Water and Carbon Flashcards
1
Q
What are systems composed of?
A
- inputs: matter or energy that is added to the system
- outputs: matter or energy that leaves the system
- flows: matter or energy that moves in a system
- boundaries: limits to the system (e.g. watershed)
2
Q
What are open systems?
A
Systems which have inputs and outputs of both energy and matter.
3
Q
What are closed systems?
A
Systems which have inputs and outputs of energy only.
4
Q
What are isolated systems?
A
Systems which have no inputs or outputs of energy or matter.
5
Q
What is the balance of a system?
A
The difference between the inputs and outputs.
6
Q
What is a positive balance?
A
When inputs exceed outputs.
7
Q
What is a negative balance?
A
When outputs exceed inputs.
8
Q
When is a system in equilibrium?
A
When inputs and outputs are equal.
9
Q
What are some characteristics of systems?
A
- systems are a generalisation of reality - often more complex than the system makes out
- they have a structure that is defined by its parts and processes
- systems tend to function in the same way, involving inputs and outputs of material that is then processed causing it to change in some way
- the various parts of a system have a relationship with each other
- the fact that functional relationships exist between the parts suggest the flow and transfer of some type of energy/matter
10
Q
What is positive feedback?
A
A chain of events that amplifies the original event.
11
Q
What is an example of positive feedback in the water cycle?
A
Water evaporates from the ocean, water vapour is a greenhouse gas so atmospheric greenhouse gas increases, this leads to warming, leading to more evaporation.
12
Q
What is an example of positive feedback in the carbon cycle?
A
Permafrost begins to melt in the arctic tundra, transferring methane from the lithosphere to the atmosphere. As methane is a greenhouse gas, the enhanced greenhouse effect will become more pronounced, leading to more permafrost melting.
13
Q
What is negative feedback?
A
A chain of events that dampens the impacts of the original event, leading to a dynamic equilibrium.
14
Q
What is an example of negative feedback in the water cycle?
A
As ice sheets melt, there is more water vapour in the atmosphere, leading to increased cloudiness. Because clouds reflect 1/3 rd of incoming solar radiation, there will be less energy absorption on the earth’s surface, decreasing the rate of ice sheet melt.
15
Q
What is an example of negative feedback in the carbon cycle?
A
An increase in atmospheric carbon dioxide leads to a faster rate of photosynthesis, expanding the biosphere and decreasing atmospheric carbon dioxide.
16
Q
What is dynamic equilibrium?
A
A systems tendency to restore equilibrium state after a change.
17
Q
What is an example of dynamic equilibrium in the water cycle?
A
Water evaporates from the hydrosphere’s surface, it rises and cools condensing into clouds. When these clouds are large enough, the water will be returned to the hydrosphere through precipitation.
18
Q
What is an example of dynamic equilibrium in the carbon cycle?
A
Humans burn fossil fuels, increasing global temperatures. This encourages more plant growth, which takes in more carbon dioxide, reducing global temperatures.
19
Q
What is the largest store of water?
A
The oceans, which contain 97% of global water.
20
Q
What percentage of water stores are fresh water?
A
2.5%
21
Q
What percentage of freshwater is found in the cryosphere?
A
69%
22
Q
What percentage of freshwater is groundwater?
A
30%
23
Q
What percentage of freshwater is made up of surface and other freshwater (permafrost, lakes, swamps, marshes, rivers, biosphere)
A
1%
24
Q
How long do deep/shallow aquifers store water for?
A
Shallow - up to 200 years
Deep fossil aquifers - 10,000 years
Aquifers are underground water stores and are unevenly distributed on a global scale.
25
How long do glaciers store water for?
20-100 years
26
What is evaporation?
The process whereby liquid water changes into a gas when it absorbs heat energy.
27
How does evaporation drive change in the magnitude of water stores?
- approximately 90% of the atmospheric water store is from evaporation from the oceans and seas. The remaining 10% comes from plant transpiration.
- high levels of evaporation can occur in some tropical and desert areas. These are regional scale changes. Increased global changes are likely to occur due to climate change and increased atmospheric temperature.
- The level of evaporation on a global scale ocean and sea level is minimal, but within a drainage basin evaporation can have a large regional scale impact. Lakes or rivers in an area with a high maximum summer temperature will experience high levels of evaporation and hydrospheric storage will reduce significantly in this area.
28
What is condensation?
The process whereby the gaseous water vapour changes back into liquid water within the atmospheric water store.
