Ultimate Environmental Systems and Society Exam Review Study Notes

Topic 1: Foundations

1.1 Perspectives

Definition: Environmental perspectives are shaped by personal values and world views, influenced by sociocultural context and lived experiences.
Importance: How we perceive environmental issues affects our decisions and actions towards sustainability.
Key Concepts: - Environmental Value Systems - Worldviews - Anthropocentrism: A human-centered perspective prioritizing human interests. - Ecocentrism: An ecological perspective that values all living organisms and ecosystems. - Technocentrism: A viewpoint prioritizing technology and engineering solutions to environmental issues. - Stakeholders: Individuals or groups that are affected by or have an interest in environmental issues.

1.2 Systems

Systems Thinking: A method to comprehend both natural and human-constructed systems.
Structure of Systems: Includes storage and flows of energy and matter.
Feedback Mechanisms: Reveal how systems maintain equilibrium and how changes propagate through interconnected components.
Key Concepts: - Open Systems: Systems that exchange both matter and energy with their surroundings. - Closed Systems: Systems that exchange energy but not matter with their surroundings. - Feedback Loops: Processes that amplify or dampen changes in a system. - Equilibrium: A state of balance in a system. - Tipping Points: Critical thresholds at which a small change can lead to significant effects.

1.3 Sustainability

Definition: Sustainability is the balance of three pillars: Environmental, Social, and Economic, ensuring intergenerational equity and environmental justice.
Natural Capital Management: Responsible management of natural resources using measurable indicators and frameworks, e.g., UN Sustainable Development Goals (SDGs).
Key Concepts: - Three Pillars: Environmental, Social, Economic. - Natural Capital: The world's stocks of natural assets. - Intergenerational Equity: Fairness in resource allocation across generations. - Ecological Footprint: A measure of human demand on Earth's ecosystems. - Sustainability Indicators and Frameworks.
Higher Level (HL) Concepts: - Strong Sustainability: A model embedding economy within society, which is in turn within the natural environment. - Planetary Boundaries: Nine earth system processes that, when crossed, pose irreversible risks to life on Earth (e.g., climate change). - Biocapacity: The capacity of an ecosystem to produce biological materials and absorb waste. - Donut Economics: A model aiming for sustainable development within an ecological ceiling. - Circular Economy: An economic system aimed at eliminating waste and promoting the continual use of resources.

Topic 2: Ecology

2.1 Individuals, Populations, Communities, and Ecosystems

Ecosystem Functioning: Ecosystems operate as open systems where populations interact. Biotic (living) and abiotic (non-living) factors shape species distribution.
Carrying Capacity: The maximum population an environment can sustain, affected by density-dependent factors (e.g., competition) and density-independent factors (e.g., climate).
Population Growth Patterns: Follow predictable patterns affected by these factors.
Key Concepts: - Carrying Capacity - Ecological Niches: The role of a species within its ecosystem. - Population Growth Curves: Graphical representation of population size over time. - Biotic Interactions: Interactions among living organisms.
HL Concepts: - Exponential Growth: A growth pattern where individuals reproduce at a constant rate. - Logistic Growth: A growth pattern that stabilizes when carrying capacity is reached, depicted as an S-curve. - Boom and Bust Patterns: Occur when populations exceed carrying capacity and subsequently experience die-back.

2.2 Energy and Biomass in Ecosystems

Energy Flow: Energy moves in one direction through trophic levels (e.g., from producers to various consumer levels).
Efficiency of Energy Transfer: Energy diminishes at each level due to heat loss and biochemical processes.
Key Concepts: - Trophic Levels: The hierarchical levels in a food chain. - Energy Transfer: The transfer of energy through food chains. - Productivity: The measure of energy captured by producers in an ecosystem. - Biomass: The total mass of living matter in a given area.
HL Concepts: - Gross Productivity: Total energy captured by producers. - Net Productivity: Remaining energy after respiration is accounted for. - Ecological Efficiency: The percentage of energy transferred between trophic levels (typically around 10%).

