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
Role of living organisms in carbon cycle
Plants - photosynthesis (atmosphere to biosphere)
Animals and plants - respiration (biosphere to atmosphere)
Decomposition of dead plants and animals by bacteria and fungi - carbon back to soil and atmosphere
links between water and carbon cycles
photosynthesis
CO2 in atmosphere affects global temperature
- affects evaporation and precipitation
carbon and water combine to make acid rain
- chemical weathering
Why is the carbon cycle important for sustaining life
- CO2 in atmosphere used in photosynthesis, needed for plant growth and releases oxygen
- greenhouse gas, keeps earth warm (but enhanced greenhouse effect)
- trees 50% carbon, used for fuel and habitats
what is the enhanced greenhouse effect?
increased concentration of greenhouse gases in the atmosphere are causing more energy to be reflected back to earth
(rather than into space)
absorbed and heats earth
affects of climate change
patterns of precipitation
- wetter places wetter, drier become drier
- water shortages
extreme weather events
- more frequent
- LICs at risk
decrease in agricultural productivity
- food shortages
sea level rise
- flood risk
decline in species
- eg plankton
- affects whole marine food chain
strategies to mitigate climate change
renewable energy
- less use of fossil fuels
- less carbon transferred to atmosphere
- electric cars
afforestation
- increase carbon removed from atmosphere into biosphere
carbon capture and storage
- CO2 released from fossil fuels captured
- stored underground (doesn’t go to atmosphere)
(expensive)
international agreements
- Paris Agreement
- 195 countries agreed to reduce global co2 emissions by 60% of 2010 levels by 2050
carbon trading
- countries and business given limit on emissions
- produce less, sell credits
adaptations to cimate change
adapt farming practises
- crops that can withstand hotter temperatures and less water
- also withstand flooding if coastal
adapt to rising sea levels
- defences against flooding and erosion
but still experience the impacts (see other flashcard)
issues with mitigation
expensive
eg CCS
people often unwilling to change behaviours
eg electric cars/ less use
not everyone signs up to international agreements
some more worried about profits than protecting environment
feedback loops affecting climate change
release of methane from permafrost
- increased temperatures melt permafrost
- methane trapped released in atmosphere
- increased ghg concentration
= warming needs to be reduced
eg international agreement
deforestation
- less photosynthesis, less carbon removed
- carbon in wood released
- slash and burn releases carbon in combustion
= reduce deforestation
eg afforestation and selective logging
vegetation breezing
- clearing areas leads to soil erosion
- localised areas of low pressure
- more rainfall so more erosion
- no tress grow so permeant clear area
= reduce complete deforestation
eg selective logging
but - increased global temperatures = longer growing seasons so more photosynthesis, reduced carbon
factors affecting carbon budget
deforestation
- reduced photosynthesis
- carbon in wood released
- effects climate and species in rainforest
- drought due to less evapotranspiration
+ but can be mitigated
eg international agreement and protected areas
farming
- leads to deforestation
- ploughing and fertilisers release carbon
- increased co2 in atmosphere
- effects climate and drought
but negative feedback
+ increased co2 means more photosynthesis so more sequestered
