Carbon & Water cycles - 4 mark questions - A Level Geography

Explain the concept of Negative Feedback in the Water Cycle

When the affects are nullified (1)

For Example; Increased evaporation due to higher temperatures decreases storage in drainage basins.

As a result, there is lower potential evaporation

Explain the concept of Positive Feedback in the Water Cycle

When the affects are multiplied (1)

For Example; Increased rainfall means increased storage in a drainage basin. Therefore there is greater potential evapotranspiration which increases humidity leading to greater potential rainfall.

Explain the concept of Dynamic Equilibrium in the Water Cycle

When there is a balance between inputs and outputs (1)

The balance can become upset if an element is changed (1)

For Example; Increase in temperature means increased Evapotranspiration

Explain the concept of Positive Feedback in the Carbon Cycle

When the effects are multiplied (1)

Positive loops can contribute to the enhanced greenhouse affect and climate change (1)

For Example; Increase in atmospheric CO2 increases atmospheric temperatures which can lead to the melting of permafrost. This results in the release of CO2 into the atmosphere = more warming

Explain the concept of Negative Feedback in the Carbon Cycle

When the effects are nullified (1)

For Example; Burning fossil fuels increases atmospheric CO2 leading to a global temperature increase. This in turn leads to more evaporation and increased low altitude cloud cover which reflects insolation reducing surface temperatures

Outline the causes of Precipitation

Precipitation forms in the clouds when water vapour condenses into water droplets that when heavy enough, fall to Earth.

This happens when the air has cooled to dew point (1) and then condenses to form clouds (1)

Outline the size and distribution of major water stores in the Water Cycle

The Ocean is the largest store (accounts for 96% of global water) (1)

The Cryosphere is the largest store of freshwater (accounts for 65% of freshwater) which is stored within glaciers, ice caps and ice sheets (1)

The rest of freshwater is mostly terrestrial and stored in Rivers, Lakes and Groundwater (1)

Some water is stored as atmospheric water within vapour however water here has a very short residency (1)

Outline the size and distribution of major water stores in the Carbon Cycle

99.9% of Carbon is stored within the Lithosphere (1)

Carbon can also be found within the Hydrosphere, Biosphere and Cryosphere (1)

Long term stores of carbon include sedimentary rock and the deep ocean (1)

Short term stores include animals and plants where carbon has a short residency time (1)

Outline the process of Cloud Formation

Convection and Evaporation causes warm air containing water vapour to rise into the atmosphere (1)

As it rises further into the atmosphere it begins to cool and the vapour condenses (1)

Here there is a release of latent heat as the vapour changes state from a gas to a liquid (1)

Explain the role of cryospheric change in the Water Cycle

The cryosphere is the largest store of freshwater (65%) (1)

It has a regulatory role in sea levels (1)

Melting of sea ice due to warmer climates has led to a reduction in the size of the cryosphere (1)

This can make the ocean store larger

The Cryosphere is the frozen water on the earth's surface

Explain the role of the Ocean pump in the Carbon Cycle

The Ocean pump is a transfer of carbon from the oceans upper layers into the deep sea (1)

It is a natural form of sequestration (1)

The pump is driven by phytoplankton which absorb CO2 through photosynthesis. Their Carbon deposits then sink with gravity to the ocean floor (1)

Explain the role of Combustion in the Carbon Cycle

Combustion is the transfer of carbon from the biosphere into the atmosphere (1)

It can be as a result of human activity such as the burning of fossil fuels or slash and burn techniques (1)

It can also be as a result of physical/natural causes like wildfires (1)

Explain the role of Photosynthesis in the Carbon Cycle

Photosynthesis is the process of removing CO2 from the atmosphere and creating O2 (1) using energy from the sunlight and water (1)

Carbon is then distributed into the biosphere (1)

For Example; A tree as it takes CO2 from the atmosphere & stores it making trees a carbon sink (1)

Explain the role of Sedimentation in the Carbon Cycle

Sedimentation is when carbon moves away from the hydrosphere back into the lithosphere (1)

The process is aided by ocean pumps (1)

Carbon can be naturally removed from the lithosphere by processes such as weathering and volcanic activity (1)

It rarely has output forces acting upon it and therefore acts as a carbon sink (1)

Outline the role of Fusion in driving change in the magnitude of water stores

Fusion = Phase change of water (1)

Increase of Energy = Melting (1)

Decrease of Energy = Freezing (1)

For Example; The rising of global temperatures = Melting of the cryosphere = increase in magnitude of oceanic store (1)

Explain the concept of Carbon Sequestration

Capturing carbon from the source (1)

Purpose of sequestration is to reduce the amount of carbon in the atmosphere (1)

Can be split into Geological sequestration where it is stored underground (1)

Or terrestrial sequestration where it is stored in Plants (1)