2.3 Biogeochemical Cycles

Cycle of Matter: Matter cycles continuously through ecosystems via biogeochemical processes (e.g., carbon cycle, nitrogen cycle).
Disruption by Humans: Human activities alter natural cycling processes, affecting ecosystems.
Key Concepts: - Carbon Cycle - Nitrogen Cycle - Decomposers: Organisms that break down dead organic matter. - Eutrophication: Nutrient enrichment of water bodies causing excessive growth of algae.
HL Concepts: - Nitrogen Cycle: Involves fixation, nitrification, and denitrification processes. - Human Impacts: Doubling of reactive nitrogen leading to pollution and greenhouse gas emissions.

2.4 Climate and Biomes

Climate Influence: Global temperature and precipitation patterns inform which biomes exist where on Earth.
Species Adaptation: Climate shapes the adaptations of species and ecosystem productivity.
Climate Change Impact: Alters biological event timing and biome boundaries.
Key Concepts: - Biomes: Large ecological areas on the Earth's surface. - Climate Zones: Areas with distinct climates and organisms. - Tricellular Atmospheric Model: Explains global atmospheric circulation.
HL Concepts: - Hadley, Ferrel, and Polar Cells: Key features of atmospheric circulation. - Ocean Currents: Interact with climate zones to modify regional climates.

2.5 Zonation, Succession, and Change in Ecosystems

Ecosystem Change Over Time: Ecosystems evolve through the processes of succession.
Spatial Change: Changes in ecosystems from one region to another (zonation).
Diversity and Resilience: The development from pioneer species to climax communities determines ecosystem resilience and productivity.
Key Concepts: - Primary Succession: Establishment of an ecosystem on lifeless ground. - Secondary Succession: Recovery after disturbances. - Pioneer Species: First organisms to colonize previously disrupted or damaged ecosystems. - Climax Community: A stable community that represents a final stage of succession.
HL Concepts: - R-strategists vs. K-strategists: Different reproductive strategies impacting community dynamics and stability. - Net and Gross Productivity Patterns: Changes during succession are predictable.

Topic 3: Biodiversity and Conservation

3.1 Biodiversity and Evolution

Levels of Biodiversity: Physical diversity exists at three levels: genetic, species, and habitat diversity.
Natural Selection: Drives evolutionary processes, shaping biodiversity through environmental interactions.
Key Concepts: - Genetic Diversity: Variability in the genetic makeup among individuals. - Species Diversity: Variety of species in a given area. - Habitat Diversity: Variation of habitats in a region.
HL Concepts: - Reproductive Isolation: Can lead to new species via geographical, ecological, or behavioral barriers. - Human Influence: Activities such as poaching and habitat fragmentation alter evolutionary trajectories, impacting biodiversity.

3.2 Human Impacts on Biodiversity

Direct and Indirect Threats: Overharvesting, poaching, pollution, and habitat loss threaten biodiversity.
Amplification of Threats: Ecosystems often experience multiple threats simultaneously, degrading resilience.
Key Concepts: - IUCN Red List: Tracks the conservation status of species. - Tragedy of the Commons: The overexploitation of shared resources.
HL Concepts: - Biodiversity Hotspots: Regions rich in biodiversity that face significant threats. - Key Biodiversity Areas (KBAs): Sites identified for their importance in global ecosystems. - Traditional Indigenous Land Management: Sustainable practices at risk from economic development pressures.

3.3 Conservation and Regeneration

Conservation Justifications: Aesthetic, ecological, economic, ethical, and social arguments for conservation strategies.
Types of Conservation Strategies: - Ex-situ Conservation (XC2): Protecting species outside their natural habitats (e.g., zoos). - In-situ Conservation (INC2): Protecting species within their natural habitats (e.g., national parks).
Key Concepts: - Convention on Biological Diversity (CBD): Supports conservation strategies at international levels. - Restoration Ecology: Can involve reintroducing apex predators and connecting habitats.
HL Concepts: - Effectiveness of Conservation: Depends on protected area size, shape, buffer zones, and connectivity via wildlife corridors. - Rewilding: Involves reintroducing species and restoring ecosystems, potentially creating positive feedback loops.