29
How does condensation drive change in the magnitude of water stores?
Tiny, microscopic water molecules that develop around dust and smoke particles (aka aerosols) will be carried invisibly in the air. Where they combine into larger molecules of liquid ware or ice they may be seen as mist, fog, or clouds. This occurs on a global scale but could alter as climate change increases global atmospheric temperature.
30
How does cloud formation drive change in the magnitude of water stores?
Clouds form when water molecules aggregate. They are frequently noticed at the altitude where air temperature has fallen to a point where condensation of invisible water vapour occurs (condensation - or dew point), or where the humidity content has risen such that water cannot remaining in that state and condenses. As the molecules grow, clouds form with the tiny water or ice particles kept aloft by rising air currents (thermals).
31
What are cryospheric processes?
Processes that affect the total mass of ice at any scale from local patches of frozen ground to global ice amounts.
32
How do cryospheric processes act at hill slope?
Ice forms from the compression of falling snow. As layer upon layer of snow is added it can exert a pressure on the snow at the base, compressing that snow and forcing air out of it. This will slowly form a denser substance called Névé and eventually ice. Melting and refreezing of previously fallen snow can also assist in this process.
33
How do cryospheric processes act in a drainage basin?
Cryospheric changes affect hydrological processes not only in the increase or decrease of runoff, but also in its seasonal distribution, thereby affecting the use of water resources.
34
How do cryospheric processes act globally?
Cryospheric changes cause global sea-level change and also global water-cycle processes. Cryospheric changes impact the ocean–freshwater balance, which drives the ocean thermohaline circulation, and thus global ocean circulation.
35
What is precipitation?
Any water that falls to the earth's surface from the atmosphere including rain, snow, and hail.
36
What causes convectional rainfall?
Due to heating by the sun, warm air rises and then cools and condenses at higher altitudes, then falls as rain.
37
What causes orographic rainfall
Warm air is forced upwards by a barrier such as a mountain, causing it to condense at a higher altitude and fall as rain.
38
What causes frontal rainfall?
A warm air mass rises over a cooler, denser air mass. It condenses at a higher altitude and falls as rain.
39
What are the outputs to the drainage basin?
Evapotranspiration and streamflow.
40
What is evapotranspiration?
Composed of evaporation and transpiration, it occurs in plants when they respire through their leaves, releasing water they absorbed through their roots when it evaporates from their leaves.
41
What is streamflow?
Water leaving the basin in streams. They may flow as tributaries into other rivers or directly into lakes and oceans.
42
What are the flows in the drainage basin?
- infiltration
- overland flow
- percolation
- throughflow
- groundwater flow
- streamflow
- stemflow
43
What is infiltration?
The process of water moving from above ground into the soil. The infiltration capacity refers to how quickly the infiltration can occur.
44
What is overland flow?
When precipitation falls at a greater rate than the infiltration capacity, water flows above ground as sheetflow (lots of water flowing over a large area) or rills (small channels similar to streams that are unlikely to carry any water when there is not any rainfall).
45
What is percolation?
Water moving from the ground/soil into porous rocks or fractures. The percolation rate is dependent on the fractures present and the permeability of the rock.
46
What is throughflow?
Water moving thorough the soil into streams and rivers. The speed is dependent on the type of soil. Sandy soils drain quickly because they have a low field capacity, large pore spaces, and natural channels from animals such as worms.
47
What is groundwater flow?
Water moving through the rocks.
48
What is stemflow?
Flow of water that has been intercepted by plants down a stem, leaf, branch, or other part of a plant.
49
What are the stores in a drainage basin?
- soil water: water which is stored in the soil and utilised by plants
- groundwater: water which is stored in the pore spaces of rocks
- river channel: water that is stored in a river
- interception: water which is intercepted by a plants branches and leaves before it reaches the ground
- surface storage: water stored in puddles, ponds, lakes, etc.
50
What is the water balance equation?
Precipitation = Total runoff + evapotranspiration + change in storage
Water balance is used to express the process of water storage and transfer in a drainage basin.
51
What is discharge in a hydrograph?
The volume of water passing though a cross-sectional point of a river at any one point in time, measured in cubic metres per second (CUMECS). It is made up of the base flow and stormflow.
52
What is the rising limb of a flood hydrograph?
The line on the graph which represents the discharge increasing.
53
What is the falling limb of a flood hydrograph?
The line on the graph which represents the discharge falling.
