Topic 6: The Carbon Cycle And Energy Security

Question 1

What are the four main carbon stores?

Answer 1

• The atmosphere; gases like CO2 and methane
• The hydrosphere (oceans, lakes etc); dissolved CO2
• The lithosphere (earth’s crust); carbonates in limestone and fossil fuels
• The biosphere; living and dead organisms

Question 2

Explain how geological processes store carbon for a long period of time (8 marks)

Answer 2

• Limestone rocks contain a high concentration of calcium carbonate which is formed by shell building organisms that extract the mineral from seawater as well marine phytoplankton that absorb carbon through photosynthesis
• The remains of these animals go through sedimentation
• Carbon in mountain ranges is eroded by acid rain, is washed into the sea and cemented and lithified with other carbon matter
• Carbon in shale is formed by the aerobic compression, with heat and pressure, of mud containing dead organisms
• When dead organisms decay in silt and mud anaerobically over millennia, the become fossil fuels which store masses or carbon

Question 3

Explain how geological processes release carbon into the Atmosphere (8 marks)

Answer 3

Chemical weathering:

• CO2 reacts with water in the atmosphere to form carbonic acid (acid rain)
• When this rain falls, it reacts with surface minerals in rocks and dissolves them
• The dissolved ions are transported to seas and oceans where they are deposited in the sea floor and form sedimentary rock such as limestone
• These rocks May then come into contact with extreme heat, such as magma, which causes the release of CO2 gas into the atmosphere, know as degassing

Volcanic outgassing:

• Outgassing is the release of CO2 that is stored in pockets of the earth’s crust
• Outgassing occurs during volcanic eruptions when the magma reacts with sedimentary rocks to form CO2
• Outgassing occurs in dormant and non active volcanoes trough hot springs and geysers
• Outgassing also occurs at plate fractions and hot spots where the store of CO2 in the ground releases

Question 4

Explain the role of the ocean in the carbon cycle (8 marks)

Answer 4

-The ocean stores 38,000 gigantones of carbon, making it one of earth’s most significant carbon stores

Biological pump:

• Carbon is stored in organic matter such as algae, plants and coral and is dissolved in water as CO2. This pump sequesters carbon from the atmosphere through the growth of phytoplankton
• Carbon is kept in the ocean and passed along the ocean food web. It is then returned to the atmosphere through biological decay
• This pump operates on a scale of hours to years and the flux between the ocean and the atmosphere is 11 gigantones a year

Carbonate pump:
-The Carbon pump occurs when dead organic material sinks to the ocean floor and sediments to eventually become carbonate rock like limestone

Physical pump:
-The physical pump in the form of ocean currents and the thermocline cycle moves carbon vertically and horizontally in the ocean

Question 5

Explain why the soil is significant in the carbon cycle

Answer 5

• 20 to 30% of global carbon is stored in the soil. 2x the amount in the atmosphere and 3x the amount in terrestrial stores
• Carbon cycling occurs in the soil: decomposition and new plant growth
• Carbon can stay in the soil for decades and centuries if: the carbon is in dead organisms, the soil is clay, or the soil is covered by mangroves
• Soils in cold regions can store 800 tonnes of carbon per hectare. This is especially the case in permafrost soils

Question 6

Why is carbon important for the nutrient and water cycle?

Answer 6

• Carbon support microorganisms that break down plant nutrient matter and that maintain the nutrient cycle
• Carbon also provides pore spaces for water to infiltrate and be stored in the soils
• Carbon also enhances plant growth
  
  • Enhanced plant growth also allows for plants to sequester and store more carbon

Question 7

Why are global temperatures hotter nearer the equator?

Answer 7

• The angle of the sun’s ray’s cause them to be concentrated near the equator and more intense. This causes temperatures to be higher. These rays disperse when heading towards the pole sand so the area becomes cooler
• When heading towards the poles, the suns rays also have to travel further and through thicker air which causes the rays to lose energy and so become cooler
• Finally, the albedo effect has an impact on global temperatures. The equator and surrounding area tends to consist of dark ecosystems like rainforests. This helps to absorb solar energy and so warms the area up. Areas near the pole tend to be lighter and whiter which reflects the suns rays and so cools the area down

Question 8

What are some main human causes of increased green house gas emissions?

Answer 8

• Combustion of fossil fuels (electricity generation)
• Deforestation
• Loss of soil carbon (Cash cropping)
• Cattle ranching
• Cement/concrete manufacturing
• Wetland/peatland loss
• Transport
• Industry

Question 9

What are the main issues caused by the combustion of fossil fuels?

