2.1.10: Feedback within and between carbon and water cycles Flashcards

1
Q

Feedback

A

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

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2
Q

Negative feedback

A

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

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3
Q

Positive feedback

A

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

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4
Q

Example of positive feedback

A

Albedo effect

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5
Q

The system threshold

A

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

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6
Q

Example of crossing the system threshold

A

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

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7
Q

Feedback and system threshold in relation to climate change

A

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

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8
Q

Cryospheric feedback

A

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

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9
Q

Albedo

A

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

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10
Q

Albedo of ice

A

high - reflects 80% of all incoming solar radiation

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11
Q

Albedo if large scale ice melting turns to water

A

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

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12
Q

Methane feedback example of +/- feedback?

A

positive

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13
Q

Methane

A

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

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14
Q

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

A

1/4

23 million km2

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15
Q

Example of regions/ biomes with permafrost

A

Tundra, polar and mountain regions

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16
Q

When did permafrost form

A

past glacial periods

17
Q

Steps in methane positive feedback loop

3

A

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

18
Q

Increasing water vapour in the atmosphere could lead to

3 step positive feedback loop

A
  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)
19
Q

Carbon sequestration ability of warmer water

A

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

20
Q

Possible changes to the global biome pattern due

2 and overall prediction

A
  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
21
Q

System threshold as known as

A

tipping point