Physical - Carbon Cycle and Energy Security Flashcards
What is the Earth’s largest carbon store?
Oceans
How large of a store are the oceans compared to the atmosphere?
50x larger
What % of carbon dioxide is stored in undersea algae, plants and coral?
93%
Carbon cycle pumps
The processes operating in oceans to circulate and store carbon
Thermohaline circulation
The global system of surface and deep water ocean current is driven by temperature and salinity differences between areas of oceans
Biological pump
- This is the organic sequestration of carbon to oceans by phytoplankton
- They photosynthesise at the surface waters of oceans, and release carbon via respiration
- They are then passed up the food chain when they are eaten by consumer fish and zooplankton, which also respire and release carbon
- After death, carbon is released by decomposition. Phytoplankton may die and sink, where they decompose or are turned into sediment
How much of the Earth’s biomass is phytoplankton accounted for?
1/2
Phytoplankton have rapid growth rates. Where does this occur the most?
Shallow waters of continental shelves, where rivers carry nutrients out to sea, and in nutrient upwelling locations
Which oceans are the phytoplankton most productive in?
Arctic and Southern oceans
After dead phytoplankton sink, how much carbon reaches the sea floor?
0.1%, as most is recycled in surface waters
How many tonnes to phytoplankton sequester annually to the deep ocean?
Over 2 billion metric tonnes
Carbonate pump
- Marine organisms use calcium carbonate for the inner skeletons and outer shells (plankton species, oysters, coral, lobsters)
- When they die and sink, they decompose, adding carbon to deep ocean currents
- If their shells and skeletons reach the sea floor, they will build up to form limestone sediments (e.g. White Cliffs of Dover)
Physical pump
- This is based on the oceanic circulation of water including upwelling, downwelling and the thermohaline current
- Colder water absorbs more carbon than warmer waters
- Warmer waters release carbon to the atmosphere
- As major ocean currents such as the North Atlantic Drift (Gulf Stream) move waters from the tropics to the poles, the water cools and can absorb more atmospheric carbon dioxide
Carbon dioxide concentration is __% higher in deep oceans than at the surface?
10%
More than _____ as much carbon dioxide can dissolve into cold polar waters than in warm equatorial waters
Twice
Fastest part of the carbon cycle?
Terrestrial sequestration
Terrestrial sequestration
- Plants take in carbon from the atmosphere via photosynthesis and release it via respiration
- Animals eat plants, adding carbon to their fats and proteins
- Microorganisms and detritus feeders (beetles) feed on waste material from animals, and absorbs the carbon from them
- Plants and animals die and decay (tissues decay quicker than other resistant materials, such as wood)
Where does decomposition happen fastest?
Tropical climates
Which factors speed up the rate of decomposition?
High rainfall, high temperatures, high oxygen levels
Globally, which biomes are the most productive?
Tropical rainforests, savannahs, grasslands
Carbon fluxes vary diurnally
During the day the fluxes are positive, from the atmosphere to the ecosystem; at night the flux is negative, with loss from the ecosystem to the atmosphere
Carbon fluxes vary seasonally
In the northern hemisphere winter, when few land plants are growing and many pre-decaying atmospheric carbon dioxide concentrations rise; during the spring, when the plants begin growing again, concentrations drop
How much area does the Amazon rainforest cover?
5.3 million sq km
How much terrestrial carbon does the Amazon rainforest sequester globally?
17%
__% of the Amazon’s ____ tree species store __% of its carbon
1%, 16,000, 50%
Wetlands and peatlands
- Wetlands the contain peat, an organic sediment, are important carbon stores
- Formed during the Holocene
- Have been a store for thousands of years
- However, they’re becoming net carbon sources following climate change and overuse
What % of global carbon is stored in soils?
20-30%
Humus soils are what % carbon?
60%
In permafrost regions, over __% of carbon is stored deeper than 30cm
61%
How does climate determine the capacity of soil to store organic carbon?