Answer 9

Production of sulphur dioxide = acid rain
Production of black carbon = particulate matter = respiratory problems
Increased ocean acidification
Positive feedback cycles e.g. permafrost thawing
Alteration to carbon and water cycles

Question 10

What is the difference between primary and secondary energy sources?

Answer 10

• Primary sources are those consumed in their raw form e.g fossil fuels, nuclear and renewable sources
• The electricity created by the use of these primary sources is a secondary energy source

Question 11

How is Norway energy secure?

Answer 11

• HEP accounts for 40% of all Norway’s electricity production
• Norway’s sovereign wealth fund invests large amounts of money into renewable energy to ensure that energy security is future proofed
• Fossil fuels account for 54% of all Norway’s electricity production
• Norway is a net exporter of fossil fuels, most notably oil and gas

Question 12

How is the U.K. energy insecure?

Answer 12

• The U.K. is in energy deficit
• In 2010 it imported 50% of its energy, mostly gas and oil
• The UK is becoming slightly more energy secure by increasing the amount of nuclear and renewable energy it uses

Question 13

What is the role of TNCs in energy pathways?

Answer 13

• They explore exploit and distribute energy resources
• The own the supply lines and invest in the distribution and processing of raw materials and energy production
• They respond to market conditions to secure shareholder profits

Question 14

What is the role of OPEC in energy pathways?

Answer 14

They seek to stabilise the worlds oil markets by coordinating their members so they secure:

• An efficient and regular supply of petroleum
• A steady income for producers
• A fair return for those who invest in the industry

E.g. they boost oil supply to meet high demand and vary prices to keep competitive

Question 15

What is the role of national governments in energy supply lines.

Answer 15

• They secure energy supplies for the nations present and future demands
• They regulate the role of private companies and set environmental priorities
  
  • E.g. they set CO2 emissions targets

Question 16

What is the role of consumers in securing energy pathways?

Answer 16

• They create demand by buying energy from around the world
• They cut energy costs by starting to move away from oil
• They can protest and oppose the expansion of certain energy sources

Question 17

Is there a mismatch between the producers and consumers of coal?

Answer 17

There is a small mismatch as coal is very costly to import which means it makes little economic sense for countries to rely on coal. The main producers of coal are also the main consumers

Question 18

Is there a mismatch between supply and demand for oil?

Answer 18

There is a large mismatch. This is because there is a high demand for oil globally since it is used in numerous industries e.g. plastics and aviation. It is also cheap and easy to transport which helps to boost its transport

Question 19

Is there a mismatch between supply and demand for natural gas?

Answer 19

There is a large mismatch between the two as many countries have a demand for natural gas. Gas is also cheap and easy to transport which allows suppliers to meet the demand

Question 20

Why are energy pathways prone to disruption?

Answer 20

-There are many choke points for fossil fuel transport across the world. The can get blocked and so inflate energy prices.
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Sometimes they may be subject to attacks by pirates e.g the Strait of Malaca. Between 2009 and 2015 there were 500 criminal attacks

• Energy pipelines may be subject to geopolitical tensions e.g. Russian pipelines in Ukraine may be subject to disruptions due to ongoing political tensions
• Pipelines can be damaged. E.g. in 2013 the U.K. was left with 6 hours left of natural gas after a pipeline was damaged

Question 21

What is Oil Shale, how is it extracted and where in the world is it being extracted?

Answer 21

• Deposits of kerogen in sedimentary rock that have not had enough heat or pressure to become oil
• The shale is mined and heated to a high temperature for the oil to be released
• Mainly in the US which has 77% of all shale oil reserves (equivalent to 800 billion barrels)

Question 22

What are Tar Sands, how are they extracted and where are they being extracted?

Answer 22

• A mixture of sand, clay, water and bitumen that occurs naturally
• It has to be strip-mined due its thickness. It then has to be heated to separate the oil
• It is mainly mined in Alberta, Canada and Venezuela

Question 23

What is Shale Gas, how is it extracted and where is it being extracted?

Answer 23

• Natural gas that is trapped in fractures and pores of sandstone and shale
• Hydraulic fracking where water and chemicals force the gas into a wall where it is then collected
• Occurs mostly in the US but also in some places in the U.K.

Question 24

What is deepwater oil, how is it extracted and where is it being extracted?

Answer 24

• Oil reserves that are deep in the ocean and far off the coast
• The same way conventional oil but with longer and deeper drills
• Brazil and the Gulf of Mexico

Question 25

What are some strengths of biofuels?