54
What is lag time?
The difference between peak rainfall and peak discharge.
55
What is baseflow?
The level of groundwater flow.
56
What is stormflow?
Overland flow and throughflow.
57
What is bankfull discharge?
The maximum capacity of the river. If the river exceeds this then it will burst its banks and be in flood.
58
What are the characteristics of flashy hydrographs?
- short lag time
- steep rising and falling limb
- higher flood risk
- high peak discharge
59
What are the characteristics of subdued hydrographs?
- long lag time
- gradual rising and falling limb
- lower flood risk
- low peak discharge
60
What natural factors make a flashy hydrograph more likely?
- High intensity rainfall - higher discharge potential from river as it is more likely for the soil to reach its field capacity, increasing runoff and decreasing lag time
- Prior rainfall - increased surface runoff as soil is already saturated/reached field capacity
- Impermeable bedrock - decreased percolation leading to more throughflow
- Many tributaries - increases speed of drainage, decreasing lag time
- Small basin - water reaches the river quicker, decreasing lag time
- Low temperature - less evapotranspiration leading to greater peak discharge
- Vegetation cover - forested areas intercept rainwater, decreasing lag time
61
What human factors make a flashy hydrograph more likely?
- Urbanisation - more impermeable surfaces, increasing runoff and reducing infiltration and surface storage
- Pastoral farming - ground trampled so less interception and more surface runoff
- Deforestation - less interception by trees, so water reaches ground and river quicker
62
What does the soil water budget show?
The annual balance between inputs and outputs in the water cycle and their impact on soil water storage/availability. The budget is never the same due to varying conditions year on year and the process is affected by how much rainfall their is in the previous year.
63
What does the soil water budget depend on?
Type, depth, and permeability of the soil and bedrock.
64
What is the soil field capacity?
The maximum possible level of storage of water in the soil.
Once the field capacity is reached, any rainfall after this will not infiltrate the soil and is likely to cause flooding.
65
What is the soil water budget like in the autumn?
There is a greater input form precipitation than there is an output from evapotranspiration as deciduous trees lose their leaves and the cooler temperatures mean that the plants photosynthesise less. Soil moisture levels increase and water surplus occurs.
66
What is the soil water budget like in the winter?
Potential evapotranspiration from plants reaches a minimum due to the colder temperatures and the precipitation continues to refill the soil water stores. Infiltration and percolation will also refill the water table.
67
What is the soil water budget like in the spring?
Plants start to grow again and potential evapotranspiration increases with temperature and plants are photosynthesising more. There is still a water surplus.
68
What is the soil water budget like in the summer?
The hotter weather leads to utilisation of soil water as evapotranspiration peaks and rainfall is at a minimum. The output from evapotranspiration is greater than the input from precipitation so the soil water stores are depleting. A water deficit may occur if there is a long hot summer and spring, a lack of winter rainfall, or a drought the year before.
69
How does the inter-tropical convergence zone change the water cycle over time?
The global atmospheric circulation model is the main factor that determines cloud formation and rainfall. There are different zones of rising and falling air which lead to precipitation through convectional rainfall. This creates a low pressure zone along the equator which has very heavy rainfall and is partially responsible for monsoons. This zone moves with the seasons as the sun's position changes. Unstable weather occurs where the ferrel and hadley cells meet, and this weather is moved by the jet stream which is responsible for the UKs changeable weather.
70
What natural processes change the water cycle over time?
- seasonal changes
- storm events
- droughts
- El Nino and La Nina
- cryospheric processes
71
How do seasonal changes change the water cycle over time?
- less precipitation, more evapotranspiration in the summer because of higher temperatures
- reduced flows in the water cycle in winter as water is stored as ice
- reduced interception in winter when deciduous trees lose their leaves
72
How do storm events change the water cycle over time?
Cause sudden increase in rainfall, leading to flooding and replenishment of some water stores.
73
How do droughts change the water cycle over time?
Cause major stores to be depleted and the activity of flows to decrease. They may cause long term change as they become more frequent through climate change.
74
How do El Nino and La Nina cause change in the water cycle?
- They occur every 2-7 years and cause change in a predictable way
- El Nino weakens the trade winds, which means warmer waters are pushed towards the Americas. This causes the pacific jet stream to move south, leading to wetter conditions in the southern US and drier, warmer conditions in the northern US and Canada.
