Water And Carbob Cycles- PMT Essential Notes Flashcards
(219 cards)
1
Q
What are the main components of a system?
A
Inputs, Outputs, Stores, Flows, Boundaries
2
Q
Define an open system.
A
A system that receives inputs and transfers outputs of energy or matter with other systems
3
Q
Define a closed system.
A
A system where energy inputs equal outputs
4
Q
What is an isolated system
A
no interactions with anything outside the system bondary eg a lab experiment- not found in nature
5
Q
What is dynamic equilibrium in a system?
A
A state when inputs equal outputs despite changing conditions
6
Q
What occurs during positive feedback?
A
A chain of events that amplifies the impacts of the original event
7
Q
What occurs during negative feedback?
A
A chain of events that nullifies/counteracts the impacts of the original event
8
Q
Are the carbon and water cycles open or closed systems on a local scale?
A
Open systems
9
Q
Are the carbon and water cycles open or closed systems on a global scale?
A
Closed systems
10
Q
In a local drainage basin system, what is an example of an input?
A
Precipitation
11
Q
In a local drainage basin system, what are two examples of outputs?
A
- Evapotranspiration
- Streamflow
12
Q
What is evapotranspiration?
A
The combined return of water to the atmosphere from evaporation and transpiration
13
Q
List three stores of water in a local drainage basin system.
A
- Groundwater
- Soil Water
- Rivers
14
Q
What is interception in the context of water storage?
A
Water stored temporarily by trees before it reaches the ground
15
Q
Define infiltration.
A
Water moving from above ground into the soil
16
Q
What is percolation?
A
Water moves from the ground or soil into porous rock or rock fractures
17
Q
What is throughflow?
A
Flow of water through the soil
18
Q
What is surface runoff?
A
Water that flows over the ground surface
19
Q
Define groundwater flow.
A
Flow of water through the rocks
20
Q
What is stemflow?
A
Flow of water that has been intercepted by plants or trees down a stem, leaf, branch, or other part of a plant
21
Q
What is the water balance formula?
preciptiation = ……………… + ………….. +/- …………………
A
Precipitation = Total Runoff + Evapotranspiration +/- Storage
22
Q
Why is the water balance important?
A
It helps explain droughts or floods.
23
Q
What local factors impact the water cycle?
(ACDSSU)
A
Deforestation,
Storm Events,
Seasonal Changes,
Agriculture,
Urbanisation
24
Q
How does deforestation affect the water cycle?
A
It leads to less interception and soil that is less able to store water.
25
What effect do storm events have on the water cycle?
They increase runoff and water storage.
26
How do seasonal changes impact the water cycle?
Spring has more interception; snow reduces flows; hot weather reduces precipitation.
27
What is the impact of pastoral agriculture on the water cycle?
Livestock trampling reduces infiltration.
28
How does arable agriculture affect the water cycle?
Ploughing increases infiltration, while decreases increase runoff.
29
What is the effect of urbanisation on the water cycle?
Impermeable surfaces increase runoff.
30
What does the soil water budget show?
The annual balance between inputs and outputs in the water cycle.
31
When does soil water recharge occur?
In autumn, when precipitation exceeds evapotranspiration.
32
When is water utilized from the soil?
In spring and summer, when potential evapotranspiration is highest.
33
What happens when evapotranspiration exceeds precipitation?
Soil water stores deplete, leading to a deficit.
34
What is field capacity?
The maximum storage of water in the soil.
35
What factors affect the water budget?
Type, depth, and permeability of the soil and bedrock.
36
What are the four areas where water can be stored?
Hydrosphere, Lithosphere, Cryosphere, Atmosphere
37
What is the hydrosphere?
Any liquid water
38
What does the lithosphere refer to in terms of water storage?
Water stored in the crust and upper mantle
39
What is the cryosphere?
Any water that is frozen
40
What is the atmosphere in the context of water storage?
Water vapour
41
How long can shallow groundwater aquifers store water?
Up to 200 years
42
How long can deeper fossil aquifers last?
May last for 10,000 years
43
How long may glaciers store water?
20-100 years
## Footnote
This water may feed lakes that store water for 50-100 years.
44
How long does seasonal snow cover and rivers store water?
2-6 months
45
How long does soil water act as a temporary store?
