ELSS part 3 Flashcards
1
Q
3what is dynamic equilibrium?
A
when a system has continuous inputs, throughputs, outputs etc
2
Q
what is an example of water cycle as a negative feedback loop?
A
- Heavy rain increases the water in aquifers
- This raises water table and increases flows from spring until it returns to normal levels
3
Q
what is negative feedback?
A
A change occurs
The system counteracts that change to bring it back to ‘normal’ levels
4
Q
what is an example of carbon cycle as a negative feedback loop?
A
- Burning fossil fuels releases carbon
- This increases photosynthesis which removes carbon to keep equilibrium
5
Q
what are the land use changes that cause change in water and carbon cycles?
A
Urbanisation
Farming
Forestry
6
Q
what changes on the water cycle does urbanisation have?
A
Reduces infiltration
More surface runoff
Higher flows into the river
Higher risk of flooding
7
Q
what changes on the carbo cycle does urbanisation have?
A
More energy used from lights
More transport
Release of harmful gases
8
Q
what changes on the water cycle does farming have?
A
Crops intercept less than forest trees
More surface runoff
Reduced runoff rates
9
Q
what changes on the carbon cycle does farming have?
A
Agricultural crops hold 10x less carbon than forest trees
More carbon in the atmosphere
10
Q
what changes on the water cycle does forestry have?
A
Increased evaporation
Higher interception rates on forest trees
Reduced runoff rates
11
Q
what changes on the carbon cycle does forestry have?
A
Forest trees extract CO2 and hold it for year
Forest trees hold 10x more carbon than agriculture
12
Q
what is forestry?
A
growing and taking care of trees in forests
13
Q
what are the factors causing changes in the water and carbon cycles?
A
Land-use changes
Water abstraction
Fossil Fuels
14
Q
what is the example of surface extraction?
A
River Kennet
14
Q
what are the types of abstraction?
A
Surface extraction - from rivers/groundwater
Sub-surface extraction - fro aquifers and artesian basins
14
Q
what has the impact of surface extraction been on the water cycle?
A
- Groundwater extraction rates have exceeded recharge rates, meaning water table fell and reduced the river flow by 10-14%
- 2003 drought meant flows fell by 20% and 40% in dry conditions in 1990s
- lower flows mean reduced flooding and temporary areas of wetland
- lower groundwater levels cause springs to dry - reduce overland flow on chalk
14
Q
how much did the river flow fall due to surface extraction?
A
10-14%
15
Q
how much did river flows fall by during the 2003 drought?
A
20%
16
Q
how much did river flows fall by during 1990s dry conditions?
A
40%
17
Q
where do aquifers form?
A
where sedimentary rocks form a basin and groundwater is confined by impermeable rock layers
18
Q
what is the example of sub-surface extraction?
A
London Basin
19
Q
what happened to London Basin in 19 century?
A
Increased demands for water so groundwater was really important
20
Q
what happened to London basin’s water table now?
A
it has recovered but is at high risk of flooding due to increased buildings
21
Q
what is an atersian aquifer?
A
when boreholes are used to tap groundwater out of an aquifer then the water will flow to the surface under its own pressure
22
what is the potentiometric surface?
Level to which the water will rise.
It is determined by height of water table in areas of recharge on the edges of the basin
23
how much of the global energy consumption is fossil fuels
over 80% of global energy consumption in 2021
24
how much of the global energy consumption is nuclear and renewable?
20%
25
how much CO2 is added to the atmosphere from fossil fuels and industry?
37 billion a year
Increased atmospheric CO2 concentration by over 2.45 ppm
26
how much has atmospheric CO2 concentration increased by from 1750 to 2022?
from 280ppm to 421ppm
CO2 in atmosphere at the highest its been for the last 800,000 years
27
what is an artesian well?
A well where groundwater reaches the surface due to natural pressure within a confined aquifer.
28
what is a confined aquifer?
A confined aquifer is a water-bearing geologic formation that lies beneath an impermeable layer of rock or clay, which restricts water movement to and from the aquifer.
29
how much carbon is stored in the deep ocean?
37,100 gigatons
Roughly 15-20 times more than that in land plants
30
how much more carbon is stored in deep ocean than land plants?
roughly 15-20 times more
31
what is the solution to capture and store CO2?
Carbon capture and storage (CCS)
32
what is carbon capture and storage?
A process in which carbon dioxide from industrial sources is separated, treated and transported to a long-term location
33
what are the stages of carbon capture and storage?
