Feedback Loops

In a positive feedback loop, each action creates a consequence that _____________________ the other action.

• decreases

• has no effect on

• amplifies

A ________________ feedback loop makes a system more stable.

• Positive

• Neutral

• Negative

• Circular

A _________________ feedback loop moves a system to an extreme.

• Positive

• Neutral

• Circular

• Negative

Negative Feedback Loops:

• amplify processes
• prevent small changes from getting larger
• are initiated during childbirth
• are found only in plants

As the Earth warms, increased evaporation produces more clouds. Clouds increase albedo, reflecting more light away from the Earth. The temperature falls. Rates of evaporation fall.

• Positive Feedback Loop

• Negative Feedback Loop

As the Earth warms, upper layers of permafrost melt, producing waterlogged soil above frozen ground. Methane gas is released into the environment. The greenhouse effect is enhanced. The Earth warms, melting more permafrost.

• Positive Feedback Loop

• Negative Feedback Loop

As the Earth warms, ice cover melts, exposing soil or water. Albedo decreases. More energy is absorbed by the Earth’s surface. Global temperature rises. More ice melts.

• Positive Feedback Loop

• Negative Feedback Loop