Student Sheet 1
PROBLEM SOLVING ACTIVITY
:
CLIMATE CHANGE AND FEEDBACK LOOPS
Systems are made up of parts and the interactions
between them. They are composed of:
Storages of matter/energy: tree
biomass in trunk & leaves.
Flows: inputs & outputs: light, oxygen
and heat.
Processes which transfer or transform
the energy/matter): photosynthesis.
Feedback loops: affecting the stability
of the system.
To be stable, all systems need to be self-regulating. Feedback loops permit
systems to adjust their response to change (forcing factors) to return to stable
conditions. Systems diagrams contain boxes that show circles and arrows which
indicate flows.
A feedback is similar to a cause and effect loop, where
information about a system is sent back to the system to
improve its performance. An example is your body's
ability to control temperature. The condition of the
body's temperature is the information fed back to the
brain, which is the controller. If the temperature is high,
the body sweats in order to cool down. Since the process
of sweating is done to stop the temperature change, this
is a negative feedback.
Feedback loops come in two flavors: positive and negative. A negative feedback
loop reduces the effect of change and helps maintain balance. A positive feedback
loop increases the effect of the change and produces instability. In this case, the
positive and negative naming of the loops do not indicate whether the feedback is
good or bad. In climate change, a feedback loop is something that speeds up or
slows down a warming trend. A positive feedback accelerates a temperature rise,
whereas a negative feedback slows it down.