1-2 months
46
What seasonal changes affect the water cycle?
Less precipitation and more evaporation in summer; reduced flows in winter as water is stored as ice
47
How does reduced interception occur in winter?
When deciduous trees lose their leaves
48
What increases evapotranspiration in summer?
Deciduous trees having their leaves and higher temperatures
49
How do farming practices impact the water cycle?
Ploughing increases infiltration;
arable farming increases interception and evapotranspiration;
pastoral farming compacts soil,
reducing infiltration and increasing runoff
50
What happens to precipitation and evaporation in summer?
Less precipitation, more evaporation due to higher temperatures.
51
What occurs to water flows in winter?
Reduced flows as water is stored as ice.
52
How does winter affect interception?
Reduced interception occurs when deciduous trees lose their leaves.
53
What is the effect of summer on evapotranspiration?
Increased evapotranspiration occurs as deciduous trees have their leaves and temperatures are higher.
54
How does ploughing affect soil infiltration?
Ploughing breaks up the surface, increasing infiltration.
55
What impact does arable farming have?
Arable farming can increase interception and evapotranspiration.
56
How does pastoral farming affect soil?
Pastoral farming compacts soil, reducing infiltration and increasing runoff.
57
What is the impact of deforestation on water processes?
Deforestation reduces interception and evapotranspiration, but increases infiltration.
## Footnote
Dead plant material in forests usually prevents infiltration.
58
How does construction affect water processes?
Construction **reduces infiltration and evapotranspiration, but increases runoff.**
59
What is water abstraction?
Water abstraction is the removal of water from stores for human use.
60
What is the effect of water abstraction on surface water stores?
Water abstraction reduces the volume of water in surface stores (e.g. lakes).
61
When does water abstraction typically increase?
Water abstraction increases in dry seasons, as water is needed for irrigation.
62
What is a consequence of human abstraction from aquifers?
Human abstraction from aquifers often exceeds inputs, leading to a decline in global long-term water stores.
63
What is the impact of deforestation on water processes?
Deforestation reduces interception and evapotranspiration, but increases infiltration.
## Footnote
Dead plant material in forests usually prevents infiltration.
64
How does construction affect water processes?
Construction reduces infiltration and evapotranspiration, but increases runoff.
65
What is water abstraction?
Water abstraction is the removal of water from stores for human use.
66
What is the effect of water abstraction on surface water stores?
Water abstraction reduces the volume of water in surface stores (e.g. lakes).
67
When does water abstraction typically increase?
Water abstraction increases in dry seasons, as water is needed for irrigation.
68
What is a consequence of human abstraction from aquifers?
Human abstraction from aquifers often exceeds inputs, leading to a decline in global long-term water stores.
69
What is a flood hydrograph?
A flood hydrograph represents rainfall for the drainage basin of a river and the discharge of the same river on a graph.
70
What are the key components of a flood hydrograph?
The key components include the rainfall and discharge of the river.
71
What characterizes a flashy flood hydrograph?
A flashy flood hydrograph has a
short lag time,
steep rising and falling limb,
higher flood risk, and
high peak discharge.
72
What characterizes a subdued flood hydrograph?
A subdued flood hydrograph has a long lag time, gradually rising and falling limb, lower flood risk, and low peak discharge.
73
What factors increase surface runoff and create a flashy hydrograph?
Factors include urbanization, deforestation, and steep slopes.
74
What effect does pastoral farming have on interception?
Ground trampled so less interception.
75
How does deforestation impact interception?
Deforestation leads to less interception.
76
What is the effect of high rainfall intensity on discharge potential?
Higher discharge potential.
77
What happens to surface runoff during antecedent rainfall?
Increased surface runoff as ground is saturated.
78
How does impermeable underlying geology affect infiltration?
Decreased infiltration.
79
What is the impact of high drainage density?
Many tributaries to main river.
80
What effect does pastoral farming have on interception?
Ground trampled so less interception.
81
How does deforestation impact interception?
Deforestation leads to less interception.
82
What is the effect of high rainfall intensity on discharge potential?
Higher discharge potential.
83
What happens to surface runoff during antecedent rainfall?
Increased surface runoff as ground is saturated.
84
How does impermeable underlying geology affect infiltration?
Decreased infiltration.
85
What is the impact of high drainage density?
Many tributaries to main river.
