Carbon Cycle Flashcards
What is the carbon cycle?
The natural C Cycle is the movement (fluxes) and storage of C between the land, ocean and the atmosphere
What is inorganic Carbon?
Inorganic carbon refers to carbon found in non-living forms
Found as carbon dioxide (CO₂) in the atmosphere carbonates in rocks and minerals, and bicarbonates in water.
It plays a key role in the carbon cycle, moving between the atmosphere, oceans, and Earth’s surface.
What is organic carbon?
Organic carbon is carbon found in living organisms or derived from them, such as in plants, animals, and decaying matter.
It plays a key role in the carbon cycle, moving between organisms, the atmosphere, soil, and oceans.
What is Gaseous carbon and where is it found?
Gaseous carbon is carbon in the form of carbon dioxide (CO₂) in the atmosphere, which plays a role in photosynthesis, respiration, and the greenhouse effect.
Found in C02 and CH4
What is carbon sequestration?
It is the capturing, storage and transfer of C from the atmosphere to other stores and can be natural and artificial (e.g. Carbon Capture and Storage).
A plant sequesters C when it photosynthesises and stores the C in its mass.
Where is carbon stored, and which is the highest store and which is the lowest store?
Highest:
Lithosphere = as carbonates in limestone and fossil fuels (e.g. coal, oil and gas)
Hydrosphere = as dissolved carbon dioxide
Pedosphere
Cryosphere = biological carbon is stored in permafrost, which prevents bacterial decay
Atmosphere = as carbon dioxide and compounds such as methane
Biosphere = in living and dead organisms
Lowest:
Large
Hamster
Pigs
Cry
At
Butchers
What are the lithosphere stores?
- Marine sediments (ocean floor) and sedimentary rocks (biggest store). Long-term (up to millions of years).
- Fossil fuel deposits (e.g. coal) – originally long-term, but dynamic due to human exploitation
- Soil organic matter – mid-term (deforestation, agriculture and land-use change are affecting this store)
What are the hydrosphere stores?
Oceans – dynamic.
The second biggest store, but only a tiny fraction of that stored in the lithosphere.
The C is constantly being utilised by marine organisms, lost as an output (diffusion) to the lithosphere (sedimentation on the ocean floor), or gains from inputs from rivers and coastal weathering and erosion
What are Atmosphere stores?
Stores Co2
A dynamic store
Human activity has caused CO2 levels to increase by 40% since 1750 and is accelerating in the 21st Century.
What are Biosphere stores?
Terrestrial plants (mid-term, but very dynamic). Vulnerable to Climate Change deforestation.
What are Cryosphere stores?
Methyl clathrates are molecules of methane that are frozen into ice crystals. If the temperature rises or pressure changes, the ice that imprisons the methane will break apart, and the methane will escape.
Organic matter frozen in permafrost. Permafrost is permanently frozen ground, and it contains a lot of frozen organic matter. This organic matter is made of dead plants and animals that have been frozen deep in permafrost for thousands of years. The carbon in this organic matter is locked up because it is frozen. With global warming, if this permafrost melts the organic matter will decay, and this will release carbon dioxide or methane into the atmosphere.
What are fluxes between carbon stores?
The transfers in the C Cycle cause changes/movement of C in stores over varying degree of time.
They can be categorised as either fast flows or slow flows.
Why is photosynthesis a fast flow?
Plants sequester C by converting CO2 from the atmosphere and water from the soil into O2 and glucose using light energy. This helps to maintain the balance between O2 and CO2 in the atmosphere.
Why is respiration a fast flow?
Respiration occurs when plants and animals convert O2 and glucose into energy, which is opposite of photosynthesis. Plants photosynthesise by day and respire at night. Plants are net oxygen producers because they absorb more than they emit.
Why is combustion a fast flow?
When fossil fuels and organic matter e.g. trees are burnt they emit CO2 into the atmosphere. This is obviously a human influence on the C Cycle (indirectly for some wildfires due to CC).
Why is decomposition a fast flow?
When living organisms die they are broken down by decomposers (e.g. bacteria and fungi) which respire returning CO2 in to the atmosphere. Some organic matter is returned to the soil where it is stored.
During the water cycle, why is diffusion a fast flow?
The oceans can absorb CO2 from the atmosphere which has increased ocean acidity by 30% in the last 250 years, which is harming aquatic life by causing coral bleaching. At the surface, where air meets water, carbon dioxide gas dissolves in and ventilates out of the ocean in a steady exchange with the atmosphere.
Why is sedimentation a slow flow?
Can happen on land or sea floor.
When shelled marine organisms die, their shell fragments sink to the ocean floor and become lithified over time to form limestone.
Organic matter from vegetation can be compacted over time to form fossil fuel deposits.
Why is weathering and erosion a slow flow?
(Long Answer)
Inorganic C is released slowly through weathering e.g. solution of alkaline rocks (e.g. chalk) by carbonic acid in rain/river/sea water. The C is moved through the water cycle and enters the oceans. Marine organisms use the C to build their shells – eventually die and sedimentation occurs on the sea floor. Increasing CO2 levels in the atmosphere are accelerating this process.
