Environmental Science: Environmental Systems

Introduction

• Presented by: Mr. Andersen
• Main Topic: Environmental Systems
• Understanding systems can tackle major environmental problems (e.g., Aral Sea).

Case Study: Aral Sea

• Location: Border of Kazakhstan and Uzbekistan
• Once the 4th largest lake on Earth
• Soviet Union used Aral Sea for inefficient irrigation (cotton and rice)
• Outcome: Became a desert by 2014
  • Economic collapse (fish died, fishing industry collapsed)
  • Mismanagement of system inputs and outputs

Earth as a System

• Earth is a large system separated from surroundings
• Key Components: Matter and Energy
  • Matter: Composed of atoms (closed system, conserved over time)
  • Energy: Ability to do work (open system)

Matter

• Conserved on Earth; no new matter from space
• Components:
  • Minerals are finite
  • Must find existing minerals (cannot grow them)

Energy

• Laws of Thermodynamics:
  1. Conservation of energy (energy cannot be created nor destroyed)
  2. Useful energy decreases with each interaction (energy lost as heat)
• Systems analysis: Steady state or equilibrium
  • Negative Feedback Loop: Moves towards steady state
  • Positive Feedback Loop: Moves away from steady state

Types of Systems

• Closed System (e.g., Matter on Earth)
  • No new matter, no loss to space
• Open System (e.g., Energy)
  • Continuous flow from surroundings

Atomic Composition on Earth

• Finite number of atoms, e.g.,
  • Humans: Mostly water (oxygen and hydrogen), carbon, nitrogen, etc.
  • Water: Oxygen and hydrogen, salts (sodium and chloride)
  • Rocks: Oxygen, silicon, aluminum, iron
  • Atmosphere: Nitrogen, oxygen, trace elements
• Atoms recycled, no creation of new atoms

Energy Measurement

• Quantified by James Joule
  • Joule: Unit of energy
  • Watt: Joule per second
• Examples: Energy transitions from sunlight > ancient rainforest > crude oil > gasoline > car motion

Systems Analysis and Feedback Loops

• Equilibrium: Input = Output
• Negative Feedback Loops: Stabilize systems
  • Examples: Lake levels, Earth's heat loss to space
• Positive Feedback Loops: Destabilize systems
  • Examples: Evaporation warming, melting ice reducing albedo

Conclusion

• Summary of Key Points:
  • Earth as a system with inputs and outputs
  • Steady state through feedback loops
  • Energy (open system) vs. Matter (closed system)
  • Conservation principles (thermodynamics)
• Encouragement for further study

Additional Points

• Importance of understanding pH, buffers, and biological molecules
• Reference to additional resources (videos on specific topics)