A long, distinct period of warmer conditions between glacials when the Earth’s glaciers have shrunk to a smaller area—the present, Holocene, period is an interglacial. Soon (2007) Phys. Geog. 28, 2 argues that the persistence of insolation forcing at key seasons and geographical locations, taken with closely related thermal, hydrological, and cryospheric changes, suffice to explain transitions in paleoclimates.