Feedback Loops

Question 1

What is a feedback loop?

Answer 1

A feedback loop is a type of chain reaction, where one process leads to another process, leading to another process, and so on.

Question 2

How many types of feedback loops are there?

Answer 2

There are two types of feedback loops: positive and negative.

Question 3

What is negative feedback?

Answer 3

In negative feedback, the process that occurs is counteracted by an opposing process.

Question 4

What is the effect of negative feedback?

Answer 4

The effects cancel each other out and nothing to change.

Question 5

What is positive feedback?

Answer 5

In positive feedback, a process occurs, which causes another process to occur.

Question 6

What is the effect of positive feedback?

Answer 6

This starts a chain reaction as it heightens the first process.

Question 7

What are examples of positive feedback?

Answer 7

Wildfires, ice and albedo effect, permafrost

Question 8

How are wildfires linked to positive feedback?

Answer 8

Wildfires are more likely in hotter and drier climates created by global warming.

Question 9

What do wildfires release?

Answer 9

Large quantities of CO₂ into the atmosphere.

Question 10

What is the effect of wildfires?

Answer 10

This in turn then increases the warming effect.

Question 11

What role does ice play in reflecting radiation?

Answer 11

Ice reflects radiation from the sun, reducing surface warming.

Question 12

What happens as sea temperatures rise?

Answer 12

Ice melts.

Question 13

What is the effect of melting ice?

Answer 13

The warming effect is amplified as there is less ice to reflect the radiation.

Question 14

What does further melting cause?

Answer 14

The process continues.

Question 15

What happens to permafrost as temperatures increase?

Answer 15

Higher temperatures are thawing the permafrost.

Question 16

What does thawing permafrost release?

Answer 16

CO₂ and methane.

Question 17

Why is methane significant?

Answer 17

Methane has 20 times the warming effect of CO₂.

Question 18

What does the effect of CO₂ cause?

Answer 18

Warming on a local and global scale.

Question 19

What is permafrost?

Answer 19

Frozen ground that remains at a temperature of 0°C or lower for at least 2 consecutive years.

Question 20

What do higher temperatures cause in relation to permafrost?

Answer 20

The higher temperatures cause more permafrost to melt.

Question 21

What is the result of permafrost melting?

Answer 21

Causing further gas releases and further warming.

Question 22

How does increased photosynthesis by plants act as negative feedback?

Answer 22

Increased photosynthesis by plants and rising global temperatures allows vegetation to grow in new areas, e.g. where permafrost has melted. New vegetation absorbs CO₂ from the atmosphere, decreasing the warming effect.

Question 23

How do higher temperatures and CO₂ affect carbon fertilisation in plants?

Answer 23

Higher temperatures and more CO₂ cause a greater carbon fertilisation in plants, so they absorb more CO₂. This reduces the levels of CO₂ in the atmosphere and the rates of warming and carbon fertilisation will decrease.

Question 24

What may limit how much CO₂ plants can continue to sequester?

Answer 24

Carbon fertilisation is limited by water and nitrogen levels.

Question 25

How can decreased rainfall affect carbon fertilisation?

Answer 25

If rainfall decreases as a result of climate change, then carbon fertilisation may decrease as a result, as water is required for photosynthesis.

Question 26

How do higher CO₂ levels affect phytoplankton?

Answer 26

Higher CO₂ levels causes phytoplankton to grow (as they feed off CO₂).

Question 27

How do higher temperatures affect phytoplankton growth and cloud formation?

Answer 27

Higher temperatures causes phytoplankton to grow and photosynthesise quicker. Phytoplankton release substances that lead to the formation of clouds, meaning cloud cover increases.

Question 28

How does increased cloud cover affect phytoplankton?

Answer 28

Radiation from the sun is therefore less able to reach the oceans, reducing temperatures. This therefore causes phytoplankton to grow less quickly and photosynthesise slower, reducing cloud cover.