Section C - Carbon Cycle Flashcards
(86 cards)
1
Q
What is the carbon cycle and what are its four main stores?
A
The carbon cycle is the process given to the exchange of carbon between its four main reservoirs – atmosphere, hydrosphere, lithosphere and biosphere
2
Q
What are the three main types of carbon in the carbon cycle?
A
- Inorganic – Found in rocks as bicarbonates and carbonate (the Earth’s largest carbon store)
- Organic – Found in plant material
- Gaseous – Found as CO2, methane and carbon monoxide
3
Q
What are the four key processes of the carbon cycle?
A
- Photosynthesis – Removing CO2 from the atmosphere to promote plant growth
- Respiration – Releasing CO2 into the atmosphere as animals consume plant growth and breathe
- Decomposition – Breaking down organic matter and releasing CO2 into soils
- Combustion – of biomass and fossil fuels – releasing CO2 into the atmosphere
4
Q
What are fluxes in the carbon cycle and give two examples?
A
Fluxes is the name given to carbon being exchanged between stores - EG Photosynthesis and decomposition of organic matter
5
Q
What is carbon sequestration?
A
The removal and storage of carbon from the atmosphere – usually occurs in oceans, forests, and soil through photosynthesis
6
Q
What is thermohaline circulation?
A
An ocean current that produces both vertical and horizontal circulations of warm and cold water around the world’s oceans
7
Q
What is thermohaline circulation?
A
An ocean current that produces both vertical and horizontal circulations of warm and cold water around the world’s oceans
8
Q
What is the biological carbon pump and what does it involve?
A
- The exchange of CO2 at the ocean’s surface
- Involves phytoplankton sequestering CO2 through photosynthesis
- When they die, phytoplankton sink to the ocean floor and stay there, transferring carbon into the ocean store
9
Q
What % of a tree’s biomass stores carbon?
A
95% - very important to the carbon cycle
10
Q
The role of mangrove forests in the carbon cycle (how much carbon it sequesters, what happens if they are cut down)
A
- Mangrove forests sequester 1.5 metric tonnes of carbon per year
- If mangrove forests are drained or deforested by human activity, carbon is released back into the atmosphere
- If just 2% of the world’s mangrove forests are lost, the rate of carbon sequestration will be 50 x the normal sequestration rate
11
Q
What role do tundra soils play in the carbon cycle?
A
Much of the soil in tundra regions is permanently frozen and contains ancient carbon as roots and decayed organic matter are frozen, locking up the carbon
12
Q
What role do tropical rainforests play in the carbon cycle?
A
- Massive carbon sinks but extremely fragile
- Carbon is stored in trees, plants, and dead wood and is recycled as these stores decay
- Tropical forests absorb more atmospheric CO2 than any other biome - account for 30% of the planet’s net primary production
13
Q
What does the natural greenhouse affect do?
A
The natural greenhouse affect keeps air in the Earth, making the Earth 16 degrees hotter than it otherwise would have been and allowing for life on the planet
14
Q
What % of GHGs does CO2 account for?
A
89%
15
Q
How much have concentrations of GHGs in the atmosphere increased since 1750?
A
Concentration of GHGs in the atmosphere have increased by 25% since 1750
16
Q
What % of CO2 emissions have come from burning fossil fuels since the 1980s and what has this contributed to?
A
Since the 1980s, 75% of CO2 emissions have come from burning fossil fuels – this has contributed to the enhanced greenhouse effect
17
Q
Impacts of burning fossil fuels - Balance
A
- Human activity and burning FFs have increased carbon inputs from fossil fuels without a corresponding increase in carbon sinks leading to the carbon cycle being more out of balance
18
Q
Impacts of burning fossil fuels - Implications for climate (3)
A
- Across Europe, annual average land temps are projected to increase
- Annual average precipitation rates are also expected to increase in Northern Europe and decrease in Southern Europe
- Extreme weather events are also likely to increase in frequency and severity
19
Q
Impacts of burning fossil fuels - Arctic amplification
A
- Arctic is warming twice as fast as the global average – known as arctic amplification – this releases CO2 into the atmosphere contributing to higher temps and more melting and more CO2 and so on
- Climate change and burning FFs has resulted in less snow in the winter months and more melting in the summer months, threatening plant and animal life
20
Q
Impacts of burning fossil fuels - Implications for the water cycle
A
- In the summer months, much of Europe’s water comes from melting ice in the Alps but by 2100 climate scientists predict that the Eastern-Alps will be completely ice-free along with a majority of the Western-Alps, affecting the water cycle like this:
- Precipitation in the form of snow could diminish and rainfall patterns could change
- River discharge patterns may change with more floods in winter and more droughts in summer
21
Q
Cities contain what % of the world’s people, consume what % of the world’s energy, and produce what % of the world’s GHGs?