- Seperating CO2 from power stations emissions
- Compressing/transporting CO2 by pipe to where its stored
- Injected into porous rocks deep underground for permenant storage
34
how effective is carbon capture and storage?
It has potential to reduce emissions by 80-90% however due to its cost its been stopped in the UK
35
how much can carbon capture and storage reduce emissions?
by 80-90%
36
why was carbon capture and storage stopped in UK?
due to its cost
37
what is capital cost?
The initial set up cost
38
what are the factors limiting the effectiveness of carbon capture and storage?
- High capital costs involved (£1 billion)
- Energy intensive (20% of power plant outputs are used to compress the carbon)
- Specific geological conditions required for area to be storage (porous rocks etc)
39
how much did the Drax/Peterhead carbon capture and storage cost?
£1 billion just to set it up
40
why is carbon capture and storage energy intensive?
20% of the power plant outputs are used to compress the carbon
41
what are the geological requirements for carbon capture and storage?
Porous rocks and impermeable layer on top
42
what is the equation to find the net flux?
Net flux = Inputs - Outputs
43
what is residence time?
How long molecules stay in the system
44
what is positive feedback?
Initial change causes more of the same change, leading to the snowball effect
45
what is the example of positive feedback loop?
Arctic sea ice melting
- Ice melts
- Less heat is reflected by ice
- Oceans and land warms
- More ice melts
46
what is negative feedback?
Counters change and restores equilbrium
47
what are the ways of monitoring change in water and carbon cycles?
- Sattelite technology and remote sensing
- Use of GIS (geographical information systems)
48
what are GIS?
Geographical information systems
49
how many satellites are in orbit?
10,000
50
what is remote sensing?
Measuring change from a distance
51
what are the features that GIS montior changes?
Arctic sea ice
Ice cap/glaciers
Sea surface temperature
Water vapour
Deforestation/albedo
52
what is the analysis of the GIS used for arctic sea ice?
- Measure microwave energy radiated from Earth's surface
- It compares images over time to show change
53
what is the main observation from the GIS monitoring arctic sea ice?
- It retreats and advances depending on the year, but it has overall retreated from the median
- It changes with seasons
54
what is the analysis of the GIS used to monitor ice caps/glaciers?
- Measure the height of ice sheets and glaciers using laser technology
- Shows the extent and volume of ice and changes
55
what is the main observation from the GIS used to monitor ice caps/glaciers?
- It shows the gain or loss of ice
- Most loss is in the south-west of Antarctica ranging from -1m to -3m
56
what is the analysis of the GIS used to monitor sea surface temperature?
- Radiometres measure the wave band of radiation from the ocean surface
- Show changes in temperature, and areas of up/downwelling
57
what is the main observation from the GIS used to monitor sea surface temperature?
- Hottest temperatures are around the equator at 29C
- Coldest temperatures are in the poles, around 0C
58
what is the analysis of the GIS used to monitor water vapour?
- It measures cloud liquid, precipitation etc
- Show long term trends in cloud cover and water vapour in atmosphere
59
what is the main observation from the GIS used to monitor water vapour?
- There is most water vapour around the equator, moving with the inter-tropical convergence zone
60
what is the analysis of the GIS used to monitor deforestation/albedo?
- Shows measurements of reflectivity of Earth's surface and land use changes
61
what is the main observation from the GIS used to monitor deforestation/albedo?
- There is a higher albedo in Greenland and in areas with less trees, e.g. North Africa
62
what is the analysis of the GIS used to monitor atmospheric CO2?
- New satellite measures global atmospheric CO2
- Shows effectiveness of plant absorption
63
what is the main observation of the GIS used to monitor atmospheric CO2?
- CO2 is focused around the equator however the majority is in South America
64
what is the analysis of the GIS used to monitor primary production in oceans?
- Measures net primary production in oceans and on land
65
what is the main observation of the GIS used to monitor primary production in oceans?
It is higher closer to land and the equator
66
what are the types of short term changes in the water and carbon cycles?
Diurnal changes (day)
Seasonal changes
67
what are the diurnal changes in the water cycle?
- Major 24 hour changes - lower temperatures means low evapotranspiration
- Convectional rainfall daily due to direct heating of ground by sun
68
what are the diurnal changes in the carbon cycle?
- growth during the day means CO2 flows from the atmosphere to vegetation but not at night
- same with the phytoplankton in oceans
69
what are the seasonal changes in the water cycle?
- Evapotranspiration is highest in summer and lowest in winter - due to variations in intensity of solar radiation
- Rivers are lowest in late summer - due to exhaustion of soil moisture
70
what are the seasonal changes in the carbon cycle?