Why is volcanic outgassing a slow flow?
Pockets of carbon dioxide exist in the Earth’s crust. Volcanic eruptions and earthquakes can release these gas pockets.
Outgassing is the release of gas, previously dissolved, trapped, frozen or absorbed in some material (e.g. rock). It occurs mainly along mid-ocean ridges, subduction zones and at magma hotspots.
How long can carbon remain in different stores? (Residence time)
Lithosphere – from 10,000 – 300,000,000 years (sedimentary rocks)
Hydrosphere – ocean surface – up to 25 years; deep oceans – up to 1250 years
Cryosphere – up to millions of years
Atmosphere – up to 6 years
Biosphere – average is 13 years (but can be much shorter)
How does chemical weathering impact the carbon cycle?
(Long answer)
- Rainwater reacts with atmospheric CO2 to form a weak carbonic acid. The rain reaches the surface and reacts with some surface minerals slowly dissolving them into their component ions.
- Calcium ions are transported by rivers to the ocean. These combine with bicarbonate ions to form CaCO3 and precipitate out as minerals such as calcite.
- Deposition and burial turns the calcite into limestone.
- The ocean floor is eventually subducted under continental plates.
- Some of the C rises up within magma and degassed as CO2 back into the atmosphere.
How does volcanic outgassing impact the carbon cycle?
The Earth’s crust contains pockets of carbon dioxide which can be disturbed by volcanic eruptions or seismic activity
This release of gas that has been dissolved, trapped, frozen or absorbed in rock is called outgassing
- Outgassing occurs at subduction zones and spreading ridges; hot springs and geysers and as direct emissions from fractures in the Earth’s crust
- Volcanoes currently emit 0.15-0.26 Gt CO2 annually. In comparison, humans emit about 35 Gt, mainly from fossil fuel use, so volcanic degassing is relatively insignificant
- The CO2 emitted by both active volcanoes and at constructive plate margins is roughly the same
What is oceanic sequestration?
Oceanic sequestration refers to the process by which the ocean absorbs and stores carbon dioxide (CO2) from the atmosphere.
93% of carbon dioxide is stored in undersea algae, plants, coral and dissolved form, making oceans the largest carbon store on Earth
The CO2 gas exchange flux between the oceans and atmosphere operates on a timescale of over several hundred years. There is also a significant input of both organic C and carbonate ions from rivers. Only a small proportion of this will end up buried in sediments, but these are important long-term stores operating over millennia, unlike most terrestrial systems.
The exchange of CO2 between the oceans and atmosphere takes place over hundreds of years. Rivers also contribute organic carbon and carbonate ions, with only a small portion getting buried in sediments. These buried materials act as important long-term carbon stores, lasting thousands of years, unlike most land-based systems. (SIMPLIFIED)
What is the biological pump?
The biological (organic) pump is driven by ocean phytoplankton absorbing CO2 via photosynthesis (carbon fixation)
These organisms form the bottom of the marine food web, and live in the ocean’s surface layer
Phytoplankton are consumed by other organisms and carbon is transferred along food chains
Organic carbon may eventually be transferred to the deep ocean when dead organisms sink towards the ocean floor
What is the physical pump?
The physical (inorganic) pump involves the movement of carbon dioxide from the atmosphere to the ocean by a process called diffusion
CO2 dissolved in the surface of the ocean can be transferred to the deep ocean in areas where cold dense surface waters sink
This downwelling carries carbon molecules to great depths where they may remain for centuries
CO2 diffusion determines the acidity of the oceans
What is the carbonate pump?
Formation of sediment from dead organisms - sedimentation sequesters
What is thermohaline circulation?
Ocean currents circulate C – it takes 1000 years for a cubic metre of water to travel around the system
Warm surface waters are depleted of nutrients and CO2 but are enriched as they sink towards the bottom layers of the ocean through the circulation of currents
The foundation of the Earth’s food chain depends on the cool, nutrient-rich waters that support algae and seaweed growth. C flows from the carbonate pump cycle in surface waters to the deep ocean
The balance of C uptake (92 PgC) and C loss (90PgC) from the ocean is dependent on organic and inorganic processes acting in both surface water and deep ocean.
Increased ocean acidification, due to Climate Change, means that oceans have less capacity to sequester C than previously – therefore more CO2 in the atmosphere
What is terrestrial sequestration, and how does the process occur?
Terrestrial sequestration is the process by which carbon dioxide (CO2) is captured and stored on land
The fastest part of the C Cycle – seconds, minutes and years
Primary producers (plants) take C out of the atmosphere through photosynthesis and release it back via respiration
When consumers eat plants, C from the plant becomes part of fats and proteins
Micro-organisms and detritus feeders such as beetles feed on waste material from animals – C is transferred to them
Decomposers then take up C from dead plants and animals
C storage is mainly in plants and soils, with smaller amounts in animals and micro-organisms (bacteria and fungi)
The largest store is in trees, which can live hundreds and even thousands of years
Carbon fluxes vary diurnally – during the day positive from atmosphere to the ecosystem and negative at night
Carbon fluxes vary seasonally – in N hemisphere winter atmospheric CO2 rises, but falls again during the spring
What is biological carbon?
