BY5.8 Carbon Cycle

Carbon cycle:

• CO2 is added to the atmosphere from:
  • repsiration of plants, animals and microorganisms
  • combustion of fossil fuels

• photosynthesis uses about as much CO2 as it releases

• production of carbs, fats and protein contains carbon which is needed for plant and animal growth
  • remains of dead animals are decomposed by saprophytes in the soil which release CO2

• accumulation of dead animals in aerobic coditions forms coal, oil and other fossil fuels
  • burning these releases CO2

Humans and the carbon cycle:

2 main reasons for the increase:

• burning fossil fuels
• deforestation

burning fossil fuels

• leads to a 70% increase in CO2 levels
• most of this is form industrialised countries

deforestation

• leads to a 30% increase in CO2 levels
• estamted that 50% of the world forests have been removed
• forests help to maintian the balance of CO2 and O2
• CO2 is a green house gas thet absorbs radiation from the Earth
• this accumulation leads to global warming
• CO2 represents 49% of all green house gases

• other green house gases including CFC's are used as aerosol propellants and coolants in fridges
• the amount of these green house gases in the environment is rising

• green house gases form a layer in the atmosphere that allows high energy colar radiaiton…