biodiversity and could have adverse effects on the soil profile of an area, thus affecting its ability to yield crops in the future.

Population Growth

Population growth can be defined in terms of birth rate, death, doubling time, migration, and fertility rate.

The total fertility rate (TFR) is the average number of children that each woman has over her lifetime. Calculating this helps show the potential for population change in a country.

TFR > 2.0 = population increase
TFR < 2.0 = population decrease
TFR = 2.0 = stable population

Factors that impact our environment apart from population size, is the amount and distribution of wealth as well as the resource desire and need.

Population Growth and Food Shortages

There are two opposing theories on this subject: one by Thomas Malthus, and the other by Ester Boserup. Malthus states that the population is increasing geometrically while the food supply increases aritmethically. This means that the population will surpass the amount of food available, causing excess individuals to die off.
Boserup on the other hand states that while the population keeps growing it will develop the technology needed to meed the food demand. While Malthus is too pessimistic, Boserup is too optimistic. I think we need to find a middle ground. Also, population keeps growing and each country's demands are different. Will the population grow so much that it will cause a dramatic dieback? Have we surpassed our carrying capacity?