Why can't the varying distance between the sun and the earth account for season?

Let's look at the following facts:

1) The distance between the Earth and the Sun is 149.6 million kilometers, the change of that distance is less than 1%.

2) When it's summer in the northern hemisphere it's winter in the southern - and vise versa. So the reason for the seasons cannot be the distance from the sun, but a property of Earth - it's axial tilt.