Environmental Notes

1.1 Continents and Oceans

  • 7 Continents: Africa, Antarctica, Asia, Europe, North America, South America, Oceania

  • 5 Oceans: Atlantic, Pacific, Indian, Arctic, Southern

    Characteristics of Oceans:

  • Pacific Ocean: 33% of Earth's surface, largest, contains Mariana Trench (11,034 m deep)

  • Atlantic Ocean: 20%, divided into North and South

  • Indian Ocean: Third largest

  • Southern Ocean: Site of southern circulation

  • Arctic Ocean: Smallest, around North Pole

    1.2 Income Level Classification

  • LICs: GNI per capita ≤ $1,086 (e.g., Ethiopia, Haiti)

  • MICs: GNI per capita $1,086 - $13,205 (e.g., India, Brazil)

  • HICs: GNI per capita > $13,205 (e.g., USA, Sweden)

    Characteristics:

  • LICs: Water scarcity, reliance on raw materials, corrupt governments, high emigration

  • HICs: Clean water, stable governments, low emigration

    1.3 Sustainability

  • Definition: Ability to meet present needs without compromising future generations.

  • Resources:
      - Renewable: Timber, soil, freshwater
      - Nonrenewable: Fossil fuels, minerals

    1.4 Water Cycle

  • Stages:
      - Through-flow: Horizontal flow in soil
      - Interception: Precipitation trapped by vegetation
      - Infiltration: Water movement into the soil
      - Run-off: Water flowing on surface
      - Evaporation: Liquid to gas
      - Transpiration: Water vapor from plants
      - Condensation: Gas to liquid
      - Groundwater: Water stored underground

    1.5 Atmosphere Structure

  • Composition: 78% Nitrogen, 21% Oxygen

  • Layers:
      - Troposphere: Weather and water vapor, greenhouse effect
      - Stratosphere: Ozone layer, temperature increases with altitude
      - Mesosphere: Coldest layer
      - Thermosphere: High temperatures, auroras

    1.6 Ecosystems

  • Definitions:
      - Population: Same species
      - Community: Different species
      - Ecosystem: Interactions between organisms and environment
      - Biome: Geographic area with similar climate

  • Components:
      - Abiotic: Non-living (water, climate)
      - Biotic: Living (producers, consumers)

  • Trophic Levels:
      - Producers: Autotrophs (photosynthesis)
      - Consumers: Primary, secondary, apex predators

  • Energy Transfer: 10% transfer efficiency, 90% lost as waste.

    1.7 Biodiversity

  • Indices: Measures species richness and evenness

  • Simpson's Index: Ranges from 0 (no diversity) to 1 (max diversity)

    2.1 Environmental Research and Climate Change

  • Reliable Data: Consistent and replicable results

  • Bias: Influences on data interpretation

  • Challenges: Limited historical climate data, model uncertainties

  • Sampling: Random and systematic sampling methods

    Direct approaches for data collection: surveys, environmental observations, etc.

  • Environmental Data Techniques:
      - Quadrats and Sampling: Estimate cover, abundance, and record species
      - Mark-Release-Recapture: Estimate population size for mobile species
      - Observational Tools: GPS, satellite data, etc.

  1. Population Density:
       - Definition: Number of people per square mile/km.
       - Influencing Factors:
         - Environmental: Climate, Topography, Natural Resources, Hazards.
         - Economic: Job Opportunities, Industry, Infrastructure, Cost of Living.
         - Social: Social Services, Quality of Life, Cultural Identity.
         - Political: Government Policies, Conflicts.
         - Historical: Legacy of Settlement, Urbanization, Land Use.

  2. Population Change Factors:
       - Immigration (i): Increase in population size.
       - Emigration (e): Decrease in population size.
       - Birth Rate (b): Births per 1,000 people/year.
       - Death Rate (d): Deaths per 1,000 people/year.
       - Growth Rate: Includes immigration, emigration, birth, and death rates. Natural change refers to birth and death rates only.

  3. Population Size Formula:
       - Population Size = Population + [(Immigration + Birth) - (Emigration + Death)].

  4. Age Structure Diagram:
       - Left: Males, Right: Females.
       - Bottom: Pre-reproductive (0-14 years).
       - Middle: Reproductive (15-64 years).
       - Top: Post-reproductive (65+ years).
       - Segment widths proportional to population sizes.
       - Larger 0-14 cohort indicates future growth; narrower indicates decline. A wider 65+ cohort reveals longevity and better healthcare access.

  5. Dependency Ratio:
       - Measures dependent population (under 15 and over 65) to working-age population (15-64).
       - Higher dependency indicates economic burden on working-age group.
       - Example:
         - Expanding: Guatemala, Nigeria.
         - Stable: United States, Australia.
         - Declining: Germany, Bulgaria.

  6. High vs. Low-Income Countries (HICs and LICs):
       - HICs:
         - Low infant mortality; access to healthcare, education, contraception.
         - Social stability; age structure: young (0-14) + older (65+).
       - LICs:
         - High infant mortality; lack of healthcare, education.
         - High total fertility rate due to replacement births and early pregnancies.

  7. Impacts of Population Change:
       - Aging populations lead to: Lower tax revenues, higher pension spending, pressure on healthcare, and increased dependency ratio.

  8. Managing Population Change:
       - Improved contraception availability and education.
       - Women’s health and education improvements.
       - Pro-natalist Policies: Encouraging higher birth rates via financial incentives and support.
       - Anti-natalist Policies: Reducing birth rates through family planning and economic disincentives.
       - United Nations Agenda 21: Focuses on sustainable development and awareness.
       - The Club of Rome: Advocates for awareness of population growth impacts on the environment and resources.