IB ESS Topic One Review Notes

Foundations of ESS

Influences on the Modern Environmental Movement

• Historical events shape perceptions and responses to environmental issues, forming what's known as an environmental value system.

• Inputs to value systems come from:

  • Literature

  • Media

  • Environmental disasters

  • International agreements

  • Technological developments

Literature

• Henry David Thoreau's "Walden" (mid-1800s): Introduced transcendentalism, the idea that nature is divine, and promoted self-reliant soft ecologism.

• Aldo Leopold's "Sand County Almanac" (mid-20th century): Introduced the concept of human stewardship over natural systems.

• Rachel Carson's "Silent Spring" (1962):

  • Linked pesticide use to ecosystem health.

  • Signaled the beginning of the end for DDT.

• Edward Abbey: Books like "Desert Solitaire" and "The Monkey Wrench Gang" spurred environmental activism in the US during the mid to late 20th century.

Media

• John Muir and the Sierra Club (19th century):

  • Raised awareness of the Yosemite Valley's beauty.

  • Established the first large-scale environmental preservation society with an earth-centered value system.

  • Lost the battle against dams, leading to the inundation of some protected lands.

• Bhopal Disaster (mid-1980s):

  • Thousands died due to a gas leak.

  • Showed the negative impacts of industrialization and exploitation of impoverished communities.

  • Union Carbide paid minimal penalties relative to the loss of human life.

• Chernobyl (mid-1980s):

  • Worst nuclear disaster at the time.

  • Illustrated that environmental issues are not confined by national borders as radiation spread across Europe.

• Deepwater Horizon Explosion (2010):

  • Record-setting oil spill covered on live television.

  • Negatively impacted offshore oil drilling and resource valuation.

Natural Disasters

• Passenger Pigeon Extinction (early 20th century):

  • Changed attitudes about endless resources.

  • Aroused interest in conservation.

• Dust Bowl (mid-1930s):

  • Wiped out families, prompted migration.

  • Led to new soil conservation techniques.

• Minamata Disease: Mercury poisoning from fish in Minamata Bay, Japan.

• Love Canal: Exposure to toxic waste led to grassroots activism.

• Three Mile Island: Nuclear meltdown covered by the media.

• Fukushima (2011): Ongoing media attention due to the release of contaminated water.

International Agreements

• Yellowstone National Park (late 19th century): Formation of protected areas.

• CITES (Convention on the International Trade in Endangered Species): Focuses on international trade in endangered species.

• Brundtland Report: Introduced the concept of sustainable development.

• Montreal Protocol:

  • Considered the most successful international environmental agreement.

  • Will be studied in Topic Six.

• Earth Summits (COP Summits), Kyoto Accord, Paris Climate Conference (2015): Shape the perception of environmental issues globally, influencing behaviors and worldviews (environmental value systems).

Systems and Models

Systems

• Definition: A set of interrelated parts working together to form a complex whole.

• Example: Ecosystems, comprised of living and non-living components interacting and exchanging matter and energy.

• Systems Approach: A way of visualizing complex interactions (ecological or societal) to understand how factors affect each other and the whole system.

• Barry Commoner's quote: "Everything is linked to everything else."

• Benefits: Reveals emergent properties.

• Emergent Properties: Characteristics not found in individual parts but arising from their interactions (e.g., biodiversity in an ecosystem).

• Scale: Systems exist at microscopic (cells) to global (Earth) scales.

• Components:

  • Storages: Accumulation of matter or energy within the system.

  • Flows: Movements of matter or energy into or out of the system, providing inputs and outputs.

• Types of Flows:

  • Transfers: Movement from point A to point B (e.g., water moving through precipitation).

  • Transformations: Change of form or state (e.g., photosynthesis transforming light energy into chemical energy).

• Systems Diagrams:

  • Storages: Rectangular boxes.

  • Flows: Arrows, indicating direction; size can represent magnitude.

