Carbon Cycle and Climate Change

Question 1

Energy balance of the Earth

Answer 1

Determined by the amount of solar radiation absorbed by the planet versus the amount radiated back into space.

Question 2

Role of carbon in the atmosphere

Answer 2

Carbon dioxide and methane absorb long-wave radiation and trap heat

Question 3

Carbon Cycle: Key processes

Answer 3

1. Photosynthesis
2. Respiration
3. Decomposition
4. Ocean uptake
5. Fossil fuel combustion

Question 4

Fast carbon cycle

Answer 4

Involves short-term processes like:
- Photosynthesis
- Respiration/Oxidation
- Ocean uptake/off-gassing
- Biodegradation
- Sedimentation
- Advection

Question 5

Slow carbon cycle

Answer 5

Long-term geological processes:
- Weathering of rocks
- Ocean sedimentation
- Fossil fuel formation
- Volcanic eruptions

Question 6

Coal formation

Answer 6

1. Huge forests grew 300 million years ago covering most of the land
2. The vegetation dies and forms peat
3. Peat is compressed to form lignite
4. Further compression forms bituminous coal
5. Eventually anthracite forms

Question 7

Natural gas and oil formation

Answer 7

1. Marine plants and animals die and sink to the bottom of the seabed
2. The plant and animal layer gets covered with mud
3. Overtime, more sediment creates pressure, compressing the dead plants and animals into oil
4. Oil moves up through the porous rocks and eventually forms a reservoir

Question 8

Oil and natural gas extraction (4)

Answer 8

Conventional drilling
Fracking
Offshore drilling

Question 9

Peak Oil

Answer 9

The point in time when the maximum rate of extraction of crude oil is reached, and after that the extraction is expected to enter final decline

Question 10

Climate tipping points

Answer 10

Levels of climate change that trigger “large-scale discontinuities” in the climate system that commit the world to long-term irreversible change

Question 11

What are the climate tipping points? (6)

Answer 11

Permafrost
Amazon
Coral reefs
Atlantic circulation
Ice sheets
Boreal forests

Question 12

Permafrost tipping point

Answer 12

Melting ice facilitates mass decomposition of organic matter releasing massive amounts of methane.

Question 13

Amazon tipping point

Answer 13

Drought causes enough forest loss to permanently reduce rainfall and shift to savanna

Question 14

Coral reefs tipping point

Answer 14

Mass die-off from combination of heating, acidification, and pollution

Question 15

Atlantic circulation

Answer 15

Melting Greenland ice sheet weakening flow of warm nutrient rich water to North Atlantic

Question 16

Ice sheets

Answer 16

Melting reduces albedo causing more warming and exposes more ice causing more melting

Question 17

Boreal forests

Answer 17

Sub-Arctic forests more prone to fire and mass die-off from pests, releasing more carbon to atmosphere

Question 18

Carbon budget

Answer 18

Refers to the maximum allowable CO₂ emissions to limit global temperature rise.

To limit global warming to 2°C, cumulative anthropogenic emissions must stay below 1000 Pg of carbon.