Carbon and Water Cycle Flashcards
Case Studies: Calder Valley 2015 Flood Amazon Rainforest + Rondonia
What are power geometries?
The unevenly distributed power relations between different communities, individuals or places
What is a system?
Set of interrelated components working together for a purpose
What is an open system?
A system which receives inputs and transfers outputs of energy and matter across boundaries
What is a closed system?
A system where energy is transferred both in and out but matter is not transferred
What is a cascading system?
The transfer of mass and energy along a chain of component subsystems such that the outputs of one system become the inputs for the adjacent subsystem
What is positive feedback?
Enhances or amplifies an effect by it having an influence on the processes which caused it. E.g. deforestation
What is negative feedback?
Dampens or reduces the effect, often meaning the consequences of a change are less severe. E.g. increase in surface temperatures
What is the atmosphere?
The inputs, flows and outputs are all associated with the layer of gases surrounding our planet
What is the lithosphere?
The inputs, flows and outputs are all associated with the cold, hard, solid layer of the Earth’s crust
What is the hydrosphere?
The inputs, flows and outputs are all associated with the planet’s liquid water
What is the biosphere?
The inputs, flows and outputs are all associated with the biology and ecosystems of our planets
How much water on Earth is freshwater?
2.5%
How much of the Earth’s surface is covered by water?
71%
What factors affect global freshwater stores?
Geology, climate and rivers
How does climate affect global freshwater stores?
Influences the availability of rainfall and snowfall and the rates of evaporation. The climate can vary over time and this can vary water availability
How does the atmosphere hold water
Holds water as gas, clouds and precipitation
How much of available freshwater is found in the atmosphere?
8%
What is sea ice?
Ice that floats on the surface of our seas and oceans, this grows in size in winter and shrinks in summer. When it melts it has no impact on sea levels
What are ice shelves?
A type of sea ice formed when ice sheets and glaciers extend out from the land, they break off to form icebergs
What are ice sheets?
A mass of glacial land ice extending more than 50,000km^2, the two on Earth are the Antarctic and Greenland. They contain more than 99% of the Earth’s freshwater ice.
What is permafrost?
Soil that is frozen for more than two consecutive years. Current permafrost was created during the last ice age, but is at risk of melting due to global warming, forming a positive feedback loop as it melts and releases methane
What are ice caps?
Masses of ice which cover less than 50,000km^2 of land, found in mountainous areas and their meltwater is a significant source of water for millions.
What are the four types of terrestrial water?
Surface water, groundwater, soil water and biological water
Why is ocean pH changing?
Due to an increase in atmospheric carbon and ocean acidification
When does evaporation occur?
When energy from solar radiation hits the surface of water or land and causes liquid to change to water vapour
What factors impact the rate of evaporation?
The amount of solar energy, the availability of water, the humidity of the air, the temperature of the air
How does humidity impact the rate of evaporation?
The closer the air is to saturation point, the slower the rate of evaporation
What happens to the temperature of the surroundings when water evaporates?
The temperature cools, as water evaporating uses energy in the form of latent heat
What is the dew point temperature?
When air becomes saturated and the excess water in the air is converted to a liquid through condensation
What is condensation nuclei?
Small particles of dust and sand on which water vapor condenses
(clouds) What happens as the Earth’s surfaces heat the air?
Some liquid water evaporates from the heat energy into water vapour
(clouds) Why can warm air rise?
Because it is less dense
(clouds) What happens to air as it rises?
It expands, releasing head energy as it does and this is called adiabatic cooling
(clouds) How does rising air reach the dew point temperature?
As it is releasing heat energy and cooling
(clouds) What happens at dew point temperature?
Air is able to condense onto condensation nuclei
(clouds) How do ice crystals form?
At high altitudes the temperature is low, so the liquid water on the condensation nuclei freezes to become ice crystals
(clouds) what causes precipitation?
When the ice crystals in the clouds become too heavy that they drop to Earth
When does convectional rainfall occur?
When hot air rises and condenses as higher temperatures have a colder temperature, one closer to the dew point temperatre, to form clouds and therefore causes precipitation
When does relief rainfall occur?
When air gets pushed over a hill and the air cools and condenses to form clouds and therefore causes precipitation
When does frontal rainfall occur?
When warm air meets cold air and is forced to rise. As it rises it cools adiabatically and condenses to form clouds and therefore causes precipitation
What type of pressure does rising air cause?
Low
What is differential heating?