Soils store 20-30% of global C – although location is important when considering whether it is a sink or a source of C
There are 2 sources of C in soils. Arid and semi-arid soils contain inorganic C (very little plant life)
The most important store is from organic sources through plant photosynthesis and decomposition. C can be stored as dead organic matter in soils for years, decades or centuries in colder climates and wetlands
Humus is the dark layer in a soil where decomposition is taking place.
Humus soils are 60% C and are important for sequestration
What does the capacity of soil to store carbon depends on?
Climate – rapid decomposition occurs at higher temperatures or under waterlogged conditions. Places with higher rainfall have increased potential C storage
Soil type – clay soils have higher C content than sandy soils
Management and use of soils – soils lose C through cultivation and disturbance – a huge factor on intensively farmed grasslands (US/Russia)
What role does C play in regulating the Earth’s average temperature?
Green house effect, fossil fuel combustion
What does NPP refer to?
Net primary producer - amounts of energy or biomass produced by plants through photosynthesis
Which ecosystems have the highest NPP?
Rainforests, estuaries and corals = high rates of sunlight
What does the concept of ‘fertilisation’ mean?
human activity speeds up rates of photosynthesis, however plant growth is limited by nutrient and water availability needed in order to utilise CO2
What does soil health depend on?
depends on the amount of organic carbon stored in the soil, this depends on its inputs and outputs
What is meant by the term ‘soil carbon balance’?
if plant residue is added to the soil at a faster rate than soil organisms covert it to CO2, carbon will gradually be removed from the atmosphere and sequestered in the soil
Why does the selva-tropic rainforest have the highest nutrient cycling
warm, humid, moist condition
Why does the tundra (permafrost) ecosystem have the highest density of carbon storage?
slow decomposition rates
How does fossil fuel combustion lead to ‘climate forcing and what are the global and regional implications of this?
increase co2, enhance greenhouse effect, increase global warming
Why is the concept of ‘positive feedback’ actually negative for the global climate, in reality?
positive feedback accelerates temperature rise which is bad for the environment
Are there any potential positive aspects of global climate change?
crops and other plants grow better in the presence of higher carbon dioxide levels and seem to be more drought-tolerant
What are the implications of global warming for the hydrological cycle? Give specific examples.
speeds the processes up, enhances evapotranspiration, precipitation, and intense precipitation
What is energy security?
Is the uninterrupted availability of energy sources at an affordable price
What is long term energy security?
Long-term security mainly deals with timely investments to supply energy in line with economic developments and environmental needs
What is short term energy security?
Short-term energy security focuses on the ability of the energy system to react promptly to sudden changes in the balance between energy demand and energy supply
What is energy insecurity?
A measure of how efficiently a country is using its energy and is calculated as units of energy used per unit of GDP
High intensity = high price
Energy intensity decreases with economic development (service sector economies use less energy than manufacturing economies)
What is primary energy?
Primary energy is the energy found in nature that has not been subjected to any human engineered conversion process. It encompasses energy contained in raw fuels and other forms of energy, including waste, received as input to a system. Primary energy can be non-renewable or renewable.
What is secondary energy?
Secondary energy: When we convert primary energy into a transportable form we speak of secondary energy. For example, when we burn coal in a power plant to produce electricity, electricity is a form of secondary energy. Secondary energy includes liquid fuels (such as petrol and diesel – which are refined oil), electricity, and heat.
What is biomass?
Biomass uses waste from plants or animals that can be converted to energy. Examples of biomass are plant matter, food waste and human and animal waste. Biomass can be gassy and smelly
What are the factors affecting energy consumption?
Physical availability - having access within country is cheaper than imports. Accessibility is also important - surface coal mining is much easier and cheaper than deep coal mining
Technology - particularly important in coal/gas/oil exploration, although uses a lot of energy
Cost - includes physical exploitation of resources (e.g oil/gas); processing (converting primary energy to secondary) and delivery to the consumer
Economic development– developed countries have relatively high
energy consumption (see previous graph)
Climate– places with temperature extremes (e.g. Canada/Saudi
Arabia) need more energy to provide a more comfortable living
environment
Environmental priorities– countries with ‘greener’ energy policies
will prioritise renewable energy use. The population will be more
aware of the environmental impact and consumption may also fall
What was Britain’s 2024 energy mix?
Gas = 26.6%
Wind = 34.8%
Nuclear = 11.1%
Biomass = 6.6%
Coal = 0.9%
Solar = 2.1%
Imports = 13.9%
Hydro = 2.9%
Storage = 1%
What is the difference between slow and fast flows?
