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Man made climate change vs meteor question...

Discussion in 'Environmental Discussion' started by burritos, Feb 19, 2013.

  1. burritos

    burritos Senior Member

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    Meteorite Impact Rendered Dinosaurs Extinct Millions of Years Sooner Than Previously Thought

    Just a philosophical exercise. One could say that the meteor that killed off the dinos was an extreme, punctuated extinction event. Even so, it still took an estimated 33,000 years after the impact to finally cause extinction. If you asked the average person who acknowledges man made climate change, do they think it's more or less cataclysmic than the meteor that killed the dinosaurs? I'm going to guess the answer would be no. Would that average person then know that it took another 33k years to finish off the dinosaurs? Could that perspective affect the alarmist view of climate change?
     
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  2. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    Be aware that the 33,000 years is not an agreed upon number. That value has much more to do with a lack of precision dating of dinosaur fossils. Specifically, it reflects much of the error range in fossil dating.

    That does not affect you question all that much since whatever the actual number is, it definitely is a vast number of human generations. The problem is the "average person" often thinks dinosaurs were around when cavemen were around. I'm not sure that a knowledge level that primitive really is in a good position to judge the time scale aspects of climate changes.
     
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  3. tochatihu

    tochatihu Senior Member

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    My understanding is that some other large changes (like Deccan traps eruptions) happened at about the same time as the asteroid in question, and the 'ecosystem reorganization' that followed may have been much less extensive w/o both together.

    Climate changes (human caused or human assisted) need not be nearly so large to mess with the human enterprise. As I frequently assert here, we are farming the heck out of this planet to feed 7+ billions. Increasing everything will put greater pressure on water supplies. I think that expanding humanity (including with respect to diseases that affect humans or crop plants) is climate-sensitive. Others suggest that, with all this fossil-fuel power, we are extremely adaptable and will perhaps even prosper from limited climate changes. I have to hope that the latter view is correct and that mine is not. Because the game is underway.

    Back to dinos, there is new evidence of a large Jurassic impact crater in Australia. It may be that earlier animals got 'moved out' by that ecosystem reorganization. It is interesting to consider that dinos (surely the #1 animal success story at least until 10,000 years go) may have had meteoric 'bookends'.
     
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  4. tochatihu

    tochatihu Senior Member

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    Not all sizable 'hits' are followed by mass extinctions:

    What if a Meteorite Struck the United States? | Science Features

    35 MYA, would have messed up DC pretty badly, to be sure. But higher plants and mammals (the 2 leading terrestrial groups at the time) continued to do OK. It is another question entirely whether an (arguably) overpopulated species with a serious energy addiction would sail through.
     
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  5. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    "higher plants and animals"? It took a while to realize you must have been talking about giraffes and sequoias.
     
  6. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    I have encountered extremely little scientific concensus on what evolutional mechanism underpinned the dinosaur demise. Specifically, dinos had quite extensive evolutionary adaptations for 100s of millions of years and birds still are a big continuation of dinos. Yet little rat sized mammals took over fantastically quick. Why? (A biology question, not a physics question)
     
  7. austingreen

    austingreen Senior Member

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    Its an evolutionary question, not a biological one. IIRC the theory goes that the two drivers were darkness - from volcanic activity, and low oxygen high pollution. The darkness meant less vegetation, less food, which would cause mass starvation for big creatures. The big dynos ate the animals that were eating the mammals. Add in the hard to breath element and mass extinction happens. Dinos ate each other, and suffocated leaving room for small creatures to evolve.
     
  8. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    If we presume that a very large meteor strike in inevitable, and that such an impact would immediately cause a mass extinction event, then wouldn't we be interfering with evolution by trying to alter that impact?

    -or- perhaps even more interesting...if we're going to be wiped out by a meteor...why all the worry about AGW? ;)
     
  9. austingreen

    austingreen Senior Member

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    Evolutionary imperative says not to simply be eaten just because it is natural. The gazelle runs away from the lion. The human should try to mitigate the damage from a natural strike.

    That is a much better question. The odds of an asteroid hurting the planet before endless ghg is low, but we should not exaggerate the risks of either.
     
  10. burritos

    burritos Senior Member

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    Did you all see Melancholia?
     
  11. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    But there were many, many different variations of small dinos as well. So while the big creatures were certainly at a bigger disadvantage, what was the relative shift in disadvantages of the small fry?

    Some of the smaller dinos did make it because they had feathers. While we have a lot of flying mammal, we have vastly more flying dinos. That round goes to the small dinos, not the small mammals. In other major niches, the round went to the small mammals. Why?

    If darkness matters, was it a difference in dino eyesight vs mammal eyesight? Pollution tolerance, etc? My original point was almost entirely focused on how few high end publications really delve into that question vs. the great many publication covering what was happening. I know all factors interact, but genetic information processing has advanced enough to probably provide clues, if not tentative answers.
     