86
What is the carbon cycle?
The carbon cycle occurs on a local scale in a plant or sere such as the lithosere.
87
What is a lithosere?
A lithosere is a vegetation succession that occurs on bare rock.
88
How does soil build up in a lithosere?
Soil builds up on the rock from decaying organic matter.
89
What is the climatic climax?
The climatic climax is the final stage of a vegetation succession when the ecosystem can develop no further.
90
What is an example of a climatic climax?
An example of a climatic climax is when a woodland is formed.
91
What is photosynthesis?
Living organisms convert Carbon Dioxide from the atmosphere and Water from the soil into Oxygen and Glucose using Light Energy. This process removes CO2 from the atmosphere.
92
What is respiration?
The opposite of photosynthesis.
93
What does combustion do?
Releases CO2 into the atmosphere through burning fossil fuels, wildfires, etc.
94
What happens during decomposition?
When living organisms die, they are broken down by decomposers which respire, returning CO2 into the atmosphere. Some carbon is also returned to the soil.
95
What is diffusion in the context of carbon transfer?
The oceans can absorb CO2 from the atmosphere, but this harms aquatic life by causing coral bleaching.
96
What occurs during weathering and erosion?
Rock particles are broken down and transferred to the ocean, where the carbon is used by marine organisms to create shells.
97
What is burial and compaction?
Sea shell fragments become compacted over time to form limestone, and organic matter may form fossil fuels.
98
What is carbon sequestration?
Transfer of carbon from the atmosphere, which can be both natural and artificial.
99
What are the main carbon stores in order of magnitude?
1. Marine Sediments and Sedimentary Rocks (Lithosphere - Long-term)
2. Oceans (Hydrosphere - Dynamic)
3. Fossil Fuel Deposits (Lithosphere - Long-term but currently dynamic)
4. Soil Organic Matter (Lithosphere - Mid-term)
5. Atmosphere (Dynamic)
6. Terrestrial Plants (Biosphere - Mid-term but very dynamic)
100
What is the lithosphere's role in carbon storage?
The lithosphere is the main store of carbon, with global stores unevenly distributed.
101
Where is carbon storage mainly found in the biosphere?
Storage in the biosphere mostly occurs on land.
102
Where is terrestrial plant storage focused?
Terrestrial plant storage is focused in the tropics and the northern hemisphere.
103
What is the effect of wildfires on carbon?
Wildfires transfer carbon from the biosphere to the atmosphere as CO2 is released through burning.
## Footnote
Wildfires can encourage the growth of plants in the long term.
104
How does volcanic activity affect carbon storage?
Volcanic activity releases carbon stored within the earth during eruptions, mainly as CO2 gas.
105
What is the impact of fossil fuel use on carbon?
Fossil fuel use transfers CO2 to the atmosphere from a long-term carbon sink.
106
How does deforestation impact carbon storage?
Deforestation rapidly releases carbon stored in plants and interrupts the forest carbon cycle.
## Footnote
It is often used to clear land for farming or housing, using slash and burn techniques.
107
What is a consequence of arable farming?
Arable farming releases CO2 as animals respire.
108
How does ploughing affect CO2 levels?
Ploughing can release CO2 stored in the soil.
109
What role does farm machinery play in CO2 emissions?
Farm machinery such as tractors may release CO2.
110
What is the Carbon Budget?
The Carbon Budget is the balance between carbon inputs and outputs to a store at any scale.
## Footnote
E.g. The carbon budget in the atmosphere has inputs from respiration and combustion, but outputs including the oceans/photosynthesis.
111
What is a Carbon Source?
A Carbon Source is a store that emits more carbon than it absorbs.
## Footnote
E.g. a damaged rainforest.
112
What is a Carbon Sink?
A Carbon Sink is a store that absorbs more carbon than it emits.
## Footnote
E.g. a virgin rainforest.
113
What is the Enhanced Greenhouse Effect?
The Enhanced Greenhouse Effect is the process causing global warming due to high levels of greenhouse gases produced by humans.
114
How does the Enhanced Greenhouse Effect contribute to climate change?
It traps radiation from the sun, leading to global warming and climate change.
115
Why is it important to discuss the Enhanced Greenhouse Effect?
It is important to assess human impacts on the global climate.
