I apologise for the brief intrusion of something vaguely related to climate science on this rowing-n-wiki blog; we’ll return you to your usual programming shortly.
Maurizio Morabito attempts to establish that there was a consensus for global cooling in the 1960′s (this is all part of a rather dull campaign to discredit the mighty number one climate paper “The Myth of the 1970s Global Cooling Scientific Consensus”; generally he appears to have failed to understand what we said, so I won’t bore you by attacking it further). Evidence is apparently found in a 1961 UNESCO / WMO conference Symposium on Changes of Climate with Special Reference to Arid Zones which UNESCO have had the good manners to put online. Well, fascinating stuff, let’s read on…
Since MM (prodded by good ol’ boy Nigel Calder) found the thing, it is only fair to quote his best (or at least the first; I didn’t bother read the whole thing) attempt at cherry picking:
Admittedly, it is easy to miss something in a document so big, but I am fairly confident the following are the most relevant findings for the present discussion (note that “some 115 scientists from 36 countries took part in the symposium”): (page numbers in the following refer to the PDF’s, not the original) (1) At page 182, an intervention by E. Kraus of the Woods Hole Oceanographic Institution, Woods Hole, Mass., U.S.A., commenting a presentation by J. Murray Mitchell Jr. United States Weather Bureau, Washington, D.C. Perhaps the most interesting part of the evidence presented by Dr. Murray Mitchell, Dr. Rodewald and some of the other speakers is the way in which it falls into a pattern. Not only air temperature, but also subtropical rainfall, the tendency of hurricanes to move along certain tracks or seasurface temperatures, show a reversal of the preceding [warming] climatic trend during the last one or two decades. The true physical signiñcance of Dr. Murray Mitchell’s result lies perhaps in the combined evidence, based on so many different variables.
I’m afraid I haven’t read the report as far as page 182. But it seems reasonable to begin at the beginning, with the introductory review paper by Veryard (Met Office, Air Ministry, London) who proposes a “review of studies on climate fluctuations during the period of the meteorological record”. This pretty well confirms what I already knew: that during this period, the global records that we take for granted today were only just being collated and were not widely available. Anyone publishing such a paper today would inevitably include a graph of the various temperature records: there is nothing like that (before you say: tech limitations prevented graphs: it isn’t so: there are others elsewhere in the volume). Table 1 presents two studies that indicate the world has warmed between 1890-1920 and 1920-1950. There are various tentative patches of text such as In a more recent global study on secular change to be given in a paper by Mitchell at this symposium there is some confirmation that the “world-wide” warming trend of earlier decades was apparently reversed in the 19480s although temperatures have continued to rise in some places. Or: In trying to fit all the many bits of evidence together, one can hardly avoid the conclusion that during the period of the instrumental record there has in fact been a fairly general if not an overall warming-at least up to the 1940s. It would appear that this was slow and irregular at first but became more rapid later reaching a peak somewhere in the 1930s-4’0s. There can be no doubt that the rise has not been uniform or symmetrical in respect to the Pole ; it has been least or nil in middle latitudes of the Southern Hemisphere and greatest in high latitudes of the Northern Hemisphere, especially in areas bordering the Atlantic Ocean. It also appears that the rise of temperature in some areas has lagged behind the rise in others ; in fact, for a time at any rate, the fluctuations in some places have been opposed to those in others. Moreover, the warming has embraced
short-period variations, and might only be part of a much larger period fluctuation covering perhaps some hundred years.
I don’t see any great endorsement of a clear cooling trend there. I see what I expected (don’t you always?): uncertainty.
That refers to Mitchell (not the Mitchell) so we may as well skip ahead to P 161 to see what he has to say “ON THE WORLD-WIDE PATTERN OF SECULAR TEMPERATURE CHANGE” (don’t shout, Murray, I can hear you). Oh look, there is his figure 1 on the right. Apart from the bizarre choice of units on the y-axis it is about what you would expect to see. And he says The fluctuations have consisted primarily of the well-known warming of the earlier decades of the century, and a tendency for cooling since about 1940 which appears to have not only halted but reversed the warming in most latitudes. You might complain that the cooling was fairly short-lived at that point an possibly a blip, a point that Mitchell was quite aware of, and tested for: It will be seen in Table 2 that the observed warming trends between 1890 and 19-49, with the exception of those in the Southern Hemisphere, remain highly significant (2-5 standard errors). According to Table 3, however, the cooling since 1940 loses much of its significance when viewed in this manner.
Does anyone want to read more?
