If the climate system is in a fairly stable, if chaotic orbit, as it has been in the late Holocene (say the last 7000 years) then there is some room for climate heuristics. An anomalously warm North Atlantic indicates how far north the tropical convergence zone will migrate in Brazil that July, hence whether the north coast of South America will have a dry year.
Now I have to admit that I can’t recall which way it works!
I avoided chemistry and biology as a student because I have trouble committing facts to memory. I had a great work-around for exams, mind you. I would create a dense single page of notes for any closed book exam. I would copy and recopy it about eight times. If the exam was a morning exam, I’d stay up all night doing so; for an afternoon exam I’d just do this in the morning. I would not vary the format in any way. Thus, I would commit the materials to short term memory, secure in the knowledge that I would forget them the next day. I did well as an undergraduate.
In grad school, I tended to expect being tested on understanding, not on memorization, but I did have to resort to the page-recopying trick for Dr. Hastenrath’s class on Tropical Meteorology. His class and his book were a thick compendium of observations, rather light on principles. (There were a couple of very crude equations, concessions to basics like the thermal wind law, for instance). One of them was whether a warm north Atlantic was good news or bad for Northern Brazil. It was one or the other, and I’m sure I had the fact ready at hand during the exam.
This sort of heuristic has some modest value I suppose. If you can say this will be a dry year more likely than not, or a year with more tropical storms than usual, based on a collection of heuristics, then to the extent that is reliable, you can help people plan. And you can just comb through the data looking for correlations with some predictive value. It’s an activity which looks like science. It has enough value that you can get grants for it. NOAA regularly puts out seasonal outlooks for the US which have a couple of regions marked as ‘>60% chance of above normal temperatures’ or the like.
I’ve always had a couple of problems with this technique. First, I’m unconvinced it actually helps anybody do anything. 60% chance of above normal really isn’t a very strong statement. Are there really activities which are rationally conducted differently in the light of such information? Second, it confuses people about climate science; this is neither climate science nor weather prediction, both of which are based in physics. It’s pure heuristics. Yet it’s usually called a “short-term climate prediction”. Given the importance of climate change in the future, this is unfortunate and misleading nomenclature. Third, there is indeed accelerating climate change, so the value of heuristics will decline as the underlying conditions which supported the heuristics also change. The heuristic method is pretty much guaranteed to get worse.
(Now, if we ever get to predictive models of deep ocean circulation, maybe short term predictions of climate will be physically meaningful. At present this seems rather speculative, but people do seem to be working on it quite seriously.)
There’s a another issue, though. The empiricists have always, to some extent, treated the physicists as a threat. Somebody who is good at digging into history should look into this, but I have several points of corroboration. First, there is the (from where I sit) unexplained tension between the famed empiricist Reid Bryson and the groundbreaking climate physicist Vern Suomi that is at the heart of the meteorology program at Wisconsin splitting into two institutions. Second, there was my brief meeting way back in 1993 or so with Bill Gray, the famous hurricane prediction guy, the classic empiricist. I hadn’t even made a name for myself on sci.environment in those days; and it was really unlikely that he had heard of me. My advisor, John R. Anderson, was known more as a modeler than as a climate change guy. In those days there was little sense that the topics were tightly connected. John introduced me to Gray just as a grad student, period. It wasn’t a minute into the conversation before Gray was ranting and raving about how hurricanes were more important than global warming, and how his money was drying up, etc.
So it’s interesting to see that Gray is not alone among tropical storm researchers in this hostility. There are certainly signs of more than ordinary strife within the tropical storm science community. I can’t say I have an inside view of what’s going on but I note that Knappenberg and Curry both come out of the tropical storm community. I don’t know how close they come to the Bill Gray tradition but I suspect there is some connection.
See, empiricism lacks consilience. When the science moves in a particular direction, they have nothing to offer. They can only read their tea leaves. Empiricists live in a world which is all correlation, and no causation.
This is the third installment of the empiricism series.
Next: Empiricism and Denialism
Image: NOAA. Extra credit: why do Mexicans and Canadians find this map irritating?