Researchers found signs of increased air mass transport from the North Atlantic.
The remains of a buried pine forest at the foot of Mont Saint Genis in Southern France yield insightful information on a drastic climate change event. The pine tree stand initiated around 12,900 years ago during the relatively warm “Allerød” period, and continued growing into the cold snap of the "Younger Dryas" period. Researchers at the GFZ German Research Centre for Geosciences in Potsdam, together with international colleagues, have for the first time combined classic tree-ring width measurements with chemical (stable isotope) analyses of carbon and oxygen in tree-rings to reconstruct climate variables. Thus, they were able to calculate local soil water composition (precipitation) and relative humidity at annual time resolution. This resulted in novel insights into the hydrological variability and atmospheric circulation changes during an abrupt climate change event. The team reports about its findings in the journal Scientific Reports.
The sudden cold snap in the northern hemisphere between 12,700 and 11,600 years ago has been found in climate records from Greenland ice cores and Central European lake sediments. It was named after the mountain avens (Latin: Dryas octopetala) – an Arctic plant species that predominantly spreads during cold conditions. The discovery of fossil pines in a French river valley near Avignon now close an important knowledge gap, as they shows how the climate in the Mediterranean changed in this period. With accurate radiocarbon dating, the scientists were able to prove that the buried pines had started their growth in the warm days of the Allerød just before the Younger Dryas and had survived the sudden cold snap for several decades. They were thus witnesses of this extreme climate change.
Continue reading at GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre
Image via GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre
