Carbon Flashcards
What is the carbon cycle?
The movement of carbon in fluxes between different stores. It has been developing for billions of years and achieved its present balance around 290 million years ago, although human activities in the last 200 years have upset it
What are the 3 processes within the carbon cycle?
Biological processes
Geological processes
Chemical processes
What are biological processes?
Living plants and animals
What are geological processes?
Erosion, deposition and rock formation
What are chemical processes?
Reactions under heat and pressure
What is the terrestrial carbon store?
Sedimentary rocks have high concentrations of carbon (limestone is 42%)
Geological processes have also trapped carbon in the form of coal, oil and natural gas
The terrestrial store is the largest
What’s the largest carbon store?
Terrestrial
What is the atmospherics carbon store?
Volcanic activity, respiration, wildfires and out gassing emit carbon dioxide into the atmospheric store
> this store is very small compared to others
Small changes in concentration affect global temperatures and between 2012 and 2017 the average CO2 atmospheric concentration increased by 3% mostly due to humans
What is the ocean carbon store?
Carbon dioxide is dissolved by oceans from the atmosphere but it only makes up a tiny proportion of sea water mass
Most CO2 is stores in intermediate and deep sea water with only about 2.5% in surface waters
Which kind of rocks contain the most carbon?
Sedimentary
Metamorphic and igneous contain much less
How are sedimentary carbon rocks formed?
Shells and skeletons that collect at the bottom of the ocean as well as from calcareous ooze
Marine creatures and phytoplankton absorb carbon from sea water and when their remains collect on the sea bed the calcium carbonate is compacted by the weight of new layers above them and cemented together to form limestone
Calcerous oozes are not found where the ocean is too deep (over 6000m) becasue the pressure causes calcium carbonate to dissolve
What are biologically derived carbon rocks?
These are formed from the remains of living organisms deposited in layers within sedimentary rocks such as shale
Organic carbon from tropical coastal swamps is buried to produce coal, the hardness of which depends on the amount of pressure and heat when squashed during rock formation
Anaerobic reactions may convert organic carbon layers into a liquid - this is oil- that can move between the layers
A by product of coal and oil creation is methane which also becomes trapped between the rocks
What’s 2 ways carbon can be released?
Volcanic out gassing
Chemical weathering of rocks
What is volcanic outgassing? How does this release carbon?
Tectonic forces may bring limestone rocks into contact with extreme heat which causes chemical reactions and releases co2 into the atmosphere
Volcanic activity at plate boundaries or intra plate hotspots may release co2 into the atmosphere
Geothermal areas also release CO2 through hot springs
Degassing occurs because CO2 is not dissolved easily and so is released early in eruptions
What is chemical weathering of rocks? How does this release carbon?
Limestone rocks are very easily weathered by rain becasue it becomes a weak carbonic acid as it falls through the air and absorbs some CO2. This acid then dissolves the calcium carbonate of the rock and dissolved carbon is then carried away by the water to be deposited on the sea bed (calcium carbonate) or released as gas (carbon dioxide).
How is coal formed?
- Formation of Coal
Coal is formed primarily from the remains of plant material that accumulated in swampy, forested environments 300-400 million years ago (Carboniferous period).
Stages of Coal Formation:
1. Peat Formation – Dead plants accumulate in waterlogged, oxygen-poor environments (e.g., swamps).
2. Lignite (Brown Coal) – Over time, peat is buried and compressed by sediments, starting to lose moisture.
3. Bituminous Coal – Further heat and pressure drive out volatile compounds, increasing carbon content.
4. Anthracite (Hard Coal) – The highest-grade coal, formed under extreme heat and pressure, with a very high carbon content and energy value.
Key Processes:
• Anaerobic decomposition (low oxygen) prevents complete decay.
• Compaction and lithification due to sediment accumulation.
• Increased pressure and temperature transform peat into coal.
How is oil and natural gas formed?
- Formation of Oil and Natural Gas
Oil and natural gas are formed from the remains of marine microorganisms (plankton, algae) that lived in ancient seas 50-500 million years ago.
Stages of Oil and Gas Formation:
1. Organic Sediment Deposition – Plankton die and sink to the seafloor, mixing with mud.
2. Kerogen Formation – Over millions of years, layers of sediment build up, and heat and pressure transform organic material into a waxy substance called kerogen.
