evidence: Changes to the tilt of Earth's axis (obliquity) Our planet spins on an axis that is tilted toward the orbital plane. Currently, this tilt (also called obliquity) deviates by 23.4 degrees from what would be a 90-degree angle toward the orbital plane. But this obliquity oscillates over time. Over the last million years, it has been swinging from 22.1-degrees to 24.5-degrees, according to NASA. [...] Climate change deniers like to argue that our planet would warm up no matter what, even without the greenhouse gas emissions that humankind is releasing into Earth's atmosphere.