What is the reason for all these geological changes with the earth?

Almost all of the energy that affects the climate on the Earth originates from the Sun.

The energy emitted by the sun passes through space until it hits the Earth’s atmosphere.

Only about 40 per cent of the solar energy intercepted at the top of the atmosphere passes through to the Earth’s surface.

The rest is reflected or absorbed by the atmosphere. The energy output of the sun is not constant, it varies over time and it has an impact on our climate.