- It dictates plant growth and microbial and detritivore activity
- Rapid decomposition occurs at higher temperatures or under waterlogged conditions
- Areas with higher rainfall have an increased potential carbon storage than the same soil type in areas with lower rainfall
- Arid soils store only 30 tonnes per hectare compared with 800 tonnes per hectare in cold regions
How does soil type determine the capacity of soil to store organic carbon?
Clay-rich have a higher carbon content than sandy soils, as clay protects carbon from decomposition
How does management and use of soils determine the capacity of soil to store organic carbon?
Cultivation and disturbance has caused soils to lose billions of tonnes globally
Since 1850, how many tonnes have soils lost globally?
40-90 billion tonnes
Carbon balance
The carbon stores of the atmosphere and soils are in constant exchange. The carbon balance in soils is regulated by plant productivity, microbial activity, geology, erosion, climate and the amount of upward and downward (leaching) water movement in the soil
What % of shortwave solar radiation is reflected by clouds, aerosols and gases in the atmosphere and by the land surface?
31%
What % of shortwave solar radiation is absorbed?
69%, almost 50% is absorbed at the Earth’s surface, especially by oceans
What % of shortwave solar radiation is re-radiated to space as longwave radiation?
69%; however, a large proportion emitted by the surface is re-radiated back to the surface (‘trapping’ of longwave radiation)
Carbon dioxide has increased in volume by what % in the last 300 years?
40%
Energy security
- Long-term - timely investments to supply energy in line with economic developments and environmental needs
- Short-term - focuses on the ability of the energy system to react promptly to sudden changes in the balance between demand and energy supply
How is energy security vital for a country?
- It powers most forms of transport
- It lights our homes
- It warms or cools our homes and powers domestic appliances
- It is vital to modern communication
- It drives most forms of manufacturing
Why is energy consumption increasing?
Global population increases, meaning global needs also increase (form of development, rise in living standards)
Energy intensity
A measure of how efficiently a country is using its energy
Energy mix
The energy mix is a group of different primary energy sources from which secondary energy for direct use - such as electricity - is produced
Energy mix sources
- Non-renewable fossil fuels or carbon fuels, such as oil, natural gas and coal
- Recyclable fuels such as nuclear energy, general waste and biomass
- Many types of renewable energy, such as wind, solar, water and geothermal
Fossil fuels account for what % of global energy mix?
80%
Which factors affect the consumption of energy
- Physical availability - imported?
- Technology - drilling?
- Cost - physical exploitation? Processing? Delivery to consumer?
- Economic development, standard of living
- Climate - hot/cold conditions?
- Environmental priorities
Energy pathway
The route taken by any form of energy from its source to its point of consumption. The routs involve different forms of transport, such as tanker ships, pipelines and electricity transmission grides
USA vs France
- USA ranks 2nd in terms of energy consuming countries globally, whereas France ranks 10th
- France’s total consumption is only 1/10 of that of the USA
- This is due to differences in population (USA = 318.9 million, France = 64.6 million) and climate (USA experiences extremes of heat and cold)
USA energy mix
- Fossil fuels: 82%
- Renewables: 10%
- Nuclear energy: 8%
France energy mix
- Fossil fuels: 50%
- Renewables: 9-10%
- Nuclear energy: 41%
How many nuclear reactors does France have in operation currently?
50
What % of France’s energy is imported?
46% - high dependency on imported primary energy
What % of USA’s energy is imported?
15% - less dependency on imports
TNCs
- e.g. Gazprom, BP, Petrobas
- Nearly half of all the large TNCs supplying energy are state owned, therefore are under government control
- Most are involved in a range of operations, including: exploration, extraction, transportation, refining, and producing petrochemicals
Organisation of the Petroleum Exporting Countries (OPEC)
- Has 12 member countries
- Between them, they own 2/3 of all the world’s oil reserves
- Due to its influence, it is in a position to control the amount of oil and gas entering the global market, as well as the prices of the commodities
- It has been accused of holding back production in order to drive up oil and gas prices
Energy Companies
- These convert the primary energy (oil, gas, water and nuclear) intro electricity and then distribute it
- They have considerable influence when it comes to setting consumer prices and tariffs
Consumers
- Transport
- Industry
- Domestic users
- Largely passive players when it comes to fixing energy prices
Governments
They can play a number of different roles:
- They are guardians of national energy security
- They can influence the sourcing of energy for geopolitical reasons
Mismatch of coal
- Consumption is declining, but production continues to increase
- China is the largest producer, followed by the USA - this also makes them the largest consumers
- This reflects the fact that coal is characterised by high transport costs relative to a low energy density
Mismatch of oil
- Well over half comes from the international groups of OPEC and North America (Canada, USA and Mexico)
- High demand due to its role as a transport fuel, with very little alternatives - this creates a deeper global market, producing varying differences between consumers and producers
How many millions of barrels of oil do China import per day?
