Physical causes of climate change

• Milankovitch's theory


  • Changes in the earth's orbit/tilt alter the amount of energy reaching the Earth
• Changes in the tilt of the Earth's axis

  1. Every 41,000 years

  2. Greater tilt means more sunlight in polar regions

  3. Over a 97,000-year cycle, the Earth's orbit stretches
• Peaks of sunspot activity

  Can raise global temperatures
• Sunspot activity follows an 11-year pattern
• Volcanic eruptions


  • Large amounts of dust and droplets of sulphur may absorb and reflect the sun's rays lowering temperature
• Retreating ice caps

  Release additional fresh water leading to changes in oceanic circulation,
• Retreating ice caps effect 


  Reduces the albedo effect as more land is exposed
• Methane is being released from melting permafrost