Changes to the carbon cycle

Question 1

What is the carbon budget?

Answer 1

The carbon budget is the amount of carbon that is stored and transferred within the carbon cycle.

Question 2

What is the slow carbon cycle?

Answer 2

The long term carbon cycle which takes million of years. The carbon is built up into sedimentary rocks and slowly released as they’re weathered.

Question 3

What is the fast carbon cycle?

Answer 3

Takes place over a short time period, may even be over a lifetime.
Vegetation takes in carbon through photosynthesis and its released through leaf litter over several months.

Question 4

What do natural carbon processes involve?

Answer 4

1. Respiration-
   Chemical process which happens in all cells in both plants and animals. Converts glucose into energy which is used for growth and repair.
2. Photosynthesis-
   Where plants use light energy to convert CO2 into glucose.
3. Decomposition-
   When biomass dies they’re consumed by decomposers. CO2 stored within is released.
4. Combustion-
   When material is burned it’s converted into CO2 and energy,
5. Burial and compaction-
   Organic matter is buried/compacted becomes hydrocarbons.
6. Sequestration-
   Describes transfers of carbon from atmosphere into other stores.

Question 5

What are the three natural causes of change in the carbon cycle?

Answer 5

1. Natural climate change
2. Wildfires
3. Volcanic eruptions

Question 6

What does natural climate change do to change the carbon cycle?

Answer 6

• Past 450,000 years there has been a general trend that when carbon levels change so does temperature and vice versa.
• 200,000 until 150,000 years ago temperatures dropped to -5 to -10 degrees.
• During these time periods amount of carbon in the atmosphere dropped. At the end when temperatures increased, carbon levels rose from 200ppm to 300ppm.

Question 7

What is the impact of cold conditions?

Answer 7

• Weathering processes more active, as cold water holds more CO2.
• Forest coverage would be different in area and location so affects processes such as photosynthesis.
• Decomposers would be less active so carbon transfer would be reduced.

Question 8

Whats the impact of warm conditions?

Answer 8

• Melting of permafrost in tundra regions, carbon stored within the ground is released. Positive feedback.
• Wildfires can be started naturally by lightning strikes, turns forests from carbon sinks into sources. More significant in the past.
• Volcanic activity returns carbon which has been stored in rocks for millions of years. More common during the Palaeozoic era.

Question 9

What are the Milankovitch cycles?

Answer 9

Differences in the earths orbit can affect the temperature and the carbon cycles.

1. Eccentricity (100,000 years)
   - When orbit becomes elliptical not circular.
2. Tilt axis (41,000)
   - Tilt of the axis varies, greater tilt = more solar energy
3. ‘Wobble’ axis (24,000)
   - Gradual change in the arbitration of the axis.

Question 10

How does the Milankovitch cycles affect the carbon cycle?

Answer 10

• When earth is closer to the sun temperatures increase, this means that cryosphere stores containing carbon begin to melt releasing CO2 into the atmosphere. This accelerates the greenhouse affect. (Positive feedback)

Question 11

How have human factors caused changed to the carbon cycle?

Answer 11

• Keeling curve takes measurements of the amount of CO2 in the atmosphere, has been doing this since 1950’s in 1960 it was 315 ppm while its currently 409ppm.
• Records show enough carbon has been released to reach 500ppm but it has been absorbed by other stores.

Question 12

What are the human causes for the release of carbon (BUDA)?

Answer 12

Burning fossil fuels
Urbanisation
Deforestation
Agricultural processes

Question 13

How does burning fossil fuels affect the carbon cycle?

Answer 13

When the fuels made of hydrocarbons are burnt, CO2 is released. Since industrial revolution fossil fuels have been burnt in increasing amounts.
Burning fossil fuels is the human factor which is causing the most drastic change in the carbon cycle.

Question 14

How does urbanisation affect the carbon cycle?

Answer 14

Has a significant impact on the local carbon cycle as important stores such as vegetation is removed or covered up.
Urban areas account for 97% of all anthropogenic CO2 emissions.

Question 15

How does deforestation affect the carbon cycle?

Answer 15

Accounts for 20% of CO2 emissions as the carbon previously stored within the trees is released immediately when they are cut down.
Carbon is released further when they are burnt through combustion.

Question 16

How do agricultural processes affect the carbon cycle?

