physical

• physical causes of climate change

  (the Milankovitch theory)

  • Milankovitch's theory involves changes in the earth's orbit(1)
  • Altering the amount of energy reaching the earth(1)
  • Every 41,000 years there is a change in the tilt of the earth's axis(1)
  • A greater tilt means more sunlight in polar regions(1)
  • Over a 97,000 year cycle, the earth's orbit stretches(1)
  • As the earth moves further away from the sun, less energy reaches the surface causing changes in climate(1)
• physical causes of climate change

  (volcanic eruptions)

  • After volcanic eruptions, large amounts of dust and sulfur(1) may reflect the sun's rays, lowering temperatures(1)
  • E.g. After the eruption of Mount Pinatubo in 1991(1)
  • Very large volcanic eruptions can inject significant amounts of carbon dioxide into the atmosphere(1)
  • This greenhouse gas traps the radiation from the sun from escaping back into space(1) Warming temperatures over periods of time(1)
• physical causes of climate change

  (sunspots)

  • Global temperatures can be raised by peak sunspot activity(1)
  • Follows an 11-year pattern(1)
• physical causes of climate change

  (melting permafrost)

  • Methane being released from melting permafrost(1) Worsens the natural green-house effect. Increasing global temperatures(1)