The fast carbon cycle moves carbon through life forms, while the slow carbon cycle moves carbon through rocks, soil, oceans, and the atmosphere. The fast cycle is faster, and it’s measured in a lifespan. The slow cycle is slower, and it can take millions of years.
Why are forests important to us?
Forests functions and threats:
- Estimated 1.6 billion people depend on forests
- More than 90% of these are in developing countries
Forests are essential for human well-being through their services as well as being the source of 80% of global biodiveristy
- 1.1% of the global economy income
- 13.2 million ‘formal’ and 41 million ‘informal’ jobs
- Improve food and nutrition security
- Source of livestock fodder in arid and semi-arid areas
- Fuelwood source for one in three people globally for cooking and boiling drinking water
- A genetic pool: a source for improving plant strains and medicine
Regulation of Earth Systems:
- Earth’s ‘green lungs’ regulating climate, floods, disease
- Water purification
Cultural Value:
- Aesthetic
- Spiritual
- Educational
- Recreational
Supporting functions:
- Nutrient cycling
- Soil formation
- Primary production
Provision of goods:
- Food
- Freshwater
- Wood and fibre
- Fuel
What is the environment Kuznet’s curve?
Measures the correlation between environmental degradation and economic growth (GDP per capita)
- Pre industrial economies = environment worsens
- Industrial economies = turning point
- Post-industrial economies = environment improves
Societies reach a ‘tipping point’ where exploitation changes to protection because?
Countries become wealthier and move towards service - sector economies
Education about the importance of protecting the environment increases - awareness increases participation
Aid given to poorer countries can reduce environmental exploitation
Political systems can change in a country and environmental laws will be enforced more strictly - TNC’s may also be
forced to comply with environmental regulations too
Kuznet’s curve - Uk v China case study research
Uk = post industrial society and according to the model the environment should be improving
China = just before the ‘tipping point’ as they have a mixture of an industrial economy and national parks
Deforestation creates
- Water-related risks (landslides, local floods and droughts)
- An ongoing loss of biodiversity
- Loss of direct reliance by many indigenous people
- Some cultures and religions see forests as sacred
- Leisure and tourism
What are carbon stores?
Where carbon is held
What are sources?
adding carbon to the atmosphere
What are sinks?
removing carbon from the atmosphere
How does chemical weathering impact the carbon cycle?
(Summarised)
Rainwater reacts with CO2 to form carbonic acid, which dissolves surface minerals into ions.
Calcium ions are carried by rivers to the ocean, where they combine with bicarbonate to form calcium carbonate (CaCO3), which precipitates as calcite.
Over time, this calcite becomes limestone through deposition and burial.
Eventually, the ocean floor is subducted, and some carbon is released as CO2 from magma back into the atmosphere.
Why are weathering and erosion a slow flow?
(Summarised Answer)
Inorganic carbon is released through weathering, such as the dissolution of alkaline rocks like chalk by carbonic acid in water.
This carbon moves through the water cycle and enters the oceans, where marine organisms use it to build shells.
When these organisms die, their remains are deposited on the sea floor.
Rising CO2 levels are accelerating this process.
What is Sedimentation?
Sedimentation is the process where particles, like sand, mud, or the remains of organisms, settle and build up at the bottom of a body of water, forming layers over time.
What is Lithification?
Lithification is the process by which sediments are compacted and cemented together over time to form solid rock.
It happens when layers of sediment build up, and pressure from above squeezes the particles together while minerals in the water act as glue, binding them into rock (limestone).
What is a carbon sink?
A carbon sink is any reservoir that absorbs more carbon than it releases.
What is a carbon store?
A carbon store e.g. lithosphere maintains a constant amount of carbon
How much greater is the ocean as a carbon sink compared to the atmosphere?
The oceans are the Earth’s largest C sink (50x greater than in the atmosphere.)
Where is 93% of carbon stored?
In undersea algae, plants and coral, with the remainder in dissolved form
What are the most productive biomes?
Tropical rainforests, savannah and grasslands which account for half of global net primary producers
Is carbon most active in top soil or lower soil?
C cycling and formation is most active in topsoil
In permafrost regions how much C is stored deeper than 30cm?
Over 61% of C is stored deeper than 30cm
What is pyrogenic carbonaceous matter?
Matter produced during wildfires is resistant to microbial decomposition and can remain in soils for long periods
What is renewable energy?
Renewable energy comes from naturally replenished sources like solar, wind, and hydro, and is sustainable over time.
What is recyclable energy?
Recyclable energy refers to the reuse or recovery of energy, often from waste or industrial byproducts.
What does anthropogenic mean?
Human induced
What are the two types of feedback loops?
Positive = bad
Negative = good
When talking about ocean warming which part is affected?
Top sea layer/surface
Why are countries still buying fossil fuels from Russia in 2023?
They cannot afford to not purchase from Russia die to dependence/reliance
What are types of conventional fossil fuel energy resources?
Gas, Coal, Oil
What is the difference between recyclable and renewable energy?
