✅C&W 3.1.1.3 - The Carbon Cycle Flashcards
What is a Carbon store?
The lithosphere, hydrosphere, cryosphere, atmosphere etc
What is a carbon sink?
A store that takes in more carbon than it releases
What is a carbon source?
A store that releases more carbon than it takes in
What is a carbon transfer?
Processes that transfer carbon between stores
What is a GtC?
A gigatonne of Carbon, 1 gigatonne = 1 billion tonnes
What is anthropogenic CO2?
Carbon Dioxide generated by human activity
What is a greenhouse gas?
Any gaseous compound in the atmosphere that is capable of absorbing infrared radiation, therefore trapping and holding heat in the atmosphere
What is the lithosphere?
The crust and uppermost mantle, the hard rigid outer layer of the earth
Includes organic and inorganic carbon
organic carbon in the lithosphere
in soil- 1500 GtC
humus, litter
Medium residence time, 100 years in soil
Farming can disrupt stores, release Carbon
inorganic carbon lithosphere
Fossil fuel deposits, 4,100 GtC
Marine sediments and sedimentary rock- very long term, up to 100 million GtC- biggest store
Carbon in hydrosphere
up to 40,000 GtC in ocean
Living organic matter only 30GtC- significant but not major carbon release if killed due to warming
Sedimentary layer in ocean: organisms die, sink to bottom, decay, material forms rock over millions of years
What is weathering?
The breakdown of rocks in situ by weather, plants and animals
What is the biosphere?
The total sum of all living matter
What is Carbon Sequestration?
The capture of CO2 from the atmosphere, or capturing anthropogenic CO2 from large scale stationary sources such as power stations - put into long term storage
Why is recycling carbon essential for life?
It enables food to be provided for plants and animals and creation of energy sources
What can carbon form?
Biological molecules, Gases (eg CO2, CH4), Hydrocarbons
What is the primary source of Carbon?
The Earth’s interior
What are some of the stores in the carbon cycle?
Sedimentary rock, coal, oil, gas, plants, atmosphere, phytoplankton etc
What are some of the transfers in the carbon cycle?
Weathering and erosion, rock cycle, photosynthesis, respiration, burning, decomposition, diffusion
What is the largest store of carbon?
Marine sediments and sedimentary rock
How is the ocean a store of carbon?
CO2 is absorbed directly from the air and river water discharges carbon in solutions
How is soil organic matter a store of carbon?
They contain rotting organic matter and are important carbon stores. Carbon can remain in the soils for hundreds of years
How is carbon in the biosphere divided up?
How much GtC overall?
Into terrestrial and oceanic
3,100 GtC overall
What are the main sources of carbon in the biosphere?
Living vegetation- 19% of biosphere's carbon Plant litter Soil humus- in forests 69% of all C is in soil- 2500GtC Peat- saturation, no oxygen, decay is slowed due to anaerobic respiration, longer residence time- 250GtC Animals
Where is most of the carbon in the cryosphere?
In the soil areas of permafrost where decomposing plants and animals have frozen into the ground
What are methyl clathrates?
Molecules of methane frozen into ice crystals
What does most frozen organic matter in permafrost consist of?
Partially decayed roots, whole roots and other plant material
When is cryospheric carbon released into the atmosphere?
When the permafrost melts
What are oceanic carbon stores divided into?
Surface later (euphotic zone)
Intermediate and deep layer
Living organic matter
What is the euphotic zone?
The surface of the ocean where sunlight can penetrate and photosynthesis can take place
Why are sediments and rocks in the ocean so carbon rich?
Because when organisms die, they sink to the bottom of the ocean and decay, releasing carbon
What are fluxes?
Measurements of rate of flow of material between stores
What are processes?
Physical mechanisms which drive movement and fuxes
What type of system is the carbon cycle?
Closed
What is burial and compaction?
Organic matter is buried by sediments and becomes compacted
What is the geological component?
Where the carbon cycle interacts with the rock cycle in the processes of weathering, burial, subduction and volcanic eruptions
What is a sere?
A succession which relates to a specific environment
What is a lithosere?
Vegetation succession which occurs on bare rock
When was the quaternary period?
2.6 million years ago to today
Cold rainwater can hold…
…more CO2
If rainwater hold more CO2, how is the rock affected?
It is weathered more
What is eccentricity?
