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Thread: Hurricanes and climate change

  1. #21
    tWebber seer's Avatar
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    Quote Originally Posted by HMS_Beagle View Post
    OK, you didn't read the paper and have no idea what the paper is discussing.
    I just quoted the paper, they are speaking of the earth's climate, with local readings confirming the abrupt oscillation.
    "We can understand hell in its aspect of privation. All your life an unattainable ecstasy has hovered just beyond the grasp of your consciousness. The day is coming when you will wake to find, beyond all hope, that you have attained it, or else, that it was within your reach and you have lost it forever.” C.S. Lewis

  2. #22
    tWebber TheLurch's Avatar
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    Quote Originally Posted by seer View Post
    The paper I linked: Although the D-O climate cycles have now been found in many other climate proxy records around the globe (Voelker 2002), the reason why Earth's climate was so much more variable during the last ice age is still unknown.

    They had a much more rapid and greater warming than what we see today, yet we do not know why.
    Unfortunately, your link appears broken.

    But there's two things to point out:
    There are a lot of ideas about what could be causing D-O events, and if they were happening currently, we could test these ideas.
    There's no indication that D-O events happen outside glacial periods. We're not in one of those.

    So, basically, you seem to be taking a single type of cycle that's irrelevant to the present, and saying we can't identify any climate cycles.

  3. #23
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    Quote Originally Posted by TheLurch View Post
    Unfortunately, your link appears broken.

    But there's two things to point out:
    There are a lot of ideas about what could be causing D-O events, and if they were happening currently, we could test these ideas.
    There's no indication that D-O events happen outside glacial periods. We're not in one of those.

    So, basically, you seem to be taking a single type of cycle that's irrelevant to the present, and saying we can't identify any climate cycles.
    No, I'm saying that nature warmed the earth more and more quickly than anything we see now. And the fact that we can't figure out why suggests that we do not understand all the mechanisms that play into climate fluctuation.
    "We can understand hell in its aspect of privation. All your life an unattainable ecstasy has hovered just beyond the grasp of your consciousness. The day is coming when you will wake to find, beyond all hope, that you have attained it, or else, that it was within your reach and you have lost it forever.” C.S. Lewis

  4. #24
    tWebber TheLurch's Avatar
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    Quote Originally Posted by seer View Post
    No, I'm saying that nature warmed the earth more and more quickly than anything we see now. And the fact that we can't figure out why suggests that we do not understand all the mechanisms that play into climate fluctuation.
    Just to clarify something first: D-O events resulted in extreme warming in Greenland, not globally. Many of them didn't even register in the souther hemisphere. So it's not clear that they drove a global climate change faster or larger than we're seeing now.
    https://en.wikipedia.org/wiki/Dansga...re-isotope.png

    But you're right. We don't understand every mechanism that could potentially change the climate. But we have extensive monitoring of the global climate system, using floats, weather stations, satellites, etc. We monitor the incoming solar radiation. We keep track of the chemical composition of the atmosphere. etc. etc. You're suggesting that a major driver of the climate could act without affecting any of these.

    That's what i mean by "it's not magic." Major drivers of a changing climate can't occur without some sort of physical trace.

    And that's not even getting in to the fact that we know carbon dioxide is a greenhouse gas, so you'd have to explain why it suddenly was not changing the climate.

  5. #25
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    Quote Originally Posted by TheLurch View Post
    Just to clarify something first: D-O events resulted in extreme warming in Greenland, not globally. Many of them didn't even register in the souther hemisphere. So it's not clear that they drove a global climate change faster or larger than we're seeing now.
    https://en.wikipedia.org/wiki/Dansga...re-isotope.png

    But you're right. We don't understand every mechanism that could potentially change the climate. But we have extensive monitoring of the global climate system, using floats, weather stations, satellites, etc. We monitor the incoming solar radiation. We keep track of the chemical composition of the atmosphere. etc. etc. You're suggesting that a major driver of the climate could act without affecting any of these.

    That's what i mean by "it's not magic." Major drivers of a changing climate can't occur without some sort of physical trace.

    And that's not even getting in to the fact that we know carbon dioxide is a greenhouse gas, so you'd have to explain why it suddenly was not changing the climate.
    Well again, from my link:

    Earth's Climate During the Last Ice Age

    Unlike the relatively stable climate Earth has experienced over the last 10,000 years, Earth's climate system underwent a series of abrupt oscillations and reorganizations during the last ice age between 18,000 and 80,000 years ago (Dansgaard 1984, Bond et al. 1997, 1999). These climate fluctuations were first discovered when scientists reconstructed past temperature variability over Greenland by analyzing tiny changes in the relative abundance of the oxygen-16 isotope versus the oxygen-18 isotope (noted as δ18O and reported in parts per thousand) in ice cores recovered from Greenland glaciers. Each successively deeper ice layer represents a snapshot of Earth's climate history from the past, and together, the oxygen isotope record told a story of abrupt, millennial-scale climate shifts in air temperatures over Greenland between extremely cold stadial conditions and relatively mild interstadial periods during the last ice age (Figure 1) (Alley 2000, Alley et al. 2003). There are twenty-five of these distinct warming-cooling oscillations (Dansgaard 1984) which are now commonly referred to as Dansgaard-Oeschger cycles, or D-O cycles. One of the most surprising findings was that the shifts from cold stadials to the warm interstadial intervals occurred in a matter of decades, with air temperatures over Greenland rapidly warming 8 to 15°C (Huber et al. 2006). Furthermore, the cooling occurred much more gradually, giving these events a saw-tooth shape in climate records from most of the Northern Hemisphere

