IB ESS HL 1.2.10 Positive Feedback Loops Question Bank
Explain how positive feedback amplifies disturbance and drives systems away from equilibrium.
- Syllabus
- First assessment 2026
- Course
- ESS HL
- Level
- HL
Exam points
- identify amplification rather than correction
- trace a reinforcing loop through successive changes
- apply the concept to warming, albedo or population examples
1.2.10—Positive feedback loops question 1
[Maximum number: 2]
Outline how a reduction in snow cover in the Alps can act as a positive feedback loop for climate change.
a. Less snow means a reduction in albedo/reflectivity/more insolation/radiation is absorbed by (darker) bare ground;
b. warmer ground melts surrounding snow, reducing snow cover further / warmer ground heats lower atmosphere, increasing air temperatures reducing snow cover further / warmer conditions allow vegetation to grow lowering albedo/absorbing more sunlight further reducing snow accumulation; OR
c. Less snow cover results in greater absorption of sunlight, warming the ground and melting permafrost therefore releasing methane;
d. Methane contributes to global warming/increase in temperature which results in further melting/loss of snow cover;
Note to examiners: Accept the above points in a diagram. Answer must indicate closed loop for full marks.
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