Carbon Cycle Flashcards
1
Q
Why is the carbon cycle a closed system?
A
There are no inputs or outputs
2
Q
What is a carbon flux?
A
The flows of carbon between different stores - these differ in size
3
Q
3 parts of the carbon cycle
A
- Stores
- Fluxes
- Processes
4
Q
What are carbon stores measured in?
A
Pentagrams of carbon (PgC)
5
Q
What is the hydrosphere and how much carbon does it store?
A
38,000 PgC
Dissolved carbon stored in bodies of water
6
Q
What is the lithosphere and how much carbon does it store?
A
100,000 PgC
Rocks like calcium carbonate and fossil fuels
7
Q
What is the biosphere and how much carbon does it store?
A
2,000 PgC
Animals and plants (dead and living)
8
Q
What is the atmosphere and how much carbon does it store?
A
750 PgC
Gases like carbon dioxide
9
Q
3 forms carbon can be stored in
A
- Solid (e.g. calcium carbonate)
- Liquid (e.g. dissolved in bodies of water)
- Gas (e.g. carbon dioxide)
10
Q
How do organisms contribute to the carbon cycle?
A
- Photosynthesis - plants remove CO2 from the atmosphere
- Respiration - all organisms release CO2 as they breathe and grow
- Decomposition - decaying organisms release CO2 as they break down
- Combustion - burning fossil fuels or biomass releases CO2
11
Q
How does natural gas form?
A
- Aquatic organisms (organic matter) fall to the ocean bed after death
- Due to compression and cementation they form into sedimentary rock
- During these processes, crude oil and natural gas can form
12
Q
How do carbon fluxes vary in time?
A
The quickest processes (i.e. photosynthesis) is completed in seconds while it can take years for dead organic matter to return its carbon
13
Q
How can terrestrial carbon be converted into atmospheric carbon?
A
Terrestrial carbon stored within the mantle is released into the atmosphere through the process of ‘out-gassing’ during volcanic eruptions
14
Q
How does coal form?
A
When land-based plants die and enter into swamps they slowly settle and compact into peat and coal
15
Q
How does limestone form?
A
- Phytoplankton die and sink to the bottom of the ocean
- As sediment falls on them, they are compacted
- When they are 100m in depth, pressure and chemical reactions cause cementation to take place
- This forms limestone
16
Q
How does crude oil form?
A
- Fine-grain sediments and biologically degraded materials settle
- There needs to be 2% organic carbon
- A series of anaerobic reactions turn the organic carbon into a liquid
17
Q
Why might crude oil be able to migrate upwards?
A
Due to its light density, it may be able to move up through permeable or porous rocks
18
Q
How is methane formed?
A
Created as a by-product during the formation of coal and crude oil
19
Q
What is volcanic out-gassing?
A
Extreme heat from tectonic processes leads to sedimentary rock undergoing chemical changes, causing CO2 to be released into the atmosphere
20
Q
Example of a place where out-gassing is common
A
Geothermal locations like New Zealand
21
Q
What happens when acid rain hits carbon-rich rocks (e.g. limestone)?
A
It dissolves the material and forms calcium carbonate
22
Q
What is the process of chemical weathering?
A
- Slightly acidic rainwater forms from carbon dioxide in the atmosphere being dissolved in rainwater
- Acidic rain hits carbon-rich rocks, dissolving them and forming calcium carbonate
23
Q
How do primary producers make their energy?
A
From sunlight and carbon dioxide through photosythesis
24
Q
What is the process of photosynthesis?
A
Green plants sequester carbon dioxide through chloroplasts in their leaves to produce energy
25
How do primary consumers return carbon to the atmosphere?
Respiration
26
What is the role of decomposers?
They consume dead organic matter and return the carbon to the atmosphere via respiration
27
How does photosynthesis occur in surface waters?
- Phytoplankton take carbon out the atmosphere through photosynthesis
- As phytoplankton sequester carbon, they build up their shells from calcium carbonate
- These organisms are then consumed by other organisms who return carbon through respiration
28
How can atmospheric carbon be turned into biological carbon?
When ocean organisms use carbon to form their shells from calcium carbonate
29
What happens when carbonate shells sink?
- Sink to ocean floor
- They accumulate as sediment
- Eventually transformed into sedimentary rock
- SOME decomposed by bacteria which can return carbon
30
What is the carbonate pump?
When dead organisms die and fall to the ocean floor, forming sedimentary rock over time
31
What is thermohaline circulation?
