The Quaternary is determined to be an ice age due to the presence of a permanent ice sheet on Antarctica.

During the pleistocene epoch there were fluctuations between cold glacial periods and warm interglacial periods. This brought the expansion and contraction of ice sheets.

The Holocene marks the beginning of the current interglacial period and the current period of relative climate stability.

Evidence for this can be seen in ice cores and ocean sediment; more recent changes are often described in historical records and tree rings.