Milankovitch was right!
Peter Huybers statistically evaluates the contribution of the Earth’s ~20 thousand year precession cycle to deglaciations over the last million years, and concludes that both obliquity (how tilted the Earth’s axis is) and precession (the orientation of the tilt) play a role:
Ice sheets tend to collapse in response to unusually large maxima in insolation forcing that result from the coincidence of high obliquity and alignment of perihelion with Northern Hemisphere summer solstice, consistent with the models hypothesized by Milankovitch1 and others5, 6, 7, 8, 9, 10. During these forcing maxima, summer insolation is as much as 40 W m−2 greater at high northern latitudes (Fig. 3b). However, this consistency is not exclusive of all other orbital contributions to deglaciation. For instance, when perihelion aligns with the Northern Hemisphere summer solstice, aphelion occurs during the Southern Hemisphere summer, causing the length of the Southern Hemisphere summer to be longer (Fig. 3b) and, possibly, increasing the escape of CO2 from the Southern Ocean into the atmosphere26, 27, 28, 29. The climate system is thoroughly interconnected across temporal and spatial scales, and, just as neither obliquity nor precession act in isolation, no one region should be expected to exert exclusive influence upon deglaciation.
