Carbon Flashcards
What is the carbon cycle?
The biogeochemical cycle by which carbon moves from one sphere to another. It acts as a closed system made up of linked subsystems that have input, throughputs and outputs.
What stores is carbon present in?
▪ The atmosphere as CO2 and methane
▪ The hydrosphere as dissolved CO2
▪ The lithosphere as carbonates in limestone and fossil fuels like coal, gas and oil
▪ The biosphere in living and dead organisms
Why is carbon important?
- regulates climate
- provides major building blocks for life on earth
What is carbon storage measured in?
Petagrams Pg
What are residence times?
The average length of time that material spends in a given pool
What are fluxes?
Fluxes refer to the movement/transfer of
carbon between stores.
Carbon store: Marine sediment and sedimentary rock
Easily the biggest store. 66,000 - 100,000 million billion metric tons of carbon. The rock cycle and continental drift recycle the rock over time, but this may take thousands, if not millions of years.
Carbon store: Oceans
The second biggest store contains a tiny fraction of the carbon of the largest store. 38,000 billion metric tons of carbon . The carbon is constantly being utilised by marine organisms, lost as an output to the lithosphere, or gains as an input from rivers and erosion.
Carbon store: Fossil fuel deposits
Fossil fuel deposits used to be rarely changing over short periods of time, but humans have developed technology to exploit them rapidly, though 4000 billion metric tons of carbon remain as fossil fuels.
Carbon store: soil organic matter
The soil can store carbon for over a hundred years, but deforestation, agriculture and land use change are affecting this store. 1500 billion metric tons of carbon stored.
Carbon store: atmosphere
Human activity has caused CO ₂ levels in the atmosphere to increase by around 40% since the industrial revolution , causing unprecedented change to the global climate. 750 billion metric tons of carbon stored.
Carbon store: terrestrial plants
Vulnerable to climate change and deforestation and as a result carbon storage in forests is declining annually in some areas of the world. 560 billion metric tons of carbon.
What is the geological carbon cycle?
- Very long turnover rate over 100,000 years
- Organic matter that is buried in deep sediments, protected from decay, takes millions of years to turn into fossil fuels. Carbon is exchanged with the fast component through volcanic emissions of CO2, chemical weathering, erosion, and sediment formation on the sea floor.
What is the biological carbon cycle?
- Carbon is sequestered in, and flows between, the atmosphere, oceans, oceans sediments, and on land in vegetation, soils and freshwater.
- relatively large exchange fluxes and rapid turnover rates
How is oil and natural gas formed?
Formed from the remains of tiny aquatic animals and plants. Gas and oil occur in pockets in rocks, migrating up through the crust until meeting caprocks. Natural gas, such as methane, is made up of the fractions of oil molecules, so small they are in gas form not liquid, usually found with crude oi. Other carbon deposits include oil shales, tar sands and gas hydrates.
How is coal formed?
Formed from the remains of trees, ferns and other plants. There are four main types:
- anthracite - the hardest coal, with the most carbon and therefore a higher energy content
- bituminous coals - second in hardness and carbon content
- soft coals such as lignite and brown coal are lower in carbon and energy potential; these are the major global source of energy supplies but emit more CO2 than hard coals
- peat is the stage before coal, an important carbon and energy source
What is lithification?
where freshly deposited loose grains of sediment are converted into rock
What is decomposition?
the breakdown of animals and plant structures by bacteria and the release of carbon compounds into the atmosphere, soil and to the ocean floor. Plants and animal particles from decomposition store carbon
What geological processes release carbon?
- Volcanic outgassing
- Chemical weathering
Explain volcanic outgassing
- Disturbance by volcanic eruptions or earthquake activity may allow pockets of CO2 that exist in the earths crust to be released into the atmosphere.
- Volcanoes currently emit 0.15-0.26 Gt CO2 annually, compared to humans emitting about 35 Gt annually, mainly from fossil fuel use, so volcanic degassing is relatively insignificant.
- An example of major degassing as a pulse is the 1991 eruption of Mt Pinatubo in the Philippines.
Where does outgassing occur?
○ Active or passive volcano zones associated with tectonic plate boundaries including subduction zones and spreading ridges
○ Places with no current volcanic activity such as the hot springs and geysers in Yellowstone National Park USA
○ Direct emissions from fractures in the earth’s crust
Explain chemical weathering
- The geological aspect of the carbon cycle interacts with the rock cycle.
- The processes through which the materials of the earth change can be broken down into 5 phases
- Chemical weathering - acid rain, formed from water reacting with atmospheric CO2 making carbonic acid, reacts with surface minerals, dissolving them into their component ions
- Transportation of calcium ions by rivers from the land into the oceans - the calcium ions combine with bicarbonate ions forming calcium carbonate and precipitate out as calcite and other materials
- Deposition and burial turns the calcite sediment into limestone
- Subduction occurs
- Some carbon rises to the surface within heated magma, then is “degassed” as CO2 and returned to the atmosphere. This is proved by diamonds (the purest form of carbon) being discovered to be formed up to 700km deep, proving that carbon is cycled between the earth’s surface and the lower mantle.
