Figure 3. Alignment of the Earth’s obliquity and the boreal and austral precessional insolation minima around glacial inceptions over the last 900 kyr.

The alignment is expressed by the duration of offset between the insolation minimum and the nearest obliquity minimum as shown in Fig. 1b. The horizontal dashed line shows the empirical value of 5 ka, below which the alignment of obliquity and precessional insolation minima are considered to be in phase³.