Answer 16

Many farms now use artificial fertilisers which release a lot of CO2 + methane .
Land use change responsible for 10% of carbon release as land is being cleared due to an increasing demand for crops.

Question 17

What are consequences of increased carbon in the atmosphere?

Answer 17

• Greenhouse affect is a natural process where greenhouse gases reduce the loss of the suns energy, so it becomes trapped and warms the planet by 23 degrees, this is vital for life.
• EGE is when more of these gases are released and the temperatures rise above levels that they should.

Question 18

What are the consequences of increased carbon in the lithosphere?

Answer 18

• High temperatures in cold climates increase rates of decomposition, releases further carbon.
• Leads to more photosynthesis and longer growing conditions. Known as carbon fertilisation.

Question 19

What are the consequences of increased levels of carbon on the hydrosphere?

Answer 19

• Ocean acidification means less carbonate animals cannot form proper shells and they become weaker. Causes reef loss which threatens marine bio-diversity. Water may become corrosive.
• Ocean warming, may limit the oceans ability to absorb co2, also kills off algae that is needed for coral to survive this leads to coral bleaching.
• Melting sea ice, ocean is able to absorb more sunlight as less reflection making it even warmer conditions which algae thrive in.
• Ocean salinity will decrease due to increased rainfall and melting of ice, may slow down important ocean circulations such as North-Atlantic drift.

Question 20

How can we help to reduce these outcome by modifying combustion?

Answer 20

• Involves reducing the amount of CO2 in the atmosphere by carbon capture.
• Uses technology to capture co2 as a gas and is turned back into liquid form and put back where it originally came from (oil stores).
• Could help to cut carbon emissions by up to 19%.
• May be used as a reason to increase oil use.
• Extremely high costs and delays.

Question 21

How can we help to reduce these outcomes by modifying land use change?

Answer 21

• One crop is replaced by another with absorbs more CO2.
• Change on a much smaller scale.
• Huge incentives are needed to get farmers to change their practices as likely to reduce profits.

Question 22

How can we help to reduce these changes by modifying photosynthesis?

Answer 22

• Involves planting plants which absorb more CO2, plantation forests are where trees are planted as they will act as a carbon sink.
• Afforestation is not too costly
• Uses valuable space
• Takes 20-50 years for them to become effective sinks.

Question 23

How can we reduce these changes by modifying deforestation?

Answer 23

• Involves different ways of reducing deforestation.
  Done by:

1. Buying timber which has been grown sustainably.
2. Paying to protect forests and planting trees (Paying for the extra carbon).
3. Sustainable approach to logging.
   - Not huge costs incurred although all need large amounts of valuable space needed. Can only be done in areas with access to lots of space.

Question 24

Why will it be difficult to combat EGE (economic reasons)?

Answer 24

• Economic opportunities given priority over sustainability.
• Businesses do not want to sacrifice profits for more expensive practices.
• Low income families are unable to pay more for luxuries such as renewable energy.

Question 25

Why will it be difficult to combat EGE (temporal reasons)?

Answer 25

• Takes too long to build new factories and plant trees etc.
• Legislation takes too long to implement.
• 20-50 years for trees to be effective stores.

Question 26

Why will it be difficult to combat EGE (social reasons)?

Answer 26

• Needs a large scale of people to make a change.
• Not everyone believes in climate change.
• People choose to use cars due to ineffective public transport.
• No one wants to reduce quality of life.

Question 27

Why will it be difficult to combat EGE (political reasons)?

Answer 27

• May be reluctant to change if it causes conflict.
• Government receive tax on profits so they don’t want to reduce.
• Subsidies to all farmers is too expensive.
• Focused on short term gain and profits.

Question 28

Why will it be difficult to combat EGE (demographic reasons)

Answer 28

• Population becoming more urbanised which uses more carbon.
• The increasing population means an increase in demand for resources and space.

Question 29

What is the Paris climate agreement?

Answer 29

A consensus signed by 187 countries on the need to cut greenhouse gas emissions and unites all of the world’s countries to tackle climate change.

Question 30

What are the key elements of the Paris climate agreement?

Answer 30

• Aim to keep global temperatures below 2 degrees above pre-industrial times.
• LImit the amount of gas released by human activity to the same that environment can absorb.
• Review each countries contribution every 5 years.
• Rich countries will give climate finance to LICs of $1bn per year to help them bypass fossil fuels.