As Climate Worsens, a Cascade of Tipping Points Looms

Discussion in 'Environment & Conservation' started by skepticalmike, Dec 15, 2019.

  1. AFM

    AFM Well-Known Member Past Donor

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    The references have been provided many times.
     
  2. AFM

    AFM Well-Known Member Past Donor

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    Exactly.
     
  3. skepticalmike

    skepticalmike Well-Known Member

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    I don't understand this statement, "the reason the CO2 is so low is that we have been in a 2.5 million year ice age". The CO2 is not low and we are in an interglacial period.

    Also, I disagree that increasing CO2 is beneficial and I did not point out that warmer temperatures do not correlate with CO2.

    I pointed out that the Eemian, Last Interglacial period, was warmer than the present by at least 1 degree Celsius and that the CO2 level was lower at 280 ppm. I also mentioned that

    orbital insolation was greater in the Eemian than it is today and that was why the Eemian was warmer than today.

    The text and graph below is from from Skeptical science, "The Last Interglacial Part 2". https://skepticalscience.com/LIG2-1906.htm

    The IPCC Assessment Report 4 describes palaeoclimatic proxy evidence from the Last Interglacial, which estimates that the largest warming then was in northern Greenland and Eurasia of ~3 to 5oC, though some individual sites may have been even warmer. Models have determined that much, if not all this warming can be explained by increased insolation from orbital forcing as the Earth travels around the Sun, shifts its axial tilt and changes the amount of eccentricity in its orbit in regular cycles; effectively acting like a long-term climate pacemaker. In itself, this additional warming from the Sun is too small and too regional to fully explain all the observed warming during the period. It's likely that lowered albedo, increasing CO2 and other carbon feedbacks have amplified this warming from the orbital pacemaker.

    For the first half of the Last Interglacial (~130 to 123 Ka) orbital forcing produced a large increase in summer Northern Hemisphere insolation (IPCC AR4). The orbital eccentricity was higher, giving a more elliptical orbit. The effects of precession, a wobbling of Earth's axis of rotation, on insolation was also more pronounced. These warm conditions lasted around 11,000 years (Muller, 2009) and summer insolation at 65oN was at a maximum at 126 ka (Berger 1978, as described in Born et al., 2009). Modelling studies using Last Interglacial orbital parameters determined that precession was the main contributor to climatic change during the period. Kaspar et al (2005) compared temperature proxy reconstructions with results from an Atmosphere-Ocean General Circulation Model utilizing greenhouse gas concentrations and orbital parameters to simulate climate at ~125 ka. The model results were consistent with the temperature proxy reconstructions and indicated that the differences in orbital parameters compared to today were sufficient to explain the higher temperatures over most parts of Europe in summer. They argue that greater axial tilt and eccentricity of orbit, together with perihelion, Earth's closest approach to the Sun, happening during summer in the Northern Hemisphere, amplified seasonal insolation at 125 ka

    Figure 1: The precession, obliquity and eccentricity components of Earth's orbit around the Sun, plus the resulting changes in insolation at 65oN for the past 250,000 years. (illustration: jg at brightstarswildomar

    The Eemian period is in orange starting at 130,000 years ago when insolation
    was at a peak.

    [​IMG]
     
    Last edited: Dec 20, 2019
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  4. Hoosier8

    Hoosier8 Well-Known Member Past Donor

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    Earth has been in a 2.5 million year ice age interspersed with short interglacials. CO2 has been dangerously low due to that. You even prove the Eemian was warmer with the low CO2. Plants die at 150ppm of CO2.
     
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  5. skepticalmike

    skepticalmike Well-Known Member

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    This graph is from Wikipedia, "Milankovitch Cycles", showing the 420,000 year Vostok, Antarctica ice core data. The bottom orange graph shows the solar insolation at a
    peak 129,000 years ago and reaching a minimum at 117,000 years ago.The carbon dioxide, methane, and temperature all reach a peak at approximately the same time,
    129,000 years ago. The carbon dioxide increased from 180 ppm to 280 ppm which results in an approximately 2.36 watts per square meter of radiative forcing. The rise
    in methane also adds to the increase in radiative forcing. The CO2, methane, temperature, and solar insolation are all at a minimum 140,000 years ago and appear to
    rise in a synchronous manner. The increase in insolation is the initiator of the other changes and if you look closely at the graphs (I used a transparent triangle) you can
    see that the rise in temperature leads the rise in CO2 and methane by about 1000 years. This is a consequence of the time required for the oceans to warm (thermal
    inertia) and slowly release increasing amounts of carbon dioxide since CO2 solubility decreases with rising temperature. This was something predicted by scientists
    before they had this data.

