http://www.climate-skeptic.com/2008/01/overestimating.html Sat, 11 Feb 2012 16:51:39 +0000 hourly 1 http://wordpress.org/?v=3.0.3 http://www.climate-skeptic.com/2008/01/overestimating.html/comment-page-1#comment-372 Josh Mon, 07 Jan 2008 12:23:41 +0000 http://climate-movie.com/wordpress/2008/01/overestimating.html#comment-372 <p>I read this post from Spencer several months ago and I have yet to find mention of it elsewhere (e.g. realclimate). It seems like a HUGE issue. My take on it is that he's basically saying, "Assume that a change in, e.g. cloud cover causes temperature to rise (and NOT the other way around). Then, if something changes the amount of cloud cover, we would expect a corresponding rise in temperature. But if we average our data too much, AND instead assume that the causality runs the other way (i.e. temperature rises change the amount of cloud cover), because of the positive correlation, an increase in temperature (which we incorrectly assume is exogenous) will show a corresponding increase in cloud cover, confirming our incorrect assumption." This leads to a diagnosis of positive feedback when in fact, there is no feedback (or maybe a negative one). I can't find any logical flaw in the argument, and I don't doubt that there is serious averaging in the data used by the models. How can we proceed with any confidence without resolving this issue? And yet no one seems to be taking it seriously.</p> I read this post from Spencer several months ago and I have yet to find mention of it elsewhere (e.g. realclimate). It seems like a HUGE issue. My take on it is that he’s basically saying, “Assume that a change in, e.g. cloud cover causes temperature to rise (and NOT the other way around). Then, if something changes the amount of cloud cover, we would expect a corresponding rise in temperature. But if we average our data too much, AND instead assume that the causality runs the other way (i.e. temperature rises change the amount of cloud cover), because of the positive correlation, an increase in temperature (which we incorrectly assume is exogenous) will show a corresponding increase in cloud cover, confirming our incorrect assumption.” This leads to a diagnosis of positive feedback when in fact, there is no feedback (or maybe a negative one). I can’t find any logical flaw in the argument, and I don’t doubt that there is serious averaging in the data used by the models. How can we proceed with any confidence without resolving this issue? And yet no one seems to be taking it seriously.

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