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Earth’s Life Support System 2024 > OCR A Level ELSS - Entire Course 1 > Flashcards

OCR A Level ELSS - Entire Course 1 Flashcards

1
Q

Importance of water on earth?

A

-oceans moderate temperatures by absorbing, storing and slowly releasing heat
-clouds reflect incoming solar radiation and lower surface temperatures
-water vapour absorbs long wave radiation from the earth and maintains global temps 15 degrees higher than they usually would be

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2
Q

Uses of water on Earth?

A

-Makes up 65-95% of living organisms and is vital for their growth, reproduction and metabolic functioning
-plants need water for photosynthesis, respiration and transpiration.
-water is used in all chemical reactions in humans and animals.
-important economic resource, used in agriculture, food manufacturing and to generate electricity.

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3
Q

Importance of carbon on earth?

A

-Life is carbon based, built on large molecules such as proteins, carbohydrates and nucleic acids.

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4
Q

Uses of carbon on Earth?

A

-economic resource, used in fossil fuels which power global economy
-agriculture, crops and forest trees store lots of carbon, used by humans for food, timber, paper, etc.

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5
Q

why is earth the only planet able to support life?

A

-climate - temperatures do not go from one extreme to the other
-light - all plants receive light from the sun which they need in order for photosynthesis
-atmosphere - breathable atmosphere, 21% oxygen and small amounts of CO2 (0..04%), atmosphere is kept on earth by gravity
-water - most important chemical needed to sustain life, drinkable and not acidic
-sun - in Goldilocks zone, right amount of heat and light to support life

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6
Q

spheres of the earth

A

-atmosphere (gas envelope surrounding the earth)
-biosphere (space between earth + atmosphere occupied by living organisms)
-lithosphere (crust + upper mantle, divided into tectonic plates)
-cryosphere (frozen part of earths surface)
-hydrosphere (all water on earths surface)

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7
Q

What is the Goldilocks zone?

A

-its ‘just the right distance’ from the sun to allow the presence of liquid water on earth

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8
Q

At a global scale, water and carbon flow in __________ systems (driven by the sun’s energy) between the ________________, the oceans, land and the _____________.

A

-closed
-atmosphere
-biosphere

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9
Q

The global water cycle consists of 3 main stores: the ______________, oceans and land. The oceans are the _____________ store and the atmosphere is the ______________.

A

-atmosphere
-biggest
-smallest

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10
Q

Water moves between stores by….

A

precipitation, evapotranspiration, run-off and groundwater flow.

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11
Q

Long term storage in sedimentary rocks holds…

A

99.9% of all carbon on earth.

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12
Q

Carbon in circulation moves rapidly between the…

A

atmosphere, the oceans, soil and the biosphere.

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13
Q

The main pathways between stores in the carbon cycle include…

A

photosynthesis, respiration, oxidation (decomposition, combustion), and weathering.

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14
Q

Systems are…

A

groups of objects and the relationships that bind the objects together

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15
Q

At smaller scales (drainage basin or forest ecosystem), ___________ as well as the sun’s energy cross system boundaries. These systems are….

A

-materials
-open systems

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16
Q

Sizes of stores of water?

A

Oceans- 97%
Ice caps + sheets- 2%
Groundwater- 0.7%
Lakes- 0.01%
Soils- 0.005%
Atmosphere- 0.001%
Rivers- 0.0001%
Biosphere- 0.00004%

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17
Q

Sizes of stores of carbon?

A

-Sedimentary rock- 60-100 million GT
-Ocean deep layer- 38,000 GT
-Fossil fuels- 4,130 GT
-Soil- 2300 GT
-Ocean surface- 700 GT
-Atmosphere- 600 GT

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18
Q

How much water does the global water circulate per year?

A

505, 000 km3 per year between stores

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19
Q

Inputs and outputs of water in the water cycle?