3. Cracking Process – At 50-100°C (oil window), kerogen breaks down into crude oil. At 100-200°C (gas window), it further breaks down into natural gas.
4. Migration and Trapping – Oil and gas migrate through porous rocks until trapped by impermeable rock layers (cap rocks), forming reservoirs.
Key Processes:
• Sedimentation and burial under anoxic conditions (low oxygen).
• Thermal maturation (heat and pressure convert organic matter into hydrocarbons).
• Migration through porous rock and accumulation in reservoirs.
What is the geographical importance of coal oil and gas? Where are they found?
Geographical Importance
• Coal is found in continental landmasses (e.g., USA, China, Russia).
• Oil and gas are primarily found in marine sedimentary basins (e.g., Middle East, Gulf of Mexico, North Sea).
• Fossil fuel extraction has led to economic growth, geopolitical tensions, and environmental concerns such as carbon emissions and climate change.
What are phytoplankton and why are they useful?
Microscopic single celled plants found in the warm surface waters of the ocean
They consume carbon dioxide from the atmosphere and photosynthesise, storing it in their body as a carbohydrate
When they die they transfer carbon deeper into the ocean (forming calcium carbonate layers when they sink to the sea bed) or are eaten by zooplankton
This is a biological carbon pump
What is the marine carbonate pump?
The marine food web extends from phytoplankton to zoo plankton and then to other organisms like corals, oysters and crabs which consume carbon and also use it to make their shells and skeletons
These creatures return some carbon dioxide to the atmosphere via respiration but also use enough to create room for the sea to absorb more from the atmosphere
In a short time period, carbon is taken from the atmosphere into the ocean and then chemically transferred to the sea bed to become sedimentary rocks
This is the marine carbonate pump
What kind of sea water sinks and what does this allow?
Colder denser sea water sinks to deep ocean areas where slow moving currents enable CO2 to be stored
What is the thermohaline circulatory system?
- Warm salty ocean currents transfer energy heat from tropical areas towards the poles, and cold less salty currents transfer colder water towards the equator. The temperature and salinity differences cause the large scale circulation of sea water
- Warmer water travel nearer to the surface because heat rises, while large volumes of cold water move at depths of 3km or below. This moves sea water around the world between oceans: warm surface currents and cold deep currents
- Parts of the thermohaline circulatory system help to transfer CO2 from oceans around to equator to polar ocean sinks. Currents that push water up and downwards (upwelling and down welling) move dissolved CO2
This is the physical carbon pump
What is the physical carbon pump
The thermohaline circulatory system
What is the biological carbon pump?
Phytoplankton
What is the marine carbonate pump?
The shells and skeletons of dead organisms that sink and compact at the bottom of the ocean into sedimentary rocks and return some carbon to the atmosphere
What are terrestrial primary producers?
Plants in land based ecosystems that use and store the suns energy to change CO2 and water into carbohydrates through the process of photosynthesis which allows the plants to grow
Primary producers also absorb CO2 from the atmosphere especially during the growing season and daylight hours
Do plants release co2?
During the conversion of carbohydrates into energy , respiration takes place and some water and CO2 is released back into the atmosphere. However, overall all plants absorb more than they release
Is there a pattern of CO2 concentration in the atmosphere?
Yes - during the northern hemispheres growing season, in spring and summer months, there are lower atmospheric co2 concentrations and during winter, concentrations increase because plants are dormant
What type of biome has the most productivity in terms of the carbon cycle?
Tropical rainforests have a much higher global productivity than any other biome with 1/3 of all global productivity
This biome takes 4x more co2 from the atmosphere than the next more productive biome
What is the equation for respiration?
Glucose + oxygen = carbon dioxide + water + energy
What are consumers and why are they called that?
Animals are known as consumers because they use oxygen produced by plants during aerobic respiration and eat plant carbohydrates. As part of this process they refine carbon dioxide to the atmosphere
What type of animal emits methane?
Herbivores
How is carbon passed through the food web?
Energy is passed from one consumer to another through food chains, like from a herbivore to a carnivore. In this way carbon is passed up the tropic levels throughout the food web.
