It is an unresolved puzzle why the south of Greenland was only successfully populated by North men in the early Middle Ages, but was left quite suddenly after a few centuries. There are some theories about the reasons for the abandonment of the settlements in the early 15th century: It is obvious that the worldwide cooling in the small ice age has made life in Greenland creeping. In addition, there may have been a non -sustainable handling of resources due to growing global competition. A new analysis is now the main cause of the climate as the main cause - but in Greenland it was probably not too cold for the settlement in the long run, but above all clearly too dry.
This is the conclusion reached by a team of researchers led by Raymond Bradley from Amherst University in the journal "Science Advances". The researchers were the first team to collect data on site in the old settlement area in order to reconstruct the microclimate there in the Middle Ages. Previous studies had carried out historical climate reconstructions using ice cores that were extracted from the Greenland ice at a higher altitude almost 1000 kilometers further north. In the south of Greenland, however, other conditions prevailed in the 15th century as well, as the new studies show.
Bradley's team took rehearsals from »Lake 578« for over three years, a lake that is in the immediate vicinity of one of the largest abandoned settlements of the northern men in the southeast of Greenland. It reconstructed the weather changes from the ice drilling nuclei over two millennia. Temperature changes reveal about so -called GDGTS, certain branched lipid molecules that are produced by bacteria and archae and are contained every year frozen ice of the drilling nuclei. The branching structure of this molecules depends on the ambient temperature in which the bacteria have lived. In addition, the researchers were able to determine the change in humidity over time; In addition, a certain waxy molecule served as a marker, which spans plants in more or less large quantities on their leaf surfaces in order to protect themselves more or less from drying out.
As the analysis shows, it was not unbearably cold in the Little Ice Age in the south of Greenland. True, the ice tongues of the glaciers grew on the spot: according to the calculations of the working group, the Kangiata Nunaata Sermia, for example, increased up to 115 meters of ice year after year and quickly approached the settlements of the Greenlanders. However, this should not have bothered them very much. Presumably, the rapidly growing glacier tongue calved even fewer icebergs into the sea, which may have made it easier for local people to access the sea.
What was striking, however, was: while the average temperature over the entire settlement duration of the northern men of 985 AD. Z. remained almost the same until the 15th century, the drought increased. This must have had difficult consequences, especially in winter: the Nordmänner rely on keeping their cattle alive with stored food until spring. The authors of the study probably could probably no longer be grown enough under the dry conditions. The problem was apparently aware of the boilers: At the end of the settlement phase, they had started digging irrigation grooves for fields - a ultimately insufficient countermeasure. In addition, they increasingly had to fall back on other food sources such as fish and seafood.
In the eastern settlements, up to 2000 people had lived for the wedding of the Greenland settlement. There were further settlements in the west of the island. These were given up earlier: A Norwegian priest had already found no living »Grænlendingar« there in 1350.
