Lecture v - Role of Human Activities, Feedback Mechanisms

Question 1

Describe climate feedback mechanisms

Answer 1

processes that can either amplify or reduce effect of CC

TWO TYPES:
1. +ve
- accelerate (amplify) response of climate when triggered by specific factors (both natural & anthropogenic)
=> destabilise climatic system
eg shrink ice coverage decrease albedo w darker ocean surface

2. -ve
   - suppress (reduce) response of climate triggered by specific factors (both natural & anthropogenic)
   => stabilise climatic system
   eg ice sheet melt leading to more clouds so more albedo

Question 2

What are monsoons?

Answer 2

large scale seasonal winds bringing associated rainfall/precipitat n

Question 3

Describe cold regions and warm regions

Answer 3

cold (dry)
- sinking cold air inhibiting cloud form n
=> little/no rainfall

warm (wet)
- rising hot air promotes cloud form n
=> heavy rainfall

Question 4

How do human activities affect climate change through feedback processes?

Answer 4

• earth’s climate is complex system, many processes drive interact n btw global temp & conc of carbon on land, in ocean, in atmos
• stability of climate system rely on natural balance of diff feedback loops
• human activities causing increased ghg emis n accelerate warming
• human mitigat n measure to global warming suppress warming

Question 5

How do human activities accelerate warming through positive feedbacks?

Answer 5

i) involve human activities causing increased ghg emis n
1. Industrial activities
- burn FF generate energy in manufacture gds
- increase use transport (airplane, car, truck, bus, etc.) to deliver gds, svcs
2. Agri activities - change in landuse
- livestock rearing eg cattle ranching
- cash crop cultivat n eg palm oil
3. Domestic activities
- cooking, heating, aircon, refrigerat n increased public, private transport, etc.

ii) involve human activities causing reduct n carbon sinks
- large scale deforestat n
- warming, acidificat n of ocean water

eg industrial activities emit much ghg
-> such ghg act as thermal blanket, re-emit longwave rad n back into earth’s surface, cause enhanced gh effect/global warming
-> increased global temp caused more ice sheet melt in polar region
-> less ice coverage, darker ocean water surfaced = less albedo
-> more insolat n heat up ocean water, further accelerate effect of rapid warming

Question 6

How do human activities suppress warming through negative feedbacks?

Answer 6

• involve human activities limiting effect of global warm by adopting mitigat n measure
  –> increase carbon , reduce ghg, etc

eg
mitigat n measure (afforestat n, planting of trees on virgin lands)
-> afforested areas hv trees to absorb atmos CO2 as part of food-making process aka photosynthesis
-> such areas act as carbon sink carrying out biological carbon sequestrat n (process of capture, store carbon)
-> less atmos CO2 = less longwave rad n re-emitted back into earth’s surface, reducing effects of warming