causes

• Milankovitch cycle - orbital change

  variations in the Earths orbit and Earths proximity to the sun

  global temperature increa/decrease
• sunspots - solar activity

  dark area's on Earths surface created by changes in the mantle

  decreases temperature
• volcanic eruptions

  when material is forced out the mantle/volcanic vent

  (short term) increases temperature + lots of ash (blocks out sun - cold)

  increases number of greenhouse gases
• greenhouse effect

  solar radiation enters the earth

  they hit the earth

  some get absorbed, but most are re-emitted

  some of the re-emitted rays make it back out to space

  some of the re-emitted heat hits greenhouse gases, they are absorbed and after a short pause, re-emitted in random directions

  the re-emitted rays then continuously hit greenhouse gases (a small amount gets re-emitted into space) - this keeps in the heat from the sun

  this increases the earths temperature
• human causes of climate change

  • methane released by livestock - growing population
  • deforestation
  • burn fossil fuels
  • cars
  • carbon cycle needs to be at equilibrium - deforestation changes it
• climate change = natural but humans increase its rate