Update to My Best Skeptic’s Argument

Based on a lot of comment activity to this post, I wanted to add a bit of an update.  It is sometimes hard to summarize without losing important detail, and I think I had that happen here.

Commenters are correct that positive feedback dominated systems can be stable as long as the feedback percentage is less than 100%.  By trying to get too compact in my arguments, I combined a couple of things.  First, there are many catastrophists that argue that climate IS in fact dominated by feedback over 100% — anyone who talks of "tipping points" is effectively saying this.  The argument about instability making stable processes impossible certainly applies to these folks’ logic.  Further, even positive feedback <100% makes a system highly subject to dramatic variations.  But Mann et. al. are already on the record saying that without man, global temperatures are unbelievably stable and move in extremely narrow ranges.   It is hard to imagine this to be true in a climate system dominated by positive feedback, particularly when it is beset all the time with dramatic perturbations, from volcanoes to the Maunder Minimum.

To some extent, climate catastrophists are in a bind.  If historic temperatures show a lot of variance, then a strong argument can be made that a large portion of 20th century warming is natural occilation.  If historic temperatures move only in narrow ranges, they have a very difficult time justifying that the climate is dominated by positive feedbacks of 60-80%.

The point to remember, though, is that irregardless of likelihood, the historical temperature record simply does not support assumptions of feedback much larger than zero.  Yes, time delays and lags make a small difference, but all one has to do is compare current temperatures to CO2 levels 12-15 years ago to account for this lag and one still gets absolutely no empirical support for large positive feedbacks.

Remember this when someone says that greenhouse gas theory is "Settled."  It may or may not be, but the catastrophe does not come directly from greenhouse gasses.  Alone, they cause at most nuisance warming.  The catastrophe comes from substantial positive feedback (it takes 60-80% levels to get climate sensitivities of 3-5C) which is far from settled science.

9 thoughts on “Update to My Best Skeptic’s Argument”

  1. “is that irregardless of likelihood…” And this is a good non word to describe your logic path: circular. Having no regard for having no regard is having regard so you are ‘back to one’ as we say on the movie set. It amazes me that any old job all who come from a particular political bent think they can dismiss the work of every reputable scientist and agency on Earth. Amazing omnipotence from ignorance!Of course you dare not discuss your differences with Dr. Mann or Schmidt as you’de be dispatched quickly for well ignorance. That commodity is free though. I’ll give you that much. Problem is free isn’t worth much without substance.

  2. Mark A York: Boy, that was a stunning argument against the skeptic’s view. So in-depth, so well-intentioned. No appealing to authority here. No using of ad hominem attack. What a contribution to dialogue!

    By the way:
    From Mirriam Websters: “usage Irregardless originated in dialectal American speech in the early 20th century. Its fairly widespread use in speech called it to the attention of usage commentators as early as 1927. The most frequently repeated remark about it is that “there is no such word.” There is such a word, however. It is still used primarily in speech, although it can be found from time to time in edited prose. Its reputation has not risen over the years, and it is still a long way from general acceptance. Use regardless instead.”

  3. Mark, you must do a lot of reading to be familiar with “the work of every reputable scientist and agency on Earth.” If you’re referring to the IPCC then just say so and don’t exaggerate.

  4. I’ve gotten into a fair number of debates on internet discussion boards about AGW.

    Inevitably, the fallback position of the “warmers” is that (1) I’m arguing against essentially all of the world’s scientists; and (2) anyone on my side of the debate either has some kind of connection to the oil industry or is published in a non-peer-reviewed journal or both.

  5. Some good comments on feedback on the Svalgaard thread at CA

    Leif Svalgaard says:

    “Jack, the issue here is that it is almost dogma that the sun is the cause of the climate swings the last few thousand years [LIA, MWP, etc]. This is so because we don’t know what else could do it [certainly not man-made CO2, if we except that last 100 years]. The problem is that the latest solar data seem to indicate [and this is still controversial] that the sun varies less than what we thought just a few years ago, so if we will maintain that the sun is still the culprit, then we have to crank up significantly the sensitivity of the climate to solar forcing.”


    The new solar data pretty much shreads the IPCC argument that CO2 is the only known explaination for the current warming since CO2 cannot be blamed by default until someone comes up with a credible explaination for the MWP and LIA and demonstrates that the same cause is not at work today.

    My gut feel is random variations – chaotic weather patterns that vary over centuries instead of days.

  6. I’ll say again what I said before. There is incontrovertible evidence for feedback within the climate system. You have to ignore basic physics and a wealth of observational evidence to believe otherwise. Some feedbacks require only simple common sense to understand. How could melting ice and thereby reducing the albedo of the planet fail to cause further warming? How could outgassing of CO2 from warmer oceans fail to cause further warming?

    There is very good evidence not only for feedbacks but also for sudden regime changes in the climate. For example, the Paleocene-Eocene thermal maximum saw ocean temperatures in the arctic rise to 20°C. This dramatic climate shift led to a mass extinction and is believed to have been caused by a release of CO2 and/or methane into the atmosphere.

    The existence of feedbacks is extremely well-established and observationally verified. The existence of the potential for sudden regime shifts is clear. Your arguments are based on wrong assumptions.

  7. “How could melting ice and thereby reducing the albedo of the planet fail to cause further warming?”

    In that case, why do we have any ice caps at all?

  8. Did you know that the north pole is expected to be ice-free in summer within 100 years and possibly much sooner?

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