116
What is the difference between the Enhanced Greenhouse Effect and the Greenhouse Effect?
The Greenhouse Effect is a natural process, while the Enhanced Greenhouse Effect is driven by human activities.
117
How do tropical rainforests impact regional climates?
High rates of photosynthesis and respiration in forests lead to greater humidity, cloud cover, and precipitation.
118
What is the effect of deforestation on the carbon cycle?
Deforestation reduces photosynthesis and respiration, further reducing humidity and cloud cover and decreasing precipitation.
119
How do warmer oceans affect plankton growth?
Warmer oceans cause more plankton growth.
120
What is the role of plankton in cloud formation?
Through plankton chemical production, clouds can potentially form.
121
What effect do wildfires have in hotter and drier climates?
Wildfires are more likely in hotter and drier climates due to global warming, which releases large quantities of CO2 into the atmosphere, increasing the warming effect.
122
How does melting ice affect global warming?
Ice reflects radiation from the sun, reducing surface warming. As sea temperatures rise and ice melts, the warming effect is amplified due to less ice reflecting radiation, leading to further melting.
123
What gases are released from thawing permafrost?
Higher temperatures are thawing the permafrost, releasing CO2 and methane, which has 20 times the warming effect of CO2, causing warming on both local and global scales.
124
What is the cycle of permafrost melting and gas release?
Higher temperatures cause more permafrost to melt, leading to further gas releases and additional warming.
125
How does increased vegetation affect CO2 levels?
Increased photosynthesis by plants and rising global temperatures allow vegetation to grow in new areas, such as where permafrost has melted, absorbing CO2 from the atmosphere and decreasing the warming effect.
126
What is carbon fertilization in plants?
Higher temperatures and more CO2 cause greater carbon fertilization in plants, allowing them to absorb more CO2, reducing CO2 levels and rates of warming.
127
How do phytoplankton contribute to cloud formation?
Phytoplankton photosynthesize to gain energy, and warmer oceans and more sunlight boost this process, leading to the production of a chemical that causes cloud formation.
128
What is the effect of increased cloud cover on warming?
Increased cloud cover decreases warming by the sun, while more photosynthesis reduces CO2 levels, further reducing warming.
129
What happens when phytoplankton growth decreases?
When phytoplankton grow less quickly, less of the chemical is produced, decreasing cloud cover and continuing the cycle.
130
What happens to precipitation in a natural rainforest water cycle?
75% is intercepted by trees; 35% reaches the ground and infiltrates the soil, while another 35% is used by plants and returns to the atmosphere through transpiration.
## Footnote
25% evaporates almost immediately and returns to the atmosphere.
131
What is the effect of deforestation on the water cycle?
Most precipitation reaches the ground immediately with little vegetation to intercept it, leading to high surface runoff and a higher flooding risk.
## Footnote
Less evapotranspiration results in a less humid atmosphere and decreased rainfall.
132
How do trees contribute to the carbon cycle in a natural rainforest?
Trees promote photosynthesis, absorbing large amounts of oxygen and acting as an important carbon sink.
## Footnote
Decomposition and respiration release CO2 back to the atmosphere and soil.
133
What are the consequences of deforestation on the carbon cycle?
Photosynthesis is reduced due to the lack of trees, and fires to clear land release CO2 into the atmosphere, turning forests into a carbon source instead of a carbon sink.
## Footnote
There are low rates of decomposition and a lack of life until new plants grow.
134
How does rain over intact tropical rainforest affect deforested land?
Rain may fall over deforested land due to wind, causing erosion, with soil and ash flowing into rivers, increasing the carbon content of rivers. The water leaves the rainforest cycle as an output through streamflow due to reduced interception and increased surface runoff.
135
What is the effect of deforestation on rainfall in intact forests?
There is reduced rainfall in the intact forest, as there is less evapotranspiration in the deforested area, causing drought periods and the deterioration of the intact rainforest.
136
What impact does deforestation on peatlands have on water storage?
Deforestation on peatlands and the digging of drainage channels reduces water storage. The organic peat matter decomposes quickly, releasing CO2 into the atmosphere.
137
What are the consequences of increased weathering and erosion in deforested areas?
Weathering and erosion increase, speeding up decomposition. There is a greater wildfire risk from the hotter temperatures.
