Clovis Comet & North American Mass Extinction

Discussion in 'Earth Science' started by John L, Jun 8, 2008.

  1. Tht1Gy! Life, The universe, and e... Registered Senior Member

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    780
    Benign as global warming??? WTF? It's an issue we are in control of, more or less, political issues notwithstanding.

    Further, what exactly do you propose we do about the "impactor" issue? Bruce Willis is already booked.

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    Tho I do have to say, some interesting ideas here, thread wise.
     
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  3. Repo Man Valued Senior Member

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    No; you see, worse cataclysms have happened in the past, so we shouldn't worry about a relatively minor cataclysm in the present time. And you have to get your climate change deniers classified correctly - there are still a minority that deny that global temperatures are changing at all, then there are the ones that concede that they are, but still refute that it has been caused by humans. One thing I have yet to comprehend is the way they seem so happy at the idea that global climate change isn't caused by human activity. If it isn't caused by human activity, then there really is nothing to be done, and we are truly helpless in the face of negative consequences (for humans) that will follow a relatively minor change in global temperatures. This is good news?
     
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  5. Tht1Gy! Life, The universe, and e... Registered Senior Member

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    That so much clearerer.

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  7. Fraggle Rocker Staff Member

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    Yes. I have always said that scientists should stop emphasizing the human connection, even if it's true, and focus mankind's attention on the effects of global warming rather than the cause. Our descendants won't really care whether global warming was our fault as long as we fixed it. And if we don't fix it and it's really as bad as the models predict, the few who survive will probably be so primitive that they won't retain any knowledge of our history.
    Why do you say that? Most of the endeavors that have been recommended for slowing or reversing global warming are good science, regardless of whether it was caused by our carbon footprint, cow farts, sunspots or the randomness of Mother Nature. Even if there's an underlying cause we haven't yet discovered that has nothing to do with us, continuing to belch carbon will make it worse and not continuing to belch carbon will make it better. The question is whether we can make it enough better to solve the problem, and the majority of respectable scientists seem to think so... as long as Mother Nature doesn't decide to pick up the tempo.
    I don't think that's a logical conclusion to derive from the facts that we have gathered so far, so it's not news at all. The models of the climate don't include "how it got this way" as an important variable.
     
  8. Tht1Gy! Life, The universe, and e... Registered Senior Member

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    Oh, come on F.R. He wasn't supporting those positions. He was expressing their inexplicability. That's what I understood him to be saying, anyway
     
  9. Repo Man Valued Senior Member

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    To clarify my position, I think it is good news if climate change is caused by human activity, and bad news if it is not. I think it is more likely that we will take effective action in a timely manner if we are the cause. We possess the capability to undo changes we have caused, though we may choose not to out of apathy or selfishness and greed. If there are still unknown elements at work fueling climate change, we may not be able to stop it, even if we stop stoking the fires with our carbon dumping. The position that "We aren't causing it, therefore we don't even need to try and do anything about it, and it probably isn't really happening anyway" mostly confuses me as to how it is supposed to be good news.

    This position does seem to be most popular with the sort of people who believe that all of the animals on Earth were saved from a global flood by a big boat. If you can believe that sort of thing, I guess you can believe anything.
     
  10. Ophiolite Valued Senior Member

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    Thank you for the clarification. I do agree your earlier posts left me a little uncertain of what you were saying.
    I would agree with your assessment and may even - with your permission - quote it on other fora as a reflection of what I think on the matter.
     
  11. Repo Man Valued Senior Member

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    You flatter me. Of course you have my permission.
     
  12. iceaura Valued Senior Member

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    The idea that global warming is not human influenced seems wedded to the notion that the current warming is part of a natural cycle,

    and the notion that it is part of a natural cycle seems to me to lead to the conclusion that we can't do anything about it, so we shouldn't spend money trying.

    And the reason that is goods news is that its proponents don't want to spend any money trying, or rearrange their lives in troublesome ways on such abstract grounds. They have enough problems, and not enough money, already.

