Food Supply

Important Terms


Food security: This expression means that every person in a given area has a daily access to enough nutritious food to have an active and healthy life.
Food insecurity: The opposite of the first one. There are not enough food supply or simply people have not the needed resources to access them.

Undernutrution	Malnutrition	Overnutrition
Food consumed doesn't provide enough energy	Food has enpugh nergy but lacks nutrients, vitamins, proteins  and minerals	Food consumes has an excess of energy than the one needed and used

Basic Nutrients which cause malnutrition:

Vitamin A	Iodine	Iron
Blindness and children become prone to infection	Afects metabolism processes and causes stunted growth and may lead to goiter	Anemia, fatigue , risks of infection and increases risk for hemorrhage in labor.

Famine: A famine is a situation of severe shortage of food supply in an area accompanied by mass starvation, many deaths, economic chaos, and social disruption. 

Population Pyramids

Demographic Transition Model

• DTM describes the pattern of decline in mortality and natality (fertility) of a country due to social and economic development
• Can be described as a 5-stage model
• Pre-industrial
• LEDC
• Wealthier LEDC
• MEDC-stable
• MEDC-population decline

Environmental Economics

• How do we value resources
• Economic --> money
• Ecological --> support systems
• Scientific --> research
• Intrinsic --> cultural

• Natural capital
• Natural resources, services, and processes
• Natural income

• Types of natural capital
• Renewable
• Replace or restock themselves
• Non-renewable
• Exist in finite amounts on the planet
• Replenishable
• Between renewable and non-renewable
• Example Groundwater
• Recyclable
• Resources that can be transformed into usable materials after already being used for something else
• Iron, aluminum, etc

• Sustainability
• Living within the means of nature, on the "interest" or sustainable natural income generated by natural capital.
• However, economist and environmentalists may have very different views on what is sustainable
• Any society that supports itself in part by depleting essential forms of natural capital is unsustainable.

Population and Resource Use

• Population size is not the only factor that determines our species' impact on the environment
• Amount of wealth, including distribution
• Resource desire
• Resource need

• Many environmental impact models are based on the assumption that all individuals in a population have the same resource use and waste profile and thus impact the environment equally

Population Growth and Food Shortages

• Thomas Maltus was an English clergyman and economist who lived back in the day (1766-18434)

Population Size

• Four main factors that affect  population size
• Birth rate
• Death rate
• Immigration
• Emigration

• The measures of population change are
• Crude birth rate (CBR)
• The Crude Birth Rate (CBR) includes the number of births per 1000 individuals. So, the formula for this is:

• CBR = (Number of births / population size) x 1000
• The CBR in the world is 20.3 per 1000 per year.
• Crude death rate
• The number of deaths per 1000 individuals in a population per year
• Calculated by dividing the number of deaths by the size of population and multiplied by 1000
• Doubling rate
• The time in years that it takes a population to double its size
• Doubling time = 70/NIR
• Natural increase rate
• NIR=(CBR-CDR) / 10
• This gives NIR on %
• Does not consider immigration or emigration
• Total Fertility Rate
• The average number of children that each woman has over her lifetime. It shows the potential for population change in a country.
• A TRF > 2.0 results in a population increase
• A TRF < 2.0 results in a population decrease
• A TRF = 2.0 results in a stable population

S and J Curves for Growth Rate

S-curves and J-curves

• S-curves
• Start with exponential growth
• Above a certain population size, the growth rate slows down until population stabilizes
• Consistent with density dependent limiting factors
• Population size stabilizes at the carrying capacity (K) of the environment
• The area between the exponential growth curve and the S.curve is called environmental resistance

• J-curve
• Shows a boom and bust pattern
• Population grows exponentially then crashes
• These collapses/crashes are called diebacks
• Population often exceeds K before the collapse occurs which is referred to as overshoot

Growth Rates

• S and J curves are idealized
• In nature both types of limiting factors act on the same population and the result is an S/J combo curve
• The growth rate of the human population is slowing as we reach the K of our environment
• Peaked at 2.1% per year in 1965-1970
• Now: 1.3% and falling
• Back in the day world population was increasing slowly due to environmental resistance, diseases, epidemics, famine, and natural catastrophes
• MEDCs and LEDCs
• Countries are also economically classified based in the industrial development or GDP
• MEDCs
• are industrialized nations with high GDPs
• Relatively rich population and starvation is unlikely
• High Level of resource use per capita
• Relatively low population growth rate
• LEDCs
• are less industrialized or have none at all
• May have plenty of natural capital but usually this is exported and processed in MEDCs
• Lower GDP and high poverty rates
• Large population sector with low standard of living
• High population growth rates

Population Dynamics

Populations change over time due to many factors/variable. These limiting factors may be classified as: Density dependent and Density independent.

Limiting factors:

• Density dependent
• Biotic factors
• Effects increase as population increases
• Act as negative feedback mechanisms, which function to regulate or stabilize a population size
• Internal Factors
• Act within a species
• Ex. Limited food supply, territory, density dependent fertility
• External factors
• Act between different species
• Ex. Predation and disease

• Density Independent
• In general tend to be abiotic
• Effects are not related with population growth
• Not part of a feedback system
• Weather, climate, volcanic eruptions, floods