Since all of Earth’s energy is ultimately derived from the Sun, it makes sense that the planet’s position and orientation relative to the Sun would have an effect on climate. The Earth’s orbit around the sun is not a perfect circle, but an ellipse, and so the distance from the Earth to the Sun changes as the Earth travels its yearly path around the Sun.

In addition, the axis of the Earth (running from pole to pole) is not vertical with respect to the sun, but is tilted 23.5 degree. These two factors - the Earth’s orbit and it’s tilt - are responsible for seasons, which various parts of the world experience differently. The seasons represent a relatively short term change in climate, which is cyclical.

Earth’s changing distance from the sun results in variations in the amount of incoming radiation, or insolation, the planet receives. Insolation varies by month and by season, and amount of insolation is a determining factor for strength and frequency of monsoons, and size of ice sheets. Monsoons and ice sheets, in turn, affect atmospheric levels of CO2 and methane, both of which are greenhouse gases and affect the climate.