A

1)EVAPOTRANSPIRATION- water evaporates from surface water and land surface, and is transpired through leaves of plants
2)CONDENSATION + PRCIPITATION- occurs in atmosphere, vapour becomes liquid and is transferred to land as precipitation
3)ABLATION + SUBLIMATION- occurs when snow or ice melts, and sublimation occurs when ice turns into water vapour.
4)RUN OFF + FILTRATION - water runs off land surface into rivers, precipitation ends up as run off after infiltration in soil.
5)PERCOLATION- transfer of water to ground water stores (aquifers), returned to earth surface as springs.

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20
Q

Inputs + outputs of carbon in the carbon cycle?

A

1)PRECIPITATION-atmospheric CO2 dissolves in rainwater to form a weak carbonic acid, when precipitation happens CO2 flows back to lands and oceans- increased burning of fossil fuels increases acidity of rain + ocean water.
2)PHOTOSYNTHESIS - process by plants and phytoplankton, CO2 + water converted into glucose + oxygen, chemical energy stored in tissues
3)WEATHERING - involves the breakdown of rocks near earths surface by physical, mechanical and biological processes
4)RESPIRATION - process where glucose is converted back into carbon dioxide + water
-plants and animals absorb oxygen to burn carbohydrate stores to provide energy for metabolism and growth
5)DECOMPOSITION - carbon released as CO2 when organisms die by microorganisms carrying out respiration which also put mineral ions into soil
6) COMBUSTION - when organic material burns, CO2 locked up in the material is released with other gases like SO2

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21
Q

Evapotranspiration?

A

The evaporation of water from soil plus the transpiration of water from plants.

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22
Q

sublimation?

A

when ice turns into water

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23
Q

ablation?

A

when glacial ice or sheets melt to release water

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24
Q

infiltration?

A

Downward movement of water through soil.

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25
Q

run off?

A

water flowing off the land into bodies of surface water (for example, lakes or rivers).

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26
Q

what is water balance?

A

the relationship between precipitation, stream flow, evapotranspiration, soil moisture and ground water storage in a drainage basin over a year

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27
Q

The principal flows in the water cycle that link the various stores are:

A

precipitation, evaporation, transpiration, run-off, infiltration, percolation and throughflow.

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28
Q

percolation?

A

The downward movement of water through soil and rock due to gravity.
-Goes deep underground into an aquifer.
-Returned to earth’s surface as springs.

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29
Q

water cycle budget?

A

the annual volume of movement of water by precipitation, evapotranspiration, run-off etc. between stores such as oceans, permeable rocks, ice sheets, vegetation, soil, etc.

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30
Q

through flow?

A

A horizontal movement of water through the soil to rivers or oceans

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31
Q

base flow?

A

Water input to streams and rivers from natural reservoirs such as aquifers, pear bogs, soils etc.

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32
Q

interception loss?

A

rainwater stored temporarily on the leaves, stems and branches of vegetation which is evaporated and does not reach the ground surface

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33
Q

water balance equation?

A

precipitation = evapotranspiration + streamflow +/- storage

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34
Q

Process of the water cycle: Evaporation?

A

Requires a lot of energy to change state from liquid to vapour

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35
Q

Process of the water cycle:
Transpiration?

A

Transfer of water from plants to the atmosphere (10% of atmospheric water originates from transpiration).
-Influenced by temperature, wind speed and water availability to plants.

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36
Q

Process of the water cycle:
Precipitation?

A

-Water and ice that falls from clouds.
-Forms when vapour in the atmosphere cools to its dew-point temperature and condenses into tiny water droplets to form clouds.
-These droplets then aggregate, reach a critical size and leave the cloud as precipitation.

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37
Q

Process of the water cycle:
Condensation?

A

Change of water vapour to liquid, occurs when air is cooled to its dew point and clouds form.

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38
Q

4 ways that cause clouds to form?

A

Clouds form when moist air cools.
1)Air warmed by contact with ground or sea surface, rises through the atmosphere (convection). As the air rises and pressure falls it cools by (adiabatic) expansion.
2) Warm air mass meets cold air mass = forms stratus and cumuliform clouds
3) Large air mass moves across cooler surface = stratus
4) Air is forced to rise over elevated land (hills), causing it to cool.

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39
Q

Cumuliform clouds?

