10
$\begingroup$

Today, Northern Russia is considered quite cold. It is not populated because it has low biological productivity: low light and cold. It can be below -50 at winter and 10 C at summer peak. It is low populated because there is basically nothing to eat. Poor reindeers dig some moss from below the snow, which grows there a little during short summer period.

I am telling all of that, because I cannot even imagine what the hell Yakutiya would have been when all north of the continent was 1 km below the ice! Siberia stays permafrost even now, when you have warm summer days +5 Celsius. Certainly, it had to be frozen at glacier time permanently. Meantime, it is curious how people managed to cross the Bering Land Bridge during that latest glacier. How was that possible at that time, was it a Polar Voyage?

Now, I read that Yakutiya was a wild life refugee during the last ice age. It had much more rich wild life than now, comparative to what we have in Africa today. People appeared there 12 000 years ago, when half of the Great Glacier was melted

enter image description here

and slaughtered mammoth. The mega-fauna extinction collapsed Siberian ecosystem, say scientists who undertake an attempt to recover it. They tell that mammoth grazed grass. Did they procure it from below the snow, like reindeer do? Ok, Beringia says that

During the ice ages, Beringia, like most of Siberia and all of north and northeast China, was not glaciated because snowfall was very light. It was a grassland steppe, including the land bridge, that stretched for hundreds of kilometres into the continents on either side.

Fine. But, the fact that all ice was concentrated over Europe and Canada does not mean that Beringia surface was not permanently frozen. If there is so cold that whole Europe is under 1 km of Ice, the cold Beringia must be frozen either, despite all ice is over Europe. We can have low temperatures without ice, right? And, if it was terribly cold in Europe, it must be at least that cold in Beringia, right? So, what could poor animals eat there, in the frozen desert?

To summarize, my question is:

How is this nonsense possible that the 'freezer' of our planet was flourishing, whereas the rest of the Planet was starving in frozen state during last glacier period?

PS! I was suggested to look at the climate zones during Last Glacier. I have seen it but I cannot believe that northern Canada and Greenland was thriving forest whereas almost whole US was under permanent ice sheet. Similarly, we see that Tundra (current Eastern Siberia state) ruled in permafrozen Beijing whereas Eastern Siberia was enjoing same thriving steppe Forest that Alaska did

enter image description here

That is unbelievable and that is what I basically ask to explain. I guess that I have just mismapped the colors. There are too few colors. On the other hand, if anomaly did exist, I want to hear that explicitly, desirably with explanation. Is it really large animals who maintained the warmth at the very north (see "Park" above) before people exterminated them or what?

PS2 I have revised the climate zones map and realized that we had Polar Desert in Siberia and Alaska rather than Forest Steppe. This makes more sense. But how did we had the large animals and thriving greenlands there anyway? Polar Desert is incompatible with green land, obviously. Polar Desert at zones map seems also to contradict the Beringia article, attributing Beringia to grassland steppe during Ice Age.

$\endgroup$
  • 1
    $\begingroup$ Climate is a complicated and complex field. Precipitation is the source of glaciers and changed wind patterns distributed moisture and temperatures differently. Moreover, 'whole Europe' was never under 1km of ice. This: eprints.uni-kiel.de/3566/1/2004_Svendsen-etal-Late_QSR-23.pdf and this: sciencedirect.com/science/article/pii/S0277379108000346 discuss some of the aspects, but I don't know any good references for eastern Siberia. $\endgroup$ – Tactopoda Jun 15 '15 at 23:42
  • 1
    $\begingroup$ This Wikipedia article also shows the climate zones during LGM: en.wikipedia.org/wiki/Last_Glacial_Maximum $\endgroup$ – Tactopoda Jun 16 '15 at 0:04
  • 1
    $\begingroup$ @Recognize Your question has some weird broken-off sentences around the picture. Can you edit and fix it? I looked, but I have no idea what you want to say there. $\endgroup$ – Jan Doggen Jun 16 '15 at 7:46
  • 1
    $\begingroup$ @Recognize Also explain the use of the sea-level rise curve in the context. $\endgroup$ – Tactopoda Jun 16 '15 at 8:01
  • 5
    $\begingroup$ Siberia was warmer during LGM than it is now. Look up on the work by Prof. Sergey Zimov. He's a scientist based in Cherskii at the Arctic coast of northeastern Siberia and he is an extraordinarily memorable individual and a great scientist. If I recall correctly, albedo was one aspect, biodiversity and bioproductivity was much higher before human hunting made mammoths extinct and Siberia turned from a park landscape to a dense forest. I don't recall the details, but do look up his work. $\endgroup$ – gerrit Jun 16 '15 at 10:21
1
$\begingroup$

This paper basically summarizes the thinking behind the highly-productive mammoth step theory:

Zimov, S.A., Zimov, N.S., Tikhonov, A.N., Chapin, F.S., 2012. Mammoth steppe: a high-productivity phenomenon. Quaternary Science Reviews 57, 26–45. https://doi.org/10.1016/j.quascirev.2012.10.005

The idea is basically that a large herbivore density (comparable to modern day intact African Savannah ecosystems) kept soil moisture low and reduced permafrost temperatures. This was favoring gramminoids (grass like plants) that are much more productive than the present day prevailing mosses. Plant productivity in these regions is usually limited by nitrogen (other ecosystems are carbon limited). The higher than today herbivore population provided a lot of nitrogen input from dung and urine propelled the productivity of plants, which in turn allowed for more herbivores. Low temperatures and shorter summers also limited damage to gramminoids, thus they could grow faster in the next season. The ecosystem had several positive feedback mechanisms sustaining high productivity.

When humans arrived in the region, they hunted all the herbivores. The system collapsed and lost its productivity.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.