Солтүстік Еуропаның Атлантикалық климат кезеңі

Period of Blytt–Sernander sequence of north European climatic phase

The Atlantic in palaeoclimatology was the warmest and moistest Blytt–Sernander period, pollen zone and chronozone of Holocene northern Europe. The climate was generally warmer than today. It was preceded by the Boreal, with a climate similar to today's, and was followed by the Subboreal, a transition to the modern. Because it was the warmest period of the Holocene, the Atlantic is often referenced more directly as the Holocene climatic optimum, or just climatic optimum.

The Atlantic is equivalent to pollen zone VII. Sometimes a Pre atlantic or early Atlantic is distinguished, on the basis of an early dividing cold snap. Other scientists place the Atlantic entirely after the cold snap, assigning the latter to the Boreal. The period is still in the process of definition.

According to the ice core criterion it is extremely difficult to find a clear boundary, because the measurements still differ too much and alignments are still under construction. Many find a decline of temperature significant enough after 4800 BC. Another criterion comes from bio stratigraphy: the elm decline. However, this appears in different regions between 4300 and 3100 BC.

The Atlantic was a time of rising temperature and marine transgression on the islands of Denmark and elsewhere. The sea rose to 3 m above its present level by the end of the period. The oysters found there required lower salinity. Tides of up to 1 m were present. Inland, lake levels in all north Europe were generally higher, with fluctuations. The temperature rise had the effect of extending southern climates northward in a relatively short period. Thermophilous ("heat loving") species migrated northward. They did not replace the species that were there, but shifted the percentages in their favor. Across middle Europe, the boreal forests were replaced by climax or "old growth" deciduous ones, which, though providing a denser canopy, were more open at the base. The dense canopy theory, however, has been questioned by F. Vera. Oak and hazel require more light than is allowed by the dense canopy. Vera hypothesizes that the lowlands were more open and that the low frequency of grass pollen was caused by the browsing of large herbivores, such as aurochs and wild horses, a thesis referred to as the wood pasture hypothesis.

During the Atlantic period the deciduous temperate zone forests of south and central Europe extended northward to replace the boreal mixed forest, which found refugia on the mountain slopes. Mistletoe, Water Chestnut (Trapa natans) and Ivy (Hedera helix) were present in Denmark. Grass pollen decreased. Softwood forests were replaced by hardwood. Birch and pine were replaced by oak, linden (lime, both small and large leaf species), beech, oak, hazel, elm, alder, and ash, spreading to the north from further south. The period is sometimes called "the alder elm lime period". In northeast Europe, the Early Atlantic forest was but slightly affected by the rise in temperature. The forest had been pine with an underbrush of hazel, alder, birch, and willow. Only about 7% of the forest became broad leaved deciduous, dropping to Boreal levels in the cooling of the Middle Atlantic. In the warmer Late Atlantic, the broad leaved trees became 34% of the forest. Along the line of the Danube and the Rhine, extending northward in tributary drainage systems, a new factor entered the forest country: the Linear Pottery culture, clearing the arable land by slash and burn methods. It flourished about 5500–4500 BC, falling entirely within the Atlantic. By the end of the Atlantic, agricultural and pasture lands extended over much of Europe and the once virgin forests were contained within refugia. The end of the Atlantic is signaled by the "Elm decline", a sharp drop in Elm pollen, thought to be the result of climate, disease or
human food producing activities.

Human cultures of Northern Europe were primarily Mesolithic. The Kongemose culture (6400–5400 BC) settled on the coastline and lake margins of Denmark. Late in the Atlantic, Kongemose culture settlements were abandoned because of the rising water of the Littorina Sea; and the succeeding Ertebølle culture (5400–3900 BC) settled more densely on the new shorelines. Northeastern Europe was uninhabited in the Early Atlantic. When the Mesolithic Sertuan Culture appeared there in the Middle Atlantic, around 7000 BP, it already had pottery and was more sedentary than earlier hunter gatherers, depending on the great abundance of wildlife. Pottery was being used around the lower Don and Volga from about 8000 BP. In the Late Atlantic, Sertuan culture evolved into Rudnya culture, which used pottery like that of the Narva and Dnieper Donets cultures. That use of pottery upsets the idea that pottery belongs to the Neolithic. Further to the south, the Linear Pottery culture had already spread into the riverlands of Central Europe and was working a great transformation of the land. On the steppe to the east, the Samara culture was deeply involved with large numbers of horses, but it is not yet clear in what capacity.