The summer strays, which europe has experienced since 2015, were far more serious than in the approximately 2100 years before. This resulted in an international study, in the artist nature geoscience has been published. The scientists used a specific procedure for the analysis of tree rings and thus created a huge data set, which reflects the hydroclimatic conditions in central europe from the romance time to the present. The aufenhonen dry period is, according to the researchers on the climate change caused by people climate change.
More and more heat tote
Europe experienced extreme summer heat waves and milling in 2003, 2015 and 2018. The consequences had not only affected agriculture and forestry, but also let the number of heat notes up and writing the scientists. Actually had a study, the results of which in the journal the lancet were published, determined that alone in germany 2018 around 20.200 death trap at ober 65-year-old related heat stood.
"We are all of the heap of exercise and deliberately aware of dry summers, which we had in recent years", fits ulf mountains from the university of cambridge, first author of the current study, together. "But we needed precise reconstructions of historical conditions to see how these youngest extremes fail compared to early years." for this classification, nichtgen and his colleagues took more than 27.000 sets of tree rings of 147 oakes, which a period of 2100 years (75 v. Chr. Covered until 2018). The samples came from archaological remnants and historic building materials, but also of living tree from today’s czech republic and parts of the bavarian’s sudely.
Analyzed isotopes in tree rings
Extracted and analyzed the researchers from each of the tree rings and then analyzed the stable carbon and oxygenisotopes. While normal tree ring quantities are roughly restricting ring width and woodproof, the stable isotopes studied here reflect the physical conditions and the reactions of the tree. "The carbon values depends on the photosynthetic activity, the oxygen values are influenced by the spring water. Together they correlate closely with the terms of the growth period", guide kautor paolo cherubini. In this way, the stable isotopes of the annual rings yielded "a much more accurate archive to reconstruct the hydroclimate conditions in mobilized areas where convicted studies with annual rings often fail", jan esper supplies from the university of mainz.
In reconstruction, the tree ring isotope data showed that it gave a very damp summer in europe, such as 200, 720 and 1100 n. Chr., but also very dry summer as in the years 40, 590, 950 and 1510 n. Chr. Overall, the continent has become more dry during the past two millennia. The samples from the years 2015 to 2018 also revealed that the string conditions of the past summer were far more serious than in the 2100 years ago. "After centuries of a slow, significant ruckle we have experienced a drastic burglary, which is particularly alarming for agriculture and forestry", comments co-author mirek trnka. "The unprecedented forest dies in many parts of central europe confirms our results."
Extreme weather conditions become more common
The researchers drove the observed cling of the unusually dry summer on the human climate heat caused by man and the associated changes of the position of the polar jet stream. This attorney to the two coarse wind vents, which compensate for the temperature vapor between the poles and the equator and excite rough effect on our weather. In fact, another international study had revealed that the waves of the polarjet stream had been stalling during the 2018 hitzesummer. "Climate change does not mean that it becomes dry drier: some places it maybe damp or cold, but extreme conditions become more common, which could be devastating for agriculture, okosystems and society as a whole", forecast ulf coloring.
This fits the youngest idea of the climate data of the german weather service (dwd): because the data of the current study ranges only by 2018, the dwd notified only a few days ago that the year 2020 has been the second warmest since the beginning of weather records in germany. Summer peak levels of 40 degrees celsius as in 2019 have failed, but especially in the plant growth particular time from april to september, dryness dominated the weather events.