Nearly 13,000 years ago, pines in southern France experienced a cold snap, which scientists have now reconstructed. The study about the consequences of a drastic climate change event in past and its implications for our future will be published tomorrow in Scientific Reports. The authors are from GFZ Potsdam, Berlin, the UK, Switzerland, and France.
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.
In their analyzes, the researchers found signs of increased air mass transport from the North Atlantic. "We were surprised that about sixty years before the actual climate change, a significant alteration in the precipitation source was recognized," says first author Maren Pauly of the GFZ.
According to the results, humid air masses arriving from the Atlantic side enhanced, while rainfall originating from the Mediterranean side diminished, evidenced by a steadily increasing variability of the oxygen isotopes of the soil water. Isotopes are atoms with a different number of neutrons in the nucleus.
From the ratios of light and heavy isotopes conclusions can be drawn on the origin of air masses and thus of precipitation. "Especially striking is the increase of extreme polar air surges, winter precipitation and winter storms at the beginning of the Younger Dryas," adds Achim Brauer, Head of GFZ’s section Climate Dynamics and Landscape Evolution and Director of Department 5 at GFZ. Maren Pauly works as a PhD student in his group.
With this study, the scientists proved that it was not a change in mean temperatures that was problematic, but rather the environmental stress presumably leading to the tree die off. This stress was caused by the accumulation of extreme weather conditions in single years or even decades. In general, this study shows that periods of massive climate change can be associated with more instability in atmospheric circulation patterns, leading to greater variability on annual or decadal scales.
"Here, paleoclimate research shows how it can close knowledge gaps with information from natural climate archives," says Achim Brauer. This is also important because "we lack experience on what exactly happens during a sudden climate change, how quickly the climate can change, and what regional differences occur."
The study was funded by the DFG project (HE 3089 / 9-1) and supported by the Helmholtz REKLIM initiative.
Subfossil trees suggest enhanced Mediterranean hydroclimate variability at the onset of the Younger Dryas” (SREP-18-03033-T)
Josef Zens | idw - Informationsdienst Wissenschaft
One-third of recent global methane increase comes from tropical Africa
11.12.2019 | European Geosciences Union
The Arctic atmosphere - a gathering place for dust?
09.12.2019 | Leibniz-Institut für Troposphärenforschung e. V.
Using a clever technique that causes unruly crystals of iron selenide to snap into alignment, Rice University physicists have drawn a detailed map that reveals...
University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making
In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...
With ultracold chemistry, researchers get a first look at exactly what happens during a chemical reaction
The coldest chemical reaction in the known universe took place in what appears to be a chaotic mess of lasers. The appearance deceives: Deep within that...
Abnormal scarring is a serious threat resulting in non-healing chronic wounds or fibrosis. Scars form when fibroblasts, a type of cell of connective tissue, reach wounded skin and deposit plugs of extracellular matrix. Until today, the question about the exact anatomical origin of these fibroblasts has not been answered. In order to find potential ways of influencing the scarring process, the team of Dr. Yuval Rinkevich, Group Leader for Regenerative Biology at the Institute of Lung Biology and Disease at Helmholtz Zentrum München, aimed to finally find an answer. As it was already known that all scars derive from a fibroblast lineage expressing the Engrailed-1 gene - a lineage not only present in skin, but also in fascia - the researchers intentionally tried to understand whether or not fascia might be the origin of fibroblasts.
Fibroblasts kit - ready to heal wounds
Research from a leading international expert on the health of the Great Lakes suggests that the growing intensity and scale of pollution from plastics poses serious risks to human health and will continue to have profound consequences on the ecosystem.
In an article published this month in the Journal of Waste Resources and Recycling, Gail Krantzberg, a professor in the Booth School of Engineering Practice...
03.12.2019 | Event News
15.11.2019 | Event News
15.11.2019 | Event News
09.12.2019 | Earth Sciences
09.12.2019 | Information Technology
09.12.2019 | Life Sciences