A

-flat bases, vertical development
-form when air is heated by the Earth’s surface
-causes air parcels to rise freely in the atmosphere, as the parcel of air cools and expands due to decreasing pressure, dew point is reached.

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40
Q

Stratiform clouds?

A

-Form when an air mass moves across a cooler surface (ocean). This is called advection.
-Low, white, little rainfall

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41
Q

Cirrus clouds?

A

-short, wispy clouds
- form at high altitude, consist of ice crystals.
-form after a warm front where air masses reach high levels
-do not produce rain, no impact on water cycle.

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42
Q

Condensation near the ground surface produces ______ and fog.
Both deposit large amounts of moisture on ______________.

A

-dew
-vegetation

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43
Q

Lapse rates…

A

Describe the vertical distribution of temperature in the lower atmosphere, and the temp changes that occur within an air parcel as it rises vertically from the ground.

44
Q

What causes air to reach its water holding capacity (dew point)?

A

1) the amount of water in the air increases, and air cannot hold any more water
2)the air has cooled to its dew point, air cannot hold any more water

45
Q

dew point

A

The temperature at which condensation begins

46
Q

the two main sinks of carbon?

A

-sedimentary rocks - 60-100 million GT - 99.9% of the carbon store
-ocean deep layer - 38,000 GT - 2nd biggest store

47
Q

what is GT - carbon store measurement?

A

billion tonnes

48
Q

Describe the slow carbon cycle

A

-involves the long term store of carbon
-CO2 dissolves from atmosphere into ocean where marine organisms (shell fish and phytoplankton) make their shells and skeletons
-by fixing calcium and carbon to form calcium carbonate
-when they die, they accumulate on the ocean floor and over millions of years become compressed to form carbon rich sedimentary rock
-carbon stored in rock for 150 million years
-oceanic rock containing sedimentary rock is sub-ducted, causing it to melt and carbon is released during volcanic eruptions
-sedimentary rock on surface releases carbon when weathered

49
Q

describe the fast carbon cycle

A

-transfer between stores is 10x faster than the slow carbon cycle
-land plants and microscopic phytoplankton in oceans are the key components
-absorb CO2 during photosynthesis, transforming it into carbohydrates stored in their tissues
-during respiration they release CO2 into the atmosphere by evaporation

50
Q

sedimentary rock

A

-A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together

51
Q

the water and carbon cycle at global scales?

A

-considered as closed systems which are driven by the suns energy which is external to the earth and only energy crosses the boundaries / not matter
-carbon and water flow between atmosphere, oceans, land and biosphere

52
Q

the water and carbon cycle at local scales?

A

-considered as open systems as materials and energy both cross boundaries
-ex = drainage basin or forest ecosystem

53
Q

main processes of the water cycle?

A

-evaporation
-transpiration
-condensation

54
Q

main inputs and outputs of water in the water cycle

A

-evaporation and transpiration
-ablation, sublimation, condensation, precipitation
-run off and infiltration
-percolation

55
Q

what does residence time mean?

A

the length of time a molecule of water or carbon remains in natural storage

56
Q

what are phytoplankton?

A

tiny photosynthesising marine organisms in surface waters of oceans

57
Q

carbon cycle and precipitation?

A

-atmospheric CO2 dissolves in rainwater to form a weak carbonic acid
-when precipitation happens carbon flows back to lands and oceans
-as CO2 concentrations have increased in the atmosphere due to humans burning more fossil fuels, the acidity of precipitation has increased
-leading to acidity of ocean water

58
Q

carbon cycle and photosynthesis?

A

-process used by land plants and phytoplankton to convert light energy into chemical energy
-CO2 + H20 - O2 + GLUCOSE
-chemical energy is stored in carbohydrate molecules such as sugars which plants use to maintain growth, reproduction and respiration
-glucose used as building block for cell walls, for respiration in plant cells and as an energy store

59
Q

carbon cycle and weathering?

