Environmental Science 101: Introduction to Environmental Science - What is Environmental Science Definition Interdisciplinary Nature Sustainability

What This Is

Environmental science is the study of the relationships between human societies and the natural world. It examines the impact of human activities on the environment and the consequences of environmental degradation. A key concept in environmental science is the tragedy of the commons, which explains why shared resources are overexploited when individuals act in their own self-interest. For example, the overfishing in the North Atlantic is a classic case of the tragedy of the commons, where individual fishermen prioritize short-term gains over long-term sustainability.

Key Concepts, Laws & Models

• First Law of Thermodynamics (Energy Conservation): Energy cannot be created or destroyed, only converted – explains why all the energy in an ecosystem ultimately comes from the sun and why energy pyramids narrow.
• Second Law of Thermodynamics (Entropy): Energy conversions are never 100% efficient, leading to a decrease in available energy – explains why ecosystems tend towards equilibrium and why waste management is crucial.
• Tragedy of the Commons (Hardin): Shared resources are overexploited when individuals act in their own self-interest – underpins modern challenges like overfishing and groundwater depletion.
• Sustainability (Brundtland Commission): Meeting the needs of the present without compromising the ability of future generations to meet their own needs – guides decision-making in environmental policy and management.
• Carrying Capacity (Ehrlich): The maximum population size an environment can sustain without degrading – informs population growth models and resource management.
• Ecological Footprint (Wackernagel): The amount of land and resources required to produce the goods and services consumed by an individual or population – measures the impact of human activities on the environment.
• IPAT Equation (Ehrlich): Impact = Population × Affluence × Technology – links human population size, consumption patterns, and technological advancements to environmental degradation.
• Kaya Identity: CO2 emissions = Population × GDP per capita × Energy intensity × Carbon intensity – breaks down the drivers of greenhouse gas emissions.
• Environmental Kuznets Curve (EKC): Economic growth can lead to environmental degradation, but at a certain point, pollution decreases as income increases – describes the relationship between economic development and environmental quality.
• Precautionary Principle: When there is a risk of harm to the environment or human health, action should be taken to prevent harm – guides decision-making in the face of uncertainty.

Step-by-Step Application

1. Calculate a carbon footprint: Estimate the amount of greenhouse gas emissions associated with an individual's or organization's activities, using data on energy consumption, transportation, and waste management.
2. Evaluate an environmental impact assessment: Assess the potential environmental consequences of a proposed project or policy, using tools like life cycle assessments and risk assessments.
3. Predict population growth using the rule of 70: Estimate the time it takes for a population to double, using the formula: time = 70 / growth rate (in %).
4. Analyze the impact of climate change on ecosystems: Use models like the IPCC's climate scenarios to predict changes in temperature, precipitation, and sea level rise, and assess the consequences for ecosystems and human societies.
5. Design a sustainable development project: Integrate environmental, social, and economic considerations to create a project that meets the needs of present and future generations.

Common Misconceptions

• Misconception: "Global warming is caused by the ozone hole."
• Correction: The ozone hole is a separate issue, caused by the release of chlorofluorocarbons (CFCs), which deplete the ozone layer. Global warming is primarily caused by the increase in greenhouse gases, such as carbon dioxide and methane.
• Misconception: "All pollutants are visible."
• Correction: Many pollutants, like particulate matter and ozone, are invisible but still pose significant health risks. Other pollutants, like heavy metals and pesticides, can be invisible but still contaminate the environment.
• Misconception: "Renewable energy has no environmental impact."
• Correction: While renewable energy sources like solar and wind power have lower environmental impacts than fossil fuels, they can still have environmental consequences, such as habitat disruption and resource extraction.

Exam / Free-Response Tips

• Multiple-choice traps: Be aware of ambiguous or misleading question wording, and choose answers that are supported by scientific evidence.
• Free-response questions (FRQs): Use the question to guide your answer, and make sure to address all parts of the question. Use evidence from the topic to support your arguments.
• Document-based questions (DBQs): Read the documents carefully, and use them to support your arguments. Make sure to address all parts of the question, and use evidence from the documents to support your claims.
• Tricky distinctions: Be aware of the differences between concepts like primary and secondary succession, bioaccumulation and biomagnification, and weather and climate.

Quick Practice Scenario

A farmer applies excessive nitrogen fertilizer. The runoff reaches a nearby lake, causing an algal bloom. Which nutrient cycle is disrupted, and what secondary effect will deplete oxygen?

Answer: The nitrogen cycle is disrupted, leading to an overabundance of nitrogen in the lake. This excess nitrogen will stimulate the growth of algae, which will eventually die and decompose, depleting the oxygen in the lake.

Last-Minute Cram Sheet

• IPCC (Intergovernmental Panel on Climate Change): A scientific body that assesses climate change impacts and mitigation strategies.
• Kyoto Protocol: An international agreement to reduce greenhouse gas emissions.
• Paris Agreement: An international agreement to limit global warming to well below 2°C and pursue efforts to limit it to 1.5°C.
• El Niño: A warm phase of the ENSO cycle, characterized by high sea surface temperatures in the Pacific.
• La Niña: A cool phase of the ENSO cycle, characterized by low sea surface temperatures in the Pacific.
• Environmental Kuznets Curve (EKC): A curve that describes the relationship between economic development and environmental quality.
• Precautionary Principle: A principle that guides decision-making in the face of uncertainty, prioritizing caution and prevention over potential risks.
• Sustainable Development Goals (SDGs): A set of goals adopted by the UN to promote sustainable development and address global challenges.
• Biodiversity Hotspots: Regions with high levels of endemism and biodiversity, often threatened by human activities.
• Carbon Trading: A market-based mechanism to reduce greenhouse gas emissions by allowing countries or companies to buy and sell emissions credits.