- La Nina strengthens the trade winds, pushing the warm water towards Asia. This pushes the pacific jet stream northwards, leading to drought in the southern US and heavy rain/flooding in northern US and Canada.
75
How do cryospheric processes lead to change in the water cycle over time?
In the past glaciers and icecaps have stored significant proportions of freshwater through the process of accumulation. Almost all of the world's glaciers are shrinking, leading to sea level rise.
76
What human processes cause change in the water cycle over time?
- Farming practices
- Land use change
- Water abstraction
77
How do farming practices lead to changes in the water cycle over time?
- ploughing breaks up the surface, leading to infiltration
- arable farming can increase interception and evapotranspiration
- pastoral farming compacts soil, decreasing infiltration and increasing runoff
- irrigation removes water from local rivers, decreasing their flow
78
How does land use change lead to changes in the water cycle over time?
- deforestation decreases interception and evapotranspiration, but increases infiltration as dead material on the forest floor usually prevents infiltration
- construction reduces infiltration and evapotranspiration, but increases runoff
79
How does water abstraction lead to changes in the water cycle over time?
- reduces volume of water in surface stores
- water abstraction increases dry season
- humans abstract water from aquifers at a greater rate than water is input into the aquifers, leading to a decline in global long-term water stores.
80
What is a carbon sink?
Any store which takes in more carbon than it emits, for example an intact rainforest.
81
What is a carbon source?
Any store that emits more carbon than it stores, for example a damaged rainforest.
82
What is the largest store of carbon?
Marine sediments and sedimentary rocks
83
Which sphere is the main store of carbon?
The lithosphere
84
Why is the distribution of carbon globally uneven?
The oceans are larger in the southern hemisphere, and the storage in the biosphere mostly occurs on land. Terrestrial plant storage is focussed in the tropics and northern hemisphere. Different amounts of carbon are stored worldwide.
85
Where in the world are forests declining the most?
The southern hemisphere. Brazil and Indonesia have seen a decrease in carbon stores of around 5 GT in the past 25 years.
86
Where in the world are forests increasing the most?
The northern hemisphere. Russia, USA, and China have all seen an increase of around 2 GT in the past 25 years.
87
How is the amount of forested land changing?
- Non tropical forests have seen an increase in carbon sequestration in recent years, especially in Europe and Eastern Asia due to conversion of agricultural land and plantations to new forests
- Forests in industrialised regions are expected to increase by 2050 but in the global south, forested areas will decrease
- Rate of forest loss has decreased from 9.5 million hectares per year in the 1990s to 5.5 million hectares per year in 2010-2015
- Brazil has the most carbon stored on land and the most extensive deforested area
- China has the largest amount of afforested area
88
What is photosynthesis?
Living organisms convert carbon dioxide from the atmosphere and water from the soil into oxygen and glucose using solar energy. Plants are sequestering carbon and reducing the potential impacts of climate change.
89
What is respiration?
Plants and animals convert oxygen and glucose into energy which produces the waste products of water and carbon dioxide. During the day, plants photosynthesise, absorbing more carbon than they emit from respiration. During the night they do not photosynthesise, but they do respire, releasing more carbon than they absorb. Overall, plants absorb more carbon than they emit.
90
What is combustion?
When fossil fuels and organic matter such as trees are burnt, they emit carbon dioxide into the atmosphere.
91
What is decomposition?
When living organisms die, they are broken down by decomposers (such as bacteria and detritivores) which respire, returning carbon to the atmosphere. Some organic matter is also returned to the soil where it is stored.
92
What is diffusion?
The oceans can absorb carbon from the atmosphere, which has increased ocean acidity by 30% since industrial times. This causes coral bleaching and harms aquatic life.
93
What is weathering and erosion?
Rocks are eroded on land or broken down by carbonation weathering. Carbonation weathering occurs when carbon dioxide in the air mixes with rainwater to create carbonic acid which aids the erosion of rocks such as limestone. The carbon is moved through the water cycle and enters the oceans. Marine organisms use the carbon in the water to build their shells.
94
What is burial and compaction?
When shelled marine organisms die, their shell fragments fall to the ocean floor and become compacted over time to form limestone. Organic matter from vegetation and decaying marine organisms is compacted over time to form fossil fuel deposits.
95
What is carbon sequestration?
The transfer of carbon from the atmosphere to other stores and can be both natural and artificial. A plant sequesters carbon when it photosynthesises and stores the carbon in its mass. Factories are also starting to use carbon sequestration in the form of Carbon Capture and Storage. Carbon dioxide is captured and transported via pipeline to depleted gas fields and saline aquifers.
