The Eemian interglacial era (is analogous Sangamon era in North America, Ipswichian interglacial in UK, Riss-Würm interglacial in the Alps) is the second-to-latest interglacial era of the Ice age. It began about 131,000 years ago, consisted of an early warm period of about 3,000 to 4,000 years duration, a rapid cooling and then a much slower cooling leading to the next glacial era. However, recent ice core analyses have shown that during the course of the Eemian, there were several short periods in which glacial conditions prevailed. The onset and close of these periods were very abrupt. The warmest peak of the Eemian was around 125,000 years ago, when forests reached as far north as North Cape (now tundra) in northern Norway. Hardwood trees like Hazel and Oak grew as far north as Oulu, Finland. Sea levels at that time were higher than they were now, possibly indicating greater deglaciation than today (one presumes the ice sheets of Greenland and possibly Antarctica). Scandinavia was an island due to the inundation of vast areas of northern Europe and the West Siberian Plain.

At the peak of the Eemian, the world was generally warmer and wetter than it now is. Trees grew as far north as Baffin Island in the Canadian Arctic Archipelago instead of only as far north as Kuujjuaq , and the prairie-forest boundary in the Great Plains lay further west -- near Lubbock, Texas instead of near Dallas, Texas where it now exists. The era quickly cooled to conditions cooler and drier than the present, and by 114,000 years ago, a glacial era had returned.

Ipswichian interglacial

The Ipswichian interglacial is a name for an interglacial period which occurred between 150,000 and 115,000 years ago. The name is used by British geologists and archaeologists who named it after the town of Ipswich in the English county of Suffolk where some of the deposits it created were first found.

It is a Pleistocene stage of the Quaternary period. It was a warm period and its deposits directly overlie material from the preceding wolstonian glaciation and lie beneath those from the following Devensian glaciation

Mousterian flint tools have been found in Ipswichian deposits. .