Feedback loops

Feedback loops

1. Positive feedback loop

   • A cyclical sequence of events that amplifies or increases change.
     • They exacerbate the outputs of a system, driving it in one direction and promoting environmental instability

2. Negative feedback loop

   • A cyclical sequence of events that damps down or neutralises the effects of a system
     • This promotes stability and a state of dynamic equilibrium

3. Negative feedback example

   • An increased surface temp, leads to increased evaporation, creating more cloud cover, the clouds reflect radiation and results in a slight cooling of the surface temp
   • The increased Co2 levels, then increase the rate of photosynthesis, therefore more Co2 is removed from the atmosphere

4. Positive feedback example

   • The rising sea levels, increase the rate of calving from ice sheets, causing the sea level to rise further
   • An increase in global temp, causes ice sheets to melt, meaning there's less albedo, so more of the suns rays are absorbed my the Earth and the temp continues to rise