• System Types:

  • Open: Exchanges both energy and matter with the environment (e.g., ecosystems).

  • Closed: Exchanges energy but not matter (e.g., terrarium).

  • Isolated: No exchange of energy or matter (hypothetical, e.g., ideal thermal flask; doesn't exist in nature).

Ecosystems and Geochemical Cycles

• Ecosystems are open systems.

• Closed systems exist experimentally.

• Geochemical cycles approximate closed systems.

Models

• Definition: Simplified version of reality used to understand and predict system behavior.

• Types: Physical, mathematical, conceptual, computer-based.

• Limitations: Inevitable approximations and loss of accuracy.

• Evaluation Criteria: Validity, reliability, accuracy, usefulness.

• Construction Steps:

  • Identify key components and processes.

  • Represent them using symbols and rules.

  • Make simplifying assumptions.

  • Test and refine the model with data.

Use of Models

• Advantages: Simpler to understand, can be changed without real-world effects, predict hypothetical scenarios.

• Disadvantages: Incomplete, accuracy depends on input data, liable to human error.

• Example: Climate change predictions based on computer models.

  • Usefulness: Understand causes and effects, explore scenarios.

  • Limitations: Based on incomplete data, may not account for all feedbacks.

Energy and Equilibria

Thermodynamics

• Fundamental principles governing energy behavior in ecosystems.

• Key idea: The laws of thermodynamics govern how energy flows through ecosystems and dictate organisms' ability to do work.

• First Law of Thermodynamics (Conservation of Energy):

  • Energy can be transformed but not created or destroyed in an isolated system.

  • Total energy remains constant; it can only change form.

  • Life exists on Earth because energy can be transferred from one system to another (e.g., solar energy from the sun).

• Second Law of Thermodynamics:

  • The entropy of a system increases over time.

  • Entropy: A measure of disorder or randomness.

  • Energy transformations reduce the available energy to do work.

  • Energy is lost as heat, which cannot be used by living organisms.

  • $10\%$ rule: Only about $10\%$ of energy is transferred to the next trophic level.

  • Responsible for the structure of ecological pyramids, where higher trophic levels have less biomass.

Equilibrium

• Definition: A state where there's no net change in a system over time.

• Types:

  • Static: No movement or change (e.g., a rock on the ground).

  • Dynamic: Movement, but balanced by opposing forces (e.g., a swinging pendulum).

• Ecosystems typically exist in dynamic equilibrium (steady-state or successional).

  • Maintained by stabilizing negative feedback loops.

  • Steady-state: Constant conditions and flows (e.g., a mature forest).

  • Successional: Changing conditions and flows until a climax community is reached.

Feedback Loops

• Negative Feedback Loop:

  • Reverses the direction of initial change, counteracting deviations from equilibrium.

  • Example: Thermostat regulating temperature. The thermostat turns off the heat, causing a gradual drop in the temperature. When the temperature becomes too cool, the thermostat turns on the heat again, raising the temperature. The cycle repeats itself, maintaining a dynamic equilibrium around the desired temperature.

  • Natural systems depend on negative feedback for stability.

• Positive Feedback Loop:

  • Amplifies the initial change, driving the system towards a tipping point and adopting a new equilibrium.

  • Example: Ice melt driven by climate change.

    • $\text{Temperature Increase} \rightarrow \text{Arctic Ice Melts} \rightarrow \text{Reduced Albedo} \rightarrow \text{Increased Solar Radiation Absorption} \rightarrow \text{Further Temperature Increase}$

  • Permafrost time bomb:

    • $\text{Warmer Temperatures} \rightarrow \text{Permafrost Melts} \rightarrow \text{Methane Released} \rightarrow \text{More Warming}$

Tipping Points

• Definition: A critical threshold where a small change can have large, irreversible effects.

• Example: A runaway greenhouse effect making Earth uninhabitable.

Resilience

• Definition: A system's ability to avoid tipping points and maintain stability.

• Factors:

  • Diversity: Variety of components and processes, providing redundancy and flexibility.