The main difference is that renewable energy is naturally replenishing, while recyclable energy focuses on reusing or recovering energy that would otherwise be wasted.
What are the key factors driving anthropogenic (human induced) greenhouse gas emissions?
Demographic change - population increase
Economic change - increased globalisation and movement of goods, rapid industrialisation of NIC’s, new resource finds, less desire for TNC’s to ‘go green’ due to the recent economic downturn
Other factors - cultural and attitudinal factors, changing lifestyles as countries develop, globalisation of consumerism
How is the carbon cycle in equilibrium?
The sources equal the sinks
What does an undisturbed carbon cycle maintain?
C02 levels in the atmosphere and keeps global temperatures steady
However, when huge amounts of carbon dioxide are released into the atmosphere in a short period of time, the whole cycle can become unbalanced
What is the slowest part of the carbon cycle?
Geological carbon cycle
What is the fastest part of the carbon store?
Bio-geochemical carbon cycle
What are the geological processes in the carbon cycle?
Weathering of rocks = Mechanical, chemical and biological weathering results in the breakdown of rocks
Decomposition = Plant and animal particles from decomposition after death store carbon
Transportation = Rivers can carry particles to the ocean, where they will be deposited
Sedimentation = Over time, sediments build up, burying older sediments below e.g. shale and limestone
Metamorphosis = Pressure builds over time in the layers of sediment which eventually leads to deeper sediment changing to rock e.g. limestone becomes marble, shale becomes slate
What does sequestering refer to?
Sequestering is the movement of carbon into carbon stores which can lower the amount of carbon dioxide in the atmosphere
What is the greenhouse effect?
The natural greenhouse effect is influenced by the concentration of atmospheric carbon (carbon dioxide and methane)
The natural greenhouse effect is essential in maintaining the temperature of the Earth as a result supporting life on the planet.
The Earth’s climate is driven by incoming shortwave solar radiation
Around 31% is reflected by clouds, aerosols and gases in the atmosphere and by the land surface
The remaining 69% is absorbed with half being absorbed at the surface (e.g., oceans) and the other
half is re-radiated into space as long-wave radiation
However, much of this long-wave radiation is deflected back to the Earth’s surface by clouds and greenhouse gases
This ‘trapping’ of long-wave radiation creates the natural greenhouse effect allowing life to be supported on Earth
If the amount of carbon dioxide and methane increases then more long-wave radiation will be trapped causing global temperatures to rise
What does soil health rely on?
Soil health relies on the amount of organic carbon stored in the soil which is dependent on:
The inputs - plant and animal residues and nutrients
The outputs - decomposition, erosion and use in plant and animal productivity
How does soil play a vital role in the carbon cycle?
Carbon, within soil organic matter, helps provide soil with its water retention capacity, its structure and fertility
Soil erosion is a major threat to carbon storage and soil health as organic carbon is mainly found in the surface soil layer
What could be some benefits for the ecosystems of the increased carbon cycle?
Cool, moist regions (e.g., UK) could provide habitats for more species
What should a countries energy security be?
Reliable and uninterrupted
Affordable and competitively priced
Accessible and available
Dependent on domestic rather than imported
What is energy intensity?
Energy intensity is a measure of how efficiently a country is using its energy
What is an energy mix?
The term energy mix is used to describe the combination of different energy sources that are used to meet a country’s total energy demand
How does a countries energy mix change based on their economic development?
Developing countries usually use natural resources such as firewood for cooking
Emerging countries will see a rise of oil use as transport and car ownership increases
As countries develop they tend to start using more gas and nuclear power as technology advances
What are some factors that affect a country’s access to and consumption of energy?
Physical availability
Cost
Technology
Public perception
Level of economic development
Climate
Environmental priorities
Who are the five major players in the world of energy?
TNCs = The majority of these companies are involved in a variety of operations including exploring, extracting, transporting, refining and producing petrochemicals
Organisation of the Petroleum Exporting Countries (OPEC) = OPEC currently has 13 member countries owning around two-thirds of the world’s oil reserves between them
As a result, OPEC is able to control the amount of gas and oil in the global market along with their prices
OPEC have been accused of forcing up the price of oil and gas by withholding/slowing production
Energy companies = Most companies are involved in the distribution of both primary energy (e.g., gas) and secondary energy (electricity) which means they have a strong influence over consumer prices and tariffs
Consumers = The most important consumers are in transport, industry and domestic sectors
Consumers tend to have little impact on energy prices
Governments = Governments can play various different roles, for example, they look after energy security and can have an impact on how energy is sourced
What is the number one fossil fuel?
In the twentieth century, oil took over from coal as the most used fossil fuel
Today, oil is now being challenged by gas as the number one fossil fuel
How much of France’s electricity is generated by Nuclear power?
70%
What is most of Norway’s energy produced by?
Hydroelectricity
What is the majority of Saudi Arabia’s electricity generated from?
Oil and Gas and has 1/4 of the worlds known oil reserves
How is there a mismatch between supply and demand of fossil fuel resources?