A

-involves the breakdown of rocks, near the surface by physical, mechanical and biological processes
-chemical weathering involves rainwater thats a weak carbonic acid which weathered rocks through carbonation or solution
-as the rock reacts with the carbonic acid it forms calcium bicarbonate which is soluble
-running water releases carbon into rivers and oceans
-physical weathering does not involve any altering of the carbon composition
-biological weathering involves chelation (organic acids) - as organic material decomposes it makes the soil become acidic which attacks rock minerals

60
Q

carbon cycle and respiration?

A

-the process where carbohydrates formed in photosynthesis are converted into CO2 + water
-plants and animals absorb oxygen which allows them to burn carbohydrate store to provide energy needed in metabolism + growth
-respiration + photosynthesis are elements of the fast carbon cycle

61
Q

carbon cycle and decomposition?

A

-carbon is released as CO2 when living organisms die and are decomposed by microorganisms
-decomposer organisms release CO2 into the atmosphere and extract mineral nutrients from the soil
-rates of decomposition depend on climatic conditions, which are faster in warm, humid environments

62
Q

carbon cycle and combustion?

A

-when organic material burns, carbon locked up is released which other gases like SO2
-combustion can happen naturally by wildfires which are caused by lightening strikes
-benifical to ecosystem as it leads to an increase in nutrients and carbon cycling, leading to more growth
-due to a long winter, forest litter can build up on the forest floor therefore a fire releases the jam with nutrients and opens up the candy to create new habitats and increase biodiversity
-combustion happens due to humans actions for example deliberate firing of forests or grassland to clear space for cultivation or improve grazing quality

63
Q

what is Catchment Hydrology?

A

Water studies within a drainage basin

64
Q

what is a water basin?

A

a region drained by a river or its tributaries

65
Q

catchment hydrology - 2 processes?

A

-evaporation
-interception
-

66
Q

catchment hydrology - evaporation?

A

-evaporation is the phase when liquid water is converted into vapour
-heat energy is required break molecular bonds of water which is absorbed as latent heat and released later in condensation
-process allows huge amounts of heat to be transferred around the planet, for example from the tropics to the poles

67
Q

catchment hydrology - interception?

A

-vegetation intercepts a proportion of precipitation storing it temporarily on branches, stems and leaves
-eventually this moisture evaporates or falls to the ground
-throughfall is when water is intercepted before dripping to the ground
-stemflow occurs during prolonged periods of rainfall when intercepted water may flow along branches and stems

68
Q

factors effecting interception loss?

A

-interception storage capacity - as vegetation becomes saturated, output of water through stem flow and through flow increases
-wind speed - evaporation rates increase with wind speed
-vegetation type - larger surface areas (trees) have a larger interception losses than grasses
-tree species - some species have leaves all year round, some do not

69
Q

infiltration, through flow, ground water flow and run off?

A

-rain falling to the ground and not entering storage follows one of two paths
1-infiltration by gravity into the soil and lateral movement to through flow to stream or river channels
2-overland flow across the ground surface as a sheet or as trickles to stream or river channels
-a few ideas explain the two paths, one is overland flow due to infiltration capacity
-second idea is due to rainfall always infiltrating the soil

70
Q

what pattern does ground water stores follow?

A

-by late October the water table is beginning to rise as temperatures and evapotranspiration fall
-recharge continues until late January
-groundwater levels then decline throughout late winter, spring and summer, reaching their lowest point in early autumn

71
Q

Cryospheric processes

A

-ablation is loss of ice from snow, ice sheets and glaciers due to a combination of melting, evaporation and sublimation
-meltwater is an important component of river flow in high latitudes and mountain catchments in spring and summer
-rapid thawing of snow in winter is a common cause of flooding in adjacent lowlands

72
Q

physical (inorganic) pump?

A

-involves mixing of surface and deep ocean waters by vertical currents
-creates a more even distribution of carbon in oceans
-CO2 diffuses into the oceans from atmosphere
-surface currents transport dissolved CO2 polewards where it becomes dense and sinks (downwelling)
-individual carbon particles may remain deep in the ocean for many centuries
-eventually deep ocean currents transport carbon back up to the surface (upwelling)
-cold, carbon rich waters rise to the surface where CO2 diffuses back into the atmosphere

73
Q

biological (organic) pump?

