Jag vill gärna tipsa om en intressant studie av Brauer, Haug, Dulski, Sigman och Negendank (Tracking down abrupt climate changes) som publicerats i Nature Geoscience. Författarna bevisar för första gången att en extremt snabb klimatförändring i Västeuropa skedde på grund av snabba skift i vindsystem.
The proof of an extreme cooling within a short number of years 12 700 years ago was attained in sediments of the volcanic lake “Meerfelder Maar” in the Eifel, Germany. The seasonally layered deposits allow to precisely determine the rate of climate change. With a novel combination of microscopic research studies and modern geochemical scanner procedures the scientists were able to successfully reconstruct the climatic conditions even for individual seasons. And so it was particularly the changes in the wind force and direction during the winter half-year, which caused the climate to topple over into a completely different mode within one year after a short instable phase of a few decades.
Up to now one assumed that it was the attenuation of the Golf Stream alone that was responsible for the strong cooling in Western Europe.
The examined lake deposits show however that the atmospheric circulation, probably in connection with the spreading of sea-ice, probably played a very important role. At the same time, these new results also show that the climate system is long not understood, and that especially the mechanisms of short-term change and the time of occurrence still hold many puzzles. Micro-layered lake deposits represent particularly suitable geological archives, with which scientists want to track down climate change.
“An abrupt wind shift in Western Europe at the onset of the Younger Dryas cold period”, Achim BRAUER, Gerald H. HAUG, Peter DULSKI, Daniel M. SIGMAN, Jörg F.W. NEGENDANK, Nature Geoscience 8, 520 – 523
Kan onekligen vara intressant att läsa hela studien. Läs även vad Discovery News skriver om studien.