Key Role in Supporting Life (AQA A Level Geography)

Revision Note

Jacque Cartwright

Written by: Jacque Cartwright

Reviewed by: Bridgette Barrett

Carbon & Water as Life-support

  • The water and carbon cycles interact directly

  • Volcanic eruptions transfer water and carbon from the lithosphere to the atmosphere

  • Water has the ability to absorb and transfer CO2 

  • Water transports weathered material and organic matter, (containing carbon) from land to the oceans as part of the carbon cycle and ocean acidification  

  • Calcium carbonate in the ocean is used for coral, shell and skeletal formation by marine animals

  • Changes in atmospheric carbon concentrations affect water cycling and precipitation patterns

  • Photosynthesis and respiration transfer carbon and water between the biosphere and the atmosphere

  • Evapotranspiration increases with higher levels of CO2 in the atmosphere 

  • Changes in the carbon cycle are melting parts of the cryosphere (permafrost), releasing more carbon dioxide and methane into the atmosphere

  • Ecosystems play a key role in carbon cycling and the availability of moisture for plant and animal distribution and growth is important

  • Limits of water, reduce plant growth; limited plant growth reduces carbon cycling and transfer of nutrients to the soil; lack of nutrients and water exposes soil erosion; soil erosion can lead to desertification

carbon-and-water-relationship
The water and carbon cycle interaction, note the absorption and transfer of carbon by water

In the atmosphere

  • When CO2 atmospheric concentration levels increase, air temperature increases too

  • This raises ocean temperatures and evaporation rates increase transferring more water vapour into the atmosphere

  • This amplifies the greenhouse effect

  • Water vapour contributes more to the overall natural greenhouse effect than CO2 

  • Water vapour in the atmosphere is controlled by levels of atmospheric CO2 

  • The natural greenhouse effect is generated through concentration levels of:

    • 20% carbon dioxide

    • 8% trace gases and aerosols

    • 17% clouds

    • 55% water vapour

  • Hydro and halo carbons are industrial gases and contribute to the enhanced greenhouse effect

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Jacque Cartwright

Author: Jacque Cartwright

Expertise: Geography Content Creator

Jacque graduated from the Open University with a BSc in Environmental Science and Geography before doing her PGCE with the University of St David’s, Swansea. Teaching is her passion and has taught across a wide range of specifications – GCSE/IGCSE and IB but particularly loves teaching the A-level Geography. For the past 5 years Jacque has been teaching online for international schools, and she knows what is needed to get the top scores on those pesky geography exams.

Bridgette Barrett

Author: Bridgette Barrett

Expertise: Geography Lead

After graduating with a degree in Geography, Bridgette completed a PGCE over 25 years ago. She later gained an MA Learning, Technology and Education from the University of Nottingham focussing on online learning. At a time when the study of geography has never been more important, Bridgette is passionate about creating content which supports students in achieving their potential in geography and builds their confidence.

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