138
How can blocking drainage ditches in peatland rainforests help restore the environment?
Blocking drainage ditches helps restore the natural environment by increasing soil water storage and decreasing runoff. This can raise the water table and decrease the flood risk.
139
How does a managed forest compare to a virgin forest in terms of CO2 sequestration?
A managed forest is often less effective at sequestering CO2 than a virgin forest.
140
What is the aim of the Paris Climate Deal (COP21)?
To limit global temperatures to 2°C above pre-industrial levels.
141
What support does the Paris Climate Deal provide?
Support for developing countries.
142
How often does the Paris Climate Deal meet to review goals?
Every 5 years.
143
What are the targets of the EU 20-20-20 initiative?
20% reduction in GHG emissions, 20% of energy from renewable sources, and 20% increase in energy efficiency by 2020.
144
What additional commitment has the EU suggested regarding emissions reduction?
To increase emissions reduction to 30% if major GHG producing countries improve their targets.
145
What is the target set by the Climate Change Act 2008 in the UK?
To reduce GHG emissions by 80% of 1990 levels by 2050, with a target of 34% by 2020.
146
What was created to help the UK government with climate change progress?
National carbon budgets and the Independent Committee on Climate Change.
147
What are some local scale interventions for mitigating climate change?
Improving home insulation, recycling, using energy wisely, using smart meters, public transport, and car sharing schemes.
148
What is a flow/ transfer
when matter or energy moves from one store to another
149
What is an Input
when matter or energy is added to the system
150
What is a store/component
where matter or energy builds up
151
What is matter
any physical substance involved in a system
152
What is output
when matter or energy leaves the system
153
Why is a drainage basin an example of an open system
as energy from the sun enters and leaves the system
water is an input as precipitation and an output as river discharge into the sea
154
Why is the carbon cycle as closed system
energy is an input- eg from the sun by photsyntheis
and output for respiration
but the amount of carbon on earth stays the same because there are no inputs or outputs of matter
155
What does positve feedback mean
means the system responds by **increasing the effects of the change,** moving the system even further from its previous state.
156
What does negative feedback mean
negative feedback means the system responds by **decreasing the effects of the change**, keeping the system closer to its previous state
trying to restore equilibrium
157
Input
output
energy
in a drainage basin example
Input- precipitation
output- runoff
energy - latent heat associated with changes in state of water
158
Input
output
energy
Woodland and carbon cycle example
Input- precipitation with dissolved CO2
output-dissolved carbon within runoff
energy- production of glucose via photosynthesis
159
Stores/ components
Flows/ transfers
Example for a drainage basin
Stores/ components- trees,puddles, soil
Flows/ transfers- Infiltration, groundwater flow, evaporation
160
Stores/ components
Flows/ transfers
For a wooldand or carbon cycle
Stores/ components- Trees, soil, rocks
Flows/ transfers- burning, absorption
161
Positive feedback for drainage basin
Rising sea levels (due to thermal expansion and melting of freshwater ice) can destabilise ice shelves, increasing the rate of calving
This leads to an increas in melting, causing sea levels to rise further
162
Positive feedback example for woodland or carbon cycle
Increased temperatures due to climate change cause permafrost melting.
Trapped greenhouse gases are released, enhancing the greenhouse effect raising temp more
163
Negative feedback example for drainage basi
Increased surface temps lead to increases in evaporation from the oceans.
This leads to more cloud, which reflect the sun, which leads to cooling surface temps
164
Negative feedback example for carbon cycle/ woodland
Increase atmospheric CO2 leads to warmer temps, more plant growth and photosyntheis.
This removes CO2 from the air, counteracting the rise in temp
165
Where is the largest store of total global water?
Oceans - 96.5%
166
Where is the largest store of freshwater
Glaciers and ice caps
68.7%
167
Where is the largest store of surface water and other freshwater
Ground ice and permafrost- 69%
168
What is evaporation
occurs when water changes from a liquid to a gas
increases the amount of water stored in the atmosphere
169
When are rates of evaporation high?
when there is **higher levels of solar radiation**- as heat energy is needed to break bonds between water molecules
**-higher temperatures**- warm air holds more moisture
-**a large supply of water**- eg over the oceans
**-dry air-** if evaporation exeeds condensation, air will become saturated (cant hold more water) and relative humidity is 100%
170
Condesnation
when water vaport in the air changes into liquid water
happens when air cools to its dew point temperature
171
Cloud formation (6 marker)
Clouds form when air rises and cools to its dew point tempearture, leading to condensation.
