Subatlantic
During its course, the temperature underwent several oscillations, which had a strong influence on fauna and flora and thus indirectly on the evolution of human civilizations.
With intensifying industrialisation, human society started to stress the natural climatic cycles with increased greenhouse gas emissions.
[12] If one equates the onset of the younger subatlantic with the first maximum of beech occurrence it shifts back to Carolingian times around 700 AD.
This climatic deterioration with the establishment of drier and cooler conditions might have forced the Huns to move west thus in turn triggering the migrations of the Germanic tribes.
At about the same time the Byzantine Empire reached its first acme and Christianity established itself in Europe as the leading monotheistic religion.
After this relatively short cool interlude the climate ameliorated again and reached between 800 and 1200 almost the values of the Roman Warm Period (used temperature proxies are sediments in the North Atlantic).
The end of the Medieval Warm Period coincides with the early 14th century reaching a temperature minimum around 1350, and by the Crisis of the Late Middle Ages.
[18] Human history during this time includes the Renaissance and the Age of Enlightenment, and also major rebellious events like the Thirty Years War and the French Revolution.
[19] Ice core analyses from Greenland and Antarctica show a very similar evolution in greenhouse gases.
After a temporary minimum during the preceding subboreal and atlantic the concentrations of carbon monoxide, nitrous oxide and methane slowly started to rise during the Subatlantic.
This sudden release of greenhouse gases into the atmosphere by human society represents an unprecedented experiment with unpredictable consequences for Earth's climate.
[21][22][23] Within the same context the release of juvenile water tied up in fossil fuels like coal, lignite, gas and petrol is generally overlooked.
Yet at the end of the 19th century a drastic change can be witnessed with a rate increase to 1.8 mm per year in the period 1880 to 2000.
The mixed oak forests lasted until the middle subatlantic (pollen zone IX b), which also had a wet but somewhat milder climate.
During the younger subatlantic (pollen zone X a), whose wet and temperate climate resembled already today's conditions, a mixed or an almost pure beech forest established itself.
Anthropogenic influences (i. e. agricultural land uses, grazing and forestry) that date back to the Bronze Age started to become dominant.
The actual youngest subatlantic (pollen zone X b) with its wet and temperate climate shows a distinct precipitation gradient with decreasing rainfall from west to east.
In northwestern Germany mixed oak forests take up 40% amongst the total tree pollen during the older subatlantic and are therefore dominant.
[27] According to H. M. Müller the spreading of beech was caused by an increase in humidity since 550 BC and later favoured by a decrease in human settlements during the migrations.
Freshwater taxa have even been more severely affected – they have lost up to 50%, mainly due to biotope loss and water pollution.
