Feedback Loops
Feedback Loops
A **feedback loop** happens when a change in a system causes effects that feed back into the system and cause more change.
Think of a feedback loop as a loop where the result becomes the cause.
Negative Feedback Loops (Stabilising)
A **negative feedback loop** reduces change and helps keep a system stable.
Exam tip: **Negative does NOT mean bad**. It means the system resists change and stays balanced.
[Diagram: feedback-loops] - Available in full study mode
Positive Feedback Loops (Amplifying)
A **positive feedback loop** makes the original change stronger and pushes the system further away from balance.
This happens because the effect of the change feeds back and causes even more of the same change.
Ice melt example (easy to picture)
Because melting ice leads to even more melting, this is a **positive feedback loop**.
Population example
Exam tip: **Positive does NOT mean good**. It means the change is amplified.
One-sentence exam definition
A positive feedback loop occurs when a change in a system causes effects that increase the original change.
Tourism Multiplier Effect
🏨 Tourism Multiplier Effect
What is it?: The tourism multiplier effect is a **positive feedback loop in human systems** where tourism growth feeds back to create even more tourism growth.
How it works:
This is positive feedback because the **output (more tourists) feeds back to amplify the input (tourist attraction)**.
Why it matters for sustainability
The tourism multiplier can have **both positive and negative effects**:
✅ Benefits
- Creates jobs and income
- Funds conservation efforts
- Improves local infrastructure
- Can protect wildlife as an economic asset
❌ Problems
- Increased demand on water and energy
- Habitat destruction for buildings
- More waste and pollution
- Can displace local communities
Positive feedback loops can spiral out of control — tourism growth without limits can damage the environment it depends on.
Economic Inequality Feedback
💰 Economic Inequality Feedback
Economic inequality is another example of positive feedback in human systems:
Without intervention (negative feedback like taxes or regulations), positive feedback loops keep amplifying.
📝 How to explain feedback loops
When explaining any feedback loop, follow these steps:
🧠 Quick definitions to remember
**Positive feedback:** A change causes effects that **increase** the original change. **Negative feedback:** A change causes effects that **reduce** the original change. **Multiplier effect:** When growth in one area creates growth in connected areas, which feeds back to create even more growth.
📋 Summary: Positive Feedback Examples
📋 Summary: Negative Feedback Examples
Stability and Equilibrium
⚖️ Stability and Equilibrium
Stable (Steady-State) Equilibrium
A **{{stable equilibrium|A condition where inputs and outputs are balanced, so the system stays roughly the same over time.}}** is like balancing on a bike — small adjustments keep you upright.
🎯 The Key Idea: Inputs = Outputs → the system stays stable (even if small changes happen)
⏰ Feedback Delays
A **{{feedback delay|The time gap between a change in a system and when its effects are seen.}}** means cause and effect do not happen immediately.
⚠️ Why Delays Cause Problems: Because changes are delayed, people often overcorrect. This can cause the system to <u>{{oscillate|Repeatedly rise and fall instead of settling at one stable level.}}</u>
Example: heating is turned up → room heats slowly → too much heat builds up → heating is turned off → room cools too much → the cycle repeats.
🎢 Tipping Points
A **{{tipping point|The point where a small change causes a large and often irreversible change in a system.}}** is when the system can no longer return to its original state.
🚨 Why Tipping Points Matter: Small change → positive feedback → rapid system shift
[Diagram: tipping-point-simulator] - Available in full study mode
Before tipping point
- 🏞️ Clear lake
- 🌳 Healthy forest
- 🧊 Arctic ice cover
After tipping point
- 🟢 Algal bloom → murky lake
- 🏜️ Forest dieback
- 🌊 Ice-free ocean
📝 IB Exam Tip: Positive feedback loops push systems toward tipping points. After crossing one, the system settles into a new (often worse) equilibrium.
Causal Loop Diagrams
Causal Loop Diagrams (ESS)
What is a causal loop diagram?
A **{{causal loop diagram|A diagram that shows how different variables in a system affect each other over time.}}** shows clear **cause → effect** relationships.
It helps us see whether a change is **controlled (balanced)** or <u>**{{amplifies|Becomes stronger or increases the original change over time.}}**</u>.
[Diagram: causal-loop-diagram] - Available in full study mode
Parts of a causal loop diagram
**+ and − do NOT mean good or bad. They only show how change happens.**