  12. tochatihu

    tochatihu Senior Member

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    Without regard to how climate is now changing because of IR-absorbers. Just about the K-T, from simplest to most obscure:

    Evolution: Library: Patterns of Extinction
    Mammals and the KT Event – Greg Laden's Blog
    http://www.geol.lu.se/personal/viv/Ocampo%20et%20al.%202006%20Impacts_Springer.pdf

    And darn, I lost another nice one that nicely showed how different mammalian groups ebbed and flowed, both before and after the 65 MYA reset button. This period is heavily studied and I bet that others can post up some good stuff also.

    To me it's like this: any 'paleo event' can be viewed w/in limits of the 'paleo records'. The current CO2 impulse looks faster, but one could always appeal to uncertainty in paleo records. It boils down to what you want to assert, over what time scale, and why.

    I have no doubt that another 'resetting' impact will happen in the next 100 million years; maybe much sooner. By then, the sun will have brightened up enough to move earth out of the habitable zone. Any way you look at it, we are xxxx'ed in that long term.

    This brings us back to much more proximate concerns: does this long certainty absolve us from choosing among better paths for shorter times? Mixing up vastly different time scales does not indicate high intellectual development :)
     
  13. Trebuchet

    Trebuchet Senior Member

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    It would serve us better to take all the money wasted on AGW and spend it on a anti-Metorite warning and defense system.
     
  14. Corwyn

    Corwyn Energy Curmudgeon

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    You have numbers for those risks? I would love to see them.

    If you want to put your money on meteors, here is a place that is working on it, and would appreciate your money: Sentinel Mission | B612 Foundation
     
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  15. ItsNotAboutTheMoney

    ItsNotAboutTheMoney EditProfOptInfoCustomUser Title

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    Maybe it was simply that the elimination of larger predators enabled the mammals to grow and it was the growth that allowed them to out-compete the small dinos.
     
  16. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    It's a fun thing to think about, but extremely hard to think on time scales of millions of years. What we do know is that prior to the meteor hit, the dinos had won most all of the "competing" between animal types. Whether it was the air, land, or sea, there was a set of dino's at both the top and bottom of the food chain usually. That covers just about every climate range, variation, and niche. Then it ends with a meteor hit.

    Even among mammals, it's not till placental mammals come along that the really big mammals show up. Prior to that, it was essentially only insect eating "rats". Who would have picked a rat to head up the new dominant occupiers of the planet 65 million years ago.
     
  17. tochatihu

    tochatihu Senior Member

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    Rats.

    Purely post hoc reasoning, but anyone who sees rats' successes after being introduced to islands of low animal diversity (= lots of empty niches) might give them a shot.

    Anyway, it had to be a vertebrate, because no other group could get big at ~20% O2. Another candidate might have been the crocodilians, but they did not rise to the occasion. Why not? My simple guess is that those pesky rats, freed of much predation pressure, ate a lot of croc eggs.

    What about birds? they have radiated nicely since 65MYA. But, they present 3 problems to planetary domination: They gave up teeth and chances for big brains, in exchange for flight (not that ravens aren't clever...) And there is that egg thing again!

    So we may be stuck with live birth and parental care, along with 'boniness'. Other than mammals, the candidates appear few.
     
  18. fuzzy1

    fuzzy1 Senior Member

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    "The meek shall inherit the Earth. The rest of us have other plans."

    In the long term, we will need leave this planet and move elsewhere, before the aging sun turns this home into a cinder, then dies itself. At first, that journey will be to other parts of this galaxy with plenty of unused hydrogen. Later, it will be to other galaxies that are currently low brightness, indicating an undersupply of stars today but plenty of raw hydrogen.

    In the shorter term, we need to grow our technology and economy enormously before these journeys even become possible. If AGW occurs at anything even remotely resembling the predicted rate, I think we will have trashed this home, possibly replicating the climate of Venus, long before we gain the ability to move elsewhere.

    Compared to interstellar and intergalactic migration, deflecting the future asteroid impacts ought to be a piece of cake.
     
  19. dbcassidy

    dbcassidy Toyota Hybrid Nation, 8 Million Strong

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    It is all part of the natural order of things concerning our planet. What we lack, is a more complete understanding of other life forms in the universe and how they evolved, lived, and perished. Technology will eventually allow us to learn a lot more about our universe and that takes time, commitment, and money.

    Mean while, I just settle back, have a nice cold beer and gaze at the billions of stars above me.:)

    DBCassidy
     
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  20. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    Actually, post hoc reasoning 60 some million years after the fact. Instead of "rat" a much better description would be from Science Vol 339, pg 665. Unfortunately, it does not have a name, but 90% of the population would call it a rat.