6.1 million
How many millions of barrels of oil do the USA import per day?
5.1 million
Mismatch of gas
- Global gas production is dominated by the USA and Russia
- Other noteworthy suppliers are the Middle East, Asia and Canada
- Gas production has a global but uneven spread
How many million m³ does the USA export?
4,359,000 million m³
How many million m³ of gas does Russia export?
670,000 million m³
How many million m³ of gas does Germany import?
100,000 million m³
How many million m³ of gas does Japan import?
98,000 million m³
How can energy pathways be blocked?
Geographical factors, e.g. blocking of the Suez Canal
Tar sands
- A mixture of clay, sand, water and bitumen
- Tar sands have to be mined and then injected with steam to make the tar less viscous so that it can be pumped out
Tar sands in Canada
- Has one of the largest tar sand deposits in the world
- Exploiting them for commercial use started in 1967
- The province of Alberta is most prominent, notably the Athabasca area
Tar sands produce what % of Canada’s oil output?
40%
Environmental costs of tar sands exploitation?
It requires the clearing of large areas of taiga
Oil shale
- Oil-bearing rocks that are permeable enough to allow the oil to be pumped out directly
- Either mined or shale is ignited so that the light oil fractions can be pumped out
Shale gas
- Natural gas that is trapped in fine-grained sedimentary rocks
- Extracted via fracking: pumping water and chemicals forces out the gas
US shale gas
- In 2000, shale gas provided 1% of the USA’s gas supply
- By 2015, it provided 25%
- This is due to the growing use of hydraulic fracking to release oil and gas from underground formations
- The most important shale gas fields have been found in the states of New York, Pennsylvania, Texas and West Virginia
Environmental concerns of fracking
- Possible contamination of groundwater by the chemicals in the pumping fluid
- Surface subsidence
- Producing airborne pollutants (methane, benzene and sulfur dioxide)
- Animal deaths
- Industrial explosions
Deepwater oil
- Oil and gas that is found well offshore and at considerable oceanic depths
- Drilling takes place from ocean rigs; already underway in the Gulf of Mexico and off Brazil
Brazilian deepwater oil
- Discoveries were made in 2006
- The deepwater oil came on stream in 2009
- By 2020, Petrobas (the state oil company) aims to raise production to 500,000 barrels of oil a day
- The coast between Rio de Janeiro and São Paolo has been ruined by refineries
How deep are the oil rigs drilling in Brazil?
2000m below the surface of the seabed
Example of an accident involving oil rigs
Deepwater Horizon rig in the Gulf of Mexico, 2010
Cons of unconventional fossil fuels
- They are still fossil fuels, and so their extraction will continue to threaten the carbon cycle and contribute to global warming
- The extraction is costly and requires a high input of complex technology, energy and water
- The extraction threatens environmental damage (scars of opencast mines, ground subsidence) and environmental risks (pollution of groundwater and oil spills)
Players in the harnessing of unconventional fossil fuels
- Exploration companies
- Environmental groups
- Affected communities
- Governments
Example of an exploration companies
Halliburton
Example of an environmental group?
Greenspace
Affected communities - pros and cons
- Job opportunities
- Inflows of investment
- Improved services
- Various forms of pollution
- Disturbance to traditional ways
Main forms of renewable energy
- Hydro
- Solar
- Wind
- Geothermal
- Tidal
Why might renewables might not be the way of the future?