What is the role of soil processes in the carbon cycle?
Plant litter decomposes
⬇️
Soil biota digest dead plant material and release nutrients like carbon (some co2 is emitted to the atmosphere at this stage)
⬇️
Higher humus content in soil means more carbon is stored
⬇️
Some carbon is transported by leaching through flow and groundwater flow
What are the three major greenhouse gases?
Two linked to the carbon cycle - carbon dioxide and methane
One linked to the nitrogen cycle - nitrous oxide
Why do greenhouse gases have the ability to trap heat?
They are denser than other gases in the earths atmosphere so they have the ability to trap heat and energy in the earths atmosphere
How do scientists know that the earths average temperature has changed?
Scientific research of ice core samples in Antarctica shows that over geological time the earths average temperature has changed with the changes in concentration of atmospheric carbon
How does the natural greenhouse effect work?
Heat energy from the sun heats the planet but without greenhouse gases this would not be enough to support life.
The heat energy that is reflected back towards space from the earths surface and lower atmosphere has a relatively long wavelength so it has difficulty travelling through denser gasses and is absorbed by them. Basically this means that greenhouse gases trap heat and recycle it meaning earth stays warm. When there is too many greenhouses gases this works overtime which makes the earth warmer and warmer.
Without the natural greenhouse effect the earth would be 21° cooler
How do humans throw off the balance of natural systems that regulate the atmosphere?
Greenhouse gases regulate the atmosphere but human interference can mean too much carbon is released from things like fossil fuels which can alter the balance
What is ocean and terrestrial photosynethesis? How does this regulate the atmosphere?
Photosynthesis can take place on land (terrestrial) and in the ocean where there are plants (like a rainforest or phytoplankton in the sea)
Photosynthesis regulates the composition of the atmosphere by balancing oxygen and carbon dioxide
What is soil health and how does it help keep ecosystems healthy?
Some carbon is returned to soils by dead plant material being decomposed. In this way carbon is stored in organic matter (humus) that is mixed with soil. This is important for soil health, as organic matter helps retain soil moisture and nutrients, which in turn improves the productivity of an ecosystem by providing water and dissolved nutrients for plants to absorb through their roots to grow.
What is fossil fuels consumption and when did it begin?
The Industrial Revolution in Europe began the large scale burning of fossil fuels for power stations, industry and machinery. Compared to the natural carbon cycle, this happened very fast. Atmospheric CO2 levels are now higher than at any time in the past 800,000 years so temperatures are increasing more and more
What are the implications of fossil fuels being burnt for the climate?
Temperate and tropical areas may have stronger storms because of more heat energy and moisture in the atmosphere
There are fewer extremely cold events but more extremely hot ones due to average temperature increase
Biggest increases in average temperature will be in the arctic as more heat begins to be transferred from the tropics
Precipitation patterns will also change, higher near the poles and decreasing in the subtropics as warmer air can hold more moisture.
What are the implications of fossil fuels being combustion for ecosystems?
10% of land based species will face extinction due to an inability to adapt or move when the climate change conditions they have adapted to change
> highest risk in polar areas
80% of coral reefs could be bleached by warmer temperatures and chemical weathering as oceans become more acidic
Disease and pests will increase as they thrive in warmer conditions and are not killed by cold winters
Biodiversity will reduce as habitats shift towards poles or into deeper ocean waters, changing food webs
What are some implications of fossil fuel combustion for the hydrological cycle?
Shift of subtropical high pressure areas towards poles will increase drought conditions in the Mediterranean
Permafrost will melt adding more water to arctic rivers and streams
River discharge will decrease in areas with lower precipitation and lower effective precipitation (where evaporation rates increase)
Cryosphere stores will decrease as glaciers retreat or ice sheets have surface ablation; this will also decrease river discharge at first and then decrease them
What patterns are there of energy consumption?
World average use of energy per capita increased by 17.5% between 2000 and 2014
> It is highest in developed countries and those with significant oil reserves
> It is lowest in developing countries and rapidly increasing in economically emerging countries
> it is increasing quickest in developed countries
Is there any connection to the amount of energy needed for a country to generate wealth?
