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The Arctic was once warmer, covered by trees

Discussion in 'Science & Technology' started by micropage7, May 15, 2013.

  1. micropage7

    micropage7

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    Sediments from Lake El'gygytgyn in northeastern Russia reveal that 3.6 million years ago the Arctic's summers were 8 degrees Celsius warmer than they are today.

    The Arctic wasn’t always frozen tundra. About 3.6 million years ago, the far north was blanketed in boreal forests, and summers were 8 degrees Celsius warmer than they are today, geologists report May 9 in Science.

    Researchers pieced together that picture from sediments buried beneath Lake El’gygytgyn (pronounced EL-gih-git-gin), about 100 kilometers north of the Arctic Circle in northeastern Russia
    The sediments preserve the most complete history of Arctic climate on land over the last 3.6 million years.

    “It’s an unprecedented record,” says study coauthor Julie Brigham-Grette, a geologist at the University of Massachusetts Amherst. “It gives us a way of envisioning what the future may hold.”

    The sediments preserve the end of the Pliocene epoch, which lasted from 5.3 million to 2.6 million years ago. The Pliocene was the last time atmospheric carbon dioxide concentrations were roughly 400 parts per million — a benchmark that Earth may soon reach. Because the continents were in about the same locations as they are today, events during the Pliocene may be the best analog for what could happen in the future, says geologist Gifford Miller of the University of Colorado Boulder.

    Previous geologic evidence had indicated the Pliocene Arctic was warm, but these terrestrial records are spotty, providing only isolated snapshots of time, Brigham-Grette says. Lake El’gygytgyn, by contrast, provides exceptionally well-preserved sediments over a long time frame because the region is too dry for large glaciers to grow and then erode away the record, she says. The lake formed after a meteorite struck about 3.6 million years ago, creating an impact crater.

    To get a more comprehensive look at Arctic climate, Brigham-Grette and colleagues drilled a 318-meter-long core from the lake’s bottom. From 3.6 million to 3.4 million years ago, summer temperatures were about 15°, the team determined through analyses of the sediments’ chemistry and trapped pollen. The region also received 600 millimeters of precipitation each year, making it three times as wet as today.

    From 3.26 million to 2.2 million years ago, temperatures gradually cooled in a series of steps that coincided with the beginnings of a glacial period. Forests gave way to shrubby environments, and the Arctic became more arid.

    Despite the cooling, Arctic summers generally stayed 3 to 6 degrees warmer than they are today, until about 2.2 million years ago. Even during periods when changes in Earth’s orbit should have made the Arctic cold, warm summers persisted. “We didn’t expect it to be so consistently warm,” Brigham-Grette says.

    These findings hint that the switch to a glacial period may be more complicated than scientists realized. Comparisons with other climate records from the oceans and the tropics may help researchers identify the mechanisms that drove the Earth’s stepped transition from warm to cool, Brigham-Grette says.

    The past’s high temperatures also highlight another quandary, says Ashley Ballantyne, a climate scientist at the University of Montana in Missoula. Climate simulations have a hard time replicating the Arctic’s warm Pliocene temperatures. The missing puzzle piece may be sea ice, he says.

    Lacking a complete record of sea ice, researchers have assumed that the Pliocene Arctic had no summer sea ice and small amounts of sea ice in winter. In a study accepted for publication in Palaeogeography, Palaeoclimatology, Palaeoecology, Ballantyne, Miller and others demonstrate that without winter sea ice — which normally prevents heat in the ocean from escaping to the atmosphere — simulations can achieve the extremely warm Arctic temperatures.

    That sea ice might have been completely absent from the Arctic in the Pliocene is “a bit alarming,” Ballantyne says. If that were to happen in the future, he says, “it doesn’t bode well for animals that coevolved with sea ice.”

    http://www.sciencenews.org/view/generic/id/350292/description/The_Arctic_was_once_warmer_covered_by_trees
     
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  2. marsey99

    marsey99

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    3.6 million years ago was that part of russia even in the arctic?
     
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  3. qubit

    qubit Overclocked quantum bit

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    The Arctic was warmer then due to that terrible "global warming" they keep telling us about...
     
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  4. Chevalr1c

    Chevalr1c

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    Marsey99 is right, plate tectonics likely comes into play. Better do not trust this article.
     
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  5. bear jesus

    bear jesus New Member

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    I'm curious about that as well and have been trying to try and find out at least an estimated distance traveled in that time but i am having very little luck.

    Plenty of unquoted wiki "information" like these

    "The Pliocene extends from 5.332 million years ago to 2.588 million years ago.[2] During the Pliocene continents continued to drift toward their present positions, moving from positions possibly as far as 250 kilometers (155 mi) from their present locations to positions only 70 km from their current locations."

    "The Pleistocene extends from 2.588 million years ago to 11,700 years before present.[2] The modern continents were essentially at their present positions during the Pleistocene, the plates upon which they sit probably having moved no more than 100 kilometers (62 mi) relative to each other since the beginning of the period."

    If that were anywhere near accurate then surely it could possibly have been 100 miles away?



    I would hope that continental drift would be taken in to account by the people studying this.
     
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  6. Chevalr1c

    Chevalr1c

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    Even if it was only like 100 miles, still it is about 3-4 mln years ago. In such a timeframe a lot can happen, even with the climate.
     
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  7. FordGT90Concept

    FordGT90Concept "I go fast!1!11!1!"

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    And don't forget the "expanding Earth" theory. Oh, and that the Moon was closer back then too meaning the Earth spun faster. And that climate can be changed substantially simply by reversing the flow of deep ocean currents.
     
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  8. Chevalr1c

    Chevalr1c

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    I doubt that spinning speed would influence climates in that way (it would influence it, but on a global scale).

    Anyway, the article does not "disprove" anthropogenic climate change, unlike what qubit seems to think.
     
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  9. qubit

    qubit Overclocked quantum bit

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    I know, but I couldn't resist doing the skeptic thing. :p

    The climate is obviously changing, but whether man really has much to do with it I'm not too sure. There's so much vested interest, corruption and political pressure and inconclusive scientific evidence that I don't know what to believe any more. There seems to be lots of conflicting reports out there.
     
  10. drdeathx

    drdeathx

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    There is a difference between 3.6 million years and 30 years. In 30 Years we have seen the polar caps and much more disappear. Average ocean temps climb almost 2 degrees and seen the oceans rise a few inches. In less than 100 years, 20% of Florida is predicted to be submerged in the ocean. Natural things effect the climate but not in a matter of a few decades.
     
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  11. SK-1

    SK-1

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    The earth hasn't warmed one iota in the last 15 years. But lets fleece people anyway.
     
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  12. erocker

    erocker Super Moderator Staff Member

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    Is that really a bad thing?

    [​IMG]

    Seriously though, for those who are concerned the best you can do, is do your part not to mess up the environment around you. Debating whether environmental change is true or not has no real impact on the environment. The argument can go on forever... then you die... then it doesn't really matter anyways.
     
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  13. Chevalr1c

    Chevalr1c

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    :toast:

    You deserve a medal for that.
     
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  14. theoneandonlymrk

    theoneandonlymrk

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    What ,,,, ive not done universal studios yet or bush gdns :) floridas not that bad.

    Climatic change is beyond doubt imho ,as is the lack of effect any of us can have on it imho

    Your not going to stop the Chinese growth/modernisation now.

    And 100 miles is nothing in plate tectonics or the global scale it is where it was,,, roughly.
     
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