What You Need to Know

Key Concept Diagram

Positive feedback amplifies change: melting Arctic ice reduces albedo, absorbing more heat, causing more melting

Negative feedback dampens change: warmer oceans increase evaporation and cloud cover, reflecting more sunlight

Water vapour feedback is a major positive feedback in climate warming

Methane release from permafrost as temperatures rise is a significant positive feedback

Key Vocabulary

Positive feedback

A feedback mechanism that amplifies the original change in a system

Negative feedback

A feedback mechanism that dampens or reduces the original change in a system

Albedo

The proportion of solar energy reflected by a surface; ice has high albedo

Permafrost

Permanently frozen ground that stores large amounts of carbon and methane

Knowledge Check

Select the correct answer for each question. Click "Check Answer" to see if you are right.

Question 1

Arctic sea ice melting reduces albedo and causes further warming. This is a:

Negative feedback mechanism Neutral climate process Positive feedback mechanism A short-term weather event

Question 2

If increased evaporation from warmer oceans leads to more cloud cover and more sunlight being reflected back to space, this is a:

Positive feedback Albedo effect Carbon cycle disruption Negative feedback

Question 3

Why is methane release from melting permafrost a concern for climate scientists?

Methane is a potent greenhouse gas, creating a positive feedback loop Methane is required for plant growth Methane reflects sunlight back into space Permafrost melting has no effect on the atmosphere

Climate Feedback Mechanisms