In terms of GDP wealth generated per unit of energy world average shows an increase in efficiency of about 22% between 2000 and 2014
> this means it’s taking less energy to produce wealth
Which countries use energy more efficiently to create wealth?
Developed and economically emerging countries have a higher efficiency and are improving the most
(UK 57%)
Developing countries have lower efficiency and are improving less
(DRC about 4%)
Are there any countries that are using energy less efficiently?
Saudi Arabia had a 20% increase in efficiency between 2000 and 2014 because of economic expansion and broadening their base
What’s primary energy?
Natural energy resources that have not been converted into another form of energy; this is most types of energy from fossil fuels to renewables
What’s secondary energy?
A form of energy that has been created from a primary resource
> this is usually electricity
What’s the energy mix?
The proportion of each type of energy a country uses each year
What type of energy is the world energy mix dominated by? How is this changing?
Non-renewable fossil fuels
> most developed countries are reducing their use (decarbonisation) and increasing renewables
Why might poorer countries not use renewables?
They are still developing and can be an expensive upfront cost so poorer countries often use small proportions as part of their energy mix
What’s an example of a developing country that’s using more clean energy?
China
What other recent trends are there of energy use?
Oil use is slowing down (-61% by 2040), coal is being replaced (-72% by 2040), nuclear remains quite uncertain
Renewables are growing (+95% by 2040) as costs decline and electrical energy use is also increasing
What do a lot of countries rely on that could be unreliable in the future?
Imported energy
> in 2014 China imported 15% of the energy they used
> in 2015 Belgium imported 80%
A lot of countries use this as well as their domestic supplies however, geopolitical tensions could create difficulties
What determines which countries have fossil fuel reserves? Why is it beneficial to a country to have fossil fuels?
Long term geological processes
> fossil fuels are very valuable when sold to another country but can also be used to develop the economy domestically
Why may some countries not be able to use certain renewable energy sources?
Climate and geological conditions affects the availability of some energy resources
> clear skies for solar, wind for wind power, rivers and and deep valleys for reservoirs for HEP
Why may a country not be able to benefit from their fossil fuel reserves or renewable options?
They may have the right geological or climatic conditions that provide an energy resource but not the technological ability to extract and develop it
Many developing countries lack the necessary investment for infrastructure without external assistance
> in Ghana electricity grids and economic challenges limit their use of solar energy
Countries with low levels of development also do not have a lot of demand for energy so there’s no inventive for government or FDI
Why may costs and public perception impact a country developing their energy resources?
Costs of developing any energy resource are high at all stages from extraction to production and sale. Coats are inevitably passed on to the consumer who may not be able to afford them.
> wealthier people tend do consume more energy
People have different perceptions of their energy needs based on lifestyle
> travel patterns, quality of life, needs like heating or air conditioning etc
How do different cultures view the value of the natural environment? What changes have been made to be more sustainable?
Some countries - like Russia, the USA and Nigeria - see nature as a provider of resources
Others are more concerned with the serous damage that can be caused by extracting energy resources, like fracking
Climate change concerns have led to decarbonisation like using less coal and oil
Which energy resource has been fazed out due to fears over its potential dangers?
Nuclear radiations and explosions have led to a reevaluation of this energy resource in Japan, Germany, Belgium and France
How do the energy targets of Denmark and the USA differ?
Denmark:
Half of electricity from wind power in 2020
No power from coal by 2030
All electricity and heat from renewables by 2035
Fossil fuel free by 2050
USA:
achieve energy independence from imports
Expand production and develop unconventional natural gas
Increase renewable energy sources
Minimise emissions reduction targets
What is the role of TNCs as energy players?
Provide investment for exploration and extraction of resources
What’s the role of OPEC as an energy player?
14 members including the UAE and Nigeria
> influences the supply and price of oil by controlling production
> consumers influence supply by the demand they create but may also influence the energy mix by voicing environmental concerns
What’s the role of government as an energy player?
Provide legislation on emission levels and costs for consumers, gain taxes and also act to protect energy pathways too and from the country
Why is there issues between supply and demand of fossil fuels depending on location?
The location of fossil fuels is based on geological processes - 48% of the worlds oil reserves are in the Middle East
Consumption is often greatest where there is the most industrial activity (like in China and the USA)
The location of fossil fuel supply and demand often don’t line up
What are energy pathways?