A
- More than 50% of the world’s people live in cities
- Cities consume 75% of the world’s energy
- Cities produce 80% of its GHGs
22
Q
How much carbon does London produce per year?
A
London generates 1.7 million tonnes of carbon per year
23
Q
What happened in Peru from 2006-2015 and what does this represent?
A
- Solar panel electricity was made available to 500,000 people in remote villages in Peru from 2006-15
- This is a sustainable energy source and is helping bring sustainable development to these villages
24
Q
What are primary and secondary energy sources?
A
- Energy sources that are consumed in their raw form EG fossil fuels, nuclear energy and renewable sources
- Primary sources can be used to generate electricity which is a secondary energy source
25
What are domestic and overseas energy sources? (energy security)
- Declining domestic North Sea oil and gas reserves have made the UK more reliant on imported energy
- Because the UK now imports more energy than it exports, the country has an energy deficit and is energy insecure
- By contrast countries with surplus energy EG Russia are energy secure
26
What are renewable and non-renewable sources?
- Non-renewable sources EG coal, oil or gas will eventually be used up and are finite
- Renewable EG wind, solar and wave power are continues flows of nature which can be constantly reused
- Recyclable EG nuclear power
27
What was the UK's energy mix in 1980? (oil, coal, gas, renewables, nuclear)
- Oil 38%
- Coal 34%
- Gas 19%
- Renewables <2%
- Nuclear 9%
28
What was the UK's energy mix in 2022?
Oil - <1%
Coal - 1%
Gas - 38%
Renewables - 43%
Nuclear - 18%
29
What was Norway's energy mix in 1970? (oil, hydropower, coal gas)
- Oil 51%
- Hydropower 42.5%
- Coal 6.5%
- Gas n/a
30
What was Norway's energy mix in 2010? (oil, hydropower, coal gas)
- Oil 33.5%
- Hydropower 40%
- Coal 0.5%
- Gas 20%
31
Key players in energy - Energy TNCs
- TNCs explore, exploit and distribute energy resources
- Own supply lines and invest in processing of raw materials
- Respond to market conditions to secure profits for their shareholders
- EG BP, Shell, Petrobras
32
Key players in energy - OPEC
- Organisation of Petroleum Exporting Countries – IGO
- Members are oil producing countries EG Saudi where oil is the main export and is therefore vital for economic growth
- OPEC countries control 81% of proven world oil reserves
33
Key players in energy - National govs
- Role is to meet international obligations whilst securing energy supplies for their countries now and in the future
- EG EU govs aiming to fulfil emissions targets and reduce fossil fuel dependency
34
Who are the biggest producers of fossil fuels? (Coal, oil, gas)
- Coal = USA – 250 billion metric tonnes
- Oil = Venezuela – 330 billion barrels of oil
- Natural gas = Russia – 1.6 billion cubic feet of natural gas
35
Canadian tar sands - Costs (4)
- Only viable when the price of crude oil exceeds $40 per barrel
- Very energy intensive to mine
- About 1.8 million tonnes of toxic wastewater are produced every day
- Adds to GHG emissions
36
Canadian tar sands - Benefits (4)
- Provides an alternative source of oil
- By 2030 it could meet 16% of NA’s oil needs
- Offers energy security for Canada and the USA – 28% of Canada’s oil is used in Canada
- Could serve as a fuel stopgap until more renewable energy sources become more viable
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Canadian tar sands - Implications for the carbon cycle (2)
- Carbon emissions rise due to extraction, production and use of tar sands
- Carbon absorption falls due to deforestation
38
Other types of energy - Renewable energy sources (5)
- Biomass – heat energy from wood, plants, animal and general waste
- Solar power – energy from the sun generating energy through solar panels
- Wind energy – Moving air turns a propeller-driven generator
- Wave and tidal energy – moving water flows through a barrage, driving turbines
- Hydroelectric power (HEP) – The vertical release of water turns a turbine
39
Other types of energy - Recyclable energy sources (2)
- Nuclear power – the use of atomic reactions to obtain heat, in turn heating water and generating steam to drive a turbine
- Heat recovery systems – Where heat from air inside a building is used to warm air drawn from outside
40
Alternatives to fossil fuels - Costs of nuclear power (Japan 2011)
- In Japan pre 2011 Tohoku, 27% of Japan’s electricity came from nuclear power
- Fukushima reactor meltdown led to Japan closing all of its nuclear power plants
41
Alternatives to fossil fuels - Benefits of nuclear power (UK)
- However in the UK, Hinkley Point C is an £18 billion project which will provide energy for 60 years
- Will also provide 25,000 jobs involving French and Chinese nuclear companies
42
Alternatives to fossil fuels - Wind power benefits (Hornsea)
- Hornsea Project 1 is a project where 190m high wind turbines will eventually provide power for 1 million homes once completed
- Also created 2000 construction jobs
43
