Definitive Evidence for Global Cooling Consensus in the 1970s (3)

A series of blogs analizing Thomas C. Peterson, William M. Connolley, and John Fleck’s (PCF) largely mistitled “The Myth of the 1970s Global Cooling Scientific Consensus” (Bulletin of the American Meteorological Society Volume 89, Issue 9, September 2008, pp 1325-1337). Previous considerations about a global cooling consensus in the 1960’s can be read here and here.

4 – AN INCOHERENT TIME FRAME

In the previous blogs in the series, we have seen how the very statements made by Thomas C. Peterson, William M. Connolley, and John Fleck’s (PCF) The Myth of the 1970s Global Cooling Scientific Consensuscan be used to demonstrate that there was indeed a global cooling scientific consensus, in the 1970s.

The whole concept of the “myth” is merely based on definitions. Besides, PCF’s own methodology meant disregarding almost everything written about global cooling anyway.

Moreover: they have been cavalier with the temporal series of events.

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What is the meaning of “the 1970’s”? In the “Perpetuating the Myth” Box (page 1326, page 2 in the PDF file), PCF are particularly disingenuous in their criticism of Singer and Avery (2007), Balling (1992), Giddens (1999), Michaels (2004) and pretty much everybody else.

From PCF’s own analysis, in fact, one can distinguish two eras, with a “cooling consensus” up to 1975:

PCF: “Indeed, the Earth appeared to have been cooling for more than 2 decades when scientists first took note of the change in trend in the 1960s. The seminal work was done by J. Murray Mitchell [in 1963, showing that] global temperatures had increased fairly steadily from the 1880s, the start of his record, until about 1940, before the start of a steady multidecade cooling (Mitchell 1963). By the early 1970s, when Mitchell updated his work (Mitchell 1972), the notion of a global cooling trend was widely accepted, albeit poorly understood.

The first satellite records showed increasing snow and ice cover across the Northern Hemisphere from the late 1960s to the early 1970s. This trend was capped by unusually severe winters in Asia and parts of North America in 1972 and 1973 (Kukla and Kukla 1974),which pushed the issue into the public consciousness (Gribbin 1975). The new data about global temperatures came amid growing concerns about world food supplies, triggering fears that a planetary cooling trend might threaten humanity’s ability to feed itself (Thompson 1975).

The start of the “warming” era is placed by PCF around 1976:

PCF: “It was not long, however, before scientists teasing apart the details of Mitchell’s trend found that it was not necessarily a global phenomenon.Yes, globally averaged temperatures were cooling, but this was largely due to changes in the Northern Hemisphere. A closer examination of Southern Hemisphere data revealed thermometers heading in the opposite direction (Damon and Kunen 1976).

Therefore, according to PCF themselves, scientists up to 1975 would have mostly agreed that the world was cooling. What is wrong then in stating that global cooling was at the time “scientific verity” (Bray 1991)? “Orthodox scientific opinion” in 1974, that is 25 years before Giddens wrote the text below, was exactly as he described it:

Giddens: “Yet only about 25 or so years ago, orthodox scientific opinion was that the world was in a phase of global cooling.

What one could say is that Singer, Avery, and most of those mentioned in that Box, are as guilty as PCF in viewing the 1970’s with glasses tinted with today’s mindframes (eg exaggerating any mention of “global cooling” into “ice ages”).

But is PCF’s the one truly unmissable statement:

PCF: “Clearly, if a national report in the 1970s advocates urgent action to address global warming, then the scientific consensus of the 1970s was not global cooling.

The U.S. National Research Council report they refer to, is from 1979. How could people know about that report, in 1975?

PCF’s analysis is not temporally sensible.

QED.

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In a lyrical passage, PCF state their research is all the more interesting because it shows the emerging in the 1970s of “the integrated tapestry that created the basis for climate science as we know it today“. That’s a myth in its own right, and the topic for the next blog in the series.

(continues…)