6.3A Atmospheric carbon and the greenhouse effect

• Human Interference:

  • A balanced carbon cycle is vital in sustaining other systems on earth 
  • The carbon cycles role is regulating global temperatures and climate by controlling the amount of carbon dioxide in the atmosphere which in turn affects the hydrological cycle
• The Greenhouse Effect:

  • The natural greenhouse effect is influenced by the concentration of atmospheric carbon (carbon dioxide and methane).
  • The Earth’s climate is driven by incoming shortwave solar radiation.
  • If the amount of carbon dioxide and methane increases then more long-wave radiation will be trapped causing global temperatures to rise.
• shortwave solar radiation:

  • Around 31% is reflected by clouds, aerosols and gases in the atmosphere and by the land surface
  • The remaining 69% is absorbed with half being absorbed at the surface (e.g., oceans) and the other half is re-radiated into space as long-wave radiation 
  • However, much of this long-wave radiation is deflected back to the Earth’s surface by clouds and greenhouse gases 
  • This ‘trapping’ of long-wave radiation creates the natural greenhouse effect allowing life to be supported on Earth