Earth Life Support System- Pt 3 Flashcards
What is an example of a negative feedback loop for the water cycle?
Heavy rain increases the amount of water that’s stored in aquifers, which raises the water table. This then increases the flow from springs until water returns to normal levels.
What is an example of a negative feedback loop for the carbon cycle?
Burning fossil fuels increases CO2 so increases photosynthesis, which removes CO2 from the atmosphere to maintain equilibrium.
What are the examples of how land use changes the water and carbon cycles?
Urbanisation
Farming
Forestry
How does urbanisation affect the water cycle?
The natural surfaces are replaced by impermeable surfaces so infiltration is reduced. Therefore an increased risk of flooding as there’s more surface run-off.
How does urbanisation affect the carbon cycle?
More transport means that there’s more CO2 emissions into the atmosphere so ore light is used which increases energy intake.
How does farming affect the water cycle?
The use of heavy machinery can compact the soil and increase surface run-off.
How does farming affect the carbon cycle?
The clearance of forests for farming reduces the carbon storage in, above and below ground biomass.
How does forestry affect the water cycle?
Higher rates of rainfall interception in plantations in natural forests so increased evaporation, meaning reduced run-off and stream discharge.
How does forestry affect the carbon cycle?
Changing land use from farming to forestry increases the carbon store, meaning that there’s more flux of CO2 in and out of trees.
What is our example of surface extraction?
The River Kennet
Where is the River Kennet located?
South England
What is surfaceextraction?
Extraction of water from rivers
What does the River Kennet supply water for?
Industry and agriculture.
Where is most of the flow from the River Kennet from?
Groundwater
What has been the impact of surface extraction of the River Kennet?
Groundwater extraction have exceeded rates of recharge which means water table has fallen.
Lower flows reduce risk of flooding and temporary areas of standing water on floodplain.
When was there a drought from the River Kennet?
In 2003 and flows fell by 20%.
What is sub-surface extraction?
Extraction from aquifers and artesian basins.
What is an artesian aquifer?
When a borehole is used to tap groundwater so that it will flow to the surface under its own pressure.
What is a potentiometric surface?
It is level to which the water from an artesian basin will rise to.
What does a potentiometric surface depend on?
Whether the water will come out naturally or pumped out of theground.
What is an a potentiometric surface determined by?
By the height of the water table in areas of recharge on the edges of the basin.
What is an example of an area that sits on top of an artesian basin?
London
Why was the groundwater from the artesian basin in London an important supply of water during the 19th century?
It was essential for meting the demand for industrial, commercial and public demand as London expanded.
What is the risk now of the artesian basin in London?
The water table has recovered but there is still a potential risk of flooding.
For the last 200 years what has been the industry driven by fossil fuels?
Global industrialisation and urbanisation
What percentage of our energy consumption is fossil fuels?
80%
What has the concentration of CO2 increased from 1750 to 2022?
From 280ppm to 421ppm
How long has theCO2 concentration in the atmosphere been the highestfor?
800,000 years.
What is anthropogenic CO2?
CO2 that’s produced by humans
How much do anthropogenic emissions make up of the natural flux of carbon?
less than 10%
What is one possible solution to capture and store carbon?
Carbon capture and storage
What is carbon capture and storage?
A process in which carbon dioxide from industrial sources is separated, treated and transported to a long-term storage location.
What is a negative of carbon capture and storage?
It’s not economically viable.
What is the first stage of carbon capture and storage?
Separating CO2 from power station emissions
What is stage of 2 of carbon capture and storage?
Compressing and transporting the CO2 by pipelines to where it is stored.
What is stage 3 of carbon capture and storage?
It is then injected into porous rocks deep underground for permanent storage.
How effective is carbon capture and storage?
It has the ability to reduce emissions by 80-90%.
What is an example of how the carbon capture and storage project hasn’t been effective ?
There are Pilot projects at Peterhead in NE Scotland but the increasing costs axed the project as it was too expensive.
What is the economic factor that limit the effectiveness of carbon capture and storage?
It has a high setup cost (also known as a capital cost).
How much did it cost to setup the carbon and capture storage programme in Peterhead?
£1 billion
What is the geological factor that limit the effectiveness of carbon capture and storage?
Specific geological conditions are needed for areas to act as storage.
What is an example of positive feedback loop in the water cycle?
Melting sea ice exposes the ocean and so less solar radiation is reflected. The ocean then absorbs more heat and warms up so melts more sea ice.
What is an example of positive feedback loop in the carbon cycle?
Warmer temperatures increase permafrost melting, releasing methane and carbon back into the atmosphere and driving enhanced greenhouse effect.
How are we monitoring changes to the global water and carbon cycles?
Satellite technology and remote sensing
Use of GIS
How many satellites are there above the Earth’s surface?
10,000
What is remote sensing as a way of monitoring the carbon and water cycles?
It gets info without touching/from a distance.
What does GIS stand for?
Geographical Info Systems
What do satellites enable us to do?
Monitor change so that temporal changes can be identified.
Data can then be mapped by GIS which gives us a spatial context so helps to identify trends and anomalies.
What is the mean residence time?
The amount of time molecules stay in the system on average.
How do we calculate the net flux of something?
Input-Output
What does diurnal mean?
day
What are the diurnal changes in the water cycle?
Lower night temps reduces evapotranspiration.
More humidity can reduce precipitation.
What are the diurnal changes in the carbon cycle?
Growth during daylight hours means CO2 flows from atmosphere to vegetation, same with phytoplankton in oceans.
What are the seasonal changes in the water cycle?
Evapotranspiration is the highest in the summer and lowest in winter.
River levels normally lowest in summer.
What is evapotranspiration controlled by?
The variations in intensity of solar radiation.
Why are river levels normally lowest in summer?
due to soil exhaustion of soil moisture and much precipitation lost to evapotranspiration.
What are the seasonal variations in the carbon cycle?
NPP varies monthly
Summer in N hemisphere has a net global flow of CO2 from the atmosphere to biosphere.
What are the two short term changes in the water and carbon cycles?
Diurnal
Seasonal
How many glacial cycles have there been in the last 400,000 years?
4 major
