Was sagt uns das Klima der letzten Jahrtausende über unser heutiges Klima? Dieser Frage gehen wir im heutigen Blogpost nach und schauen uns hierzu drei neue Studie an.
In den Rock Mountains war es vor 6000 Jahren offenbar wärmer als heute. Ganz ohne CO2-Effekt. Aus dem Gletschereis Tauchten jetzt Baumreste auf, die deutlich über der heutigen Baumgrenze liegen. Das holozäne thermische Maximum (HTM). Der NewScientist berichtete:
Melting ice reveals millennia-old forest buried in the Rocky mountains
Trees dating back almost 6000 years have come to scientists‘ attention due to ice melting in the Rocky mountains, offering a „time capsule“ into the past.
A 5900-year-old whitebark pine forest has been discovered due to the melting of alpine ice in the Rocky mountains. Scientists found more than 30 trees approximately 3100 metres above sea level – 180 metres higher than the present tree line – while carrying out an archaeological survey on the Beartooth plateau in Wyoming.
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Wir bleiben beim HTM. Die Prudhoe Dome Eiskappe gab es vor 7000 Jahre noch gar nicht. Das Gebiet war eisfrei, wo heute Eis liegt. Es war damals offenbar wärmer als heute. Die University at Buffalo berichtete von den Ergebnissen einer Bohrkampagne im Eis:
Greenland’s Prudhoe Dome ice cap was completely gone only 7,000 years ago, study finds
The first study from GreenDrill—a project co-led by the University at Buffalo to collect rocks and sediment buried beneath the Greenland Ice Sheet—has found that the Prudhoe Dome ice cap was completely gone approximately 7,000 years ago, much more recently than previously known.
Published today (Jan. 5) in Nature Geoscience, the findings suggest that this high point on the northwest section of the ice sheet is highly sensitive to the relatively mild temperatures of the Holocene, the interglacial period that began 11,000 years ago and continues today.
„This is a time known for climate stability, when humans first began developing farming practices and taking steps toward civilization. So for natural, mild climate change of that era to have melted Prudhoe Dome and kept it retreated for potentially thousands of years, it may only be a matter of time before it begins peeling back again from today’s human-induced climate change,“ says Jason Briner, Ph.D., professor and associate chair of the Department of Earth Sciences in the UB College of Arts and Sciences, who co-led GreenDrill with Joerg Schaefer Ph.D., research professor at Columbia University’s Lamont-Doherty Earth Observatory.
GreenDrill is a first-of-its-kind endeavor to drill down into the Greenland Ice Sheet and retrieve the frozen, ancient bedrock and sediment underneath. The scientific community has less rock and soil material from below Greenland’s ice than it does from the moon, yet it is invaluable: Chemical signatures can tell us when the material was last exposed to open sky, pinpointing when the ice sheet has melted in the past.
Weiterlesen auf phys.org
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Früher hat es immer genau richtig geregnet, heute ist der Regen außer Rand und Band? Quatsch. Auch in der Vergangenheit haben sich regenreiche und regenarme Phasen abgewechselt. Science China Press zu einer Studie zum Regen auf dem Tibetplateau während der letzten 2000 Jahre:
Spatiotemporal variations of rainy season precipitation in the Tibetan Plateau during the past two millennia
The quantitative reconstruction of the length of the rainy season and precipitation on the Tibetan Plateau (TP) is crucial for revealing the spatiotemporal evolution of the Westerlies and South Asian monsoon, as well as its ecological and environmental effects.
Accurately determining the start and end times of the rainy season on the Plateau remains challenging. A recent study, published in the journal Science China Earth Sciences, quantitatively reconstructed the spatiotemporal variations of rainy season precipitation from northern TP (Kusai Lake) and central TP (Jiang Co) during the past two millennia.