Natural cause Climate Change
Long-term climate change caused by:
changes in Earth’s orbit and angle of tilt
Short-term climate change caused by:
occurrence of sunspots
large-scale volcanic eruptions
The Earth’s orbit stretches from circular to an elliptical shape and back again in a 100,000 years. When the Earth’s orbit is the most elliptic, the Earth receives more solar radiation, hence higher temperatures are experienced
The Earth’s axis varies back and forth between 21.5° and 24.5° in a 41,000 years. When the tilt increases, the Northern Hemisphere will turn more towards the Sun, making the temperature higher.
Sunspots do have an influence on solar radiation as it changes the upper atmosphere chemistry. However, the amount of radiation received by the earth’s surface due to sunspots is less than 0.1%. Hence sunspots are not significant contributors to Earth's natural variability.
Earth's climate has always been changing due to the natural processes present, for example, Milankovitch cycles, volcanic eruptions and sunspots. Significant changes observed in our Earth's climate today are a result of human activities since industrialisation.
