Chapter 1: Science and Sustainability: An Introduction to Environmental Science – Lecture Outlines

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• Source: Lecture Outlines for Environment: The Science Behind the Stories, James Dauray, Sixth Edition (Chapter 1).
• Focus: Introduction to environmental science, sustainability, and the scientific method.
• Purpose: Prepare students to understand how natural systems work, how humans interact with them, and how science informs environmental decisions.

Note: This page sets the stage for the course by presenting the origin of the materials and the scope of topics to be covered in Chapter 1.

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Lecture objectives

• Describe the field of environmental science.

• Compare renewable and nonrenewable resources.

• Explain the importance of natural resources.

• Discuss population growth and resource consumption.

• Explain ecological footprint.

• Describe the scientific method.

• Identify major pressures on the global environment.

• Discuss sustainability and cite examples.

• These objectives frame the course, linking natural resources, population dynamics, scientific inquiry, and sustainable practices.

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Our Island, Earth

• The environment consists of all living and nonliving things around us, including humans, who are part of nature.

• Environmental science is the study of:

  • how the natural world works,
  • how the environment affects us,
  • how we affect the environment.

• This page emphasizes the interconnectedness of humans and natural systems and sets up the systems-thinking approach used throughout the course.

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We rely on natural resources

• Natural resources are substances and energy sources taken from the environment.

• Renewable natural resources can replenish over short periods of time.

• Nonrenewable natural resources are finite in supply and form far more slowly than we use them.

• Implication: Resource management depends on renewal rates and consumption rates; unsustainable use leads to depletion.

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• Some renewable resources, like sunlight, are inexhaustible because they are constantly renewed.

• Others (timber, water, soil) renew over months, years, or decades and are exhaustible when consumption outpaces renewal.

• Key distinction: inexhaustible renewables vs exhaustible renewables.

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Ecosystem services

• Ecosystem services include:

  • purification of water and air,
  • cycling of nutrients,
  • recycling of water flow,
  • flood prevention,
  • erosion reduction.

• These services arise from normal ecosystem function.

• They can be depleted or degraded through overuse, pollution, habitat loss, and climate change.

• Concept: Humans depend on ecosystem services for survival and well-being; protecting ecosystems sustains these services.

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Population growth amplifies our impact

• Agricultural revolution: humans began growing crops, domesticated animals, and settled in villages.

• Result: population growth rate began to increase.

• Insight: Early changes in land use and agriculture set the stage for later population expansion and resource use.

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The industrial revolution and its effects

• Shift to urban society powered by fossil fuels (coal, oil, natural gas).

• Fossil fuels are nonrenewable energy sources.

• Improvements in medicine and agriculture contributed to population growth.

• Connection: Technological advances increase carrying capacity and resource demand, influencing sustainability challenges.

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Resource consumption and environmental pressures

• Population growth leads to increased consumption of the planet’s resources.

• An ecological footprint expresses this consumption as the area of land and water required to provide resources or absorb waste for an individual or population.

• Framework: Footprint accounting helps visualize pressure on ecosystems and informs policy and conservation strategies.

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• Our species is estimated to be using 64\% more of the planet’s renewable resources than are sustainably available.

• This condition is called an overshoot: we are surpassing Earth's capacity to sustainably support us.

• Implication: Immediate and long-term strategies are needed to reduce overshoot, including efficiency improvements, population stabilization, and changes in consumption patterns.

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Conserving Earth’s natural capital: a bank account analogy

• Natural capital includes all resources and ecosystem services.

• Living sustainably means not taking more of Earth’s renewable resources than can be replenished.

• Analogy: This is like living off the interest produced by a savings account; the principal (stock of resources) must be preserved for future withdrawals.

• Environmental scientists aim to study and develop solutions to problems caused by depleting natural capital.

• Takeaway: Sustainability requires balancing current needs with future availability.

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Environmental science is interdisciplinary

• Environmental science integrates multiple disciplines.

• Natural sciences study the life-supporting systems and physical processes.

• Social sciences examine human interactions, institutions, policies, and behavior.

• Central idea: Complex environmental problems require cross-disciplinary approaches for understanding and solutions.

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Distinctions among related fields

• Environmental science vs environmental studies vs environmentalism:

  • Environmental science emphasizes natural sciences and empirical inquiry.
  • Environmental studies emphasizes social sciences and humanities perspectives.
  • Environmentalism is a social movement advocating for environmental protection, not a scientific discipline.

• Importance: Clarifies scope and methodology across these related but distinct fields.

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The Nature of Science

• Science is a systematic process for learning about the world and testing our understanding.

• Many societal improvements (transportation, resource management) are informed by science.

• Theme: Science provides a framework for evidence-based decision making and policy.

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How scientists test ideas

• Descriptive science collects basic information about organisms, materials, or systems.

• Hypothesis-driven science seeks deeper explanations of how and why things occur.

• Experiments test hypotheses within the framework of the scientific method.

• Distinction: Data collection vs theory-driven hypothesis testing.

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The scientific method (traditional approach)

• Technique for testing ideas via a formal series of logical steps.

• First, an observation is made about a phenomenon to be explained.