The ways oil and natural gas are transported from where they are extracted to the consumer
> oil and natural gas can be transported easily by pipeline or tanker ships
What are some of the problems with energy pathways?
These pathways are not always secure and political decisions can reduce or stop supplies
- internal problems
- wars between countries
- sanctions
- OPEC reducing global production
- one country choosing to stop supplying another
- issues like terrorism and piracy (42 tankers were attacked by pirates in 2017)
- leaking pipelines
- resources running out (North Sea)
- a sudden increase in demand from a country so that supplies are diverted
How has Europe been affected by changes to the amount of Russian gas coming in?
Russia is a big producer and exporter of energy
In 2018, Russia and countries bordering the caspian see agreed to divide up the seabed, providing more oil and gas production within pipeline reach of Europe. Russia has several pipelines to Europe like the Nord stream under the Baltic Sea)
Since Russia invaded crimea and then Ukraine, international sanctions have been in place but due to demand some countries like Germany have wanted to have a more secure supply meaning there have been changes to their energy mix. This means the pipelines are becoming more controversial.
- increasing dependence on Russian supplies
- threat to the national security of Baltic countries
- affect supplies to Ukraine
- overlook Russian policy to destabilise Europe
What are unconventional fossil fuels?
Those that are not easily accessible:
- oil from rocks underneath deep water
- oil and gas trapped in pore spaces within rocks rather than in a large reservoir of oil or gas such as oil shale (USA), tar sands (Canada) and shale gas (China)
What are the negatives of accessing unconventional fossil fuels?
High costs for new technologies to access these resources
Many of these resources are in a fragile environmental area and spills will damage them
There are uncertainties about the safety for people and the environment of new technologies and methods of extraction
Greenhouse gas emissions will continue, releasing stored carbon into the atmosphere
Extraction of oil requires a huge amount of energy, leaves open scars in the landscape, removes natural vegetation, causes water contamination and infringes on the rights of local people
Extraction of gas by fracking lowers local water levels, contaminates water with chemicals and can cause ground movements like mini earthquakes
What are the benefits of accessing unconventional fossil fuels?
As conventional fossil fuel resources run out, these resources can replace them where users currently need fossil fuels
These are very large reserves that could be developed to extending the possibility of a diversified energy mix
They are very valuable resources and provide jobs and money, especially in remote communities and tax money for governments.
What is renewable energy?
An energy source that is replaced rapidly from an existing constant natural process, such as energy from the sun or the wind
What is recyclable energy?
An energy resource that can be reused once people or nature have processed it, like HEP
What does decoupling of fossil fuels from economic growth mean?
Coal and then oil supported the economic development of industrialised countries and as usage increased, so did wealth. Recently fossil fuels have been used more efficiently but wealth has continued to increase. There are also early signs that as fossil fuels are replaced, economic development continues
What are the economic costs of renewable and recyclable energy?
Needs investment into new technologies
Electricity costs per unit may be higher than from conventional sources
Dependence on fossil fuels is only reduced if they are directly substituted
What are the social costs of renewable and recyclable energy?
Nuclear produces radioactive waste
Solar may take up farmland, reducing land for food production
What are the environmental costs of renewable and recyclable energy?
Solar and wind need large spaces which can spoil scenery
Nuclear produces radioactivity
What are the energy security costs of renewable and recyclable energy?
Difficult to store for later use
Solar and wind are climate dependent
What are the economic benefits of renewable and recyclable energy?
Can be used at scales suitable for developing countries and households
Low maintenance cost when running
Cheap costs once economies of scale reached
Reduced dependence on fossil fuels for electricity production
What are the social benefits of renewable and recyclable energy?
Solar and wind:
Safe and clean resources
Can be used by individual households (solar panels on roof)
What are the environmental benefits of renewable and recyclable energy?
No greenhouse gas emissions when operational
No air pollution
What are the energy security benefits of renewable and recyclable energy?
Electricity produced can be used or transmitted by existing systems
How has the energy mix of the UK changed?
1997-2017:
More oil used
Marginally more natural gas used
Much more bio energy used
more wind, solar and HEP
Much less coal used
Marginally less nuclear used
