feedback mechanisms

Question 1

define a negative feedback mechanism

Answer 1

a feedback mechanisms which reduces the size of the original change

Question 2

define a positive feedback mechanism

Answer 2

a feedback mechanism which increase the size of the original change

Question 3

give some examples of negative feedback mechanisms

Answer 3

1) low-level cloud cover- high temps increase evaporation so more clouds are formed which reflect UV radiation so less is absorbed at the surface and less IR is given out so temp decreases
2) photosynthesis- increased temp= more photosynthesis= more co2 taken in= less GHG= decreased temp

Question 4

give some examples of positive feedback mechanisms

Answer 4

1) forest fires= increased temp= more fires= more co2 released= more GHG= higher temp
2) albedo= high temp= more ice melting= decreased albedo= more uv absorbed= more IR= higher temp
3) soil decomposition= high temps- increased rate of decomposition= co2 released= more GHG= higher temp

Question 5

what is a tipping point

Answer 5

when human actions which cause climate change may cause changes to natural processes that themselves cause climate change to the extent that even if the human activity is stopped global climate change will continue

Question 6

give some examples of tipping points

Answer 6

1) faster soil decomposition
2) snow on land melting
3) release of CO2 by increased forest and peat fires