Coal
Whilst the consumption of coal is decreasing in comparison to oil and gas, production is increasing
China and the USA remain the two largest consumers of coal and are also the largest producers of coal
There is a small mismatch as the main producers of coal are usually the main consumers e.g., China and the USA
Oil
There is a significant mismatch as the main suppliers of oil are members of OPEC and the consumers are in Europe
Gas
Gas supply is dominated by the USA and Russia and the major importers are Western European countries and Japan
Where does the one pathway of oil from Russia go to?
Europe
How does gas flow between countries?
Gas flows either directly through pipelines or in liquid form by tanker ships
There is a major pathway from Russia to Europe which is experiencing disruption, why is this?
In 2021, around 50% of Russia’s crude oil was exported to European Countries
Following Russia’s invasion of Ukraine in February 2022, many countries have pledged to stop or restrict oil and gas imports from Russia to hinder its war effort
What are the four unconventional sources of fossil fuel which have the potential to meet future energy demands?
Tar sands
Oil shale
Shale gas
Deepwater oil
What are tar sands, how are they extracted and what is an example?
Mixture of clay, sand, water and bitumen (a heavy, viscous oil)
Have to be mined and then injected with steam to reduce the viscosity of the tar so it can be pumped out
Biggest deposits are in Canada and Venezuela.
Tar sands produce about 40% of Canada’s oil output
What is oil shale, how is it extracted and what is an example?
Oil-bearing rocks that are permeable enough to allow oil to be pumped out
Mined or shale is ignited so that the light oil fractions can be pumped out
Little exploration has taken place
What is shale gas, how is it extracted and what is an example?
Natural gas that is trapped in fine-grained sedimentary rocks
Fracking - pumping in water and chemicals forces out the gas
The USA is the leading producer and exporter
In 2015, shale gas provided 25% of the USA’s gas supply
What is deepwater oil, how is it extracted and what is an example?
Oil and gas found offshore and at considerable oceanic depths
Drilling takes place from ocean rigs
Huge oil deposits were discovered off the coast of Brazil in 2006 and Brazil are leading the way in this
What are the benefits of unconventional fossil fuel usage?
These unconventional sources of fossil fuels provide countries that currently rely on imported energy with the possibility of greater energy security
May provide a source of fuel whilst renewable energy sources are developed further
Provides jobs and boosts the local economy
What are the costs of unconventional fossil fuel usage?
The exploitation of these sources will continue to threaten the carbon cycle and contribute to global warming
Extraction is expensive and requires lots of complex technology, energy and water
Extraction can cause environmental damage
- Scars of opencast mines and possible ground subsidence
- Contamination of groundwater sources and oil spills
- Large quantities of waste are produced
- Impacts on the local ecosystem
What are the two types of ‘clean’ energy?
Renewable = hydro, solar, wind
Recyclable = nuclear, biofuels
What are the issues with nuclear energy?
Safety - nuclear incidents such as Chernobyl (Ukraine) and Fukushima (Japan)
Disposal of highly toxic radioactive waste (which has a long decay life)
Technology used means that nuclear energy is only really open to the most developed countries
Costs - despite operational costs being relatively low, the cost of building and decommissioning are high
Security of nuclear powered stations at a time when international terrorism is a concern
What are biofuels and what are the two types?
Biofuels are derived immediately from living matter, such as agricultural crops, forestry or fishing products and various forms of waste
There are two types of biofuels:
Primary biofuels which include fuelwood, wood chips and pellets that are used unprocessed for heating, cooking or electricity
Secondary biofuels are derived from the processing of crops (e.g., sugar cane, soybeans and maize) where two type of fuel are extracted (bio-alcohol and biodiesel) which are used to fuel vehicles and generate electricity
What are the disadvantages of biofuels?
The implications this can have on food supply
For example, a hectare of space used to grow energy crops is a hectare less for growing much needed food
Which country uses lots of biofuel energy?
Brazil
What does carbon capture and storage involve and what are the drawbacks?
‘capturing’ the carbon dioxide released and burying it deep underground
It is expensive because of the advanced technology required
No one can be sure that the carbon dioxide will stay underground and that it will not leak to the surface and enter the atmosphere
How do hydrogen fuel cells work?
A fuel cell combines hydrogen and oxygen to produce electricity, heat and water
A fuel cell will provide electricity as long as hydrogen is supplied and it will never lose its charge
Fuel cells are a promising technology for use as:
A source of heat and electricity for buildings
A power source for electric vehicles
Hydrogen fuel cells are considered to be one of the best strategies for reducing carbon emissions that has very little impact on the carbon cycle
What are the two radical technologies used as an alternative to fossil fuels?
Carbon capture and storage
Hydrogen fuel cells
How does afforestation provide both benefits and costs?
Afforestation and reforestation are beneficial for carbon dioxide sequestration but can be controversial in its impacts:
Commercial trees such as palm oil often store less carbon, use more water and are prone to disease
What are the two types of grassland?