    • Example: The Serengeti ecosystem has high diversity within food webs, alternative energy pathways.

  • Size of Storages: Amount of matter or energy that buffers against fluctuations (e.g., carbon or water storage).

• Human Impact: Humans reduce resilience through activities like deforestation, overfishing, and pollution.

• Delays in Feedback Loops: Make it difficult to predict tipping points, adding complexity to modeling systems.

  • Time lags in climate systems due to the atmosphere and oceans inertia.

Sustainability

Natural Resources

• Materials and services people use.

• Categories:

  • Renewable: Can be replaced or restocked.

  • Non-renewable: Finite.

  • Replenishable: Can be replenished with proper management, but slowly.

    • Example: Soils and potable water.

Natural Capital

• Definition: Storage of a natural resource.

  • Examples: Fresh water, soil nutrients, timber.

• Valuation: Monetary or intrinsic.

• Includes Ecosystem Services:

  • Example: Oxygen production by plants.

  • Carbon sequestration.

Natural Income

• Definition: How natural capital goods or services grow and increase.

  • Example: Interest on a bank account.

• For sustainability, harvest should not diminish natural capital storage.

  • If a woodlot grows 1000 board feet of timber annually, harvesting only up to 1000 board feet maintains the woodlot.

Ecological Goods and Services

• Ecological Services: Soil formation, photosynthesis, pollination, flood control, water purification, carbon sequestration.

• Ecological Goods: Food, clean water, wood, habitat.

• Relationship between Natural Capital, Natural Income, and Sustainability

Sustainable Development

• Meeting the needs of the present without compromising the ability of future generations to meet their own needs.

• Sustainable use of natural resources.

• Factors that can be quantitatively measured as environmental indicators of sustainability:

  • Biodiversity

  • Pollution

  • Population

  • Climate

• Environmental Indicators of Sustainability:

  • Biodiversity:

    • Measured with Simpson's Diversity Index, which correlates stronger, more resilient ecosystems with greater diversity.

  • Pollution:

    • Measured by types and levels of pollutants. Less pollution correlates with a lower impact on living organisms.

  • Populations:

    • Measured using the Ecological Footprint. The more stable an ecosystem is, the greater the populations and the greater the diversity due to increased genetics.

  • Climate:

    • Measured via the number of greenhouse gasses in the atmosphere to regulate a stable global temperature. By maintaining the greenhouse effect, a more sustainable approach is garnered.

Millennium Ecosystem Assessment (MA)

• Scientific appraisal of trends in world ecosystems and their services to people.

• Major Takeaways:

  • Greater diversity loss in the past 50 years.

  • Increased human wealth and health at the expense of ecological goods and services.

  • Unsustainable harvesting of natural capital.

  • Sustainable solutions require international coordination.

Environmental Impact Assessments (EIAs)

• Determining scope and environmental impacts of a party's actions.

Framework:

1. Baseline Study. Measure the current state of the environment before impacts begin; impacts on social and economic factors.

2. Planning. If the project continues, analyze how to reduce environmental impacts and how to maximize social and economic impacts to benefit as many people as possible.

3. Plan Implementation. Follow the approved plan while measuring and monitoring how things occur.

4. Assessment. Measure and evaluate if the actual project results match predicted impacts. If not, the project is changed as a result.

Criticisms

• Lack of standard practice.

• Difficulty defining system boundaries.

Ecological Footprint

• Theoretically required land and water area to provide resources sustainably.

  • If the area required is greater than what the population has available, the population is not using resources sustainably.

• A function of the resources and habits of a population.

• How much things cost to keep a population alive for a year.

• Related to ecosystem services, sustainability, and a population's ability to renew based on resource use and the amount of pollutants emitted into that environment.

• Evaluate progress by measuring environmental indicators, such as those found in a particular project.

• Evaluate EIA use via the strengths identified, and limitations, such as a conflict between environmental consequences versus the benefits to social and economic sectors.