As air rises, the surrounding presure decreases, causing the air to expand and cool by adiabatic cooling
When air cools to the dew point, it becomes saturated
Wter vapour condeses onto condensation nuclei in the atmoshphere
This forms tiny water droplets or ice ctystals, which group together to form clouds.
172
What is adiabatic cooling
air cools as it rises without losing heat to the environment
173
What is dew point
temperature when air becomes saturated
174
What is condensation nuclei
tiny particles that water vapor condenses onto
175
What is latent heat
energy released when water vapour condenses
176
Crysotheric process at hill slope- freeze-thaw weathering
1- freeze-thaw weathering- water enters cracks- freezes- expands- breaks rocks
-produces scree at hill base
177
Crysotheric process at hill slope- Frost creep
Soil particles lift during freezing- settle slightly downhill when thawing
very slow but shapes hilllslopes
178
Crysotheric process at hill slope- solifluction
thawed, watterlogged soils slowly flow downhill
leaves lobes (bulging shapes) on slopes
179
Crysotheric process at hill slope- Nivation
freeze-thaw, solifluction and chemical weathering happen under snow patches
creates small hollows on slopes
180
What is scree
a collection of loose, broken rock fragments that accumulate on a slope or at the base of a cliff or hill
181
What is convectionbal Precipitation at hill slope
sun heats ground- ground heats air above it
warm air rises (less dense)
as air rises is cools
water vapur condenses- forms clouds- leading to heavy showers/thunderstroms
common in tropical areas and uk summer thunderstorms
Key for hil slopes- sudden heavy rainfall= increased overland flow= risk of flash floods
182
What is Orographic (Relief) Precipitation at hill slope
air forced to rise over mountains or hills
Rising air cools, condenses and causes rainfall on the windward side
The leeward side (sheltered side) 0 is often dry = rain shadow
key for hill slopes= hillslopes facing wind get higher rainfall= more erosion, more landsliding
183
What is Frontal precipitation at a hillslope
Happens when two air masses meet (cold meets warm air)
warm air forced to rise over dense cold air
rising warm air cools- clouds and rain
common in uk especially with depressions (low pressure systems)
key for hillsopes
long periods of rain= waterlogging of soils = greater mass movement risk
184
Concept of water balance
The water balance is used to express the process of water storage and transfer in a drainage
basin system and uses the formula:
Precipitation = Total Runoff +Evapotranspiration +/- Storage
185
Explain drouts or using the water balance
Drough- occursc when precipitation is lower than evapotranspiration for a prolongued period
leads to a deficit in the water balance:
-water storage gets used up
-river flows and reservoir levels drop
soils dry out and vegetation struggles
on a water balance graph- see a negative balance with lines hsowing soil moisture deficit
186
Explain floods using the water balance
Floods happen when precipitation is greater than evapotranspiration and ground/storage is already saturated
creates surplus in water balance
-soils are full-new rainful become surface runoff
-rivers swell rapildy and can overflow
on a water balance graph you would see a positive balance, with soil moisture surplus
187
What is the water cycle impacted by on a local scale
● **Deforestation** - Less interception.
Soil less able to store water
**● Storm Events** - Increases runoff and
water storage
**● Seasonal Changes** - More
interception in spring; Snow reduces
flows; Hot weather reduces
precipitation
● **Agriculture** - Pastoral (Livestock)
ground trampled so less infiltration;
Arable (Crops) - Ploughing increases
infiltration. Ditches increase runoff
●** Urbanisation -** Impermeable surfaces
increase runoff
188
What is the The carbon budget and and an example of the atmosphere
The Carbon Budget is the balance between carbon inputs and outputs to a store at any scale:
E.g. The carbon budget in the atmosphere has inputs from respiration and combustion,
but outputs including the oceans/photosynthesis
189
The key role of the carbon and water stores and cycles in supporting life on Earth with particular reference to climate
The relationship between the water cycle and carbon cycle in the atmosphere
190
The role of positive feedback and link to climate change and implications for life on Earth .