There are two main types of grassland which cover 26% of the Earth’s land area
Temperate grassland - no trees and a seasonal growth pattern linked to a large annual temperature range e.g. North America
Tropical grassland or Savannah- scattered trees with a wet and dry season e.g. Africa’s serengeti
When grasslands are used too intensively for animals or agriculture it disrupts the carbon and water cycles, how does this happen?
Rapid increase in population and changes from nomadic to sedentary farming along with the impacts of climate change and poor land management
Soil and ecosystem degradation is now becoming a worldwide issue which is leading to a loss in carbon storage
What is ocean acidification?
Involves a decrease in the levels of Ph of oceans
What are the causes of ocean acidification?
Ocean acidification will be exacerbated by other factors including warming temperatures, tropical storms and pollution
How do statistics support the idea of ocean acidification?
19th century = 8.2 PH
2015 = 8.1 PH
Coral reefs stop growing at 7.8 or below
What are the effects of ocean acidification?
Increases the risk of marine ecosystems reaching a critical threshold of permanent damage
Globally, coral reefs are already experiencing bleaching from increasing temperatures
Why is ecosystem resilience important?
If the rate of acidification is slow enough, the organisms may be able to adapt to the changes and be more resilient
What can the different climate zones be simplified as?
Equatorial
Tropical
Temperate
Polar
How is the Amazon’s climate changing?
The Amazon acts as a global and regional regulator, pumping 20 billion metric tonnes of water into the atmosphere every day
Since 1990, a more extreme cycle of drought and flood has developed in Amazonia, which can be linked to shifts in the Inter-tropical Convergence Zone (ITCZ)
Rainfall has noticeably decreased downwind of deforested areas leading to São Paulo suffering a water crisis
The Amazon rainforest which is already affected by deforestation is now being hugely impacted by droughts in 2005 and 2010
How many hectares of forests between 2000 and 2010 were affected by deforestation?
13 million
What is the Kuznet’s curve?
The environmental Kuznets curve suggests that communities reach a tipping point where exploitation of forests changes to more protection
The changes in attitudes are usually dependent on:
The wealth of a country
Increasing knowledge of the role that the environment plays in our well-being
Aid given to developing countries to help reduce exploitation
Political systems and introduction and enforcement of environmental laws
The involvement of locals
The power and influence of TNCs
What does the successful regeneration of forest loss in the long term require?
Protective legislation
Community involvement in planning and developing policies
How does the arctic play an important role in global climate?
It’s sea ice regulates evaporation and precipitation
How does the impacts of global warming on oceans subsequently affect human well being?
Global warming is affecting ocean temperatures and currents as well as the supply of nutrients and marine food chains
These changes can be categorised under the following:
Bleaching
Acidification
Rising sea levels
Loss of sea ice
These changes then have an impact on distribution, abundance, breeding cycles and migration of marine plants and animals which millions of people depend
on either directly or indirectly for food and income
Research suggests that marine organisms may be responding faster to climate change than terrestrial organisms
What is the importance of ocean health on human industries?
All countries each and either sell or buy fish
Fish is essential for well - being in developing countries such as Namibia and Ghana
Coral reefs provide protection to coastal areas from waves = Hawaii
Many towns benefit from tourism associated with coral reefs
Countries that rely on exports of fish (E.g China and Thailand) will be affected by depleted stocks
Millions of small - scale fishing families rely on seafood for income as well as food
The FAO estimates that fishing supporting 500 million people (90% of whom are in developing countries)
What are the physical uncertainties about future natural factors involved in global warming?
The role of carbon sinks and their capacity to cope with changes
Possible feedback mechanisms such as carbon release from peatlands and permafrost
Tipping points associated with forest dieback and the reversal of thermohaline circulation
What are the human uncertainties about future natural factors involved in global warming?
Future rates of global economic and population growth
Planned reduction in global carbon emissions
Exploitation of renewable energy sources
What are the predicted changes to terrestrial carbon sinks?
Modelled to increase until 2050
When saturation is reached, they begin to act as sources:
Thawing of permafrost (tundra) in the Arctic
Shift of boreal forests to the north (as tundra thaws)
Tropical rainforests (currently at carbon capacity) may reduce their storage
What are the predicted changes to oceanic carbon sinks?
Increased store in sea grasses and algae, but overall reduction as sink because:
Tropical oceans have decreased carbon dioxide solubility as they are becoming warmer so absorb less
Decreased efficiency and slowing down of the biological pump
What are the drivers of anthropogenic greenhouse gas emissions?
Demographic (rising population)
Economic industrial structure = energy needs technology
Cultural lifestyle ideology attitudes
Political governance = climate change policy
Who are the top 5 countries that emit carbon dioxide?
- China = 35.4%
- USA = 19%
- India = 8.9%
- Russia = 6.3%
- Japan = 3.8%
What evidence proves the relationship between economic growth and carbon emissions?
