Watch: The 1970s Cooling Scare Was Real

Here’s a 1974 CIA report:

http://www.climatemonitor.it/wp-content/uploads/2009/12/1974.pdf (or here)

This one appears to be a different scan of the same document:

https://sealevel.info/CIAclimateResearchIntellProbs_1974.pdf

I think that’s the report referred to in the 1976 news article. My guess is that it was prepared and dated in 1974, but not released until 1976.

(Or, was there another CIA climate report in 1976?)

Here’s an excerpt, from the Summary:

“The western world’s leading climatologists have confirmed recent reports of a detrimental global climatic change… during 50 of the last 60 years the Earth has, on the average, enjoyed the best agricultural climate since the eleventh century… The world is returning to the type of climate which has existed over the last 400 years. That is, the abnormal climate of agricultural-optimum is being replaced by a normal climate of the neo-boreal era. The climate change began in 1960…”

The grim climate to which we were thought to be returning was the Little Ice Age. “Boreal” means cold:

boreal. adj. Relating to or characteristic of the climatic zone south of the Arctic, especially the cold temperate region dominated by taiga and forests of birch, poplar, and conifers…

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This was a different report, from the same time period:

https://sealevel.info/CIA1974_potentialtrends.pdf

Here’s an excerpt:

In general, the period about 7000 to 5000 years ago was warmer than today, although the records of mountain glaciers, tree lines, and tree rings reveal that the past 7000 years was punctuated in many parts of the world by colder intervals about every 2500 years, with the most recent occurring about 300 years ago.

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The U.S. National Academy of Sciences also published a long climate report, the following year:

https://sealevel.info/resources.html#nas1975

Here’s an excerpt:

A striking feature of the instrumental record is the behavior of temperature worldwide. As shown by Mitchell (1970), the average surface air temperature in the northern hemisphere increased from the 1880’s until about 1940 and has been decreasing thereafter (see Figure A.6, Appendix A). Starr and Oort (1973) have reported that, during the period 1958-1963, the hemisphere’s (mass-weighted) mean temperature decreased by about 0.6 °C. In that period the polar and subtropical arid regions experienced the greatest cooling.

Here’s another excerpt:

In summary, we may say that observational data at the earth’s surface show that during the period 1900 to 1940 the northern hemisphere as a whole warmed, although some areas (mainly the Atlantic sector of the Arctic and northern Siberia) warmed far more than the global average, some areas became colder, and others showed little measurable change (Mitchell, 1963). In the time since 1940, an overall cooling has occurred but is again characterized by a geographical structure cooling since 1958 has occurred in the subtropical arid regions and in the Arctic (Starr and Oort, 1973). There is also some evidence that the northern hemisphere oceans are cooling (Namias, 1972b), although the oceanic data base necessary to confirm this has not yet been assembled.

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Here’s a paper that it referenced:

https://link.springer.com/chapter/10.1007/978-94-010-3290-2_14

Here’s the abstract:

The trend of world temperature in this century appears to be directly related to the trends of atmospheric carbon dioxide content and atmospheric turbidity (dustiness). Both are believed by various scholars to be related to human activities. Since 1940, the effect of the rapid rise of atmospheric turbidity appears to have exceeded the effect of rising carbon dioxide, resulting in a rapid downward trend of temperature. There is no indication that these trends will be reversed, and there is some reason to believe that man-made pollution will have an increased effect in the future.

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It is interesting and disturbing that some of the papers referenced in those reports seem to have simply disappeared, like this one:

Mitchell, J. M., Jr. (1974). The global cooling effect of increasing atmospheric aerosols, fact or fiction? Proc. IAMAP/WMO Symp. Phys. and Dyn. Climatol. (Leningrad, USSR, August 16-20, 1971), World Meteorological Organization, Geneva (in press).