The difference in heating at different parts of the Earth depending on the sun’s rays
What role does differential heating play in cloud formation?
Parts of the Earth which are heated more have more cloud coverage as there is an increase in evaporation
Ablation
Where outputs exceed inputs and so more mass is lost than gained (decrease in mass)
Accumulation
Where inputs exceed outputs, so more mass is gained than lost (increase in mass)
Where does ablation occur?
Lower down the glacier
Where does accumulation occur?
Higher up the glacier
What is river discharge?
The volume of water passing a measuring point in a given time
How is river discharge calculated?
River discharge = cross-sectional channel area x velocity
What is the river regime?
The variability in discharge of a river throughout the year
What is a hydrograph?
A graph showing the discharge during a short term storm or weather event
How does saturation affect a hydrograph?
If the drainage basin is already saturated then the overland flow increases, leading to a flashy hydrograph
How does deforestation lead to a short lag time?
There is a reduced rate of interception, leading to an increase in surface run off and therefore a flashy hydrograph
How does urbanisation lead to a short lag time?
There is more impermeable surfaces, therefore an increased rate of surface run off and therefore a more flashy hydrograph
How does increased vegetation lead to a long lag time?
Vegetation can intercept and hold the water, leading to a reduction of surface run off and therefore a more subdued hydrograph
What is a drainage basin?
An area of land drained by a river and its tributaries
What is water balance?
The balance between the inputs and outputs of water into the water cycle
Where is the source of the River Calder?
Heald Moor above Todmorden, 400m above sea level
How much rain does the source of the River Calder get?
Around 1500mm annually
How big an area is drained by the Calder drainage basin?
369 square miles
In the 2015 floods, how many businesses were damaged?
4416
In the 2015 floods, how many homes were damaged?
2781
What was the estimated economic loss as a result of the 2015 floods?
£47 million
In 2015, why were many people unprepared?
Because most places lacked early warning systems to warn residents of the rapidly increasing river levels due to the prolonged periods of rainfall
Who are ‘Slow the Flow’ and what do they do?
A volunteer organisation that uses natural flood management to reduce floods. They construct ‘leaky dams’ which increase the lag time of the river by slowing the rate of water flowing
Who are ‘Treesponsibility’ and what do they do?
An organisation that planted 10,000 trees as a natural management strategy after the floods. The trees intercept the rain and reduce the flood risk, they also allow water top move through root uptake and evapotranspiration
How much money was spent on hard engineering at Mytholmroyd?
£46 million
How full were the reservoirs in the Calder Valley kept?
No more than 90% full
How much of Earth’s readily available freshwater is found in groundwater?
97%
What is the water table?
The depth at which soil pore spaces or fractures and voids in rocks become completely saturated
What is a syncline?
When the geology forms a u-shaped structure
What material is London built on and why is this significant?
Clay, which is less permeable than chalk
What happened to the London Basin Chalk Aquifer in the 19th Century?
Industrialisation caused over abstraction of the aquifer, causing the water levels decline
What happened to the London Basin Chalk Aquifer in the 1960s?
Deindustrialisation caused many industries to move overseas. This led to a reduction in industrial water usage and the aquifer levels recharged
What happened to the London Basin Chalk Aquifer in the 1990s?
The aquifer was rising by 3mm a year, there became a risk that the levels could rise so high that the London underground could flood
What happened to the London Basin Chalk Aquifer in the 2000s?
GARDIT was set up to monitor the aquifer levels, if the levels became too high then they let water out through boreholes
What are the inputs of the London Basin Chalk Aquifer?
Relief rainfall that lands on the exposed hills of the North and South Downs and the Chilterns
What happens to the London Basin Chalk Aquifer in Summer?
Potential evapotranspiration exceeds rainfall, soil moisture deficits build up and little to no percolation takes place
What happens to the London Basin Chalk Aquifer in Winter?
Potential evapotranspiration is low and soil moisture deficits are negligible so percolation takes place and the levels recharge
What percent of water is stored in the Cryosphere?
1.7%
What percent of water is stored in the Hydrosphere?
96.5%
What percent of water is stored in the Lithosphere?
1.7%
What percent of water is stored in the Atmosphere?
0.001%
What is soil drainage?
Subsurface drainage removes excess water from the soil profile. It is usually carried out through a network of perforated tubes installed 60-120 cm below the soil surface.
What is enteric fermentation?
This is the methane released as cattle digest their food.
