Lesson 5.5 - Carbon Pathways

Question 1

What are the roles of sources and sinks?

Answer 1

Source - Add carbon to atmosphere
Sink - Remove carbon from atmosphere

Question 2

When does equilibrium occur?

Answer 2

Sources = Sinks

Question 3

How has human activity affected the carbon balance?

Answer 3

Larger atmospheric CO2 inputs
No corresponding increase in natural sinks

Question 4

What is currently happening to pathways involving frozen carbon stores?

Answer 4

Becoming faster
Thawing accelerates carbon release

Question 5

How is thawing intensifying carbon fluxes?

Answer 5

Ancient veg decomposes
Water + methane released
Trapped gases seep to the surface

Question 6

How might increased thawing affect vegetation?

Answer 6

Plant + microorganism growth quickens
Respire CO2

Question 7

What is the optimistic potential pathway regarding frozen stores?

Answer 7

Trees + shrubs invade Arctic
Sinks > Sources
Short term balance

Question 8

What is the pessimistic potential pathway regarding frozen stores?

Answer 8

Decomposition in wet soils further reduces CO2 stores
Increased GG emissions