Positive Feedback:
● Wildfires are more likely in hotter and drier climates due to global warming, which release
large quantities of CO2 into atmosphere, which in turn then increases the warming effect
● Ice reflects radiation from the sun, reducing surface warming. As sea temperatures rise
and ice melts, the warming effect is amplified as there is less ice to reflect the radiation.
Further melting occurs and the process continues
● Higher temperatures are thawing the permafrost releasing CO2 and methane (which
has 20 times the warming effect of CO2), causing warming on a local and global scale. The
higher temperatures cause more permafrost to melt, causing further gas releases and
further warming
191
The role of negative feedback and link to climate change and implications for life on Earth .
Negative Feedback:
● Increased photosynthesis by plants and rising global temperatures allows vegetation to
grow in new areas, e.g. where permafrost has melted. New vegetation absorbs CO2 from
the atmosphere, decreasing the warming effect
● Higher temperatures and more CO2 cause a greater carbon fertilisation in plants, so
they absorb more CO2, reducing the levels of CO2 and the rates of warming and then the
carbon fertilisation, if temperatures decline. The process repeats
● Phytoplankton photosynthesise to gain energy and warmer oceans and more sunlight
due to climate change boost this and the production of a chemical by the plankton
which causes cloud formation. Increased cloud cover decreases warming by the sun and
more photosynthesis reduces CO2 levels, reducing the levels of warming. The plankton
grow less quickly and less of the chemical is increased decreasing cloud cover. The cycle
continues
192
What does the soil water budget show
The soil water budget shows the annual balance between inputs and outputs in the water cycle.
The soil water budget also shows how inputs and outputs impact soil water storage and
availability.
193
What happens to water throughout the months
There is a **surplus of water in the winter** months, after recharge of soil water in autumn. **Soil water
is recharged in autumn** because the inputs of precipitation exceed the outputs of
evapotranspiration (because it rains more and it is cooler).
**The water is utilised in spring and summer**, when potential evapotranspiration of plants is highest
due to warmer weather.
The stores are depleting when evapotranspiration is greater than precipitation . This can lead
to a deficit of soil water.
194
What is field capacity
Maximum storage of water in the soil is field capacity
195
What is the water budget dependenbt on?
The water budget is dependent on type,
depth and permeability of the soil and bedrock.
196
Seasonal changes in the water cycle
Seasonal Changes:
● Less precipitation, more evaporation in summer because of higher temperatures
● Reduced flows in winter as water is stored as ice
● Reduced interception in winter, when deciduous trees lose their leaves
● Increased evapotranspiration in summer; deciduous trees have their leaves/higher
temperatures
197
How does farming impact water cycle
Farming Practices:
● Ploughing breaks up the surface, increasing infiltration
● Arable farming (crops) can increase interception and evapotranspiration
● Pastoral (animal) farming compacts soil, reducing infiltration and increasing runoff
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How does land use change effect the water cycle
Land Use Change:
● Deforestation (e.g. for farming) reduces interception, evapotranspiration and but infiltration
increases (dead plant material in forests usually prevents infiltration)
● Construction reduces infiltration and evapotranspiration, but increases runoff
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How does water abstraction affect water cycle
This reduces the volume of water in surface stores (e.g. lakes).
● Water abstraction increases in dry seasons (e.g. water is needed for irrigation)
● Human abstraction from aquifers as an output to meet water demands is often greater than
inputs to the aquifer, leading to a decline in global long-term water stores
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What is a flood hydrograph
A flood hydrograph is used to represent rainfall for the drainage basin of a river and the
discharge of the same river on a graph.
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Characteristics of a flashy hydrograph
Flashy:
● Short lag time
● Steep rising and falling limb
● Higher flood risk
● High peak discharge
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Characteristics of a subdued hydrograph
Subdued:
● Long lag time
● Gradually rising and falling limb
● Lower flood risk
● Low peak discharge
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factors which would increase surface runoff of a river and therefore act to create a
flashy hydrograph
Pastoral Farming - Ground trampled so less interception
● Deforestation - Less interception
● High Rainfall Intensity - Higher discharge potential
● Antecedent Rainfall - Increased surface runoff as ground is saturated
● Impermeable Underlying Geology - Decreased infiltration
● High Drainage Density - Many tributaries to main river
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Where does the carbon cycle occur on a local scale and how does it create a woodland
The carbon cycle occurs on a local scale in a plant, or sere such as the lithosere, which is a
vegetation succession that occurs on bare rock.