Answer 25

• They are a renewable energy source
• Second generation biofuels e.g. sugar beet produce less CO2 per megajule than crude oil
• In countries where they are grown/processed e.g. Brazil they can provide thousands of jobs as well as better paid and more formal work

Question 26

What are some weaknesses of biofuels?

Answer 26

• Many first generation biofuels produce more CO2 per megajule than crude oil
• They need pesticides and fertilisers that use fossil fuels in their production
• Lots of land is cleared to grow biofuels which means the loss of a carbon sink
• Coal is needed to kick start the burning of bio fuels which sometimes produces 150-400% more CO2 than burning coal

Question 27

What are some opportunities for biofuels?

Answer 27

• They help Africa reduce its carbon emissions. They produced 24% of Africa’s emissions in 2012
• They can improve a country’s infrastructure (e.g. piped water and roads) and income
• They can provide investment and employment in rural areas which creates a positive multiplier effect

Question 28

What are some threats of biofuels?

Answer 28

• They consume lots of water which reduces the water security of many towns and villages
• Large land use inflates land prices and often makes land unaffordable to those living in local areas
• Biofuels are climate dependent which means climate change may stop the growth of biofuels

Question 29

What are hydrogen fuel cells, and how do they reduce carbon emissions?

Answer 29

They combine hydrogen and oxygen to produce electricity to power electric vehicles or to produce heat or electricity for a building.

The burning of hydrogen produces no CO2. However separating hydrogen produces emissions of their own

Question 30

What is carbon capture and storage and how does it reduce carbon emissions?

Answer 30

It is the process by which CO2 that is produced by burning fossil fuels is captured and buried deep underground.

It reduces carbon emissions by stopping CO2 from entering the atmosphere. CCS can reduce emissions by 19%

Question 31

What is the terrestrial biosphere impact of deforestation?

Answer 31

• Forests are a massive carbon sink and store
• Forests help to absorb rainfall and increase groundwater storage
• Forests are home to large amounts of biodiversity

Deforestation has a detrimental affect on all of these aspects

Question 32

Why is deforestation increasing globally?

Answer 32

• Increased demand for commodity production (palm oil, beef, paper, soy etc)
• Dams and resivoirs, mining and infrastructure
• Over exploitation of slash and burn farming
• Urban sprawl
• Illegal logging

Question 33

How does slash and burn farming and shifting cultivation affect human well being?

Answer 33

• Particles from burning forests can cause respiratory problems
• Deforestation can cause droughts
• Deforestation leads to drier soils and soil erosion which affects food supplies in the long term and so can cause many to starve

Question 34

What is the main idea of the Kuznet’s curve model?

Answer 34

• When countries first develop they focus on economic growth and so they damage and degrade the environment by Deforestation and exploration of natural resources
• As countries further develop there is less demand for natural resources and so there environmental impact reduces
• When countries fully develop they become very concerned for the environment so they start to reduce there carbon footprint and install mitigation strategies such as afforestation

Question 35

How have increased temperatures affected precipitation patterns in the Arctic?

Answer 35

• Higher temperatures increase evaporation rates which dry up arctic ponds
• The precipitation and evaporation balance will change
• Temperatures have risen twice as fast as the global average in the Arctic
• There has been a considerable loss of sea ice and permafrost in the Arctic
• Loss of ice reduces the albedo effect which in turn increases climate warming
• Increased ice melting could lead to earlier annual peak river discharge and increased flooding
• The Arctic could be ice free by 2037

Question 36

How can climate change and the loss of mangroves affect coastal communities?

Answer 36

• 520 million people rely on fisheries for the food and income, of which 90% live in developing countries
  
  • Climate change is altering the distribution and productivity of fish. Some fish species have declined by 75%

-Coral reefs protect costal communities from flooding and shelter 25%of marine species. Ocean acidification and coral bleaching damage and destroy these reefs

Question 37

What are some adaptation strategies, and what are their costs and benefits?

Answer 37

Water conservation and management:

• Strategies to manage the supply of freshwater, especially in the face of climate change
• Smart irrigation systems can be expensive to install
• Its a very effective method of managing water use

Question 38

Why might increasing drought frequency affect forests as carbon stores?

Answer 38

• Increasing droughts reduce the growth of forests as there is less water available
• Decreased growth reduces the amount of carbon that can be stored in forests
• Drier Forests are also more prone to forest fires which emit huge amounts of carbon into the atmosphere
• Drier soils also reduce the amount of carbon that can be stored and cycled through them