Cold water sinks and warm water rises in the global movement of water
32
What carbon is found in soils?
Carbon from dead organic matter
33
How can biological carbon be returned to the atmosphere?
When dead organic matter is decomposed
34
What affects the rate of decomposition?
- Temperature and climate
- Human activity such as deforestation and land-use change
35
How much carbon do mangroves sequester a year?
1.5 metric tonnes per hectare
36
What are mangrove soils made up of?
- Litter, humus and peat
- These contain over 10% carbon
37
What is special about mangrove soil?
Due to being submerged beneath tidal water twice a day, it is anaerobic. This means decomposition takes a lot longer as decomposers cannot survive without oxygen.
38
Why does tundra soil contain ancient carbon?
As the soil is permanently frozen, no microbe activity can decay the material
39
What is the natural greenhouse effect?
- Solar radiation enters the Earth's atmosphere and passes through a layer of greenhouse gases
- Radiation mostly absorbed by Earth's surface but some is reflected
- The greenhouse gas layer acts as a blanket, stopping reflected radiation from leaving the Earth's atmosphere
40
What greenhouse gases contribute to the greenhouse effect?
- Methane
- Carbon dioxide
41
Why is the natural greenhouse effect good?
It allows Earth to be at a high enough temperature to support life
42
What is the enhanced greenhouse effect?
Human activity has caused an increase in greenhouse gases in the atmosphere, leading to warmer temperatures
43
How does the greenhouse effect impact temperature distribution?
Different locations on Earth receive differing levels of solar energy. The angle of the sun's rays concentrate on the Equator whilst at the poles it is dispersed over a greater distance
44
What is the albedo effect?
The colour of the surface of the Earth affects whether heat is absorbed or reflected: white snow reflects heat while dark oceans and forests absorb heat
45
How does the greenhouse effect impact precipitation distribution?
The intense solar radiation at the equator leads to warm air rising, causing high levels of rainfall all year
46
What happens in terms of pressure and precipitation at 30 degrees north and south?
High pressure and rainfall is rare
47
How much carbon do marine phytoplankton sequester each year?
5-15 Gt
48
How much carbon do terrestrial primary producers sequester each year?
100-120 Gt
49
Do oceans or rainforests sequester more carbon?
Rainforests
50
What is a consequence of Arctic sea ice melt?
Greater areas of ocean are exposed to sunlight for longer, causing algal bloom. Algae sequesters CO2 but alters marine ecosystems
51
What factors determine how much carbon is stored in soil?
- Size of store in different biomes
- Total input (plant litter, animal waste)
- Total output (amount of decomposition, erosion and uptake by plant growth)
52
What are signs of healthy soil?
- Dark in colour
- Contain worms and other organisms
- Have good infiltration rates
53
Why does plant CO2 intake decrease in winter?
Reduced hours of sunlight mean that less photosynthesis is occurring - Climate change could make winters shorter
54
Why is the natural carbon cycle in equilibrium?
There is a balance between stores and sinks
55
How has industrialisation interrupted the equilibrium of the carbon cycle?
The combustion of fossil fuels increased, leading to an increase in the concentration of atmospheric carbon
56
How will increased levels of atmospheric carbon change the climate in Europe?
- Eastern and Northern Europe will expect to see warmer winters and increased precipitation
- Southern Europe will expect to see warmer summers and decreased precipitation
57
What is the prerequisite for a tropical storm?
Sea surface temperatures at 27 degrees for 3 consecutive weeks
58
What South American nation has invested heavily in solar power?
Peru installed solar panels on 500,000 homes between 2006-15
59
Why are many rural areas in developing countries without power?
- Lack of resources
- Lack of finance to develop energy infrastructure
60
What percentage of the world's energy is consumed in urban areas?
75%
61
In 2015, what percentage of UK energy was from renewables?
25%
62
Why is the UK energy insecure?
A decline in domestic natural gas and oil in the North Sea means that the country now relies on imported energy
63
What are primary energy sources?
Energy sources in their raw form, for example, fossil fuels
64
What are secondary energy sources?
Electricity
65
What technology advancement reduced energy consumption in the UK in the last 25 years?
Central home heating
66
What are renewable energy sources?
Energy sources that are natural continuous flows
67
Why does the UK import oil often instead of extracting it from the North Sea?
It is expensive to extract North Sea oil, so when oil prices are down, it can be cheaper to import instead
68
How many years worth of coal remains in the UK?
150 years
69
What was the UK's aim for greenhouse gas emissions established in 2015?