96
What are the advantages of Carbon Capture and Storage?
- Can be fitted to existing coal power stations
- Captures 90% of carbon dioxide produced
- There is a demand for carbon dioxide (coke, plant growth, beer), so transport systems via pipeline in liquid for already exist
- Potential to capture half the world's carbon dioxide emissions
97
What are the disadvantages of carbon capture and storage?
- High cost is the main restriction to the growth
- Increases energy demand of power stations
- May not be space to fit it to existing power stations
- Economically viable in some cases as it is used to push oil out the ground, thus further increasing fossil fuel usage.
98
What is climatic climax?
The final stage of the sere where environmental equilibrium is achieved. When a sere reaches a climatic climax, the ecosystem is fully developed and stable, and it will not change dramatically as the equilibrium will counteract any change.
99
What causes natural change to the carbon cycle over time?
Wildfires and volcanic activity
100
How do wildfires cause change to the carbon cycle?
Transfer carbon from the biosphere to the atmosphere as carbon dioxide is released through combustion. This burning can encourage the growth of plants in the long term.
101
How does volcanic activity cause change to the carbon cycle?
Carbon sored within the earth is released during volcanic eruptions, mainly as carbon dioxide gas. They contribute a relatively low proportion of carbon dioxide to the overall carbon cycle. Some eruptions can produce sulphur dioxide gas, which blocks solar radiation and lowers global temperatures. This reduces photosynthesis rates which can affect both the carbon and water cycles.
102
What human factors cause change to the carbon cycle over time?
Fossil fuel use, deforestation, farming practices
103
How does fossil fuel use cause changes to the carbon cycle?
combustion transfers carbon dioxide to the atmosphere from a long term carbon sink.
104
How does deforestation cause changes to the carbon cycle?
often used to clear land for farming/housing, rapidly releases carbon stored in plants using slash and burn techniques and interrupts the forests carbon cycle.
105
How do farming practices lead to changes in the carbon cycle?
arable farming practices release carbon dioxide as animals respire. Ploughing can release carbon stored in the soil. Farm machinery such as tractors may emit carbon.
106
What is the carbon budget?
The balance between the carbon inputs and outputs to a store at any scale or the balance of exchanges between the four major stores of carbon.
107
How does the enhanced greenhouse effect cause climate change?
Abnormally high levels of greenhouse gasses are being produced, trapping radiation from the sun, causing global warming and leading to climate change.
108
What is radiative force?
The difference between incoming solar radiation absorbed by the earth and the energy radiated back out into space.
109
Why is carbon dioxide the most important anthropogenic greenhouse gas in the atmosphere?
It contributes to around 65% of radiative forcing by greenhouse gasses.
110
What effect will increased greenhouse gasses have on the water cycle?
Increases in global temperature due to alteration of the carbon cycle will have significant impacts on the water cycle, leading to greater levels of evapotranspiration. The increase in global temperatures may make summer storms more likely but decrease the amount of rainfall in summer on average, yet increase the average winter rainfall.
111
What are the causes of the enhanced greenhouse effect?
Land use change, fertilisers, deforestation, urbanisation.
112
How does land use change cause the enhanced greenhouse effect?
Causes 1/10th of annual carbon release. Impacts short term stores in the carbon cycle, such as soil and atmosphere. For example, in the Amazon around 70% of deforestation is for cattle ranching. Cattle produce a lot of methane, contributing further to global warming.
113
How do fertilisers contribute to the enhanced greenhouse effect?
Fertilisers are a significant source of greenhouse gases as well as rice padi fields, from which methane emissions have increased as a result of increased productivity due to higher CO2 levels. More sustainable seeds and grains like quinoa are being considered as substitutes, as they require less water to produce.
114
How does deforestation contribute to the enhanced greenhouse effect?
In total, deforestation accounts for about 20% of all global greenhouse emissions. The main impact is when the cycle is interrupted and land is used for other purposes, which then reduces carbon sequestration and land becomes a carbon source.
115
How does urbanisation contribute to the enhanced greenhouse effect?
The process of replacing countryside with buildings and similar infrastructure. It affects the local and global carbon cycles, by replacing vegetation and covering soils. Urban areas occupy 2% of the world's land mass, but these areas account for 97% of all human caused global CO2 emissions. Cement is an important building material, but releases carbon dioxide during production, contributing 7% to global CO2 emissions each year.