• Core idea: Observation leads to questions that guide hypothesis formation and experimental testing.

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From observation to hypothesis

• Example question: What causes surface algae to grow heavily on a nearby pond?

• A testable explanation (hypothesis): Agricultural fertilizers running into the pond cause algae to increase.

• Process: Observation -> Question -> Hypothesis.

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From hypothesis to prediction and testing

• Prediction: If agricultural fertilizers are added to a pond, then the quantity of algae will increase.

• Next step: Conduct an experiment to test the prediction.

• Core idea: Hypotheses generate testable predictions to be evaluated experimentally.

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Variables in experiments

• Experiments manipulate conditions that can change" called variables.

• Independent variable: The variable that the researcher changes (e.g., fertilizer input).

• Dependent variable: The variable measured in response (e.g., quantity of algae).

• Example: Fertilizer input (independent) vs algae quantity (dependent).

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Controlled experiments and data collection

• In a controlled experiment, two identical groups are tested:
  • Control: not exposed to the independent variable (e.g., pond with no fertilizer runoff).
  • Treatment: exposed to the independent variable (e.g., pond with fertilizer runoff).
• Data are collected to compare outcomes between groups.

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Data types: quantitative measurements

• Researchers aim for quantitative data expressed with numbers, enabling statistical analysis.
• Examples:
  • Dry mass of algae per unit volume of water.
  • Percent of water surface covered by algae.

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Data visualization

• Graphs reveal patterns and trends in data.
• Line graphs: Show change over time.
• Pie charts: Show proportions of a whole.

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Statistical analysis

• Statistical tests assess the strength and reliability of observed patterns.
• Concepts:
  • Correlation between two variables.
  • Averaged measurements between two groups.

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Evaluating hypotheses

• Data and analysis may disprove a hypothesis, leading to rejection and new experimental design.
• A hypothesis may be supported but is never proven conclusively.
• Alternative explanations may be proposed and tested.
• Example question: Does the fertilizer kill fish and other animals that consume the algae?

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Scientific process vs scientific method (summarized diagrams)

• Two representations:

  • Scientific process (conducted by the scientific community): Observations → Questions → Hypothesis → Predictions → Test → Results → Publication → Peer review → Repeatability → Theory → (potential acceptance or revision) → New questions.
  • Scientific method (used by an individual researcher): Observations → Questions → Hypothesis → Predictions → Test → Results → Publication → Peer review → Repeatability → Theory.

• Outcome: If a hypothesis survives peer review and repeated testing, it may contribute to a theory.

• Theory: A broad explanation that integrates many hypotheses and is widely supported.

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Testing hypotheses in different ways

• Manipulative (experimental) experiments: Researchers actively control the independent variable (e.g., the pond algae study).
• Natural experiments: Occur when controlled experiments are not possible; dependent variables are naturally occurring (e.g., climate change impacts).
• Correlation: Scientists look for statistical relationships among variables.
• Example: A survey of 50 ponds reveals that ponds fed by fertilizer runoff have seven times more algae growth.

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The scientific process after data collection

• Findings are submitted to a scientific journal for peer critique.
• Reproducibility: Other scientists must be able to reproduce results.
• If hypotheses withstand peer review and replication, they contribute to theory.

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Paradigm shifts in science

• As knowledge accumulates, attitudes and interpretations may change.
• A paradigm is a dominant scientific view.
• A paradigm shift occurs when the dominant view changes due to new ideas and evidence.
• Example: The shift from an Earth-centered (geocentric) to a Sun-centered (heliocentric) solar system in the 16th century.

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Achieving sustainable solutions

• Sustainability challenge: Living in ways that Earth's resources can sustain us into the future.
• Key components:
  • Conserving resources for future generations,
  • Developing long-term solutions to environmental problems,
  • Maintaining fully-functional ecological systems.

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Population, consumption, and global impact

• More than 2\times 10^5 people are added daily to the planet.

• Consumption has increased rapidly, but not equally across populations.

• Economic inequality: The 20 wealthiest nations have 55\times the per capita income of the 20 poorest nations.

• Wealth distribution in the U.S.: The wealthiest 10% own more than 70\% of total wealth.

• Takeaway: Population growth and unequal consumption patterns drive environmental impact.

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Ecological footprint comparisons

• The ecological footprint of an average U.S. citizen is much greater than that of someone in a developing country.

• Implication: Wealth and lifestyle choices influence resource demand and environmental pressure.

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Millennium Ecosystem Assessment (2005) findings

• Over the past 50 years, humans have altered ecosystems more rapidly and extensively than ever.

• Changes to ecosystems have contributed to net gains in human well-being but at the cost of ecosystem degradation and worsening poverty for some.

• Ecosystem degradation could worsen during this century.

• Reversing degradation is possible but requires significant modification of policies, institutions, and practices.

• Significance: Provides a global assessment of ecosystem services, human well-being, and policy implications.

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Environmental science prepares you for the future

• Movements to reduce ecosystem degradation:

  • Campus sustainability initiatives aiming to reduce ecological footprints,
  • Environmental literacy to inform the public about Earth’s physical and living systems.

• Takeaway: Environmental science equips individuals to participate in sustainability efforts and informed civic actions.