- There are very few countries where renewables might completely replace all the energy currently derived from fossil fuels
- Renewables have a higher cost than fossil fuel resources, which is obviously less attractive
- Significant impacts on the environment would rise: drowning valleys for HEP reservoirs, large areas of land and the offshore zone would be covered by wind and solar farms
- Despite their popularity, locals still don’t want wind farms, etc. to be built by them
Pros of nuclear energy
- Not a fossil fuel
- Nuclear waste can be reprocessed and reused, thereby making it a recyclable energy resource
Cons of nuclear energy
- Safety - Chernobyl, Fukushima
- Security in an era of international terrorism
- Radioactive waste disposal, incredibly long decay life
- Technology involved - nuclear power is only an option for developed countries
- Costs - operational costs are relatively low, but the costs of building and decommissioning are high
UK energy mix
- Shift away from direct use of coal
- Reliance on natural gas and oil - 80% of the UK’s primary energy
- Use of natural gas as it produces slightly more electricity than nuclear energy
- The UK consumes less energy than it did in 1970, despite an increase in population to 6.5 million - hint at energy efficiency
UK households use __% less energy
12%
UK industry use __% less energy
60%
Biomass
Organic matter used as a fuel, especially in power stations for the generation of electricity
Biofuel
A fuel derived immediately from living matter, such as agricultural crops, forestry or fishery products, and various forms of waste (municipal, food shops, catering, etc.)
Primary biofuels
Includes firewood, wood chips and pellets, and other organic materials that are used in an unprocessed form, primarily for heating, cooking and electricity generation
Secondary biofuels
These are derived from the processing of biomass and include liquid biofuels such as ethanol and biodiesel, which can be used by vehicles and in industrial processes
Biofuel crops
Wheat, maize, grasses, soy beans, super cane, sugar beet, oilseed rape
What are biofuel crops converted into?
Biodiesel or ethanol, usually used as vehicle fuel
Pros and cons of biofuels
- ‘Green’ energy
- Renewable
- Requires hectares of farmland
When did Brazil take action to diversify its energy sources?
1970s
What % of Brazil’s energy mix comes from biofuels?
4%
What % of vehicles sold in Brazil are flex-fueled (petrol and sugar cane ethanol)?
90%
Brazil is the largest producer of what?
Sugar cane (concentrated in the central southern region), which also makes it a large exporter of sugar and ethanol
Brazil’s area planted with sugar cane has increased since 2003, and is expected to double by which year?
2018
What cons have the growth of biofuels caused in Brazil?
- Displacement of other types of agriculture, particularly cattle pasture
- This has led to the creation of replacement pastures, which in turn has led to large-scale clearance of tropical rainforests
- The deforestation cancels out the use of biofuels to reduce carbon dioxide emissions
Carbon capture and storage
- This method involves ‘capturing’ the carbon in the atmosphere and burying it deep underground
- It’s expensive because of the complex technology involved
- No one can be sure that the carbon dioxide will stay trapped underground; it could leak out!
Hydrogen fuel cells
- A fuel cells combines hydrogen and oxygen to produce electricity, heat, and water. It will produce electricity as long as fuel (hydrogen) is supplied
- It could be used as a source of heat and electricity for buildings, or a power source for electric venhicles
- Hydrogen is high in energy and an engine that burns pure hydrogen produces almost no pollution
- Liquid nitrogen has been used by NASA since the 1970s
- However, hydrogen is expensive, hard to extract and highly flammable
Nuclear Power examples
- Japan - before 2011, 27% of their electricity came from nuclear power. However, all plants closed after the Fukushima nuclear plant was damaged during an earthquake
- UK - Hinkley Point C - £18 billion project, will provide energy for 60 years and 25,000 jobs
Wind Power examples
- Hornsea Project 1 - (190-metre-high wind turbines) provide power for 1 million homes, located 121 km off the coast of Yorkshire, creates 2000 construction jobs
- Quarrendon Fields, Aylesbury - supply for 2000 homes
Solar Power examples
Chapel Lane Solar Farm, Christchurch - it cost £50 million, UK’s largest solar farm, supplies for 60,000 homes/75% of the houses in Bournemouth