Reduce greenhouse gas emissions by 40% by 2030
70
When is Norway committed to being carbon-neutral by?
2050
71
What are Norway's main sources of energy?
- HEP
- Oil and gas from the North Sea
72
Why is the UK limited in its ability to use gas for energy?
While the UK could extract shale gas through fracking, this is extremely unpopular
73
What is a consequence of the UK privatising its energy companies?
Suppliers include foreign companies (such as France's EDF) who have influence over sources
74
Why is there so much unextracted UK coal?
Available technology is not good enough to extract it
75
Why does Norway use HEP energy?
The physical landscape is suitable with naturally steep valleys and high rainfall
76
What percentage of Norway's renewable energy comes from HEP sources?
98%
77
How does Norway discourage the use of fossil fuels?
They tax it so it is more expensive than renewables as well as funding sustainable energy projects
78
Examples of energy players
- OPEC
- TNCs
- Governments
- Consumers
79
How do governments influence energy consumption?
- Regulate private energy companies
- Set environmental targets
- Required to meet international agreements
80
How can TNCs influence energy consumption?
- Invest in and develop their own supply lines and distribution network
- Respond to markets to ensure profits (adapting pricing)
81
Examples of energy TNCs
- BP (UK)
- Shell (UK/Netherlands)
- Petrobras (Brazil)
- Reliance (India)
82
How can consumers influence energy consumption?
- Have some control over where their energy comes from (e.g. installing solar panels)
- Their opinions influence policy (e.g. fracking protests)
- They directly influence energy demand
83
What is OPEC?
Organisation of Petroleum Exporting Countries
81% of world oil reserves are found in OPEC nations
84
What is the aim of OPEC?
Smaller oil-producing countries (e.g. UAE, Qatar), join together to create a group which dominates world oil production so they have greater influence over the oil market
85
What two countries have the highest gas reserves?
Russia, Iran
86
What two countries have the highest oil reserves?
Venezuela, Saudi Arabia
87
What two countries have the highest coal reserves?
USA (237m tonnes)
Russia (157m tonnes)
88
How have oil demands in China changed in recent years?
Doubled between 2000 and 2010
89
What energy resources does China have?
- 14th largest oil supply
- 3rd largest coal supply
90
When is China estimated to become the world's largest energy importer?
2035
91
What is an energy pathway?
The flow of an energy resource from the producer to the consumer
92
What resources are transported through pipelines?
Natural gas and oil
93
Name of the pipeline that transports gas from Russia to Germany
Yamal-Europe Pipeline
94
How long is the ESPO oil pipeline and where does it go?
4,188km
Transports oil from Siberia to China, South Korea and Japan
95
What are transmission lines?
High voltage lines that carry electricity from power points to wherever the energy is needed
96
What is the name of the UK energy transmission system?
The National Grid
97
What is a substation?
A station which takes a high voltage of energy and decreases it to the volume needed by customers
98
What is a shipping chokepoint and how can these affect oil prices?
Shipping chokepoints: Narrow sea channels where transport can be easily disrupted
If these channels become blocked, as 50% of oil is transported by sea this can cause an increase in oil prices
99
Example of a pipeline being damaged
Winter storms in 2013 damaged the importing UK gas pipeline and they were left with only 6h supply
100
Where is an area prone to piracy attacks on oil ships?
Strait of Malacca
101
What are some unconventional fossil fuel sources?
- Tar sands
- Deep water oil
- Shale gas (fracking)
- Biofuels
102
How is bitumen extracted from tar sands?
High pressure steam is injected to separate the bitumen from the tar sands
103
Economic cost of tar sands
Isn't always economically worthwhile as extraction is expensive: ~$10 more than average barrel of oil
104
How energy intensive is extracting tar sands?
Requires one barrel of oil to produce three
105
How water intensive is extracting tar sands?
Requires 2-5 barrels of water for each barrel of oil
106
What percentage of Canadian oil is exported to the US?
70%
107
What percentage of North America is expected to get their energy from tar sands in 2030?
16%
108
What rocks is shale gas trapped in?
Fractures and pores of sandstone and shale
109
What country extracts deep water oil?
Brazil
110
What are biofuels produced from?
Organic matter
111
What is biomass?
The burning of plant material and animal waste for energy
112
Three categories of biofuel
- Bio-ethanol
- Bio-diesel
- Bio-methane
113
What is bio-ethanol derived from?
Sugar cane, beet and maize
114
What is bio-diesel derived from?
Animal fats and vegetable oils
115
What is bio-methane derived from?
