Despite what NCDC’s Thomas Peterson, Wikiwrangler William Connolley, and John Fleck would like you to believe as a “myth” (The Myth of the 1970s Global Cooling Scientific Consensus), there was in fact serious consideration of the global cooling issue in the 1970’s thanks to this 1974 document from the CIA. – Anthony
The CIA Report and the Warning from Wisconsin
Guest post by David Archibald
In August, 1974, the Office of Research and Development of the Central Intelligence Agency produced a report entitled “A Study of Climatological Research as it Pertains to Intelligence Problems” – available online at:
Some interesting bits of the report follow:
“The western world’s leading climatologists have confirmed recent reports of a detrimental global climate change. The stability of most nations is based upon a dependable source of food, but this stability will not be possible under the new climatic era. A forecast by the University of Wisconsin projects that the earth’s climate is returning to that of the neo-boreal era (1600- 1850) – an era of drought, famine and political unrest in the western world.
Climate has not been a prime consideration of intelligence analysis because, until recently, it has not caused any significant perturbations to the status of major nations. This is so because during 50 of the last 60 years the Earth has, on the average, enjoyed the best agricultural climate since the eleventh century. An early twentieth century world food surplus hindered US efforts to maintain and equalise farm production and incomes.”
“The University of Wisconsin was the first accredited academic center to forecast that a major global climatic change was underway. Their analysis of the Icelandic temperature data, which they contend has historically been a bellwether for northern hemisphere climatic conditions, indicated that the world was returning to the type of climate which prevailed during the first part of the last century.” “Their “Food for Thought” chart (Figure 7) conveys some idea of the enormity of the problem and the precarious state in which most of the world’s nations could find themselves if the Wisconsin forecast is correct.”
CIA Report 1974, Figure 7
The x axis shows annual temperature in centigrade. The y axis is persons per hectare of arable land.
With respect to Figure 7, the CIA report states “As an example, Europe presently, with an annual mean temperature of 12°C (about 53°F), supports three persons per arable hectare. If, however, the temperature declines 1°C only a little over two persons per hectare could be supported and more than 20 percent of the population could be supported and more than 20 percent of the population could not be fed from domestic sources. China now supports over seven persons per arable hectare; a shift of 1°C would mean it could only support four persons per hectare – a drop of over 43 percent.
A unique aspect of the Wisconsin analysis was their estimate of the duration of this climatic change. An analysis by Dr J.E.Kutzbach (Wisconsin) on the rate of climate changes during the preceding 1,600 years indicates an ominous consistency in the rate of (sic) which the change takes place. The maximum temperature drop normally occurred within 40 years of inception. The earliest return occurred within 70 years (Figure 8). The longest period noted was 180 years.”
CIA Report 1974, Figure 8
The CIA Report warning on the impact of cooling on the stability of nations is supported by a 2007 study by Zhang et al:
“We show that long-term fluctuations of war frequency and population changes followed the cycles of temperature change. Further analyses show that cooling impeded agricultural production, which brought about a series of serious social problems, including price inflation, then successively war outbreak, famine, and population decline successively. The findings suggest that worldwide and synchronistic war–peace, population, and price cycles in recent centuries have been driven mainly by long-term climate change.
We studied a long span of Chinese history and found that the number of war outbreaks and population collapses in China is significantly correlated with Northern Hemisphere (NH) temperature variations and that all of the periods of nationwide unrest, population collapse, and dynastic change occurred in the cold phases of this period.”
The CIA Report of 1974 drew heavily on the work of Professor Kutzbach of the University of Wisconsin, who continues to warn of the danger posed by gobal cooling. Professor Kutzbach is a co-author of a study that modelled the effect of a 3.1°C cooler climate (Phillipon-Berthier et al 2010). The premise of the study is that using a carbon dioxide concentration of 240 ppm based on typical values reached during the latter stage of previous interglacials, the climate would 3.14°K cooler than it currently is. Of that cooling, 0.45°K is attributed to vegetation effects and the balance of 2.69°K is due to the carbon dioxide level being 150 ppm less than it is currently. The 2.69°K figure is an obvious and deliberate overstatement. Based on the logarithmic heating effect of carbon dioxide, the true heating differential between 240 ppm and 390 ppm is 0.32°K, as shown by this figure:
Figure 3: The logarithmic heating effect of carbon dioxide
In a world in which even papers in solar physics have to genuflect to global warming in order to get published, it is likely that this overstatement was necessary to get this paper published. Viewed in that light, it seems that the authors wanted to warn the world of the effects of a 3.0°C-odd cooling and the only way they could get the paper past the censors was to concoct a story based on carbon dioxide levels in previous interglacials. A 3.0°C cooling is very similar to what Libby and Pandolfi 1979 warned of, and what is predicted from the length of Solar Cycle 25 as determined by Altrock’s green corona emissions diagram, as shown in
So what did the study find? Philippon-Berthier and colleagues calculated that as a result of the colder and drier conditions, along with lower levels of atmospheric carbon dioxide (a plant fertilizer), terrestrial photosynthesis would decline by 39% and leaf area would decline by 30%. In the Northern Hemisphere mid-latitudes, forest cover would decline by 60% and grassland area would decline by 17%. In the high latitudes, the area of boreal forests would drop by 69% while the area of polar desert would increase by 286%. And in the Tropics, grass area would decline by 3%, forest area by 15%, and the area of bare ground would increase by 344%.
Adding back the effect of current higher atmospheric carbon dioxide levels on plant growth, the decline in terrestrial photosynthesis would be about 25% rather than the calculated 39%. That is likely to be good estimate of the decline in food production, all things being equal, that humanity has in prospect over the next twenty-five years as solar-driven cooling continues per the Libby and Pandolfi and green corona emissions-derived forecasts.
Figure 4: Total grass (top) and tree (bottom) differences (percentages) from current climate conditions with a 3.1°K cooling (source: Philippon-Berthier et al., 2010).
CIA 1974, A Study of Climatological Research as it Pertains to Intelligence Problems
Libby, L.M. and Pandolfi, L.J. 1979, Tree Thermometers and Commodities: Historic Climate Indicators, Environment International Vol 2, pp 317-333
Philippon-Berthier, G., et al., 2010. Role of plant physiology and dynamic vegetation feedbacks in the climate response to low GHG concentrations typical of the late stages of previous interglacials. Geophysical Research Letters, 37, L08705, doi:10.1029/2010GL042905.
Peterson, T.C., et al. (2008): The Myth of the 1970s Global Cooling Scientific Consensus. Bulletin of the American Meteorological Society, 89, 9, 1325-1337, doi:10.1175/2008BAMS2370.