Changes in the carbon cycle

Question 1

What are the natural processes that can change the carbon cycle?

Answer 1

• Volcanic activity

- Wildfires

Question 2

What are the human processes that can change the carbon cycle?

Answer 2

• Hydrocarbon fuel extraction and burning
• Farming practices
• Deforestation
• Land use changes

Question 3

What impact do wildfires have on the carbon cycle?

Answer 3

• Wildfires rapidly transfer large quantities of carbon from biomass (pedosphere and biosphere) into the atmos. Loss of vegetation decreases photosynthesis so less carbon is removed from atmos.
• Long term - can encourage new growth which absorb carbon from atmos. via photosynthesis. Depending on amount and type of regrowth fires can have neutral effect on atmos.

Question 4

What impact does volcanic activity have on carbon?

Answer 4

• Carbon stored within earths magma is released into atmos. as CO2 - lithosphere to atmos., carbon that has been stored for millions of yrs
• Now only 130-380 mil tonnes of carbon is emitted by volcanoes a yr compared to 30 bil by humans, sig. less
• Could potentially be a v. large eruption which could release a lot of CO2 into atmos.

Question 5

What impact does hydrocarbon fuel extraction and burning have on the carbon cycle?

Answer 5

• Extracting and combusting fossil fuels releases carbon that has been stored in the lithosphere for millions of yrs into the atmos.
• Would have remained sequestered in lithosphere for thousands or millions more yrs

Question 6

What impact has deforestation had on the carbon cycle?

Answer 6

• Forests could be cleared for agriculture, logging or making way for new developments
• Clearance reduces the size of the carbon store and if it is burned there is a rapid flow of carbon from the biosphere to the atmos.

Question 7

What impact has farming practices had on the carbon system?

Answer 7

• Animals release CO2 and methane when they respire and digest food
• Ploughing can release CO2 stored in pedosphere
• Rice paddies release a lot of methane
• As worlds population has risen so has food production so carbon emissions from farming have increased
• Mechanisation in farming has also increased CO2 emissions

Question 8

What impact has land use changes had on the carbon cycle?

Answer 8

• Deforestation as well of change from natural land to urban
• Vegetation is removed to make way for buildings, reducing storage in biosphere
• Concrete production releases lots of CO2 and lots of concrete production used when expanding urban areas

Question 9

Which carbon stores experience change at a fast rate?

Answer 9

• Ocean atmos. exchange
• Photosynthesis
• Decomposition
• Respiration
• Digestion

Question 10

Which carbon stores experience changes slowly?

Answer 10

• Farming
• Weathering
• Combustion
• Sequestration
• Sedimentation
• Ocean carbon pump
• Deforestation