How does earth's orbit affect the seasons?
The Earth orbits Sun in an elliptical orbit distance varies from 147.1 million KM to 152.1 million KM>
The reason for changing seasons are not the distance change. But the axial tilt which makes sun light to strike at different angles.
For Example Earth is nearest to Sun on January 4th when we have winter in northern hemisphere.
picture credit blogs nasa.gov.