4a. and effective human response relies on knowing what the future holds

Question 1

The importance of the carbon cycle

Answer 1

Slow cycle: Stores lock away carbon for millions of years
- Vegetation
- oceans
- carbonate rocks

Fats cycle: Circulates carbon
- The atmosphere
- Dissolved in oceans
- Stored in soils + living organisms which eventually decompose re-releasing carbon

Flows of carbon
- Decomposition
- Respiration
- Photosynthesis
- combustion

Humans are constantly imputing more carbon into the system, altering the balance

Question 2

Influence of feedback loops: Positive

Answer 2

1. decreased albedo due to snow melt = more solar energy absorbed NOT reflected = increased surface warming
2. Permafrost thaws = release of methane + CO2 = increased GHG’s in atmosphere trapping long wave energy
3. Deforestation = release of CO2 as trees decompose = less CO2 stored in biomass = warming

Question 3

Influence of feedback loops: Negative

Answer 3

1. increasing temperatures = increase evaporation = increased cloud cover = incoming sunlight reflected back to space = decreased warming
2. Increased warming = increased grow of vegetation in higher altitudes = increased volume of CO2 absorbed = decreased GHG’s in atmosphere
3. Burning of fossil fuels release particulates into atmosphere reflect incoming sunlight back into atmosphere = less warming

Question 4

Future emission scenarios: Temperature changes

Answer 4

• Temperatures predicated to rise 0.3 - 4.8 degrees by 2100
• Temperatures predicated to rise twice as much in the next 100 years compared to the last 100 years
• Temperatures will vary on geographical location

Question 5

Future emission scenarios: Sea level changes

Answer 5

• Current average sea level rise = 3.0mm/year
• Worst scenario = collapse of west Antarctic where sea levels will rise 1m
• Increase in temperatures will increase thermal expansion + rate of melting
• Increase in convectional precipitation + tropical storms = flooding