    The increase in CO2 and methane both were significant factors in the warming during the Eemian. It is the ratio of the change in CO2 (peak/trough) that matters and there was a greater change
    in that ratio during the Eemian glacial to interglacial climate change than there has been in the present day climate change. The CO2 and methane changes were positive feedbacks during
    the Eemian period but they are climate forcings in today's climate change because they are considered to be a external perturbations to the climate.

    The reduction in albedo (surface reflectivity) during the Eemian was also a positive feedback and a significant factor in the warming of the Northern Hemisphere and to a lesser extent
    the entire planet. The reduction in ice cover (Arctic sea ice, some of Greenland and West Antarctica , other land ice in the Northern Hemisphere) decreased the amount of solar radiation
    reflected back to space.

    My initial point of this discussion was to present evidence that a 1 to 2 degree increase in the GMT could cause a 10 to 22 feet sea level rise by the partial or complete meltdown
    of Greenland and west Antarctica.
    [​IMG]
     
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  6. Hoosier8

    Hoosier8 Well-Known Member Past Donor

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    Notice in your graph that CO2 lags temperature. Neither Greenland or Antarctica have melted down during this 2.5 million year ice age. In fact it is never warm enough even in the summer to melt the ice in East Antarctica and the only melting they are having now is due to ocean currents changes.
     
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  7. AFM

    AFM Well-Known Member Past Donor

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    Yes. We got down to 180 ppm in the last ice age which ended ~ 10,000 years ago.
     
  8. Bowerbird

    Bowerbird Well-Known Member

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    Then do so again

    Saying “many times” could mean 5 years and fifty threads ago
     
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  9. Bowerbird

    Bowerbird Well-Known Member

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    Link please
     
  10. Richard The Last

    Richard The Last Well-Known Member

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    I think climate change is a conspiracy theory. I think there is a conspiracy going on. I think it is nature conspiring to rid the planet of the waste that is humanity.

    Of course that is just my "conspiracy theory".
     
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  11. AFM

    AFM Well-Known Member Past Donor

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    Provided previously.
     
  12. william kurps

    william kurps Banned

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    You have a link to back that 1/5 number up?


    https://www.siliconrepublic.com/innovation/carbon-dating-accuracy-major-flaw



     
    Last edited: Dec 20, 2019
  13. Richard The Last

    Richard The Last Well-Known Member

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    Could you provide a link to the previously provided link?
     
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  14. Bowerbird

    Bowerbird Well-Known Member

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  15. Bowerbird

    Bowerbird Well-Known Member

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    Yep! It’s a game

    The game is to challenge every single thing a science believer says especially one that will keep providing more and more research representing hours of work only to dismiss it out of hand with some spurious claim and NEVER EVER provide any proof of any assertion made
     
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  16. william kurps

    william kurps Banned

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    Proxy data is just an estimate, it's like going to wiki for accuracy on something, it's a starting point.
     
  17. Bowerbird

    Bowerbird Well-Known Member

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    Do you even know what proxy data is? I am asking this because I have a suspicion that you think it is just tree rings and only encomasesvthe last couple of hundred years
     
  18. AFM

    AFM Well-Known Member Past Donor

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    No game. I posted information which I’ve provided references to previously. Your assertion that my claims are fake is untrue.
     
  19. AFM

    AFM Well-Known Member Past Donor

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    Why do you ask?
     
  20. william kurps

    william kurps Banned

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    Of course I do , ice cores , dirt cores off of Africa.. why are you even insulting my intelligence when I already demonstrated every well renown scientist, crazy ass players in this discussion?
     
    Last edited: Dec 20, 2019
  21. william kurps

    william kurps Banned

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    Exactly, in simple terms, its natural variation..
     
  22. Bowerbird

    Bowerbird Well-Known Member

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    Well, the impression you have been giving ME is that you thought it was only tree rings and you had no understanding of what a systematic review and meta-analysis was
     
  23. Bowerbird

    Bowerbird Well-Known Member

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    And NONE of those factors that usually cause this natural variation are in play now

    Unless you are about to win a Nobel prize by proving us wrong...........
     
  24. Bowerbird

    Bowerbird Well-Known Member

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    Yep references which no one seems to be able to find......

    Were those references posted this year?
     
    Last edited: Dec 20, 2019
  25. AFM

    AFM Well-Known Member Past Donor

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    Multiple times.
     

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