05 April 2014

#145 Effects of combustion of fossil fuels on CO2 level

Photosynthesis takes CO2 out of the atmosphere and replaces it with O2. Respiration and combustion both do the opposite: they use up O2 and replace it with CO2.

The equations are essentially the same, but reversed:

In order for the amount of CO2 in the atmosphere to remain stable, the rates of these processes need to be balanced. 

Processes that change the equilibrium (balance) include:
  • cutting down forests (deforestation) – less photosynthesis
  • combustion of fossil fuel (coal, oil and gas)
  • increasing numbers of animals (including humans) – they all respire.

An increase in CO2 levels in the atmosphere is thought to contribute to global warming. 

CO2 forms a layer in the atmosphere, which traps heat radiation from the Sun. This causes a gradual increase in the atmospheric temperature which can:
  • melt polar ice caps, causing flooding of low-lying land
  • change weather conditions in some countries, increasing flooding or reducing rainfall and changing arable (farm) land to desert
  • cause the extinction of some species that cannot survive at higher temperatures. 

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