[QUOTE=jshore]
intention: Thanks for your response. I understand your desire to use paleoclimate evidence to try to estimate the climate sensitivity, but why is it that the scientists who actually do this come to the conclusion that “the climate system is very sensitive to small perturbations and that the climate sensitivity may be even higher than suggested by models” while you, in what is frankly a very hand-waving way, come to a different conclusion?
[QUOTE=intention]
If that cooling system failed for a couple weeks, the town I live in (on a Pacific island at 9° S Latitude) would be unbearably hot. Hasn’t happened in recorded history.
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So, are you saying that the current climate models estimate the temperature on your Pacific island to be considerably hotter than it actually is?
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First, please dial back on the accusations of hand-waving. I have provided a citation for my claim that the Earth has an equilibrium temperature. I have provided a citation for the idea that the earth is running at a condition of maximum power production/dissipation. I have also discussed the mechanism in detail. Your insults do not strengthen your case.
In addition, your pretended shock that other scientists might come to different conclusions does not become you. The article you cited is not peer-reviewed, it is a “Perspective”. Science Magazine, where it was published, says Perspectives "are meant to express a personal viewpoint ". Why haven’t you accused the author of “hand-waving”? In any case, from the personal viewpoint you cited:
[QUOTE=Schrag]
Likewise, warm episodes in Earth’s history reveal a similar cautionary lesson. During the Eocene, 50 million years ago, palm trees grew in Wyoming (8) and deep ocean temperatures were more than 10ºC warmer than present (9). Because we do not know exactly how high the atmospheric CO2 concentration was at that time, we cannot use it as a direct measure of climate sensitivity. However, the extreme warmth at high latitudes–especially during the winter in continental interiors–cannot be simulated by climate models purely through elevating greenhouse gas concentrations (10). Special cloud feedbacks must be included that are not present in the models used to predict future climate change (10, 11). This observation suggests that feedbacks may be missing from current models and that future climate change may be underestimated in these models, particularly at high latitudes.
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This is indeed a “cautionary lesson” … but about the climate models, not the climate sensitivity. This shows that current models don’t understand the basic fundamentals of the climate, since they cannot explain the Eocene without including … hey, guess what, cloud feedback. Which is what I have been talking about, the fact that the models don’t properly represent the cloud feedback. However, his claim that including the proper cloud feedback in the models will increase estimates of future climate change is un-cited, un-referenced, and without any basis in fact. Which is OK, after all, this is his personal viewpoint … but I hope you don’t think it is more than that, I hope you don’t mistake his viewpoint for established science.
Also, his estimates of past sensitivity to small perturbations is based on these very same climate models that can’t successfully model the Eocene … which doesn’t exactly inspire confidence.
Do “the current climate models estimate the temperature on your Pacific island to be considerably hotter than it actually is?” Haven’t you been following the discussion? The problem is not that the models don’t get the rough numbers right, they’re tuned to do just that, so of course they do. How many times do we have to go over that? THE MODELS ARE TUNED TO THE PRESENT CLIMATE, SO THEY FACT THEY GET IT RIGHT PROVES NOTHING.
The problem is that they don’t get the feedbacks right, which has much larger implications. You seem to think that the models calculate the feedbacks … not so. The feedbacks in the model are set by the modelers based on their particular beliefs. They are inputs to the models, not outputs.
[QUOTE=jshore]
[QUOTE=intention]
It is noteworthy, however, that Ou’s results (in the equilibrium study I cited above) showed that with a 50% change in solar constant from todays values, the surface temperature only varied by 10°C … this does not show, or prove, or establish, that this is the solution to the paradox. It does, however, establish it as a contender.
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The more interesting question is whether Ou’s results can predict the ice age - interglacial cycles and the other recent climate changes that we have the best data for.
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That is indeed an interesting question … however, as I’ve said before, there are many interesting and unanswered questions in the study of climate, it is a newcomer to the sciences. To date, for example, I have not found a good explanation for the ~100,000 year cycles of the glaciations. Might be one, but I haven’t seen it. It is a puzzle because this frequency is not among the Milankovic cycles. Nor is there a theory about why the previous interglacial was warmer than the current one, nor why it was shorter. Heck, we don’t have an explanation as to why we’re not in an ice age right now …
w.