Over time a soil builds up on the rock from
decaying organic matter
The climatic climax (final stage of a vegetation succession) is
achieved when the ecosystem can develop no further. E.g. when a woodland is formed.
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Transfers of the carbon cycle on a global scale
Transfers:
● **Photosynthesis** - Living organisms convert Carbon Dioxide from the atmosphere and
Water from the soil, into Oxygen and Glucose using Light Energy. This removes CO2
from the atmosphere
● **Respiration -**
● **Combustion **
● **Decomposition -**
● **Diffusion** - The oceans can absorb CO2 from the atmosphere, but this harms aquatic life
by causing coral bleaching
● **Weathering and Erosion** - Rock particles broken down and transferred to the ocean,
where the carbon is used by marine organisms to create shells
●** Burial and Compaction **- Sea shell fragments become compacted over time to form
limestone and organic matter may form fossil fuels
● **Carbon Sequestration** - Transfer of carbon from the atmosphere and can be both natural
and artificial
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What is combustion
(Burning fossil fuels, wildfires etc.) - Releases CO2 into the atmosphere
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What is decomposition
When living organisms die, they are broken down by decomposers
which respire, returning CO2 into the atmosphere. Some carbon is also returned to the
soil
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What is the main store of carbon
The lithosphere is the main store of carbon
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What natural process change the carbon cycle over time
Wildfires: Transfer carbon from biosphere to atmosphere as CO2 is released through burning.
Can encourage the growth of plants in the long term
Volcanic Activity: Carbon stored within the earth is released during volcanic eruptions, mainly
as CO2 gas
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What human impacts can change the carbon cycle over time
Human Impacts
**Fossil Fuel Use** - Combustion transfers CO2 to the atmosphere from a long-term carbon sink
**Deforestation** - Often used to clear land for farming/housing, rapidly releases carbon stored in
plants using slash and burn techniques and interrupting the forest carbon cycle
**Farming Practices** - Arable farming releases CO2 as animals respire. Ploughing can release
CO2 stored in the soil. Farm machinery such as tractors may release CO2.
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What is a carbon source
A store that emits more carbon than it absorbs:
E.g. a damaged rainforest
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What is a carbon sink
Carbon Sink - A store that absorbs more carbon than it emits:
E.g. a virgin rainforest
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What is the enhanced greenhouse effect
The Enhanced Greenhouse Effect is the process that is currently causing global warming as
abnormally high levels of greenhouse gases are being produced by humans, trapping radiation
from the sun, causing global warming and leading to climate change
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Impact of the Carbon Cycle on tropical rainforests
Tropical Rainforests:
● High rates of photosynthesis and respiration in forests lead to greater humidity, cloud
cover and precipitation
● Deforestation reduces photosynthesis and respiration, further reducing humidity and
cloud cover and decreasing precipitation
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Impact of the Carbon Cycle on oceans
Oceans:
● Warmer oceans cause more plankton growth and through plankton chemical
production, cause clouds to potentially form
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Mitigating climate change with Global intervention- Paris climate deal
Global Intervention - Paris Climate Deal (COP21):
● Aim to limit global temperatures to 2°C above pre-industrial levels
● Support for developing countries
● Public interaction and awareness schemes
● Meet every 5 years to review and improve goals
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Mitigating climate change- regional intervention EU 20-20-20
Regional Intervention - EU 20-20-20:
● 20% reduction in GHG emissions and commitment to 20% of energy coming from
renewable sources and 20% increase in energy efficiency by 2020
● EU has suggested it will increase its emissions reduction to 30% if major GHG
producing countries also improve their targets
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Mitigating climate change- national intervention - Climate change act 2008 UK
National Intervention - Climate Change Act 2008 UK:
● Legally binding target for the UK to reduce GHG emissions by 80% of 1990 levels by
2050 with a target of 26% by 2020 which has recently increased to 34%
● Created national carbon budgets and the Independent Committee on Climate Change
to help the government and report on progress that is being made
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Mitigating climate change- on a local scale
Local Scale:
● Improving home insulation
● Recycling
● Using energy more wisely and use of smart meters and using public transport or car
sharing schemes and calculating personal carbon footprints