- Net primary productivity varies monthly
- Phytoplankton uptake with rising water temperature
- Net global flow of CO2 from the atmosphere to biosphere in summer
- seasonal fluctuations linked to greater concentration of continental landmass in North hemisphere
71
how much warmer was the global temperature 250 million years ago?
7-8 C warmer
72
what has been the biggest long term change in the water cycle during glacial periods?
The slowing of the water cycle
73
why has the water cycle slowed as a long term change during glacial periods?
- More freshwater is stored as snow and ice
- Reduced exchange of water between atmosphere and oceans, biosphere and soils
74
what are the long term changes in the water cycle during glacial periods?
- net transfer of water from ocean to storage in ice
- Results in sea levels falling
- Ice sheets/glaciers covering 1/3 of continental ice mass
- Advancing ice destroys forest and grassland - less water in biosphere
- Drier climate in tropics - forest replaced by desert
75
how much of continetnal ice mass do ice sheets/glaciers cover in glacial periods?
1/3
76
what are the major long term changes in the carbon cycle during glacial periods?
- Decrease in CO2 in the atmosphere
- carbon store shrinks and carbon flux slows
77
what causes the long term change of CO2 decreasing in the atmosphere during glacial periods?
- CO2 goes into the deep ocean from the atmosphere. The changes in circulation means nutrients are brought to the surface and stimulate phytoplankton which fixes large amount of co2. It is then stored in the deep ocean when phytoplankton die
- CO2 is more soluble in surface waters at lower temperature
78
what causes the long term change of carbon store shrinking and carbon flux slowing during glacial periods?
- Deserts expand, tundra replaces temperate forests, grassland replaces rainforests
- Less carbon exchanged with atmosphere as much of the land surface is buried by ice and carbon is trapped in soils
- large amounts of carbon is sequestered in the permafrost
- NPP declines so less CO2 fixed due to low vegetation and low precipitation,and low temp
- less decomposition to return CO2 to atmosphere due to cold temp
79
in what categories are the water and carbon cycles linked?
- Atmosphere
- Oceans
- Vegetation and soil
- Cryosphere
80
how are the water and carbon cycles linked in the atmosphere?
- CO2 plays a rolein the greenhouse effect
- CO2 is absorbed from the atmosphere for photosynthesis
- plants store carbon and extract water from the soil
- CO2 is used for photosynthesis
- Water is transpired
81
how are the water and carbon cycles linked in the oceans?
- If CO2 exhanges aren't in balance, the ocean acidity increases
- Solubility of CO2 increases at low sea temperature
- Atmospheric CO2 levels infleunce the sea temp, thermal expansion, ice melting, higher sea levels
82
what happens if atmospheric CO2 is higher?
Higher sea temperature
More thermal expansion
More ice melting
Higher sea levels
83
how are the water and carbon cycles linked in the vegetation and soils?
- Water available affects photosynthesis,NPP, decomposition, transpiration (take in or release CO2)
- As organic content (carbon store) increases, soils can hold more water
- Water affects decomposition, which affects the release of CO2
84
how are the water and carbon cycles linked in cryosphere?
- CO2 levels will determine greenhouse effect, affecting melting of ice, permafrost, glaciers (i.e. the amount of water in stores)
- Higher CO2 levels mean more melting levels, less albedo, increased temp, affects runoff (positive feedback)
- permafrost melting begins decomposition which releases methane
85
what changes in the water cycle does human activities cause?
- rising population means higher demand for water - led to water shortages
- Colorado River Basin
- Quality of water supplies has also been affected (Bangladesh)
- Deforestation and urbanisation increase runoff, reduce throughflow, reduce water table - cause drier climates also
86
how many tonnes of carbon has fossil fuel consumption removed from geological stores?
Currently 8 billion tonnes/year
87
how much carbon does land-use change transfer into the atmosphere?
1 billion tonnes/year
88
what carbon stores are affected by human activity?
- Biosphere store
- Ocean store
- Soil store
- Wetland store
89
what impact does human activity have on the carbon biosphere store?
- Deforestation reduces forests by nearly 50% which reduces the amount of carbon stored in the biosphere
90
what impact does human activity have on the carbon ocean store?
Ocean acidification is threatening phytoplankton
91
what impact does human activity have on the carbon soil store?
- Deforestation, poor agricultural management and desertification is depleting the soil store due to soil erosion
92
what impact does human activity have on the carbon wetland store?
- Depleted as wetlands drained for land for agriculture or building
93
