changes in carbon cycle

Question 1

carbon levels over years

Answer 1

fluctuated

carbon level inc so does temp
400,000yrs ago co2 spiked 280ppmv and temp spiced 4degrees in antartic

carbon levels relatively similar over years
projected 270ppmv to 400ppmv

Question 2

effect cold conditions

Answer 2

chemical weathering lees effective as cold transfers less carbon so more is stored

less forest cover
less carbon transfered
more stored

decomposers less effective
less transfered to soil
less stored

less water flow
less sediment tranfer
less build up ocean floor
less transfer
more stored

more stored
less transferred

Question 3

warm conditions effect

Answer 3

permafrost meted carbon transfer inc
less stored

more water flow to coean
more sediment build up
more transfer
less stored

less stored
more tranferred

Question 4

natural causes change in carbon cycel

Answer 4

natural change
wildfire
volcanic activity
orbital change

Question 5

climate forcing effect

Answer 5

Surface of sun has sun spots (storm) solar flares happen which leads to small increase in temperature on earth (decades)

Short term change example

11 years between peak and low of sunspot activity

Late 17th century there was 70 years few sunspots (maunder minimum) matches with lower temperatures – river Thames froze over and had fairs

Question 6

different glacial periods

Answer 6

Interglacial = warmer

Glacial = cold

At end glacial period its warmer so melting so more co2 to atmosphere – greenhouse effect (positive feedbach)

Question 7

orbital forcing

Answer 7

eccentricity
obliquity
precession

1000s of years
change orbit

Question 8

what is eccentricity

Answer 8

Sometimes circular orbit sometimes elliptical orbit changes every 100,000 years

Circle earth same dist sun so gets same solar energy through year

Elliptical distance changes sometimes close so more solar energy or further away so get less

Question 9

obliquity

Answer 9

earths rotating on tilted axis this angle changes – more vertical or tilted changes between every 41,000 years

Caused gravity large plants like Jupiter and Saturn pulling on earth

Determines length and strength of seasons

Question 10

precession

Answer 10

earth is wobbling, takes 26,000 years to complete one wobble, direction earth axis points slowly changes

Effects how much solar energy each hemisphere receives at different times of the year, responsible timing of seasons

Combines together cause long term changes to earths climate

Question 11

volcano impact

Answer 11

1991 eruption gave off ash and dust and gas
particles reflected the solar radiation
avg global temp fall by 0.5 degrees for 2 years (short term change)

Volcanoes emit 130-180 million tonnes co2 per year in comparison to humans 30billion tonnes from burning fossil fuels

Lava has silicates that can weather

Question 12

natural change impact

Answer 12

carbon always moving

global climate fluctuates
influence glacial intetglacial

Question 13

wildfire impact

Answer 13

Commonly by lightning strikes
Localised but has region impact

Indonesia many wildfires that burnt for month in 2003, many in Australia

Cover wide area (smoke spread across southeast Asia from Indonesia)
Released lots co2 into atmosphere

Turned forest to carbon source as combustion returned carbon to atmosphere and to pedosphere as charcoal

Question 14

reason for post glacial warm

Answer 14

Believe 90% post glacial warming occurred after rising atmospheric co2

Nobody totally convinced on clear cut reason/pattern

Fairy certain anthropogenic factors have sped up co2 level and higher temp

Question 15

human changes carbon cycle

Answer 15

cement manufacture
farming
land use change
urban growth

Question 16

natural source carbon

Answer 16

ocean atmosphere exchange which accounts for 42.84%.

Plant and animal respiration accounts for 28%

soil respiration + decomposition also accounts for 28%.

The smallest store is volcanic eruptions is 0.03%.

Question 17

human sources carbon

Answer 17

fossil fuel usage which is 87%

Land use change is the second biggest of 9%

industrial processes 4%

Question 18

fossil fuels and co2 conc data

Answer 18

fossil fuel concentration has increased steadily
- highest concentration in summer and lowest in winter

in total the co2 concentration has increased in general

In 1960, co2 concentration was 315ppmv and then it rose to 370ppmv in 2000

increased to 400ppmv in 2015

overall increase in 85ppmv over 55 years.

Question 19

shrimpling farm

Answer 19

emit 150 tonne carbon from fuel from machines

nitrous oxide emissions from crop residues and green manure

250 sheep realse 6% farm emissions (methane)

650 Ha arable farm

60% sequested from woodland
20% field margin
18% hedges
2% orchards

Question 20

land use change - deforest

Answer 20

forests cleared
sometimes burnt
releases carbon to atmosphere
less is stored

clearing of the forest
accelerates decay of wood and litter and organic carbon
more is released to the atmosphere
less is stored

less interception
water cannot infiltrate
soils dry
vegetation cant grow
so less carbon taken in from atmosphere

180 tonnes of carbon per hectare are taken up by photosynthesis of above ground biomass
so deforestation means more carbon is staying in the atmosphere.

tree dies it releases carbon however this is slow process so new vegetation can grow and take up this carbon becoming carbon neutral.

Question 21

how does cement cause co2 production

Answer 21

clinker key component cement

calcium carbonate heater to make clinker

every 10000kg cement 900kg co2 released

used in construction as affordable and strong

Question 22

farming impact carbon

Answer 22

10% carbon emissions

artifical fertilisers source carbon emissions

soil ploughed
air mix in
microbial activity inc
more organic matter decomposed
more co2 to atmosphere

livestock produce methane
US cattle emit 5mill tonnes methane each year

processes in rice paddles generate methane

Question 23

deforestation facts

Answer 23

13 million Ha forest cut a year

Trees cut and burnt or used for building

3% of forests were lost between 1990 and 2005

at a rate of 200km2 per day – meaning rainforests could vanish completely within 100 years.​

Question 24

urbanisation impact

Answer 24

As cities grow need more land

The CO2 emissions from transport, industry,  domestic use and cement manufacture for buildings have all increased.​

In 2012, cities responsible for 47% of global carbon emissions.

Replacing open countryside with concrete and tarmac is a major change in land use
- significant impact on the local carbon cycle as important stores are either replaced (vegetation) or covered up(soils) with impermeable surfaces.

2013, global CO2 emissions from fossil fuel use and cement production were 61% higher than in 1990 and 2.3% higher than 2012.