Carbon Cycle Flashcards
Define sequestration
The natural storage of carbon by physical or biological processes such as photosynthesis
What is inorganic carbon?
Carbon in rocks
What is organic carbon?
Carbon stored in plants and organisms
What is gaseous carbon?
Carbon in CO2, CH4 and CO
Define respiration
The process in which living organisms involving the production of energy, with the intake of oxygen and the release of carbon dioxide
What is the geological carbon cycle?
The movement of carbon between land oceans and atmosphere
What is the biogeochemical carbon cycle?
The exchange of carbon between its four main reservoirs - the atmosphere, terrestrial biosphere, oceans and sediments
-> the geological cycle is part of this
-> the second part is the biological carbon cycle
What is the biological carbon cycle?
The faster cycle with rapid turnovers between the atmosphere, terrestrial biosphere, hydrosphere and biosphere
What are 3 terrestrial stores of carbon?
Limestone
Shale
Fossil fuels
Define fossil fuels
Dead organic material builds at bottom of rivers and seas and decays.
Heat and pressure is exerted
This becomes coal oil and gas
What is shale?
Organic carbon from dead organisms are embedded in layers of mud. Millions of years of heat and pressure compresses this into sedimentary rock
How does carbon get from the ocean to atmosphere?
Subduction of the sea floor at plate margins means some carbon ends up in earths lower mantle
Some hidden limestone can be exposed through tectonic uplift
Pockets of C02 in crust. Can be disturbed by volcanic activity
-Eg: pinatubo eruption 1991
What are the largest carbon stores?
-Terrestrial/crustal
-sedimentary rocks
-Slow cycled
-Deep in ocean
-Inorganic carbon stored at great depths and slowly cycled
What 4 main processes make up the fast (biological) carbon cycle?
Photosynthesis
Respiration
Decomposition
Combustion
Define decomposition
Breaking down of organic matter and releasing CO2 into soils
Define combustion
Burning of biomass/fossil fuels releases C02 and other greenhouse gases into atmosphere
What are phytoplankton booms?
How do they remove Co2 from atmosphere?
-Phytoplankton are micro-algae with calcium carbonate shells
-Sunlight conditions can cause a boom
-They sequester CO2 in their shells
-This sinks to bottom of the ocean
-When they die it is stored as sediment
Biological pump
Large phytoplankton absorb co2 and convert it to organic carbon
Organic carbon is transferred through marine food web
Dead organisms sink to deeper ocean
Decomposition releases CO2
Some long term storage occurs
Carbonate pump
Marine organisms like plankton, coral, oysters use carbonate ions to form shells and inner skeletons
When they die the shells sink to ocean floor
Some shells accumulate as sediment
Or shells dissolve and carbon is in deep ocean currents
Physical pump
CO2 is easily absorbed in cold water, therefore there is a high density of CO2 in deep ocean water and at the poles
• Warm waters release more CO2 to the atmosphere
• Ocean currents move water around so that warm water cools and absorbs CO2, and so that cold water sinks due to high density, taking CO2 from the surface to the deep ocean
Thermohaline circulation
Thermohaline circulation maintains the oceans’ biological and carbonate pumps by providing the correct conditions for phytoplankton to live and reproduce.
What is the anthropogenic greenhouse effect
Greenhouse effect enhanced by humans
Less heat escapes into space
Higher concentration of greenhouse gases (25% higher) since Industrial Revolution
How does the normal greenhouse effect work?
Some solar radiation is reflected by earth and atmosphere
Some infrared radiation passes through atmosphere
Some is absorbed by greenhouse gases and remitted in all directions
This warms the earths surface
How does the carbon cycle affect temperatures?
Solar isolation is more intense at equator and more dispersed at the poles
Wind distributes heat
Greenhouse effect
How does the carbon cycle affect precipitation?
Distribution of heat affects this
Warm air rises and cools, condenses and causes clouds and rain.
This results in high rainfall around equator
Low rainfall low latitudes where air pressure rises
How does the carbon cycle affect atmospheric composition?
Photosynthesis regulates atmospheric composition
By sequestering CO2 through phytoplankton and terrestrial photosynthesis
Little CO2 absorbed in deserts
Healthy soil
Dark, crumbly, porous
Worms and organisms present
Air and water provides nutrients for microorganisms
Define energy mix
The combination of different available energy sources used to meet a country’s demand
Define energy security
Refers to the reliability and availability of energy to meet the needs of a population
Depends on supply accessibility, availability affordability and reliability
Vital for country to function
What are the main factors affecting the energy mix?
Climate change commitments -COP
Economy - Fossil fuels cheaper
Resource depletion
Availability - EG Iceland geothermal
Rising demand
Geopolitical
USA vs France energy security
USA
15% imported
82% fossil fuels
France
46% imported
50% fossil fuels
41% nuclear
What players are involved in energy security?
-Governments/regulators: eg ofgem sets energy price gap for households
-Suppliers
-Consumers
-Campaigners
-Energy analysts
What are energy pathways + examples
Transfer energy from producer to consumer, resolving the global mismatch of supply and demand between production and consumption
Examples:
Oil pipelines, shipping routes, electricity transmission lines, road, rail
How has the Russia/ukraine conflict affected oil and gas supplies in Europe?