    Although the D-O climate cycles have now been found in many other climate proxy records around the globe (Voelker 2002), the reason why Earth's climate was so much more variable during the last ice age is still unknown. Some theories suggest that changes in ocean circulation due to natural variations of North Atlantic surface water salinity were the trigger for the D-O events (the salt oscillator hypothesis) (Birchfield & Broecker 1990, Broecker et al. 1990a, Zaucker & Broecker 1992), while others argue changes in atmospheric circulation were the driver (the wind field oscillation hypothesis)

    https://www.nature.com/scitable/know...t-ice-24288097
    They are connecting the samples in Greenland to global events, and what happened in Greenland was much more severe than what we see today, even if it happened mostly in the Northern Hemisphere.
    "We can understand hell in its aspect of privation. All your life an unattainable ecstasy has hovered just beyond the grasp of your consciousness. The day is coming when you will wake to find, beyond all hope, that you have attained it, or else, that it was within your reach and you have lost it forever.” C.S. Lewis

  6. #26
    tWebber TheLurch's Avatar
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    Quote Originally Posted by seer View Post
    They are connecting the samples in Greenland to global events, and what happened in Greenland was much more severe than what we see today, even if it happened mostly in the Northern Hemisphere.
    Yes, and if i cared in particular about Greenland, this might matter deeply to me. Or if i knew Greenland consistently represented the entire globe. But something severe can happen in Greenland without much going on elsewhere.

  7. #27
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    Quote Originally Posted by TheLurch View Post
    Yes, and if i cared in particular about Greenland, this might matter deeply to me. Or if i knew Greenland consistently represented the entire globe. But something severe can happen in Greenland without much going on elsewhere.
    But it wasn't just Greenland: Although the D-O climate cycles have now been found in many other climate proxy records around the globe (Voelker 2002)

    And remember they are speaking of Global changes: Earth's climate system underwent a series of abrupt oscillations and reorganizations

    And what they found in Greenland represent the Earth's Climate history: Each successively deeper ice layer represents a snapshot of Earth's climate history from the past...

    There seems to be global evidence for these abrupt oscillations.
    Last edited by seer; 09-12-2017 at 08:43 PM.
    "We can understand hell in its aspect of privation. All your life an unattainable ecstasy has hovered just beyond the grasp of your consciousness. The day is coming when you will wake to find, beyond all hope, that you have attained it, or else, that it was within your reach and you have lost it forever.” C.S. Lewis

  8. #28
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    Quote Originally Posted by TheLurch View Post
    And that's not even getting in to the fact that we know carbon dioxide is a greenhouse gas, so you'd have to explain why it suddenly was not changing the climate.
    I'm not saying that Co2 doesn't have an effect, but how much does man produce as compared to nature? I have read that we put in about 2% of the total - is that really enough to drive all this? Or could there be forces or variables involved like we saw in the D-O climate cycles that we do not understand?
    "We can understand hell in its aspect of privation. All your life an unattainable ecstasy has hovered just beyond the grasp of your consciousness. The day is coming when you will wake to find, beyond all hope, that you have attained it, or else, that it was within your reach and you have lost it forever.” C.S. Lewis

  9. #29
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    Quote Originally Posted by seer View Post
    I'm not saying that Co2 doesn't have an effect, but how much does man produce as compared to nature? I have read that we put in about 2% of the total - is that really enough to drive all this? Or could there be forces or variables involved like we saw in the D-O climate cycles that we do not understand?
    Furthermore, CO2 is a trace gas and such a miniscule part of our total atmosphere that whatever effect it has on the global climate is negligible. As the NIPCC says in their summary paper,

    "No unambiguous evidence exists of dangerous interference in the global climate caused by human-related CO2 emissions. In particular, the cryosphere is not melting at an enhanced rate; sea-level rise is not accelerating; and no systematic changes have been documented in evaporation or rainfall or in the magnitude or intensity of extreme meteorological events. Any human global climate signal is so small as to be nearly indiscernible against the background variability of the natural climate system. Climate change is always occurring."
    Some may call me foolish, and some may call me odd
    But I'd rather be a fool in the eyes of man
    Than a fool in the eyes of God


    From "Fools Gold" by Petra

  10. #30
    tWebber TheLurch's Avatar
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    Quote Originally Posted by seer View Post
    But it wasn't just Greenland: Although the D-O climate cycles have now been found in many other climate proxy records around the globe (Voelker 2002)

    And remember they are speaking of Global changes: Earth's climate system underwent a series of abrupt oscillations and reorganizations

    And what they found in Greenland represent the Earth's Climate history: Each successively deeper ice layer represents a snapshot of Earth's climate history from the past...

    There seems to be global evidence for these abrupt oscillations.
    Again, if your link worked, i can get into the references and figure out the magnitude of the global signatures. But you're effectively saying "there's this huge change in Greenland, and other effects are seen globally. Therefore, the global effects are huge." The logic doesn't work out. A large change in Greenland could register elsewhere, but be so minor everywhere else that the total global impact is minor.

    Without knowing what Voelker 2002 is, i can't tell what's the case. Make more sense?

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