ESS Topic 8 Summary Notes

8.1 Human Population Dynamics

  • Models and indicators are used to quantify human population changes.
  • Age-sex pyramids are used for evaluation and analysis.
  • The Demographic Transition Model (DTM) shows how birth and death rates impact population change.

Demographic Tools

  • Crude Birth Rate: Number of births per thousand people.
    • A falling crude birth rate can infer societal changes.
  • Crude Death Rate: Number of deaths per thousand people.
    • High in early stages, falls with socioeconomic development.
    • Birth rates remain high initially due to cultural norms, then decline.
  • Total Fertility Rate: Average number of children a woman has in her lifetime (statistical measure based on past and future predictions).
    • High fertility rates in Sub-Saharan Africa, Afghanistan, and parts of the Middle East.
    • Low fertility rates correlate with stable or declining populations.
  • Doubling Time: Number of years for a population to double.
    • Related to the natural increase rate.
    • Faster population growth means shorter doubling time.
  • Natural Increase Rate: Difference between crude birth rate and crude death rate.
    • Calculation: NIR = CBR - CDR
    • Doubling Time Calculation: \text{Doubling Time} = \frac{70}{NIR}

Impact on Total Population

  • Equal birth and death rates lead to stable population.
  • Death rate exceeding birth rate leads to population decline.
  • Birth rate exceeding death rate leads to population increase.

Stages of the Demographic Transition Model

  • Stage 1: High birth rates and high death rates.
  • Stage 2: Falling death rates, high birth rates.
  • Stage 3: Declining birth rates approaching death rates, slowing population growth.
  • Stage 4: Low birth rates and low death rates, stable populations (MEDCs).
  • Future: Some developed nations (Japan, Sweden, Norway, Denmark) show death rates exceeding birth rates and shrinking populations.

Age-Sex Pyramids

  • Relate pyramid shapes to DTM stages.
    • Stage 1 (Rapid Growth): Wide base (high birth rate), narrow top (high death rate).
    • Stage 2 (Slow Growth): High birth rate, declining death rate (people living longer).
    • Stage 3 (Stabilizing): Straight/vertical sides indicate more people living to older ages.
    • Stage 4 (Low Birth Rates): Fewer births than before, aging population.

Model Evaluation

  • Age-sex pyramids and DTMs are models with strengths and weaknesses.
  • Important to discuss the effectiveness and use of these models.

8.2 Resource Use in Society

  • Growing population increases demands on Earth's resources.

Renewability of Resources

  • Renewable Resources: Replaced as fast as used.
  • Replenishable Resources: Replaced more slowly but can be replaced.
  • Non-Renewable Resources: Finite, cannot be replaced within human time scales.
  • Sustainability means using resources at a rate that allows for natural replacement (Topic 1.4).

Renewable Natural Capital

  • Living species and ecosystems harnessing solar energy (photosynthesis).
  • Examples: forests, fish populations, agricultural crops, groundwater, ozone layer.
  • Restock themselves through growth.

Non-Renewable Natural Capital

  • Cannot be replaced within human time scales; formed over millions of years.
  • Examples: fossil fuels (coal, oil, natural gas), minerals, soil.
  • Depleting a finite supply when used.

Sustainable vs. Unsustainable Use

  • Natural Income: Growth or yield produced by natural capital (e.g., agricultural harvests, timber growth, animal populations).
  • Sustainable approach: use only natural income and preserve original capital.
  • If harvest exceeds growth, stocks will decrease; if growth exceeds harvest, stocks will increase.
  • Sustainable use means using only what regrows (e.g., cutting trees at the same rate they regenerate).
  • Even renewable resources can become unsustainable due to extraction, transport, and processing methods.
  • Example: Fishing technologies leading to overharvesting and depletion of fish populations.

Mismanaged Resources

  • Examples:
    • Renewable: Solar energy in Africa (underutilized).
    • Non-renewable: Fossil fuels.
  • Identify sustainable management strategies, contrast with actual practices, and describe consequences.

Dynamic Status and Value of Natural Capital

  • Resources have economic, cultural, religious, or intrinsic value.
  • People with different EVSs value resources differently (ecocentric to technocentric).
  • Natural capital provides goods and services.

Ecological Goods

  • Tangible products: metals from ores, electricity from water, crops from soil, timber from forests.
  • Physical resources extracted and used.

Values of Natural Capital

  • Use Values: Require human interaction.
    • Direct use: timber.
    • Indirect use: ecosystem services.
  • Non-Use Values: Exist without human interaction.
    • Existence value: valuing something simply exists.
    • Bequest value: preserving resources for future generations.

Ecological Services

  • Benefits provided by ecosystems not monetized in markets.
  • Examples: oxygen production, carbon sequestration, water purification, flood control, climate regulation.
  • Vulnerable to degradation as value isn't reflected in market prices.
  • Mountains provide various ecological services like water storage, climate regulation, habitat, and spiritual value.

Varying Value of Natural Capital

  • Uranium price fluctuations due to technological, political, and environmental factors.
  • Coltan's value skyrocketed with technology evolution, leading to conflict mining and environmental devastation.