A

-50% of carbon fixation happens by photosynthesis in oceans
-50GT of carbon is drawn from atmosphere by biological pump each year
-marine organisms (phytoplankton) drive the pump
-phytoplankton floating near surface combine sunlight, water and CO2 into organic material
-whether consumed in the food chain or through natural death, carbon locked in phytoplankton accumulates on the ocean floor or is decomposed and released as CO2. or is used by organisms for shells and skeletons
-most CO2 ends up in sediments such as chalk and limestone

74
Q

What is permafrost?

A

a thick subsurface layer of soil that remains frozen throughout the year, occurring chiefly in polar regions.

75
Q

what is the active layer?

A

-The top layer of permafrost.
-melts

76
Q

water cycle negative feedback loop

A

heavy rainfall = increased water infiltration = more water stored in aquifers = water table is raised = more water is returned to the surface as springs = water table returns to normal levels

77
Q

carbon cycle negative feedback loop

A

burning of fossil fuels = increased atmospheric CO2 = photosynthesis stimulated = more CO2 removed form the atmosphere = CO2 levels restored

78
Q

3 land use changes?

A
  1. urbanisation
  2. farming
  3. forestry
79
Q

land use changes - urbanisation?

A

-farmland and woodland areas replaced by tarmac and brick
-artifical surfaces are impermeable and allow little water infiltration and provide minimal water storage capacity, giving rise to run off
-urban areas have drainage systems designed to remove water rapidly (gutters, pitched roofs) therefore water form precipitation flows quickly into streams and rivers, leading to a rapid rise in the water tables
-urbanisation also encroaches floodplains which are natural water stores
-overall, urbanisation reduces water storage capacity in drainage basins, increasing river flow and flood risks

80
Q

land use changes - farming and the carbon cycle?

A

-clearance of forest for farming reduces carbon storage in above and below ground biomass
-soil carbon storage is reduced by ploughing and exposure of organic material to oxidation
-harvesting of crops returns only a small amount of organic matter to the soil
-soil erosion by wind and soil is most severe when crops have been lifted and have little protective cover
-carbon exchanges through photosynthesis are lower due to a lack of biodiversity and a short growth cycle

81
Q

land use changes - farming and the water cycle?

A

-crop irrigation diverts surface water from rivers and groundwater to cultivated land
-interception of crops is less than of grasslands,
-evapotranspiration is reduced by crops
-ploughing increases evaporation and soil moisture loss
-heavy machinery compacts the soil which leads to more surface run off leading to peak flows higher in farmland ecosystems
-ploughing causes infiltration which means even more water is transferred to streams and rivers

82
Q

land use changes - forestry plantations and the water cycle?

A

-there is a higher rate of rainfall interception in natural plantations
-preferred plantation species in the uk are conifers with needle like structures, evergreen habit and high density
-increased evaporation form water stored on leaf surfaces
-reduced run off and stream discharge due to high interception and transpiration rates
-clear felling of harvest timber creates a sudden change in the water cycle, increasing run off, reducing evapotranspiration and increasing stream discharge

83
Q

land use changes - forestry plantations and the carbon cycle?

A

-in the uk a typical plantation contains 10x more carbon than grassland and 20x higher than heathland
-soil represents a large carbon pool - 500 tonnes/ha
-forest trees extract carbon for hundreds or years only after 100 years since planting
-balanced by litter inputs into the soil

84
Q

what were the CO2 levels in the atmosphere 800,000 years ago compared to today (2016)?

A

-260 ppm 800,000 years ago
-400.5 ppm 2016
-small changes over 800,000 years due to glacials and interglacials

85
Q

what were the CO2 levels in the atmosphere in 1700 compared to 2016?

A

-most people lived in rural areas in 1700
-1800 - the industrial revolution and CO2 levels rapidly increased due to coal use
-1910 - the first production line car
-1913 - coal extraction
-1960 - increase in car use and central heating fitted in homes
-1700 - 310 ppm
-2016 - 400.5 ppm

86
Q

changes in the CO2 levels in the past two years?