Alternatives to fossil fuels - Wind power negatives (Aylesbury)
- In Aylesbury a wind turbine 25m taller than other onshore wind turbines will provide energy to 2000 homes
- However, some local residents view it as a blot on the landscape
44
Alternatives to fossil fuels - Solar power (Christchurch UK)
Chapel Lane Solar Farm in Christchurch cost over £50 million and is the UK’s largest solar farm – it serves 60,000 households or 75% of the homes in Bournemouth
45
The growth of biofuels - main areas of use and comparison to electric cars
- Brazil uses bio-fuel as a cheaper alternative to petrol – cars running on bio-fuel produce 80% less CO2 than petrol cars
- Other countries such as Malaysia, the EU and the US have begun introducing biofuels as well
46
Strengths of biofuels (3)
- Renewable energy resource
- Lower emissions than fossil fuels
- Easily grown and does not need specialist machinery
47
Weaknesses of biofuels (3)
- Takes land from food production
- Requires large volumes of water
- Clearing the forests leads to the loss of a large carbon sink and increased CO2 emissions from the deforestation
48
Opportunities as a result of biofuels (3)
- Provides rural inward investment and local development projects
- Positive multiplier effect in rural regions
- Fuel earns export income
49
Threats posed by biofuels (3)
- Takes away investment from food production
- Contaminates water resources with pesticides
- Food shortages may occur which will lead to higher food prices
50
Other means of reducing carbon emissions - carbon capture and storage
- This uses tech to capture CO2 emissions from coal-fired power stations
- Gas is transported to a site where it is stored, compressed and transported by pipeline to an injection well, where it is injected in liquid form into suitable geological reservoirs
- Theoretically, CCS could cut global CO2 emissions by up to 19%
- However it is not currently financially viable
51
Other means of reducing carbon emissions - Hydrogen fuel cells
- Once hydrogen is separated from other elements, it provides an alternative to oil
- Fuel cells convert chemical energy into hydrogen with pure water as a by-product – these are far more efficient than petrol engines in vehicles
- Separating hydrogen from other elements requires energy, but this can be provided by renewable sources such as solar or wind power
52
Other means of reducing carbon emissions - Electric vehicles
- Traditionally, the problem with electric vehicles is their range and price
- However recently these factors have improved significantly with improvements made to corresponding technology
53
Deforestation rates in Madagascar - pre 1950 vs 1985
- Pre 1950 - 11.6 million hectares of tropical forest,
- 1985 - 3.8 million hectares of forest
- Loss of two thirds
54
Impacts of Madagascar deforestation on the water cycle (3)
- Infiltration decreased
- Runoff and erosion increased
- Flood peaks are higher and lag time is shorter
- Increased discharge leads to flooding
- More eroded material carried in the river
55
Impacts of Madagascar deforestation on soil health (3)
- CO2 released from decaying wood material
- Rapid soil erosion leads to a loss of nutrients
- Biomass is lost due to reduced plant growth / photosynthesis
56
Impacts of Madagascar deforestation on the atmosphere (3)
- The air is dryer
- Reduced evapotranspiration makes it less humid
- Oxygen content is reduced and transpiration rates are lowered
57
Impacts of Madagascar deforestation on the biosphere (3)
- Evaporation from vegetation is reduced
- Less absorption of CO2 means a reduced carbon store
- Decrease in habitats means that fewer animal species survive
58
Benefits of natural grassland (5)
- Traps moisture and floodwater
- Absorbs toxins from soils
- Maintains healthy soils
- Maintain natural habitats
-Acts as a carbon sink – absorbs CO2 and releases O2
59
Disadvantages of converting grassland into biofuel crops (3)
- Initial removal of grasslands releases CO2 from soils into the atmosphere
- Annual ploughing enables bacteria to release CO2
- Biofuel crops need carbon-based nitrogen fertiliser and chemical pesticides so they produce a net increase in CO2 emissions
60
What is the significance of afforestation? (4)
- Trees provide a vital carbon store as they sequester carbon during photosynthesis
- Therefore it makes sense to replant trees that are cut down or establish forests on land not previously forested
- This is known as afforestation
- The EU’s Afforestation Grant Scheme encourages the planting of forests for their value as terrestrial carbon stores and for the ecosystems they provide
61
What is the significance of ocean acidification? (how much CO2 absorbed, how much from FFs)
- The world’s oceans have absorbed about 30% of the CO2 produced as a result of human activities since 1800 and about 50% of CO2 produced by burning fossil fuels
- Ocean acidification has made the world’s oceans 30% more acidic than they were in 1750
62
Impact of ocean acidification on coral reefs?
