2.1.10: Feedback within and between carbon and water cycles

Question 1

Feedback

Answer 1

The automatic response of a system when a change to the flow of energy or materials occurs

Question 2

Negative feedback

Answer 2

A system that self-corrects after a change occurs and restores equilibrium

Question 3

Positive feedback

Answer 3

A system spirals out of control and continues to worsen when a change is made to it

Question 4

Example of positive feedback

Answer 4

Albedo effect

Question 5

The system threshold

Answer 5

Critical limit or level that means that potentially irreversible changes will occur if it is crossed

Question 6

Example of crossing the system threshold

Answer 6

possible situation where the carbon or water cycle is pushed beyond possible return equilibrium

Question 7

Feedback and system threshold in relation to climate change

Answer 7

many scientists believe that a increase in global temperatures of 2 degrees C may lead to widespread and irreversible global change to the carbon cycle

Question 8

Cryospheric feedback

Answer 8

During periods when the Earth has grown warmer in the past, temperature changes may have accelerated the loss of ice cover

Question 9

Albedo

Answer 9

Fraction of solar radiation that a surface reflects, white surfaces have a higher albedo

Question 10

Albedo of ice

Answer 10

high - reflects 80% of all incoming solar radiation

Question 11

Albedo if large scale ice melting turns to water

Answer 11

ice melted replaced by darker- coloured water which has a lower albedo and will absorb more heat
as water warms up, air masses do as well and this will accelerate the warming of the atmosphere

Question 12

Methane feedback example of +/- feedback?

Answer 12

positive

Question 13

Methane

Answer 13

powerful greenhouse gas with enormous volumes of it stored in the earth’s permafrost regions

Question 14

Proportion of the world with permanent or sporadic permafrost and area in km2

Answer 14

1/4

23 million km2

Question 15

Example of regions/ biomes with permafrost

Answer 15

Tundra, polar and mountain regions

Question 16

When did permafrost form

Answer 16

past glacial periods

Question 17

Steps in methane positive feedback loop

3

Answer 17

atmosphere warms > more permafrost melts
releases large amounts of methane
atmosphere warms up more quickly (repeat)

Question 18

Increasing water vapour in the atmosphere could lead to

3 step positive feedback loop

Answer 18

1. global temp. rise
2. terrestrial permafrost melting and release of methane
3. reduction in ability of seawater to absorb extra co2 from the atmosphere so may release it if temps. continue to rise (repeat)

Question 19

Carbon sequestration ability of warmer water

Answer 19

as water becomes warmer, it less effective at absorbing carbon dioxide

Question 20

Possible changes to the global biome pattern due

2 and overall prediction

Answer 20

1. if the tree line moves more north - the coniferous tree biome grows in size - more carbon storage
2. if desertification damages grassland - less carbon storage
   over uncertainty

Question 21

System threshold as known as

Answer 21

tipping point