Waste and sewage
116
How can the use of biofuels impact food supply?
- Plants that would've otherwise been grown for food are instead grown for fuel
- In areas where there is less food security there are questions as to whether biofuel is a productive use of food supply
117
How are bio-fuels environmentally damaging?
- Require mass deforestation for land
- Fuel is needed to burn biomass
118
How much more carbon is released from biofuels than coal?
Up to 150-400% more
119
What is bio-ethanol used as primarily?
A mix with petrol in cars and vehicles
120
How many people does the biofuel industry employ in Brazil?
1.34m
121
How many vehicles are powered by bio-ethanol?
6 million
122
What percentage of Brazil's energy is produced from biofuels?
16%
123
How has the biofuel industry casued tensions in Brazil?
- Links to deforestation
- Complaints that not enough food is being produced
124
How does nuclear energy work?
Heat from atomic reactions is used to heat water and the steam produced powers turbines
125
How expensive is solar energy?
£50-80 mW/h
126
How expensive is wind energy?
Onshore: £80 mW/h
Offshore: £120 mW/h
127
How expensive is hydroelectric power?
£100 mW/h
128
How expensive is nuclear power?
£93 mW/h
129
What are some issues with wind turbines?
- Residents complain that they are visually unappealing
- Potential harm to birds
- Intermittent as depends on strength of winds
130
What country temporarily closed all their nuclear power stations?
Japan - due to Tohoku earthquake
131
What percentage of Japan's energy previously came from nuclear?
27%
132
What are some issues with solar energy?
- Uses a vast area of land (could be used for farming instead)
- Relatively expensive for consumers
- Only productive in sunny countries
133
What is the name of the new UK nuclear power plant?
Hinkley Point C - will provide 7% of the UK's energy needs
134
Where is the UK's largest solar farm?
Shotwick
135
How is the UK government encouraging energy companies to invest in renewables?
Subsidies
136
Roughly how much of the UK's energy comes from wind?
25%
137
Examples of radical technologies to tackle carbon emissions
- Electric vehicles
- Carbon capture and storage (CSS)
- Hydrogen fuel cells
138
What are some issues with electric vehicles?
- Limited distance between charges
- Very expensive (at least £25,000)
- Charging points not yet widespread in UK
139
How does carbon capture and storage work (CSS)?
- Carbon captured from power plants
- Compressed and transported by pipeline
- Injected in liquid form into underground reserves
140
Where is carbon from CSS stored?
In underground reserves, such as depleted gas fields
141
How much COULD CSS reduce carbon emissions?
Up to 19%
142
How many CSS plants are operating in the world?
16
143
How is hydrogen fuel created?
By separating hydrogen from other elements using electricity
144
Is hydrogen fuel or oil more efficient in cars?
Hydrogen fuel
145
What are some issues with hydrogen fuel cells?
Hydrogen does not occur naturally as a gas, it must be separated from other elements such as water. This is difficult under current scientific abilities.
146
Why does deforestation occur?
- Meet demands for timber
- Clearing land for agriculture
147
Why is demand for resources increasing?
- Population growth
- Increase in economic development
- Climate change (e.g. increased water stress)
148
How does deforestation affect the carbon cycle?
- Reduction in photosynthesis
- CO2 released during decomposition
149
How does deforestation affect the water cycle?
- Reduction in infiltration and interception
- Increase surface run off and soil erosion
- Reduced EVT = reduction in annual rainfall
150
How does afforestation benefit the water cycle?
Promotes infiltration and percolation
151
How has deforestation for palm oil had a negative impact on people?
- Indigenous populations forced to relocate, affecting their traditional way of life
- There were over 700 land conflicts in 2016 between palm oil companies and indigenous people
152
What types of countries are seeing an increase in forested area?
HICs
153
Evidence that deforestation may be slowing
Annual net loss of forests is half of what it was in the 1990s
(Down from 6.6m in the 90s to 3.3m in the 2010s)
154
How has Indonesia aimed to reduce deforestation?
- Declared a 'forest moratorium' in 2011 which halted permits to clear timber
- Supported by UN ($1bn fund)
155
Was Indonesia's "forest moratorium" successful?
YES: Emissions had fallen by 2% by 2013
NO: Illegal logging remains a problem, as forest clearance only reduced 15%
156
Shape of Kuznet's curve
Normally distributed
157
What does the Kuznet's curve show in relation to environmental degredation?