China overtook the USA as a result of rapid urbanisation and industrialisation which indicates a positive relationship between economic growth and carbon emissions
What are the two types of climate change adaptation strategies?
Hard strategies which require technology e.g., wind farms
Soft strategies which involve legislation e.g., land use zoning
What are the benefits and risks of water conservation and management?
BENEFITS
Less resources used
Less groundwater abstraction
Changing attitudes e.g., use of more grey water
RISKS
Efficiency and management cannot match any increases in demand for water
Promotion and enforcement of strategies by the government needed to change habits e.g., smart meters
What are the benefits and risks of using resilient agricultural systems?
BENEFITS
High-tech, drought-tolerant species help resistance to climate change and increased diseases
Low-tech methods and better practices lead to healthier soils which may help carbon sequestration and water storage e.g., selective irrigation, crop rotation, agroforestry
More ‘indoor’ intensive farming
RISKS
Expensive technology, seeds and breeds unavailable to subsistence farmers in developing countries
Indoor and intensive farming has high energy costs
Genetic modification is still controversial but still used to create resistant strains of rich and soya
Increasing food insecurity leads to countries looking for quick fixes
What are the benefits and risks of using land - use planning?
BENEFITS
Land-use zoning, building restrictions in areas vulnerable to flooding
Enforcing strict run-off controls and soakaways
RISKS
Public dislike
Abandoning high-risk areas is often impossible as they are often megacities
Would need strong governance, enforcement and compensation
What are the benefits and risks of using flood - risk management?
BENEFITS
Hard management often used e.g., river dredging, flood defences
Simple changes can reduce flood risk e.g., permeable tarmac
Reducing deforestation and increasing afforestation upstream to absorb water and reduce flood risk downstream
RISKS
Funding sources are often debated
Land owners will often demand compensation
Constant maintenance is required for hard management e.g., dredging
What are the benefits and risks of using solar radiation management?
BENEFITS
Geoengineering involves ideas and plans to intervene to counteract global warming
Idea to use orbiting satellites to reflect some radiation back into space like a giant sunshade which would cool the Earth within months and be relatively
cheap compared to mitigation strategies
RISKS
These are untried and untested
Would not eliminate the worst effects of greenhouse gases such as acidification
Involves messing with a very complex system which could have unintended consequences
Would need to continue geoengineering for decades or centuries as there would be a rapid adjustment in the climate system if it just stopped suddenly
What can mitigation strategies help to do?
Mitigation strategies can help rebalance the carbon cycle
What did the IPCC state in 2014 regarding global warming?
Rebalancing the carbon cycle is seen as vital in preserving the Earth’s life systems
The IPCC stated in 2014 that it was possible to keep within the target of no more than a 2°C increase in average global temperatures if:
- Fossil fuel use was significantly reduced
- Fossil fuel use was totally eliminated by 2100
What different types of mitigation strategies can be used to combat global warming?
Mitigation strategies are considered vital to staying within the 2°C increase
Mitigation strategies usually operate through five specific methods:
Carbon taxation
Renewable switching
Energy efficiency
Afforestation
Carbon capture and storage (CCS)
What country is leading the way with mitigation strategies?
The UK has led the way with many of these strategies but politics and austerity measures since 2011 has had an impact
What is an example of carbon taxation in the UK?
Carbon price floor tax sets a minimum prices companies will have to pay to emit carbon dioxide which was unpopular and the policy was frozen in 2015
Lower road taxes for low-carbon cars were scrapped in 2015
In 2015, oil and gas exploration tax relief was expanded to support fossil fuels which led to the fracking debate
What is an example of renewable switching in the UK?
Renewable energy (solar, wind and wave) provide intermittent electricity, while fossil fuels provide continuous power which is vital for our current demands
The Climate Change Levy, designed in 2001 to encourage investment in renewable energy was cut in 2015
What is an example of energy efficiency in the UK?
The Green Deal scheme encouraged energy-saving improvements in homes e.g., energy efficient boilers and lights, improved insulation which was scrapped in 2015
Energy suppliers must comply with the Energy Company Obligation scheme to deliver energy efficient methods to households
What is an example of afforestation in the UK?
Tree planting in the UK is increasing which helps carbon sequestration
Tree planting involves the Forestry Commission, charities (e.g., the National Trust and Woodland Trust), landowners and local authorities,
The Big Tree Plant campaign encourages communities to plant 1 million new trees (mostly in urban areas)
What is an example of carbon capture and storage in the UK?
Few actual geologic carbon capture and storage projects exist in the world, despite its potential
Canada’s Boundary Dam is the only large-scale working scheme
In 2015, the UK cancelled its investment into full-scale projects at gas and coal powered plants in Scotland and Yorkshire
What is the difference between mitigation and adaptation strategies?
Mitigation strategies aim to reduce the cause of climate change, primarily by limiting greenhouse gas emissions.
Adaptation strategies, on the other hand, focus on adjusting to the effects of climate change that are already occurring or expected to occur.
Mitigation tackles the underlying problem, while adaptation deals with the consequences.