116
How is climate change effecting the oceans?
Ocean acidification, dissolving of calcium carbonate, warming of water.
117
How does ocean acidification effect the oceans?
About 30% of CO2 released by humans is absorbed into the oceans. When dissolved in water, carbonic acid is produced. This means that bicarbonate is produced from the reaction of carbonic acid with carbonate ions in the water. Carbonate ions would usually be used on shell building in organisms like coral.
Furthermore, calcium carbonate is more easily dissolved in acidic water, which makes the shells of marine organisms weak.
An increase in CO2 could be beneficial for marine plants and phytoplankton that take in CO2 directly from the oceans.
118
How does ocean warming effect the oceans?
Phytoplankton thrive on cool waters rich in nutrients. This means that less phytoplankton will be able to live, which would decrease the oceans ability to take in atmospheric CO2 through photosynthesis.
119
How is climate change effecting the land?
Carbon fertilisation - plants absorb around 25% of the carbon produced by humans. This increases growth rates. The warmer temperatures extend the growing season, which could mean that plants grow more, although it could also stress the plants as they would need more water to survive which may not be available.
120
How do we know that temperature changes have occurred in the the past not related to carbon dioxide?
Ice core data from Antarctica.
121
What is eccentricity in the Milankovitch cycles?
How far the Earth’s orbit departs from a perfect circle, which affects the distance between the earth and the sun. 100,000 year cycle. When earth's orbit is at its most elliptic, about 23% more incoming solar radiation reaches earth at perihelion. This will slightly increase terrestrial carbon stores as the rate of photosynthesis will increase, so plants have more glucose to use for growth.
122
What is precession in the Milankovitch cycles?
The 20,000 year cycle allows sea ice to grow faster in one hemisphere than another. As ice reflects more solar radiation than land or water, then a growth of the cap will be able to cool the planet. When the northern hemisphere (which has most land mass) precesses towards the sun, the arctic ice cap shrinks. This decreases the albedo effect, so the planet warms. Cryospheric carbon is released into the atmosphere, the hydrosphere can hold less carbon, and terrestrial stores decrease.
123
What is obliquity in the Milankovitch cycles?
A measure of the earth's axial tilt. A greater tilt makes the seasons more extreme. The earth's tilt varies between 22.1° and 24.5° over a period of 41,000 years. The seasonal amplification is not uniform across the earth, an increased tilt increases the annual solar radiation at higher latitudes, and decreases the total at the equator. More solar radiation at the poles accelerates the melting of ice caps, which releases cryospheric carbon and decreases the albedo effect. This extends the growing season and increases humidity, which leads plants to grow for longer. If plants are growing longer, they may become water stressed, which can result in them drying out, increasing susceptibility to wildfires.
124
What are sunspots?
Sunspots radiate UV radiation towards earth. The sunspot cycle is 11 years so any changes will be short term.
125
What are the interacting processes between the water and carbon cycles?
Photosynthesis and respiration, weathering, exchange between the oceans and atmosphere, thermohaline circulation, ocean warming, ocean acidification, permafrost melting, volcanic outgassing.
126
How do water and carbon interact in photosynthesis and respiration?
These two opposing processes cycle carbon and water between the atmosphere and the biosphere. Photosynthesis takes carbon dioxide from the atmosphere and water from the ground to create energy. On the other hand, organisms release carbon dioxide into the air as a byproduct of making energy through cellular respiration.
127
How do water and carbon interact in ocean acidification?
The increasing amount of carbon in our oceans has also led to an increase in their acidity. This can have significant detrimental effects on marine life, as many species can only survive in waters of a certain pH level.
128
How do water and carbon interact in ocean warming?
In addition to the rise in atmospheric temperatures, excessive amounts of carbon in our atmosphere has also led to a rise in oceanic temperature as well. The increasingly pronounced impact of the greenhouse effect has led to the warming of oceans around the globe.
129
How do water and carbon interact in thermohaline circulation?
Around the world, thermohaline circulation carries heat energy and organic matter from one place to another. The movement of ocean currents also facilitates the physical pumps that take carbon from the atmosphere and into the depths of the oceans.
130
How do water and carbon interact in weathering?
When water runs across the land as a result of precipitation or run-off, it erodes the rock and soil that it passes. As a result of this weathering, carbon that is released from the lithosphere makes its way into the atmosphere and the oceans.
131
How do water and carbon interact in permafrost melting?