- As a country develops economically, environmental degradation increases
- The country then hits a point where the environmental concern leads to action being taken
- GDP continues to grow through new industries such as green energy
158
How has Costa Rica limited environmental degredation?
- Mass deforestation from the 50s to the 80s
- Then invested heavily in eco-tourism to improve environment
159
By how much did forest area in Madagascar decrease?
2/3 between 1950-85
160
Causes of deforestation in Madagascar?
- Energy
- Trade of expensive tropical hardwood
161
What is ocean acidification?
As more CO2 is absorbed into the ocean, the pH of the ocean decreases (more acidic)
162
How does ocean acidification affect coral reefs?
Acidic water makes coral disintegrate
163
How does rising sea temperatures affect coral reefs?
- Coral reefs can only survive up to 29 degrees
- Coral bleaching happens in warm waters, causing the algae to be ejected
164
Importance of coral reefs
- Provide shelter for 25% of marine species
- Provide shoreline protection
- Tourism
165
How will increased temperatures affect evaporation?
- Increased evaporation rates
- This could result in tropical storms moving further from the equator
166
How will increased temperatures affect a drainage basin?
- In permafrost regions, increased thawing and increased surface run off
- Precipitation more likely to fall as rainfall than snow = affects river regimes
167
Why is ocean health important for humans?
- Many countries rely on oceans for tourism (coral reefs)
- Developing nations in particular rely on fish for food
168
What percentage of mangroves have been lost since the 1950s?
50%
169
How does drought cause forest loss?
- Trees die and plant growth declines
- Dried dead organic matter causes forest fires to spread easily
170
When was the recent Amazon drought?
2014/15
171
What percentage of the world's terrestrial carbon is found in the Amazon?
17%
172
Examples of natural positive feedback loops that cause uncertainty over climate change
- Increased glacial melt = sea levels rise
- Increased atmospheric carbon = oceans more acidic
173
How do oceans become more acidic?
Sequestering carbon from the atmosphere
174
What is peat?
Soil formed from vegetation which is partly decayed
175
Why does peat contain high amounts of carbon?
Low decomposition
176
What happens if peat dries out?
- Water table drops
- Decomposition rates increase
177
What greenhouse gas does peat emit?
Methane
178
Example of a UK wildfire
2018 Saddleworth Moor
Cause: Dry bushes were on peat, which is extremely flammable
Impacts: 40 homes evacuated
179
Explain the positive feedback mechanism of permafrost and CO2 emissions
- Permafrost thaws, releasing CO2 and methane
- This enhances the greenhouse effect and temperatures increase
- Increased temperatures cause more permafrost to thaw
180
Consequence of melting northern glaciers
Large amount of less dense, non-salty water entering into oceans
181
How do melting glaciers affect thermohaline circulation?
- Disturbs conveyor belt of hot water moving from the tropics to the poles
- This could cool temperatures in Northern Hemisphere
182
What is forest dieback?
- Drought causes large number of trees to die in rainforest
- So much dead vegetation that no EVT so overall rainfall reduces
- This causes further vegetation to die
183
What are adaption strategies?
Adopting new methods to adapt to changing conditions
184
3 land-use management adaption strategies
- Land-use planning
- Resilient agriculture
- Water management
185
How can land-use planning help to deal with climate change?
- Zoning areas which are at increased risk from natural hazards
- Promoting more resilient design
186
How can water management help to deal with climate change?
- Smart irrigation
- Desalination
- Reusing black water (sewage) for farming
187
Which country has invested in water management?
Israel
188
What is geo-engineering?
Adapting to climate change through altering the physical environment to protect humans from the effects of climate change
189
How can buildings be made more flood-proof?
- Raising floors
- Using water-resistant material
190
How could spraying seawater into the atmosphere reduce the impacts of climate change?
Could ultimately form clouds to reflect solar radiation and create precipitation
191
Examples of geo-engineering techniques to adapt to climate change?
- Flood proofing
- Spraying seawater into the atmosphere
- Spraying Sulphur into the stratosphere
- Small disks that orbit Earth and reflect solar radiation
192
Problem with geo-engineering techniques
Many are untested and require changing the atmosphere which could have unintended consequences
193
How has Japan used land-use zoning?
There are 12 zone types. Each zone type has a limit on the number of floors allowed.
194
Examples of mitigation strategies
- Energy efficiency
- Afforestation
- Carbon taxation
- Renewable switching
195
How is energy efficiency promoted in the UK?
Grading electrical items with A-G based on their energy efficiency
196
What was the 2016 fuel tax in the UK?
50%