The change in the shape of the Earth’s orbit around the sun
How does the eccentricity of the Earth’s orbit change?
In 100,000 year cycles. it changes from a thin ellipse to a circle and back again
What is insolation?
The amount of solar radiation that reaches the Earth’s surface
What does lower insolation mean for global temperatures?
They decrease
What natural factors can increase input of atmospheric CO2?
Periods of increased volcanicity
warmer ocean, releases more carbon
warmer atmosphere, can hold more carbon
Volcanic activities impact on carbon cycle
Eruptions release carbon
Up to 0.36 GtC of CO2/ year - but this is up to 100x less than human caused emissions
No. of erutions not increasing, about 70/ year
ALthoug ash can cover sunlight, reducing photosynthesis- e.g, in Mt Tambora eruption 1815
What human factors can increase input of atmospheric CO2?
Burning fossil fuels
Causing more wildfires- less vegetation, less photosynthesis
Climate change causing melting of tundra
Carbon in the atmosphere
750 GtC
Likely highest ever been in last 20 years
Mauna Loa Observatory, Hawaii records: 280ppm of carbon in 1958, 317ppm in 2020
45% of emitted carbon has remained in the atmosphere
What natural factors can reduce removal of CO2 from the atmosphere
Glacial periods (less vegetation)
Interglacial periods (warmer oceans, less CO2 absorebd)
Winter in the northern hemisphere, hibernation
What human factors can reduce the removal of CO2 from the atmosphere
Clearing vegetation from from areas
Climate change resulting in warmer oceans
What percentage of anthropogenic CO2 is from fossil fuel burning?
90%
Burning fossils fuels impact on carbon cycle
81% of global energy is from fossil fuels
44% of emissions from coal
Increases greenhouse effect
How does ploughing increase CO2 emissions?
It aerates soil, increasing microbial activity and therefore decomposition, more CO2 released
What are the human factors which can cause changes in the carbon cycle?
Combustion of fossil fuels Land use Farming practices Carbon sequestration in soils Deforestation Urbanisation
How does deforestation affect the carbon cycle?
Above ground biomass is burned, releasing CO2- slash n’ burn
Forest clearing may accelerate decay of dead wood, litter or below ground organic carbon
In a natural system, trees would decay very slowly
Upsets the balance of carbon in the forest
But selective logging, only cutting logs above a certain height, is more sustainable
Lots of slash n’ burn in Indonesia, for palm oil industry
How farming practices affect the carbon cycle?
Arable farming is only 14% of farming emissions
Livestock is much more, lots of respiration
land use: 1/2 of all habitable land is used for agriculture, 70-90% of deforested land is for agriculture
How does urbanisation affect the carbon cycle?
Replacing open countryside with concrete and tarmac replaces important stores
Urban areas produce far more CO2 than rural ones- is only 2% of world’s surface but accounts for 97% of anthropogenic emissions
What does terrestrial/biological sequestration involve?
The use of plants to capture CO2 from the atmosphere and store it in stems and roots
What is the carbon budget?
Uses data to describe the amount of carbon that is stored and transferred within the carbon cycle
What is the enhanced greenhouse effect?
The impact on the climate from the additional heat retained due to increased CO2
What is geo-sequestration?
Technology capturing greenhouse gas emissions from power stations and pumping them into underground reservoirs
What is radiative forcing?
The difference between the incoming solar energy absorbed by the earth and energy radiated back to space
What is soil organic carbon (SOC)?
The organic constituents of the soil, tissues from dead plants/animals, products of decomposition, microbial biomass etc.
How is the carbon budget affecting ocean salinity?
Decrease in salinity in the deep North Atlantic, more freshwater being added to the ocean. Slowing down of large scale oceanic circulation
Carbon impact on the ocean?
Acidification, can cause coral bleaching
Global Carbon emissions since 1750: Coal
670 GtC
Global Carbon emissions since 1750: Oil
500 GtC
Global Carbon emissions since 1750: Gas
202 GtC
Global Carbon emissions since 1750: Cement
36 GtC (so urbanisation increases emissions)
Global Carbon emissions since 1750: Land Use
590 GtC
Global Carbon sinks since 1750: Atmosphere
880 GtC
Global Carbon sinks since 1750: Ocean
590 GtC
Global Carbon sinks since 1750: Land Use
528 GtC
