Topic 4: The carbon cycle and planetary health

Question 1

What is the carbon cycle?

Answer 1

The biogeochemical cycle by which carbon moves from one sphere to another.
It acts as a closed system made up of linked subsystems that have inputs, throughputs and outputs.

Question 2

What are sources?

Answer 2

Adding carbon to the atmosphere

Question 3

What is a sink?

Answer 3

Removing carbon from the atmosphere

Question 4

What are the 4 main stores in the carbon cycle?

Answer 4

The atmosphere (as carbon dioxide and compounds such as methane)
The hydrosphere (as dissolved carbon dioxide)
The lithosphere (as carbonates in limestone and fossil fuels such as coal, oil and gas)
The biosphere (in living and dead organisms)