- The processes through which the materials of the earth change can be broken down into 5 phases
What is carbon sequestration?
Carbon Sequestration is the transfer of carbon from the atmosphere to other stores in solid or liquid form and can be both natural and artificial.
Why is photosynthesis important to the carbon cycle?
Living organisms convert Carbon Dioxide from the atmosphere and Water from the soil, into Oxygen and Glucose using Light Energy. By removing CO₂ from the atmosphere, plants are sequestering carbon and reducing the potential impacts of climate change.
Why is respiration important to the carbon cycle?
Respiration occurs when plants and animals convert oxygen and glucose into energy which then produces the waste products of water and CO₂. Overall, plants absorb more CO₂ than they emit, so are net carbon dioxide absorbers (from the atmosphere) and net oxygen producers (to the atmosphere).
What is the biological carbon pump?
- Phytoplankton photosynthesise, taking in carbon and forming organic matter.
- When they get eaten, carbon is passed through the food chain. CO2 is released back into the water as these organisms respire.
- Dead plankton sinks to the ocean floor, where it either decomposes or is turned into sediment
What is the carbonate pump?
- Marine organisms use calcium carbonate to make shells and inner skeletons.
- When these organisms die and sink, many shells dissolve before reaching sea floor sediment, so this carbon becomes part of deep ocean currents
- Shells that do not dissolve build up on the sea floor, forming limestone sediments
What is the physical pump?
-There would come a point where the surface layer of the ocean would become so saturated with carbon that this process would slow down or stop occurring.
- However, oceanic circulation provides a constant source of new water on the surface while transferring surface water into the deep ocean. It is this process which enables the ocean to store so much carbon. Water is not stored evenly within the water; the colder the water, the more CO2 is absorbed so the concentration of CO2 in the ocean is different around the world.
What is thermohaline circulation?
Thermohaline circulation is an ocean current that produces both vertical and horizontal circulation of cold and warm water around the world’s oceans. In addition to this, the atmospheric circulation creates large currents in the oceans which transfers water from the warmer tropical areas of the world to the colder polar regions.
1, The main current begins in polar oceans where the water is very cold, surrounding seawater sinks due to a higher density.
2. The current is recharged as it passes Antarctica by extra cold, salty, dense water.
3. Division of the main current; northward into the Indian Ocean and into the Western Pacific.
4. The two branches warm and rise as they travel northward then loop back southward and
westward.
5. The now warmed surface waters continue circulating around the globe. On their eventual return to the North Atlantic they cool and the cycle begins again.
How does ocean temperature affect rate of CO2 absorption?
The rate of absorption of CO2 into the ocean depends on ocean temperatures. The colder the water, the more CO2 is absorbed. Therefore, as ocean temperatures increase, the oceans will absorb less CO2 (possibly even emitting some of its stored carbon dioxide). This would accelerate Climate Change and lead to further ocean warming (positive feedback mechanism).
What is the enhanced greenhouse effect?
The enhanced greenhouse effect is the impact on the climate from the additional heat retained due to the increased amounts of carbon dioxide and other greenhouse gases that humans have released into the earths atmosphere since the industrial revolution.
How does the enhanced greenhouse effect work?
When the sun releases radiation towards the earth, some of it is absorbed by the earth’s surface, causing temperatures to increase. Some of it however, is reflected back towards the atmosphere. Greenhouse gases produced by humans trap this radiation and prevent it escaping, reflecting it back onto the earth’s surface. This causes global temperatures to increase more than expected and leads to global warming.
What are the causes of the enhanced greenhouse effect?
- CO2 released from burning fossil fuels
- Methane from rice and cattle farming
- Nitrous oxide from fertilisers and jet engines
- Halocarbons from industry and solvents
Examples of feedback in the carbon cycle
VANISHING ARCTIC ICE - temp rises, arctic sea ice melts, reflective ice reduced, replaced with darker oceans which absorb more heat, so temp rises more
RAINFOREST CLEARANCE - temp rises, clearance decreases rainfall storage, leads to drought/wildfires, leading to less rainfall to maintain hydrological cycle, fire releases CO2 in vegetation into atmosphere, causing temp rise
Why is soil important?
- Without carbon, the nutrient and water cycles cannot operate properly
- The amount of carbon stored depends on the system -
○ Amount of carbon stored within soil = inputs (plant litter and animal waste) - outputs (decomposition, erosion and uptake in plant growth) - Healthy soils usually -
○ Are dark, crumbly and porous
○ Contain many worms and other organisms
○ Provide air, water and nutrients for micro-organisms and plants to thrive
○ Contain more carbon or organic matter
○ Sequester carbon
○ Improve resilience to wetter weather as they enable infiltration and percolation of water
○ Retain moisture, which regulates soil temperature during heatwaves and reduces the effects of drought
- The amount of carbon stored depends on the system -
What is Arctic amplification?
