(2) changing climate

• the eruption theory?

  • big volcanic eruptions effect climate
  • volcanoes produce ash and sulphur dioxide gas
  • ash and gas rise - spread around earths surface by high-level winds
  • stops sunlight reaching earths surface = cools the planet (lowers global temperature)
  • eg. Philippines, Mount Pinatubo erupted and reduced global sunlight by 10%, cooling the planet by 0.5* for a year
• the sunspot theory?

  • black areas on the suns surface
  • spots not visible = sun is more active
  • lots of spots = less solar energy reaches earth
  • happens on 11 year cycles
  • eg. medieval ice ae and little warm period caused by sunspot activity