Will Precession Affect Climate?

Axial precession

makes seasonal contrasts more extreme in one hemisphere and less extreme in the other. Currently perihelion occurs during winter in the Northern Hemisphere and in summer in the Southern Hemisphere. This makes Southern Hemisphere summers hotter and moderates Northern Hemisphere seasonal variations.

What's the difference between obliquity and precession?

Obliquity describes the tilt of the Earth's axis in relation to its orbital plane, which ranges from 22.1–24.5 degrees with a periodicity of ~41,000 years. Precession describes the motion of the Earth's axis of rotation, which does not point towards a fixed direction in the sky through time.

Does precession cause ice ages?

In theory, insolation should average out every year as Earth wobbles back and forth with the seasons. However, changes in Earth's wobbles, or precession—occurring in roughly 20,000-year cycles and accentuating each roughly 100,000 years—allow sea ice to grow faster in one hemisphere than the other.