Cultural Differences in Resource Valuation

  • Wildlife reserves in East Africa valued differently by tourists and local communities.
  • Ethical dilemmas: wilderness preservation vs. exploration for medicinal plants.

8.3 Solid Domestic Waste

  • Growing populations and consumption patterns increase waste.

Waste Increase

  • Solid domestic waste increasing due to population and consumption rates.
  • Amount consumed directly correlates to waste produced.
  • Hong Kong data (1991-2017): Waste increased then declined, with paper, ferrous metals, and plastic being recycled.

Non-Biodegradable Waste

  • Plastics, batteries, e-waste create environmental issues.
  • E-waste contains valuable and hazardous resources.

Disposal Options

  • Landfilling, recycling, incineration, composting.
  • Each has advantages/disadvantages based on environmental impact, cost, and resource recovery.
  • Incineration also called combustion with energy recovery.

Waste Management Hierarchy

  • Prevention/reduction > reuse > recycling > energy recovery > disposal (landfill).
  • Composting falls under recycling.
  • Reduction requires changing consumption behaviors.
  • Both production and management of solid waste influence sustainability.

Circular Economy Model

  • Transforms linear take-make-dispose model to a system where materials cycle continuously.
  • Reduces virgin material extraction and conserves resources.

Three-Tiered Approach to Pollution Management

  • Tier 1: Altering human activity (most effective).
  • Tier 2: Controlling release of pollutant (regulating standards).
  • Tier 3: Cleanup and restoration (least effective, most expensive).
  • Examples: campaigns, education, legislation, economic incentives, technology for pollutant extraction.

Pollution Management Across Four Phases

  • Sourcing, production, use, end of life.
  • Each phase contains specific strategies connected to the three management tiers.

Waste-to-Energy Facilities

  • Convert solid domestic waste to electricity through combustion.
  • Include pollution control systems.
  • Address cleanup/restoration tier while generating energy but produce ash needing landfill disposal.

Shifts in Disposal Options

  • Recycling and incineration increased, landfilling decreased since 1960 due to environmental awareness, economic factors, and regulations.
  • Waste hierarchy explains preferred options based on environmental impact and conservation.

EU Data on Waste Management

  • Northern European countries emphasize recycling and incineration; southern countries rely on landfilling.
  • Reflects economic, cultural, and policy variations.

Evaluating Solid Domestic Waste Strategies

  • Consider system inputs, outputs, and connections to other systems.
  • Effectiveness relates to overall waste reduction; efficiency considers reduction per unit cost.
  • Strategies vary in effectiveness for different waste types and impacts on ecological, economic, and social systems.

Comprehensive Framework for Pollution Management

  • Evaluates recycling to landfilling.
  • Each option has specific contexts, impacts, advantages, and opportunities.
  • Mechanical recycling works for specific plastics; incineration handles diverse waste streams but produces emissions.

International and Development Influences

  • Pollution crosses borders; e-waste ships from developed to developing nations.
  • Marine litter affects international waters.
  • Development level influences solid domestic waste and management capacity.

Circular Economy as Paradigm Shift

  • Emphasizes continuous material cycling instead of disposal.
  • Changes economic model affecting resource use and environmental responsibility.

8.4 Human Population Carrying Capacity

  • Human carrying capacity is difficult to quantify.

Challenges in Measuring Carrying Capacity

  • Humans import and export resources between ecosystems.
  • We substitute resources.
  • We develop new technologies.
  • These factors make our relationship with Earth's carrying capacity unique.

Ecological Footprint (EF)

  • Model to determine if human populations live within carrying capacity.
  • Asks how much area is needed to sustainably support a population.
  • Measures land and water required to support a population at a specific standard of living.
  • Includes land for carbon absorption, forests, crop land, grazing land, fishing grounds, and built-up land; measured in global hectares.

EF Model

  • Estimates demands humans place on the environment (built environment, agriculture, fishing, forest use, grazing, fossil fuel consumption).
  • Activities vary between LEDCs and MEDCs.
  • Generally, MEDCs have higher ecological footprints.

Variations in Ecological Footprints

  • Vary by country and individual factors (lifestyle, productivity, land use, industrial activities).
  • If a population's EF exceeds available land area, they are living unsustainably.
  • Largest per-person footprints: Qatar, Kuwait, UAE, Denmark, USA.
  • African countries have smaller footprints.

Limits to Human Population Growth

  • Environmental degradation and finite resources limit growth.
  • Pollution, resource depletion, and habitat destruction reduce Earth's capacity.
  • Populations can overshoot carrying capacity, deplete natural capital, and cause a population crash.

Challenges of Rapid Population Growth

  • Food supply, resource availability, environmental quality, and economic systems face pressure.
  • Impacts felt differently across society, affecting international relations.
  • MEDCs generally have larger ecological footprints than LEDCs.

Environmental Value Systems

  • Impact ecological footprints; different worldviews lead to different consumption patterns.
  • Short-term thinking about development has long-term consequences.

International-Mindedness

  • Connects to sustainability through global resource management.
  • Resources don't respect national boundaries.

TOK Perspective

  • Measuring human carrying capacity involves objective data and subjective interpretation.
  • Environmental science combines empirical evidence with value judgments.