A

-400.5 ppm
-in spring and summer there is less CO2 in the atmosphere due to more vegetation therefore increased photosynthesis
-in winter there is increases in CO2 due to more use of heating inn homes
-increased in 5 ppm in two years

87
Q

energy consumption overtime?

A

-oil (496 GT) and coal (673 GT) are the largest carbon emission sources
-coal has been used since the industrial revolution and oil has been used since 1920s
-since 1970s there has been an increase in use of nuclear and hydroelectric sources
-overall global energy consumption has increased rapidly since the 1960s with coal and oil being the main sources

88
Q

3 stages involved in CCS?

A
  1. separate CO2 from power station emissions
  2. CO2 is compressed and transported to storage areas
    3.injected into porous rock underground and stored permanently
89
Q

what is the impact and plans of CCS?

A

-plays an important role in reducing CO2 and other emissions
-in USA, 40% of all carbon emissions could be reduced by 80-90%
-in the UK a CCS project is underway in peterhead, north east Scotland which is going to capture 2 million tonnes of CO2
-plan for carbon to be transported by pipeline to the North Sea and stored in depleted gas resevoirs

90
Q

Why is the CCS limited?

A

-involves big capital costs
-uses large amounts of energy (compress and transport CO2)
-requires storage in specific geological locations

91
Q

in 2013 what percentage did fossil fuels account for the overall energy consumption?

A

87% fossil fuels

92
Q

what sources were used the most in 2013 for global energy consumption?

A

-oil (37%)
-natural gas (27%)
-coal (23%)

93
Q

where have most of our carbon emissions come from (1750 - 2012)?

A

-coal - 673GT
-land use - 590GT

94
Q

where have our carbon emissions gone (1750 - 2012)?

A

-atmosphere (879GT)
-ocean (590GT)
-land (528GT)

95
Q

how many tonnes of CO2 is released into the atmosphere annually?

A

-10 billion tonnes
-increases the CO2 concentration over 1 ppm

96
Q

impact of anthropogenic carbon emissions in the atmosphere?

A

-since 1750, 879GT of anthropogenic co2 emissions have remained in the atmosphere, tasing co2 concentrations from 280 ppm - 400 ppm
-co2 levels today have been the highest for 800,000 years

97
Q

what is the impact of anthropogenic carbon emissions?

A

-compromise only 10% of the natural influx of from the biosphere, oceans and atmosphere
-however they impact significantly on carbon stores
-despite international efforts used to reduce carbon emissions, between 2000 and 2009 they grew faster than in any other decade
-without increased absorbtion of CO2 from oceans and biosphere, atmospheric concentrations would exceed 500 ppm

98
Q

groundwater

A

water stored underground in permeable and porous rocks know as aquifers

99
Q

aquifer

A

a water bearing band of porous or permeable rock

100
Q

artesian aquifer

A

a confined aquifer containing groundwater under pressure, which will rise to the surface under its own pressure

101
Q

artesian pressure

A

The hydrostatic pressure exerted on groundwater in a confined aquifer occupying a synclinal structure.

102
Q

abstraction

A

the extraction of water from rivers and boreholes for public demand

103
Q

impact of water extraction?

A

-rates of extraction have exceeded rates of discharge
-lower flows have reduced flood risk and temporary areas of standing water on floodplains
-lower groundwater levels ave caused springs to dry up and reduce the instance of saturated overground flow on chalk

104
Q

the water table?

A

-the level below which the ground is saturated with water.

105
Q

changes that occur in the water table levels?

A

-water table heights fluctuate seasonally by periods of lots of rainfall, drought and abstraction
-in normal years in southern England, the water table falls between march and September due to rising temperatures and increased evapotranspiration
-recharge resumes in late autumn

106
Q

artesian basins

A

-when sedimentary rock forms a syncline, a downloaded basin like geological structure
-confined between layers of impermeable rock (clay)
-may contain groundwater under artesian pressure
-when groundwater is tapped by a well or borehole water will flow to its surface under its own pressure

107
Q

what is remote sensing?

A

the scanning of the earth by satellite or high-flying aircraft in order to obtain information about it.

Earth’s Life Support System 2024 (12 decks)

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