    The problem with handling the effects alone, rather than the cause(s), is that the effects will be overwhelmingly greater if the major cause turns out to be human and has not been handled.
     
  13. Andre Registered Senior Member

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    889
    Exactly right, exactly and what is the result of that strong desire?

    Highly recommend to read this:

    http://jan.ucc.nau.edu/~dmo2/Chesser Baker 06 Chernobyl.pdf

    Ronald K. Chesser and Robert J. Baker, 2006, Growing Up with Chernobyl,
    American Scientist, Volume 94 pp 524-529

    Science is not wishful thinking.

    Another evergreen quote with the same idea:

    http://muller.lbl.gov/TRessays/23-Medievalglobalwarming.html

    The AGW swindle that looks vaguely like science will backfire so incredibly hard when the truth overtakes it.
     
    Last edited: Sep 16, 2008
  14. Repo Man Valued Senior Member

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    4,955
    Andre, I would be very happy if climate change turned out to be completely wrong. Don't confuse me with someone who takes satisfaction in the idea that industrial civilization is dooming itself. I'd also be very happy if crude oil turned out to be abiotic in origin, and would never run out. I love driving powerful automobiles and motorcycles, and using air conditioning, refrigeration, and home heating. If we could live and consume just as we are right now indefinitely into the future, that would be great news.

    I think the standard of living we take for granted in the west is great, and I'd like for it to become the standard of the world. I'm not going to let my desires for the future to be much the same as the present to cloud my judgment. Truth may not be arrived at by consensus, but when the overwhelming majority of scientists qualified in their fields say we should be worried, and that we should take action, it seems prudent to me to listen to them. The alternative seems to be that these scientists are conspiring to fool people for reasons that are not at all clear. Not being a fan of conspiracy theories, this seems incredibly unlikely to me.
     
  15. Fraggle Rocker Staff Member

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    24,690
    Um, it seems to me that you overlooked a simpler explanation: They're all wrong.

    There are two forces buffeting science these days. One is pure hubris. Many scientists think they've got it all figured out. When it comes to the climate that just has to be a big damn joke: we don't know jack shit about it. In my own lifetime those same scientists were screaming at us about the threat of global cooling.

    The other is corporate pressure. In the waning years of the Industrial Era, corporations have become forces of evil, and a good many scientists are employed by corporations. (Or by governments, which are just as bad if not worse.) They trade their integrity for a paycheck and spend their careers trying to prove their hypotheses instead of trying to disprove them, a fundamental violation of the scientific method.
     
  16. Repo Man Valued Senior Member

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    Always possible, but it certainly doesn't seem likely to me.

    This has been covered extensively, probably best by Real Climate. There were no scientists screaming, but the popular press was another thing (I remember being frightened by it as a child). It really isn't comparable to the massive consensus in the scientific community at this time.

    In my experience, education is always humbling; I jokingly refer to it as expanding the horizons of my ignorance. I would think that no one knows better just how much there is still to learned about the complexity of the Earth's climate than climate scientists. But what they are observing with the understanding of it that they have at this time seems to alarm most of them. As Isaac Asimov said, "The purpose of crying doom is to avert it."

    Astro turf science has been a very real phenomena in the past few years. If they can refute specific claims, then they do a service by making the science more accurate. But they seem to mostly serve to muddy the waters, and seem to be most successful at making laymen think there is a controversy when there actually isn't one.
     
  17. Ophiolite Valued Senior Member

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    Here is some news for you FR: assuming we manage to avoid catastrophic, run away green house, then our next big challenge in the next couple of millenia is global cooling and the return of the ice.
    That has not changed at all in the last four decades. What has changed is our time focus. When the next ice age was around the corner, in geologic terms, no one had yet noticed that something was happening to global temperatures on a much more human scale.
     
