Carbon Cycle 🌿 Flashcards
Positive feedback in carbon cycle
- increased global temperatures
- increased rates of permafrost melt
- releases greenhouse gases into atmosphere (CO2 and methane)
- increased effects of global warming
Negative feedback in carbon cycle
- CO2 in atmosphere increases
- extra CO2 increases rate of photosynthesis
- more CO2 is removed from atmosphere
- amount of CO2 in atmosphere reduces
stores in the carbon cycle
atmosphere - stored at CO2
Hydrosphere - oceans - dissolved CO2
Lithosphere - sedimentary rock - eg limestone in lithosphere
Lithosphere - fossil fuels - in lithosphere eg coal and oil
Biosphere - vegetation - wood 50% carbon
permafrost (cryosphere)
flows in carbon cycle
- photosynthesis
- combustion
- sequestration
- respiration
- decomposition
- weathering
how does photosynthesis affect carbon cycle
transfers carbon from atmosphere to biosphere
passed through food chain
released by respiration and decomposition
how does combustion affect the carbon cycle
transfers carbon to atmosphere
from biosphere - wildfire
from lithosphere - burning fossil fuels
how does sequestration affect carbon cycle
transfer from atmosphere
to lithosphere - into sedimentary rocks
to biosphere - photosynthesis
to hydrosphere - into oceans
how does respiration affect carbon cycle
transfer from living organisms to atmosphere
how does decomposition affect carbon cycle
transfer from dead biomass to atmosphere and soils
broken down by decomposers to release CO2 and methane
transfered to soil as humus
how does weathering affect carbon cycle
chemical weathering
atmosphere to hydrosphere and biosphere
atmospheric carbon reacts with water to form acid rain
dissolves rocks of calcium carbonate eg limestone
fast vs slow carbon flows
fast
- photosynthesis
- respiration
- combustion
- decomposition
slow
- sequestration into sedimentary rocks
natural processes affecting the carbon cycle (processes driving change)
- wildfires
- volcanic activity
human factors affecting the carbon cycle (processes driving change)
- fossi fuels
- deforestation
- farming practises
- land use changes
how do wildfires affect carbon cycle
rapid transfer
biosphere to atmosphere
vegetation burnt - less photosynthesis, less carbon removed
Wood 50% carbon, released
- in short term
- long term
can encourage growth of new plants, secondary succession
increasing photosynthesis - net release 0 as eventually reabsorbed
how does volcanic activity affect carbon cycle
carbon stored in magma released in eruptions
enters atmosphere
larger eruptions could have significant affects on carbon cycle
- less significant than human
how do fossil fuels affect carbon cycle
extracting and burning releases CO2 into atmosphere
released from long term lithosphere stores
would remain for millions of years with no human intervention
- 90% of anthropogenic carbon emissions
- most fossil fuels extracted from rocks 70-100 million years old
how does deforestation affect the carbon cycle
cleared for agriculture, logging or urbanisation
flow of carbon stored in biosphere to atmosphere
- wood 50% carbon
vegetation removed
- reduced photosynthesis
13 million hectares forest cut a year (and converted)
how do farming practises affect carbon cycle
release carbon into atmosphere
- livestock release CO2 respiring
- ploughing releases CO2 from soil
- rice paddies
population rises, so does need for food
increases emissions from farming
mechanisation also increased emissions
- 40% agricultural emissions in Asia from rice paddies
how do land use changes affect carbon cycle
Urbanisation
- vegetation removed
- reduces storage in biosphere
- less photosynthesis
concrete production
- releases CO2
Increasing in future as urbanisation occurs more
- 13 million hectares forest cut a year and land use changed
- urban areas = 2% land but 97% anthropogenic C02 emissions
what is the carbon budget?
difference between carbon inputs and outputs in a subsystem
- balance determines if it is a carbon sink or source
changes caused by:
Fossil fuels, land use change and farming
increasing budget in atmosphere (increasing inputs) = climate change
impacts of changes on the atmosphere
affects amount of gases containing carbon in atmosphere (ghg)
- responsible for keeping heat in earths atmosphere
as concentrations increase, temperature rise - global warming
Enhanced due to human activity
affect climate eg more frequent storms and warmer
impacts of changes on the land
cycle allows plants to grow
- could not photosynthesise
- no decomposition, nutrients not recycled
changes can reduce carbon stored on land
released to atmosphere
Eg permafrost melt and increased wildfires
However more atmospheric C02 = more photosynthesis
warmth = longer growing seasons
= more sequestered
impacts of changes on the oceans
oceans sequester carbon from atmosphere
used by organisms in photosynthesis and shells
increased CO2 in atmosphere - increase acidity of oceans
- affects marine life
- 30% increase in ocean acidity since 1750
global warming means warmer seas
- warmer water sequesters less CO2 (more in atmosphere)
- positive feedback
organisms cant survive in warmer weather, less photosynthesis, less carbon sequestered
how is carbon essential for life on earth
all living things contain carbon
used in photosynthesis - allows plants to grow
- bottom of food chain
carbon in atmosphere - keeps earth warm enough for life
- however enhanced greenhouse effect