-Sanctions: $60 per barrel price cap
-regulation and reduction of imports: EU pledge
-This has reduced value of Russian oil which is now sold discounted to India/china
175 million dollar loss
Which factors disrupt energy supply?
-Conflict
-Population growth
-Piracy - hostages/ships attacked west Africa
-Natural hazards -> eg Hurricane Ida closed 70% of offshore oil companies
$30m of oil lost
Why can’t renewables fully replace fossil fuels?
-Expensive: infrastructure required
-Fossil fuels = higher energy density
-Large land use eg wind farms/HEP NIMBYISM
-Falling oil prices results in investment
-Storage -> cannot store energy
-Reliability and dependency
Carbon capture
-captures emissions, then transported and injected into geological formations like saline aquifers
-Could reduce emissions by 19%
-Not widely implemented due to cost
-Could grow with investment
Hydrogen fuel cells
-Can produce electricity, only by product is water
-High potential in transportation
-Expensive
What are tar sands and how is oil extracted?
A mixture of clay, sand, water and bitumen
Alberta produces 40% of canadas oil output
They are mined and injected with steam to make the bitumen less viscous so it’s useable
Advantages of tar sands
-Contribute to economy through jobs and can access global energy markets
-Pipeline expansion is taking place in Canada
-Some indigenous people have been hired eg Fort McKay First Nation
-Revenue sharing agreements with indigenous people
Disadvantages of tar sands
-Environmentalists
-Deforestation
-Acid rain
-Indigenous groups - description of traditional lands, food sources, cultural losses
-Local residents - contamination of water in fort Mcmurray
What is fracking?
Water and chemicals is pumped into shale gas in sedimentary rocks, forcing the gas out of the rocks
1% of USA gas supply in 2000
Advantages and disadvantages of fracking
+
Energy independence => less reliance on foreign sources
Creates jobs in drilling, transport, development
Reduces cost of energy
Burns cleaner than coal
-
Greenhouse gas emissions + methane leakage
Contamination of groundwater
Induced seismically - small earthquakes and pressure is altered
Deepwater oil advantages and disadvantages
-Brazil- huge oil deposits found off coast in 2006
-Energy needed for development
+
Lots of energy produced
Creates jobs
-
Oil spills damage ecosystems
Afforestation vs reforestation
Afforestation = replanting in areas that didn’t have trees before
Reforestation = Replanting trees in places where they were destroyed
Indonesia deforestation
$18 billion palm oil industry
3.5% of GDP
2.3Gigatonnes of CO2 released
What is ocean acidification
Increased CO2 in worlds oceans results in it being more acidic
Ocean is now 30% more acidic than (1750) (since Industrial Revolution)
How does ocean acidification harm coral?
-Reduced availability of carbonate ions, corals need this to build there skeletons
-Without sufficient ions they cannot maintain their skeletons
What is coral bleaching and it’s causes
-Corals expel the algae living in their tissues turning them white
-Algae provide food and energy
Caused by
-Climate change => higher ocean temperature (ideally should be 23-29)
-Pollution = changes to water chemistry
Why are coral reefs so important?
-Shelter 25% of marine species
-Protect shorelines from erosion
-Fishing industries
-Tourism income
What does Kuznets curve show?
How economic development affects environmental degradation.
Curve shows societies reach a tipping point where they move from exploitation to protection (but at first they exploit to develop)
Suggesting rising income eventually reduces environmental impacts
Why is there a turning point (Kuznets curve)
Appreciation that ecosystems are crucial to human wellbeing through services they provide
Supporting services
Provisioning services: provide products to humans
Regulating services: regulate earths systems
Cultural services: Non material benefits that people gain
What services do mangrove forests provide?
-Stabilise against coastal erosion
-Tangled roots trap nutrient rich sediments
-Absorb wave energy from storms and tsunamis
-Nurseries for fish
-Eg Thailand
Threats to Thailand mangroves
-35% deforestation for farming, tourists,
-17.7% GDP from tourism
Attempts to reduce threats to Thailand mangroves
-2500 hectares recovered in Ranong
-Mangrove buffer zone and reforestation
Maldives coral reefs
-Shelter 25% of marine species globally
-Food in Asia
-1M tourists to Maldives /yr
-70% destroyed by coral bleaching
-Coral rescaping is occurring with metal frames
-eg 4 seasons hotel monitors coral bleaching
Arctic sea ice
-Store 5-14% of global carbon
-Regulages thermohaline circulation
-Melting due to temperatures
Paris agreement
Why can’t we give specific predictions about co2 emissions? Human reasons
-Rate of economic growth changes
-Demand changes due to population
-changing lifestyles eg 60% living in cities by 2050
Why might previous carbon sinks become less efficient?
-permafrost in the arctic tundra will thaw and release methane resulting in positive feedback loop
-Warming oceans slow biological pump
Peatlands
-Accumulation of partly decayed vegetation which stores lots of carbon
3% of earths land surface
-Many have been drained eg Lake District
Dam drains for restoration
-historically carbon sinks but decomposing due to temperatures