Humans and Pollution

Definition and Elements of Pollution

• Pollution is a human disturbance in the environment.

• Four elements to the definition:

  • Made or caused by people.

  • Something added to the ecosystem.

  • Added to the ecosystem faster than it can process it.

  • Has an impact on life there.

Types of Pollutants

• Discuss and give examples of each of these types of pollutants for the ESS exam!

• Organic or inorganic substances.

  • Organic: sewage and animal waste (nutrient-rich).

  • Inorganic pollutants.

• Excess energy

  • light pollution.

  • excessive sound.

  • excessive heat.

• When humans bring in invasive species.

  • Example. Kudzu was brought in for erosion control, but grew rampantly due to a lack of a predator in the environment from which it was displaced.

• Combustion of fossil fuels to produce carbon dioxide and other greenhouse gasses.

Pollution Sources

• Point source: From a single point.

  • relatively simple control due to it being easy to identify on various maps.

• Non-point source. Accumulation of pollution from a variety of sources.

  • Agricultural runoff, for example. A single farm may release relatively small amounts of pollution, but landscape-wide, that amount becomes substantial.

  • It can even be difficult to identify WHO is even responsible for it in the first place.

Persistent vs. Biodegradable Pollutants

• Persistent pollutants. Do not degrade.

  • Lead to bioaccumulation and biomagnification.

• Biodegradable. Can be degraded through living processes.

  • Organic pollutants and more modern pesticides.

Bioaccumulation and Biomagnification

• Bodies of consumers can't break down the persistent pollutants. They are not excreted. They tend to build up in each individual's bodies.

• Bioaccumulation: a buildup of pollutants within a single organism's body as it consumes pollutants over time.

• Trophic Levels Increase Pollutant Consumotion, Biomagnification Results
  Biomagnification: increasing the concentration of a pollutant in trophic levels following the matter flow in a food chain.

• persistent pollutants: DDT, heavy materials.

Acute vs. Chronic Pollutants

• Acute. Short-term. Short term example of a train derailment.

• Chronic. Long-term. Can be a low-level exposure for a long time. Respiratory or cardiovascular diseases are a classic example.

Primary vs. Secondary Pollutants

• Topic to revisit during atmospheres.

• Primary pollutants (released and active). A negative impact on living organisms.

• Secondary pollutants product of chemical change (also has a lasting impact).

  • Photochemical smog example of where a release of nitrogen dioxide reacts with water to form smog from traffic.

Pollution Management Strategies:

• Ranked most effective to least effective.

• Tier One (Most Effective): Change human behavior by ceasing the pollutant from the source. Example. replace fuel, replace plastic with protections that serve an equal manner of utility.

• Tier Two: Produce pollutants by producing less of it. Example: increase MPG in vehicles; release less $CO_2$ into the atmosphere due to there being less need to burn fuel.

• Tier Three: (Least Effective) the pollutant continues to perpetuate through an environment. Example, cleaning damage after releasing pollution; it remains an expensive solution.

• DDT Evaluation: It is important for test preparations, so it is advantageous too.

DDT

• Is a great pesticide; kills mosquitoes, which are high pathogen vectors. Helps the human population by warding off Malaria, Dengue Fever, and Yellow Fever.

• Due to the publication of Silent Spring by Rachel Carson in 1962, it was then realized that DDT use had a detrimental impact on both humans AND the environment.

  • It also has a significant and broader impact throughout the environment.

• After DDT was banned, pests moved back and diseases rose back again!

• It causes an increase in more mortality among bird species, and causes disruption to food webs.

• Bioaccumulates and biomagnifies up the food chain.

Testing and ESS Examination.

• A student will construct a system's diagram based on the given example of the impacts of a pollutant and ask a student to comment.

• Effectiveness of the three tiers of pollution impact and it's impacts based on a three-tier system.

• State each of the pros and cons of the use of DDT. Describe its impacts on the human and natural ecosystems.