In the new study, the authors examined calcite similar rocks on the walls of several caveson
Next, the researchers measured the proportions of uranium and thorium isotopes in these sediments and found that approximately 400,000 uranium and thorium were deposited.years ago, there was no permafrost in almost all of what is now Canada and Alaska beyond the Arctic Circle.Similar warming has occurred before.
On the one hand, our observations and similar measurements in Siberia show that the climateof the entire Arctic became more stable about 400,000 years ago.On the other hand, we found no evidence that there were sharp spikes in greenhouse gas concentrations due to thawing permafrost in earlier epochs.
Research text
It is noted that during the same period, the climate changed in a similar wayThis means that permafrost was unstable throughout most of the Pleistocene.However, its melting, for reasons that are still unclear, did not affect the climate in any wayEarth and the concentration of greenhouse gases in its atmosphere.
One of the reasons for such abrupt changes, the authors say, could be the periodic disappearance of permafrost, which prevented organic matter from accumulating in large quantities.
However, climatologists do not exclude that methane and carbon dioxide, which were formed in the process of decomposition of the remains of plants and animals, could be absorbed by someone or something.
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