- As CO2 in the oceans increases, its PH decreases becoming more acidic
- As the oceans become more acidic coral reefs begin to dissolve
- Corals can only survive in temps between 28 and 29 degrees – if water becomes too warm the coral turns white – known as coral bleaching
- The biggest cause of coral bleaching is climate change – if CO2 emissions continue in their current rate, the PH of the ocean surface could be lowered to 7.8 by 2100 which would dissolve coral reefs entirely
63
Ecosystem services - What are supporting services?
These keep ecosystems healthy by providing other by providing other services including soil formation, photosynthesis, nutrient cycling and water cycling
64
Ecosystem services - What are provisioning services?
These are products obtained from ecosystems including food, fibre, fuel, genetic resources, natural medicines and pharmaceuticals
65
Ecosystem services - What are regulating services?
These are the benefits obtained from the regulation of ecosystem processes including regulating air quality, climate, water, erosion, disease and pollution
66
Ecosystem services - What are cultural services?
These are the non-material benefits that people obtain from ecosystems such as spiritual well-being, recreation, education and science
67
Impacts of climate change in the Amazon
- The Amazon Basin suffered severe drought in 2005, 2010 and 2014-15 – the worst to hit Brazil in 80 years
- The Amazon Bay holds 17% of the terrestrial vegetation carbon store
- The 2010 Amazon drought saw trees die and growth rates decline
- The drought effectively shut down the Amazon’s function as a carbon sink
- Forest fires broke out – burning trees and litter and releasing CO2
- There are also further concerns that, should climate change increase temperatures and alter rain patterns further, the Amazon rainforest will change from a carbon sink to a carbon store, further accelerating global warming
68
The impact of producing palm oil (Indonesia)
- Huge swathes of forest in South-East Asia, Latin America and Africa are being bulldozed to create land for palm oil plantations – thereby releasing carbon
- In Indonesia over 700 land conflicts in 2016 were linked to the palm oil industry
- In 2011 Indonesia’s Pres declared a ‘forest moratorium’ designed to reduce deforestation with $1 billion in funding from the UN
- By 2013 emissions had fallen by 1-2.5%
- Indonesia want to reach a 29% carbon emissions reduction by 2030
69
Forest recovery/loss stats
Between 2010 and 2015, an average of 7.6 million hectares of forest were lost every year – but 4.3 million hectares were also gained – leaving a net annual loss of 3.3 million hectares
70
Impacts of climate change in the Yukon (4)
- Increasing temps lead to increased evaporation and atmospheric water vapour
- Annual precipitation rates set to increase by between 5% and 20% by 2100
- Between 1958 and 2008 the total ice area in the Yukon shrank by 22%
- Climate change is leading to the thawing of permafrost so water penetrates deeper into the soil instead of forming surface runoff
71
Why is future climate change so uncertain - Physical factors (2)
- Oceans and forests act as carbon sinks and store heat – oceans take decade to respond to change in GHG concentration – their responses to ever-increasing temps will continue to affect global climate for possibly hundreds of years
- Human factors also play a role in forests as humans dictate the global amount of net forest loss per year
72
Why is future climate change so uncertain - Human factors (3)
- Economic growth - After the financial crisis of 2008 there was a worry that rising CO2 emissions would follow the recovery of global GDP – however after rising by 4% per year since 2000, the rate of emissions rise fell to 0.5% by 2014 – nevertheless total carbon emissions still reached a new record
- Energy sources – Energy consumption grew by 2% between 2008 and 2014 – however renewable sources made up two-thirds of the increase in electricity production in 2015
- Pop change – Increasing affluence and emerging economies means a potential extra billion consumers by 2050
73
Feedback mechanisms - Peatlands
- Most of the world’s wetlands are peat – the accumulation of partly decayed vegetation that stores large amount of carbon due to the slow breakdown in cold waterlogged soils
- Warming causes peat to dry out as water tables fall as well as increasing the rate of decomposition
- A warming of 4 degrees causes a 40% loss of soil organic carbon from shallow peat and an 86% loss from deep peat
74
Feedback mechanisms - Permafrost
When permafrost melts it releases trapped CO2 into the atmosphere – increasing atmospheric greenhouse gas concentrations and leading to increased temps and melting
75
What are tipping points in the carbon cycle?
