human factors leading to change in carbon cycle

Question 1

What are the human factors leading to change in the carbon cycle?

Answer 1

fossil fuel extraction and burning
deforestation
land use changes - urban growth
farming practices

Question 2

IPCC

Answer 2

According to the IPPC 90% of human caused carbon release comes from the combustion of coal oil and natural gas

Question 3

what reabsorbs the lost carbon through fossil fuel extraction and burning?

Answer 3

vegetation and the oceans help to re absorb 50% of this with the rest being absorbed by the atmosphere

Question 4

where does most of the worlds gas and oil come from?

Answer 4

most of the world’s gas and oil comes from rocks which are 70-11 million years old
carbon has remained locked up in the deposits for all that times

Question 5

what does combustion of hydrocarbons release?

Answer 5

releases both carbon dioxide and water vapour into the atmosphere

Question 6

what is it estimated about the cement industry?

Answer 6

it is estimated the cement industry produced 5% of all human induced global co2 50% which comes from the heating of calcium carbon and 40% from the burning of fuel to power the process

Question 7

for every 1000kg of cement produced how much carbon is released into the atmosphere?

Answer 7

900kg

Question 8

the 2013 co2 emissions for fossil fuel and cement production can be broken down into:

Answer 8

43% coal 
33% oil 
18% gas 
5.5% cement 
0.6% gas flaring from oil wells

Question 9

what happened in 2013?

Answer 9

in 2013 global co2 emissions from fossil fuel use and cement production topped 36 GtC 61% higher than 1990 and 2.3% higher than 2012
emissions were dominated by china usa and india

Question 10

what is the greatest source of carbon emissions in agriculture?

Answer 10

enteric fermentation (the methane belched by livestock during digestion
in 2011 this made up 39% of all agricultural carbon emissions
this figure then increased by 11% between 2001 and 2011

Question 11

what happens when soil is ploughed?

Answer 11

the soil layers invert with each other and as a result soil microbial activity increases resulting in more soil organic matter being decomposed as a result more carbon is lost to the atmosphere

Question 12

biological processes

Answer 12

biological processes in rice paddies generate methane which makes us 10% of all agricultural carbon emissions

Question 13

what makes up the carbon emissions from farming practices

Answer 13

burning of tropical grasslands 5%

Question 14

where do agricultural green house gasses occur?

Answer 14

44% of agriculture greenhouse gas emissions occured in Asia 25% in america 12% in Europe 15% in Africa and 4% in Oceania

Question 15

co2 emissions from land use change

Answer 15

account for 30% of all human induced carbon emissions

Question 16

deforestation

Answer 16

logging operations remove forests
forests are cut out as a result of urban sprawl
some deforestation is unintentional e.g wildfires
when forests are cleared a large proportion of above-ground biomass is burned releasing most of the carbon into the atmosphere

Question 17

although deforestation does directly impact the carbon cycle it leads to further knock on effects

Answer 17

• forest soils are moist however without shade from tree cover they soon dry out
• trees also help maintain the water cycle by returning the water vapour back to the atmosphere through transpiration
• without trees may former forest land can quickly turn into barren desserts

Question 18

planting of trees

Answer 18

planting of trees has resulted in forests being extended or established on abandoned agricultural land
this has reduced the net loss of total forest area

Question 19

how much of the worlds population live in urban areas?

Answer 19

over half of the world’s population live in urban areas and this is expected to reach 60% by 2030

Question 20

urban carbon emissions

Answer 20

concentrated highly around the most polluting of cities - the world most polluting of cities contribute to 10% of all energy related carbon emissions

Question 21

what is it expected from 2012 - 2030

Answer 21

it is expected that the most polluting cities will become much worse with just the worst 10 cities contributing to the same 10% of all energy related emissions

Question 22

co2 emissions resulting from energy consumption

Answer 22

for transport industry domestic use and cement manufacture have all increased .
in 2012 cities were responsible for 47% of global carbon emissions- expected to rise to 49% in 2030

Question 23

how can trees be a carbon source and a carbon sink?

Answer 23

trees are a sink because through photosynthesis they absorb co2 it is also a store because through deforestation and wildfires they release co2