Topic 4: Water

4.1 Water Systems

Hydrological Cycle: Describes the movement of water in different states through evaporation, condensation, precipitation, runoff, and transpiration.
Water Storage: Found in oceans, ice, groundwater, and fresh bodies.
Climate Regulation: Oceans affect climate through currents, upwelling, and ENSO events.
Key Concepts: - Ocean Currents: Drive heat distribution worldwide. - ENSO: A periodic disruption in ocean-atmosphere interactions in the Pacific.

4.2 Water Access, Use, and Security

Freshwater Availability: Influenced by geography, economics, and politics.
Water Security Threats: Overextraction and pollution heighten risks.
Management Strategies: Address conservation and equitable distribution.
Key Concepts: - Water Stress: Imbalance of water supply and demand. - Virtual Water: Water embedded in products. - Water Footprint: The total volume of freshwater used for the production of goods.

4.3 Aquatic Food Production Systems

Food Sources: Wild fisheries and aquaculture serve billions but face sustainability challenges.
Management Needs: Sustainable yield practices and marine protected areas are critical.
Key Concepts: - Overfishing: Depleting fish populations faster than they can recover. - Aquaculture: Farming of aquatic organisms. - Bycatch: Unintentional capture of non-target species in fisheries.

4.4 Water Pollution

Pollution Sources: Point source (specific location) and non-point source (diffuse sources) pollution types.
Consequences: Includes eutrophication and bioaccumulation.
Key Concepts: - Biochemical Oxygen Demand (BOD): Indicator of organic matter in water. - Biomagnification: Increasing concentration of pollutants in organisms at higher trophic levels.

Topic 5: Land

5.1 Soil Systems

Soil Formation: Occurs through weathering, decomposition, and biological activity.
Key Functions: Soil supports plant growth, recycles nutrients, and serves as a habitat.
Key Concepts: - Soil Horizons: Layers in the soil. - Leaching: Nutrient loss due to water movement.
HL Concepts: - Soil Degradation: Caused by erosion, salinization, and desertification. - Conservation Methods: Strategies to prevent degradation, including crop rotation and sustainable practices.

5.2 Food Production Systems and Soil

Diversity of Production Systems: Industrial vs. organic farming systems have different environmental impacts.
Challenges: Balancing nutrient needs with ecosystem health.
Key Concepts: - Industrial Agriculture: High-input farming with significant environmental impacts. - Organic Farming: Sustainable practices that focus on soil health.
HL Concepts: - Dietary Shifts: Transitioning toward plant-based diets can enhance sustainability.

Topic 6: Atmosphere and Climate Change

6.1 Introduction to the Atmosphere

Layered Structure: The atmosphere consists of several layers with varying compositions.
Key Factors: Greenhouse gases, albedo effect, and atmospheric circulation are crucial for regulating energy balance and climate.
Key Concepts: - Troposphere: Lowest layer where weather occurs. - Stratosphere: Contains the ozone layer—important for absorbing UV radiation.

6.2 Climate Change Causes and Impacts

Anthropogenic Influences: Greenhouse gas emissions are the primary drivers of climate change.
Impacts: Include rising temperatures, altered weather patterns, and ecosystem disruptions.
Key Concepts: - Enhanced Greenhouse Effect: Increased greenhouse effect due to human activities. - Sea Level Rise: Resulting from thermal expansion and glacial melts.

6.3 Climate Change Mitigation and Adaptation

Mitigation Strategies: Focus on reducing emissions through renewable energy and energy efficiencies.
Adaptation Needs: Helps societies cope with unavoidable impacts; includes resilient infrastructure and ecosystem approaches.
Key Concepts: - Renewable Energy Transition: Shifting from fossil fuels to sustainable energy sources. - Carbon Sequestration: Capturing and storing atmospheric CO2.

