Answer:
So you need to understand that the earth's orbit does change with time consisting of eccentricity.
Eccentricity is the deviation from circularity.
This leads to an axial tilt and precession.
The precession for your understanding is the motion of the axis of a spinning body....so consider a tabletop spinner as an example.
All of this together creates solar radiation that reaches the earth's surface. This cycle is the Milankovitch cycle which describes the total effects of changes in the Earth's movements on its climate over the years we have had.
SO, when the earth is titled toward the northern hemisphere.... we can say that winter and a summer solstice will concur with aphelion and perihelion.
To understand what that means you need to know that....
Perihelion - [This is the point closest to the sun in the path of a body that orbits such as a planet].
Aphelion - [This is the opposite of Aphelion. Meaning it is the furthest.]
These are the required parameters for an ice age. Although unlikely, this is what would be required.