- A climate tipping point is a critical threshold that can transform a relatively stable system into a very different state
- Two particular phenomena lead to tipping points – forest die back and changes to the thermohaline circulation
76
Tipping points - Forest die back (Amazon)
- Rainfall in the Amazon rainforest is largely recycled from moisture within the forest
- If the Amazon is subject to drought, trees die back – a tipping point can be reached where the level of die back stops the recycling of moisture within the rainforest – resulting in further die back
77
Tipping points - Changes to the thermohaline circulation
- Cold, deep water in the North Atlantic forms part of the thermohaline circulation
- The keep the conveyor belt of warm water heading from the Tropics towards Britain, heavy salt water must sink in the North
- However, the melting of the Northern ice sheets releases significant quantities of freshwater into the ocean which is lighter and less salty – thus blocking and slowing the conveyor belt of warm water
- As ice sheets melt, the ocean circulation is susceptible to a critical tipping point
78
Adaptation strategies for the carbon cycle/climate change - Water conservation and management
- Israel has a range of strategies to manage its limited supplies of freshwater:
- Smart irrigation
- Recycling sewage for agricultural use
- Reducing agricultural consumption and importing water in food as virtual water
- Adopting stringent conservation techniques
79
Adaptation strategies for the carbon cycle/climate change - Land use planning and flood risk management
- Land-use zoning is a technique used for flood management where development on floodplains is limited to low-impact things like playing fields and parks
- This is a low cost approach to flood management where infiltration occurs naturally and surface runoff is reduced along with the risk of wider flooding
80
Adaptation strategies for the carbon cycle/climate change - Resilient agricultural systems
- Conservation cropping is growing in use, from the USA to Syria and Iraq
- It involves growing crops using a no-ploughing approach – uses fewer fertilisers, retains stubble and grows cover crops
- Benefits include increased yields and incomes for farmers, improved soil structure, healthier soils, water conservation and erosional control
81
Adaptation strategies for the carbon cycle/climate change - Solar radiation management
- This is a form of climate engineering which aims to reflect solar rays and so reduce global warming
- EG cloud brightening and space-based reflectors
- Advantages include quick deployment, offsetting of some GHGs
- Disadvantages include uncertainty about effectiveness, expense, and debate over the ethical, social and political issues surrounding its use
82
Mitigation strategies for the carbon cycle/climate change - Carbon taxation
- A carbon tax is a fee paid by users of fossil fuels that is directly linked to the level of CO2 emissions that the fuel produces
- Won’t guarantee a reduction in the level of CO2 but is meant to encourage the switch the renewables
83
Mitigation strategies for the carbon cycle/climate change -
- Germany is a world leader in energy efficiency – its policies include:
- Requiring residential and commercial bindings to reduce their emissions by 25%
- Loans to renovate older, energy-consuming properties
- Subsidies to improve efficiencies in manufacturing
84
Mitigation strategies for the carbon cycle/climate change - Afforestation and reforestation
- Canada and Sweden lead on afforestation but South Korea has had a remarkable turn around
- Forest degradation in SK accelerated during WW2 and the Korean War
- Gov included forest rehabilitation projects as part of its economic plan
- Between 1961 and 1995, the area of forested land in SK rose from 4 to 6.3 million hectares
- By 2008 11 billion trees had been planted and now almost two thirds of SK is forested
85
Mitigation strategies for the carbon cycle/climate change - Renewable switching
- Sweden leads the way in switching to renewable energy
- Oil provided 75% of Sweden’s energy compared to 20% today
- Benefits are clear – 83% of Sweden’s electricity come from nuclear and hydroelectric power – far less carbon emissions
86
Mitigation strategies for the carbon cycle/climate change - Carbon capture storage
- In 2014, Boundary Dam in Canada became the world’s first commercial carbon capture coal-fired power plant
- It aims to cut CO2 emissions by 90% before trapping it underground before it can reach the atmosphere
