EQ1: How does the carbon cycle operate to maintain planetary health?

Question 1

Where is carbon stored?

Answer 1

Atmosphere

Hydrosphere

Lithosphere

Biosphere

Question 2

What are carbon fluxes, or flows, between the carbon stores of the carbon cycle measured in?

Answer 2

Carbon fluxes, or flows, between the carbon stores of the carbon cycle are measured in either pentagrams or gigatonnes of carbon per year.

Question 3

How is most of the Earth’s geological carbon formed?

Answer 3

Most of the Earth’s carbon is geological and results from:

The formation of sedimentary carbonate rocks (limestone) in the oceans.

Carbon derived from plants and animals in shale, coal and other rocks.

Question 4

What happens to the carbon derived from plants and animals in shale, coal and other rocks?

Answer 4

Remains sank to the bottom of rivers, lakes and seas were subsequently covered by silt and mud. As a consequence, the remains continued to decay anaerobically.

Question 5

What two natural processes release geological carbon into the atmosphere?

Answer 5

Carbon dioxide in the atmosphere reacts with moisture to form weak carbonic acid.

Pockets of carbon dioxide exist in the Earth’s crust. Volcanic eruptions and earthquakes can release these gas pockets.

Question 6

How large is the oceanic store of carbon?

Answer 6

The oceanic store of carbon is 50 times greater than that of the atmosphere.

Question 7

What are the three types of oceanic carbon pump?

Answer 7

Biological pumps

Physical pumps

Carbonate pumps

Question 8

How does carbon enter the food chain?

Answer 8

Plants (i.e. primary producers in the ecosystem) sequester carbon out of the atmosphere during photosynthesis.

Question 9

What is the difference between diurnally and seasonally?

Answer 9

Diurnally: during the day, fluxes are positive - that is, from the atmosphere into the ecosystem; at night the reverse situation applies

Seasonally: during winter, carbon dioxide concentrations increase because of the low levels of plant growth. However, as soon as spring arrives and all plants grow again, those concentrations begin to decrease until the onset of autumn.

Question 10

What percentage of carbon does the human body contain?

Answer 10

18%

Question 11

What percentage of global carbon do soils store?

Answer 11

Soils store between 20% and 30% of global carbon.

Question 12

What factors affect the amount of carbon stored in the soil?

Answer 12

Climate

Vegetation

Soil type

Land use

Question 13

Why is a fully functioning and balanced carbon cycle vital to the health of the Earth in sustaining its other systems?

Answer 13

It plays a key role in regulating the Earth’s temperature by controlling the amount of carbon dioxide in the atmosphere. This, in turn, affects the hydrological cycle. Ecosystems, terrestrial and oceanic, also depend on the carbon cycle.

Question 14

What percentage of shortwave solar radiation is reflected back into space by clouds, GHGs and by the land surface?

Answer 14

31%

Question 15

What percentage of shortwave solar radiation is absorbed at the Earth’s surface?

Answer 15

69%

Question 16

What does soil health depend on?

Answer 16

Soil health depends on the amount of organic carbon in the soil.

Question 17

What is the storage amount of organic carbon stored in the soil determined by?

Answer 17

The storage amount is determined by the balance between the soil’s inputs (plant and animal remains, nutrients) and its outputs (decomposition, erosion and uptake by plant and animal growth).

Question 18

Why is carbon an important component of soil organic matter?

Answer 18

Carbon is the main component of soil organic matter and helps to give soil its moisture-retention capacity, its structure and its fertility.

Question 19

In the soil, where is organic carbon concentrated?

Answer 19

Organic carbon is concentrated in the surface layer of the soil.

Question 20

What are the climate changes resulting from the rate of carbon fluxing speeding up?

Answer 20

A rise in the mean global temperature

More precipitation and evaporation

Sudden shifts in weather patterns

More extreme weather events, such as floods, storm surges and droughts

The nature of climate change is varying from region to region - some areas are becoming warmer and drier, others wetter