keeling curve

• What is the keeling curve

  graph that represents the concentration of CO2 (ppm)
• Start of spring

  or end of winter

  Concentration of CO2 is highest because leaves fall - they can't photosynthesise - along with this micro-organisms eat the leaves and they respire therefore CO2 is highest
• Start of Autumn

  or end of summer

  Plants are photosynthesising so there is more CO2