  18. Andre Registered Senior Member

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    889
    There is no overwhelming majority

    http://mclean.ch/climate/IPCC.htm


    and here are the not-at-all-clear reasons:

    Copying from a mail:

     
  19. tt22 Registered Senior Member

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    Back to the original post



    I think the comet theory is quite intriguing and is far better than the 3 existing theories but it does not explain the similar extinctions in South America 500 years later. Nor similar earlier events in euroasia, australia and africa.

    It seems to be the case that all these extinctions coincide remarkably with human settlement, at least in the americas and australia and later big islands where the extinctions had most impact, but the overhunting theory seems far fetched. Why would those few people spend all that extra energy killing off all larger animals? A side theory I think could be more convincing is forest burning. People deliberately setting off forest fires could rapidly clear off large
    areas. This is seen later on e.g. Hawaii and could explain why the pleistocene extinctions affected mostly larger animals. Also browsers were more affected than grazers which would favor the theory of burning forests. I am not sure if there are any evidence of such fires, but a theory could be that the younger dryas black mat is actually such an evidence?

    Forest burning of that scale would probably affect climate not to cause the younger dryas period but rather trigger it.
     
  20. tt22 Registered Senior Member

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    More theories

    After reading more on the subject some authors have refined the overkill theory to overill?
    Extinctions were not caused solely by hunting but more the general impact humans had on uninhabited environments. Diseases, environment changes, livestock, hunting... The overkill theory basically has a bad name. This fits at least much better with more recent extinctions on hawaii, madagascar and new zealand.

    The picture in North and South America seems more complex though as the extinctions happened so fast.

    One thing I have been thinking about is the relationship of mammoth and the saber tooth cats. There seems to be several proof that both the smaller homotherium(scimitar cat) and the larger smilodons had mammoths on their menu. (Scimitar cats mainly fed on mammoths) Both were big cats and they seemed to be numerous throughout North and South Americas. What would happen when highly skilled human mammoth hunters from Europe entered the scene? I guess that something similar to what happens today when humans are killing off whales and killer whales (their natural predators) are starting to find food in smaller prey and almost pushing them to extinction.

    To say that there were several reasons for the North and South American extinctions is too easy. Something special happened there and I think competition between saber tooths and human could be that reason. Europe, Asia and Africa also had the scimitar cats but they seemed to die off much earlier which might explain why extinction patterns were different there.

    What other natural explanation for the saber tooths big bulk and long teeth would there be other than for killing elephant like animals?
     
  21. Ophiolite Valued Senior Member

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    Peacock tail effect?
     
  22. tt22 Registered Senior Member

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    response

    I you are pointing to that increasingly large teeth in order to show off caused the demise of the sabertooths, then I think that seems unlikely.

    - They died off in quite short timespace which do not support that theory
    - There are no proof that they suffered from health issues that would be caused by too large teeth.
    - Female sabertooth's did also have these large teeth which is said to proof that the tooth were not used only to show off.

    Otherwise I think the size of the teeth is a very interesting question as there are several other predators that during history have developed these large teeth, but they are now all extinct. The closest thing we have today is the
    clouded leopard which have teeth with the same size as the tiger even though being much smaller.
     
  23. Ophiolite Valued Senior Member

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    What makes you think I associate the extinction of sabre tooths with the length of their teeth?

    You asked what other possible natural explanation could there be for developing very long teeth other than killing elephant like animals. This was a reasonable question. It was not a question that asked anything about the extinction of the sabre tooths. You, apparently, doubted that the teeth could have evolved for any reason other than killing pachyderms.

    I offered you an explanation as to why such resource intensive structures might have developed. Resource intensive structures do not evolve without benefits to the reproductive success of the owner. We see many examples, of which the peacock's tail is perhaps the best known, where resource intensive structures are developed for 'sexual advertising' purposes. It is plausible - though I don't think very likely - that such was the case for the sabre tooth tiger's sabres.

    I would be intrigued to learn how you went from that simple answer (with nary a hint of extinction mentioned) addressing your pertinent and interesting question to one where you thing I am arguing for long sabres leading to extinction. Strange!
     

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