Practise SL questions on positive feedback by tracing complete amplification loops, tipping points, ice-albedo warming, eutrophication and population change.
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.