Climate Letter #1830

For purposes of evaluating global air temperatures, should ‘precipitable water’ (PW), a complex substance, be treated as if it were a single greenhouse gas, one having the same power as water vapor, thereby encouraging applications of the substance as a substitute for water vapor?  Regular readers of these letters will have have noticed that I have been heading in this direction lately when analyzing daily temperature anomalies.  I have been making a conscious effort to avoid talking about water vapor when doing these analyses, based on the realization that I had all kinds of valid data available for measuring volumes of PW by weight and nothing of the sort for water vapor.  Previously, when making use of PW measurements, I would talk about them in terms of water vapor measurements.  That didn’t seem right, even though the answers arrived at generally seemed to make sense.  Now I am doing the same calculations, focused as before on examining the temperature effects of rapid changes in greenhouse energy inputs, and getting the usual answers.  The only difference is that now the greenhouse effects are attributed exclusively to changes in PW measurements that are either known or subject to reasonably good estimates.

Now back to the original question, which is actually addressed to the science community at large, in very specific terms.  Is it even a legitimate question, or worthy of consideration?  If so, after taking a big leap forward, what if the best answer turns out to be ‘yes’?  What if PW, molecule for molecule, or weight for weight, really does exert greenhouse energy effects quite similar to those of water vapor alone?  The comparison does not need to be perfect, nor should this be expected, but what if it is so close, for practical purposes, that climate models would need to be adjusted in order to account for it?  To wit, PW quantities are not the same as water vapor quantities, and the factors that have control over the quantities of each are not the same. The implied changes from substitution would therefore be considerable, perhaps revolutionary, on a scale the dimensions of which are not yet knowable, yet these would be changes of a type that had to be dealt with for the same reasons that cloud cover particulars are currently being evaluated.

I am not ready to make any claims about how this effort would will turn out, but I do have a strong feeling that the question is important and should not be ignored. Do I have any evidence to back up this idea? Sure. I have been serving up illustrations in these letters almost every day since last April, and could show more of the same today. Do I have any standing for making such a request? Well—who else is out there doing analysis of the causation of almost every kind of air temperature anomaly that can be found on the daily maps? I am fascinated by this work, and can only wonder why other people are not doing it, or at least not saying anything if they are doing it. Why are there no trained climate scientists following this trail? Why just one old man, self-trained, using nothing more than a home computer?

Daily temperature anomalies are genuine natural phenomena.  Some are truly spectacular in scale.  On the upside, for example, there are a few every day that reach +20C and more.  Today I can see a few cold ones only a few degrees short of -20C. Every one of these, and everything in between, is in fact (I believe) determined by a specific set of positive and/or negative causation factors.  Those factors can all be found and evaluated, if one will take the time to root around and look for them.  Common stocks get analyzed every day for investment purposes in exactly the same open-ended way. What I have found when studying temperatures is that a measurable change in PW is involved as a cause of practically every anomaly, usually the dominating cause in cases of major anomalies.  I have even learned how to explain how it’s done, in ways that gain credibility by virtue of their extraordinary consistency.  These explanations are still evolving. They include mechanical features that have revolutionary implications of their own, relevant to how the fundamentals of climate science can be taught.  Climate forecasting might even benefit from future work aimed at acquiring a deeper understanding of how these features work and interact as circumstances change.

Carl