Arctic amplification is the phenomenon where the arctic region is warming twice as fast as the global average. Melting permafrost releases CO2 and CH4, increasing the concentration of greenhouse gases in the atmosphere and leading to increases global temperatures and further melting.
○ Climate change is altering the arctic tundra ecosystem. Rapid warming has contributed to extensive melting of sea ice in summer months, and greatly reduced snow cover and permafrost.
○ Shrubs and trees have started to establish themselves, as well as animals.
○ Not all scientists agree that melting permafrost will release stored carbon as carbon dioxide and methane
§ Some studies show that as permafrost thaws, the stored carbon remains in the soil and is used by new vegetation
§ Warmer temperatures accelerate decomposition, releasing carbon and nutrients
§ Nutrients encourage plant growth and the removal of carbon from the atmosphere through photosynthesis
What is energy security?
Energy security is achieved when there is an uninterrupted availability of energy at a national level and at an affordable price. All countries seek to achieve this; the most secure energy situation is where the national demand for energy can be completely satisfied by domestic sources. The more a country demands on imported energy, the more it is exposed to risks of an economic and geopolitical kind. Four key aspects of energy security are:
* availability
* accessibility
* affordability - competitively priced energy supply
* reliability - uninterrupted
Why is energy security important?
The importance of energy security stems from the fact that energy is vital to the functioning of a country. For example, it: powers most forms of transport, lights settlements, is used by some types of commercial agriculture; warms/cools homes and powers domestic appliances; is vital to modern communications; drives most forms of manufacturing.
How is energy consumption measured?
- in per capita terms, i.e. as kilogrammes of oil equivalent or megawatt hours per person. In general, this measure rises with economic development
- by a measure known as energy intensity, which is assessed by calculating the units of energy used per unit GDP. The fewer the units of energy, the more efficiently a country is using its energy supply. In general, energy intensity values decrease with economic development
What is the energy mix?
The energy mix is the combination of different energy sources used to meet a country’s total energy consumption. It’s an important part of energy security, and varies from country to country. There are distinctions between:
* domestic and foreign sources
* primary and secondary sources
○ primary = found in nature, not converted/transformed. It can be renewable (water/wind/sunlight) or non-renewable (coal/oil/gas)
○ secondary = derived from transformation of conversion of primary sources, usually more convenient (electricity)
What factors affect per capita energy consumption?
- physical availability
- cost
- standard of living
- environmental priorities (of governments)
○ for some, energy policy will be taking the cheapest route to meeting the nation’s energy needs, regardless of the environmental costs. Others will seek to increase their reliance on renewable sources of energy; wile still other will have in place policies that raise energy efficiency and energy saving - climate
○ Very high levels of consumption in North America, the Middle East and Australia reflect the extra energy needed to make the extremes of heat and cold more comfortable - public perception
○ for some consumers, energy is perceived almost as a human right and therefore to be used with little or no regard for the environmental consequences. Others give priority to minimising the wastage of energy and maximising security - economic development
- technology
What is the relationship between economic development and energy consumption per capita?
- Economic developments like infrastructure projects etc cause more demand for energy, which increases consumption.
- As a nation becomes more developed, they are able to obtain more energy, which will cause more energy to be used.
- The ability to obtain more energy facilitates more infrastructure projects, causing exponential growth of energy consumption relative to economic development
What are energy pathways?
The route taken by any form of energy from its source to its point of consumption. The routes involve different forms of transport, such as tanker ships, pipelines and energy transmission grids.
Energy player - TNCs
- Nearly half of these are state owned - all or in part - and thus under government control, therefore strictly speaking, aren’t TNCs.
- Most are involved in a range of operations: exploring, extracting, transporting, refining and producing petrochemicals.
- E.G. Sinopec, BP, Royal Dutch Shell, PetroChina, Exxon Mobil
Energy player - OPEC
- Made up of 13 member countries which collectively control about 2/3 of the world’s oil reserves.
- It is in a position to control how much oil and gas enters the global market, as well as the prices of both commodities.
- It has been accused of holding back production in order to drive up oil and gas prices.
- Algeria, Angola, Congo, Equatorial Guinea, Gabon, Iran, Iraq, Kuwait, Libya, Nigeria, Saudi Arabia, United Arab Emirates, Venezuela
Energy player - energy companies
- These companies are important as they convert primary energy (oil, gas, water and nuclear) into electricity, and then distribute it.
- Most companies are involved in the distribution of both gas and electricity.
- They have considerable influence when it comes to setting consumer prices and tariffs.
E.G. British Gas, EDF, Scottish Power
Energy player - consumers
- The most influential consumers are transport, industry and domestic users.
- They are largely passive players when it comes to fixing energy prices.
Energy player - governments
- They are the guardians of national energy security.
- They can influence the sourcing of energy for geopolitical reasons.
