The Bølling-Allerød interstadial was a warm and moist interstadial period that occurred during the final stages of the last glacial period. This warm period ran from c. 14,700 to 12,700 years before the present. It began with the end of the cold period known as the Oldest Dryas, and ended abruptly with the onset of the Younger Dryas, a cold period that reduced temperatures back to near-glacial levels within a decade.
In some regions, a cold period known as the Older Dryas can be detected in the middle of the Bølling-Allerød interstadial. In these regions the period is divided into the Bølling oscillation, which peaked around 14,500 BCE, and the Allerød oscillation, which peaked closer to 13,000 BCE.
Humans reentered the forests of Europe in search of big game, which they were beginning to hunt relentlessly, many to extinction. Their cultures were the last of the Late Upper Palaeolithic. Magdalenian hunters moved up the Loire into the Paris Basin. In the drainage basin of the Dordogne, the Perigordian prevailed. The Epigravettian dominated Italy. In the north, the Hamburgian and Federmesser cultures are found. The Lyngby, Bromme, Ahrensburg and Swiderian were also attested in Europe at this time. To the south and far east the Neolithic had already begun. In the middle east, the pre-agricultural Natufian settled around the east coast of the Mediterranean to exploit wild cereals, such as emmer and two-row barley. In the Allerød they would begin to domesticate these plants.
At the start of this period, worldwide sea levels rose more than 100 m due to glacial melt. Ice uncovered large parts of north Europe and temperate forests covered Europe from 29 deg. to 41 deg. north latitude. Pioneer vegetation, such as Salix polaris and Dryas octopetala, began to grow in regions that were previously too cold to support these plants. Later, mixed evergreen and deciduous forests prevailed in Eurasia, more deciduous toward the south, just as today. Birch, Aspen, spruce, pine, larch and juniper were to be found extensively, mixed with Quercus and Corylus. Poaceae was to be found in more open regions.
During this time late Pleistocene animals spread northward from refugia in the three peninsulas, Iberian Peninsula, Italy and the Balkans. Geneticists can identify the general location by studying degrees of consanguinity in the modern animals of Europe. Malt animals were able to move into regions far more northerly than they could have survived in during the preceding colder periods. Reindeer, horse, saiga, antelope, bison, woolly mammoth and wooly rhinoceros were attested, and were hunted by early man. In the alpine regions ibex and chamois were hunted. Throughout the forest were red deer. Smaller animals, such as fox, wolf, hare and squirrel also appear. Salmon was fished. When this interstadial period ended, with the onset of the Younger Dryas, many of these species were forced to migrate south or become regionally extinct.