The rise in global temperatures due to major changes in the carbon cycle also affects the cryosphere. The greenhouse effect has resulted in the melting of polar ice and permafrost. This also releases the carbon dioxide and methane trapped in the ice.
132
How do water and carbon interact in volcanic outgassing?
Volcanic eruptions lead to the melting of rock and the release of gases trapped in the lithosphere into the atmosphere. Volcanic outgassing from both above ground and underwater sources can transfer carbon and water into the air above.
133
How are humans mitigating climate change?
- Setting targets to reduce greenhouse gas emissions.
- Switching to renewable sources of energy.
- 'Capturing' carbon emissions and/or storing or burying them (sequestration).
134
What did the Paris Climate Deal (COP 21) achieve?
- Aim to limit the increase of 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.
135
What is an example of regional intervention into climate change?
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.
- The EU has suggested it will increase its emissions reduction to 30% if major GHG producing countries also improve their targets. 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.
136
How are humans mitigating climate change on a local scale?
- Improving home insulation.
- Recycling.
- Using energy more wisely and use of smart metres and using public transport or car sharing schemes and calculating personal carbon footprints.
137
What were the goals decided on at COP 26?
Secure global net zero by mid-century and keep 1.5 degrees within reach
Countries are being asked to come forward with ambitious 2030 emissions reductions targets that align with reaching net zero by the middle of the century.
138
What will countries need to do to be able to reach their targets decided at COP 26?
- accelerate the phase-out of coal
- curtail deforestation
- speed up the switch to electric vehicles
- encourage investment in renewables.
139
What are the characteristics of tropical rainforests?
28 degrees north or south of the equator
Temperatures between 20 and 30 degrees
Very old (180 million years)
More than 200 cm of precipitation per year
Hadley cell circulation delivers rainfall
Medicines may be found in the biodiversity
140
What are the layers of the rainforest?
Forest floor, understory, canopy, emergent
141
How much moisture does the amazon release into the atmosphere every day?
20 billion tonnes
142
Why are deforestation levels so high?
The Brazilian government has encouraged agriculture and mining. 2019 had levels of deforestation 9.5% greater than in 2018.
143
What are the effects of deforestation on the water cycle?
Water is transferred to the atmosphere through evapotranspiration. This forms clouds which precipitates back down to the forest. This means deforestation can result in drought. Amazon has experienced severe drought in recent years and water from the amazon can travel as far as Texas.
144
What is the Amazons average discharge into the Atlantic?
175,000 CUMECS, or between 1/5 and 1/6 of the total discharge into the oceans of all the worlds rivers.
145
What's the Amazons average annual rainfall?
2,300 mm
146
Why is only 1/3 rd of precipitation discharged into the Atlantic?
1. Up to half of the rainfall in some areas may never reach the ground, being intercepted by the forest and re-evaporated into the atmosphere.
2. Additional evaporation occurs from ground and river surfaces, or is released into the atmosphere by transpiration from plant leaves.
3. This moisture contributes to the formation of rain clouds, which release the water back onto the rainforest. In the Amazon, 50-80 percent of moisture remains in the ecosystem’s water cycle.
This shows that to some extent the water cycle in the Amazon is a closed system because much of the water may be ‘recycled’ many times before it leaves the system.
147
How is climate change increasing the rate of deforestation?
- Climate change increases the risk of extreme weather events such as wildfires which are responsible for around 10% of forest degradation per year. Storm surges and droughts also destroy millions of hectares of forest every year.
- Once forest fires have been extinguished, invasive species such as pests and diseases spread throughout the forests, destroying remains.
148
How is agriculture increasing the rate of deforestation?
- The majority of tropical equatorial rainforests are found in LICs with rapidly growing populations. Land has to be cleared for settlements but also agriculture.
- Slash-and-burn - This traditional cultivation is wasteful of space. It clears lots of forest and the fire can often become uncontrolled.
- Cattle ranching - Exposes pastures to soil erosion and produces low-quality meat.
- Plantations of cash crops - such as palm oil and soya bean - require lots of land to be cleared.
- Palm Oil production is a predominant driver of deforestation, especially in places such as Indonesia and Malaysia. Palm oil is present in 40-50% of household products and 50 million tonnes of palm oil are produced annually. It accounts for over 30% of the world’s vegetable oil production.
149
How is timber logging increasing the rate of deforestation?