6.4 Stratospheric Ozone Depletion

Ozone Layer Threats: Depletion due to chlorofluorocarbons (CFCs) leading to increased UV radiation.
Recovery Efforts: The Montreal Protocol as a model for international cooperation.
Key Concepts: - CFCs: Chemicals that harm the ozone layer. - HFCs: New refrigerants that, while replacing CFCs, are yet potent greenhouse gases.

Topic 7: Natural Resources

7.1 Natural Resource Use and Management

Natural Capital: Provides ecosystem goods and services essential for human well-being.
Management Strategies: Balancing consumption rates with regeneration rates is crucial.
Key Concepts: - Ecosystem Goods: Tangible materials obtained from ecosystems. - Ecosystem Services: Benefits provided by ecosystems. - Intrinsic Value: The inherent worth of nature.

7.2 Energy Sources, Uses, and Management

Diversity of Energy Systems: Both renewable and non-renewable energy sources are utilized.
Concerns: Sustainability varies by environmental cost, depletion rate, and carbon emissions.
Key Concepts: - Energy Security: The availability of reliable and affordable energy sources. - Fossil Fuels: Non-renewable energy sources leading to environmental degradation.

7.3 Solid Waste

Problem of Waste: Linear economies produce waste that must be managed.
Management Strategies: Include reduction, reuse, recycling, and composting efforts.
Key Concepts: - Circular Economy: A model promoting sustainability by designing out waste. - Landfills: Common waste disposal sites with environmental implications.

Topic 8: Human Populations and Urban Systems

8.1 Human Populations

Population Dynamics: Measured through demographic indicators such as birth rates and life expectancy.
Demographic Transition Model (DTM): Links development stages with population changes influenced by societal factors.
Key Concepts: - Total Fertility Rate (TFR): Average number of children born to a woman over her lifetime. - Population Momentum: Continued population growth even after replacement-level fertility is achieved.

8.2 Urban Systems and Planning

Urbanization Effects: Concentration of populations in urban centers creates complex systems.
Sustainable Planning: Incorporates green infrastructure to balance environmental, social, and economic needs.
Key Concepts: - Mixed Land Use: Combines residential, commercial, and recreational spaces. - Ecological Design: Integrates sustainable practices into urban development.

8.3 Urban Air Pollution

Pollutants: Primary (directly emitted) and secondary pollutants lead to serious health and environmental impacts.
Management: Emission controls and urban design changes can mitigate pollution.
Key Concepts: - Particulate Matter: Tiny particles that contribute to health issues and environmental concerns. - Photochemical Smog: Air pollution formed through the reaction of sunlight with primary pollutants.

Higher Level Lenses for Environmental Systems and Society

HL Lens A: Environmental Law

Regulation: Governs resource use, pollution, and biodiversity protection at various scales.
Effectiveness Factors: Varies based on enforcement capacity and political will.
Key Concepts: - International Agreements: Essential for addressing transboundary environmental issues. - Environmental Constitutionalism: Embedding environmental protections within legal frameworks.

HL Lens B: Environmental Economics

Market Failures: Occur when environmental costs are externalized, necessitating economic instruments for correction.
Valuation of Ecosystem Services: Assigns economic worth, raising ethical concerns and methodological challenges.
Key Concepts: - Payments for Ecosystem Services (PES): Financial incentives for conserving ecosystem services. - Steady-State Economics: Prioritizes ecological sustainability over GDP growth.

HL Lens C: Environmental Ethics

Ethical Frameworks: Range from anthropocentric to ecocentric perspectives on our responsibilities toward nature.
Environmental Justice: Addresses inequities in resource distribution and advocates for fair treatment.
Key Concepts: - Intrinsic vs. Instrumental Value: Differing views on the worth of non-human entities. - Indigenous Knowledge: Expands ethical considerations beyond Western frameworks.

Interconnections and Exam Preparation

All topics are interconnected through systems thinking, sustainability practices, and diverse perspectives.
Utilize these connections to enhance comprehension and application in exam contexts, particularly in paper 2 structured essays.
Regularly review key concepts and apply them to real-world case studies to deepen understanding.