This has echoes of the ice age dust/albedo theory – with no CO2 feedbacks – proposed by Ralph Ellis a few years ago. The article concludes: ‘The result thus has the potential to aid the understanding of the abrupt warming and cooling periods during the ice ages called Dansgaard/Oeschger events which bear the marks of climate tipping points.’
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Every late winter and early spring, huge dust storms swirled across the bare and frozen landscapes of Europe during the coldest periods of the latest ice age, says Phys.org.
These paleo-tempests, which are seldom matched in our modern climate frequently covered Western Europe in some of the thickest layers of ice-age dust found anywhere previously on Earth.
This is demonstrated by a series of new estimates of the sedimentation and accumulation rates of European loess layers obtained by Senior Research Scientist Denis-Didier Rousseau from Ecole Normale Supérieure in Paris, France, and colleagues.
The work, which is published in Quaternary Science Reviews is part of the TiPES project on tipping points in the Earth system, coordinated by The University of Copenhagen.
In the study Denis-Didier Rousseau and colleagues reinterpreted layers in loess from Nussloch, Germany.
Loess is a fine-silt-sized earth type found all over the world. It mainly consists of aeolian sediments, which are materials transported by the wind from dry areas without vegetation such as deserts of any type, moraines, or dried-out river beds.
Within the aeolian sediments, darker layers of paleosol alternate within the loess layers. Every layer in the loess represents a shift in climatic conditions.
At Nussloch the paleosols stem from periods of milder climate, called interstadials during the ice age. The aeolian layers were deposited during the cold periods and consist mainly of dust and silt from the dry riverbeds of the Rhine river.
Traditionally in the academic field of paleo-climate, it has been assumed that interstadial paleosols developed on top of the underlying layer, by accumulation when the shift to a relatively mild climate allowed a richer biology to flourish in the region.
Into the dust
But careful sampling and accurate dating of the loess sedimentation from Nussloch with luminescence and 14C by Denis-Didier Rousseau and colleagues have now shown that this is not the case.
Instead, in Europe, paleosols developed down into the underlying layer, not on top of the dust.
Full article here.
via Tallbloke’s Talkshop
February 2, 2021 at 06:48AM