Physical Causes of Climate Change

• Milankovitch’s theory: changes in the earth’s orbit/tilt alter the amount of energy reaching the Earth.
• Every 41,000 years, there is a change in the tilt of the Earth’s axis.
• A greater tilt means more sunlight in polar regions and over a 97,000-year cycle, the Earth’s orbit stretches.
• Global temperatures can be raised by peaks of sunspot activity, which follow an 11-year pattern.
• After volcanic eruptions, large amounts of dust and droplets of sulphur may reflect the sun’s rays lowering temperature.
• Retreating ice caps release additional fresh water leading to changes in oceanic circulation.
• This also reduces the albedo effect as reflection has decreased as more land is exposed.
• Methane being released from melting permafrost.