- 380,000 hectares of forest are cut down per year to meet the demand for wood and wood products which accounts for 60% of degradation. Furthermore, another 25% of degradation is due to fuelwood and charcoal.
- The increasing demand for valuable hardwood timber in HICs provides a reliable and essential source of income.
- Japan accounts for 11 million cubic metres of equatorial hardwood use a year.
150
How is mining increasing the rate of deforestation?
- Mining for vast reserves of valuable materials such as tin, copper and lead are only accessible once the forest has been cleared.
- The cheapest method of mineral extraction is open-cast mining. This amounts to large scale deforestation because trees and soil are stripped from the underlying rocks.
- The Carajas in Northern Brazil is the world’s largest source of iron ore.
- 10,500 hectares of rainforest were cleared for the Juruti bauxite mine in Brazil.
151
How are infrastructure and population growth contributing to the rate of deforestation?
- The construction of private, government funded road networks supports the development of the rainforest for other uses. It increases the amount of people with access to the forest and increases the amount of raw materials extracted. Deforestation also occurs to allow roads to be built.
- The Trans-Amazonian Highway extends 6000 km into Brazil’s interior.
- Population pressure comes from both natural growth and migration. The need for relocation cannot be ignored if other areas cannot support their own populations. This forces deforestation as rates of urbanisation increase.
152
What are the impacts of Amazonian deforestation on a local scale?
Slash and burn techniques are used to release nutrients and create a nutrient rich layer of soil. This usually only lasts a couple of years, after which fertilisers must be used which is harmful to wildlife. These practices mean greenhouse gases are released into the atmosphere, contributing further to environmental change. Peatlands can also be drained for agricultural purposes, which releases carbon dioxide into the atmosphere and also increases the flammability of the land, increasing the risk of large scale fires.
153
What are the impacts of Amazonian deforestation on a regional scale?
The export of timber removes protection from the soils in an ecosystem. This means that some regions are desertified and river banks can become silted due to the influx of eroded soils. If too much timber is cut, soil can become baked and dry out, leading to erosion and degradation of soil farmers so farmers cannot profit from the land.
154
What are the impacts of Amazonian deforestation on a global scale?
If the Amazons deforestation continues, it may approach a tipping point where large scale savannisation or desertification will take place. This will lead to catastrophic consequences for the global climate due to the self perpetuation collapse of biodiversity and ecosystem
155
Where is the river Wye?
The river begins in the Plynlimon mountains and then meets the Severn estuary at Chepstow.
156
What is the catchment area of the river Wye?
Over 4,000 square kilometres. It is a site of special scientific interest and one of the most important British rivers in terms of nature conservation. Most is unpolluted although certain streams in the upper catchment suffer from acidification and localised pollution problems.
157
What is the topography like around the river Wye?
Steep land, around 450 metres above sea level.
158
What is the soil like around the river Wye?
The soil drains easily, and water is quickly percolated into the permeable limestone.
159
What is the land use around the river Wye?
- 200,000 live in the Wye valley, with large towns throughout the catchment
- Large numbers of livestock which graze and trample the land, which can leave the soil waterlogged
- growth of poultry farms (500 farms) increase runoff of phosphate into the water. This damages biodiversity, which means less beavers to provide flood defence.
- Limestone quarrying in the area can lead to steeper topography.
160
What are the outputs of the river Wye?
- Abstraction to south Wales provides drinking water for 2.5 million people.
- water piped to 5 reservoirs in Birmingham
- trickle irrigation for farmers
161
Why did the Wye flood in February 2020?
- wettest February ion record following four weeks of intense rainfall and discharge across the UK
- 5th wettest month and 5th wettest winter since records began in 1862.
- Proceeded by Ciara, Dennis, and Jorge.
162
What were the immediate impacts of the February 2020 Wye flood?
- temporary homes for 1,400
- 540,000 homes experienced loss of power
- Churches and leisure centres used to take in evacuated residents
- entire villages cut off due to floods
- 55 year old woman drowned
- travel disruption
- schools closed
163
What were the long term impacts of the February 2020 Wye flood?
- £360 million damage costs
- business owners experiencing difficulty obtaining insurance at a fair cost
- property owners more flood risk aware
- flooding impacted a COVID 19 vaccine production centre
164
What management strategies are used in the Wye basin?
- embankments along the river to separate the water from the floodplain
- increase infiltration into the soils by contour ploughing and planting cover crops.
- slowing the flow of water using leaky dams designed to mimic beavers
- storing water upstream
