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“Climate Science, 50 Years Later”

14 December 2015
An October symposium—but not the media—looked back on scientific concerns about a “vast geophysical experiment.”

Almost no journalists have considered the climate-wars implications of the recent “Climate Science, 50 Years Later” symposium that Science magazine editor-in-chief Marcia McNutt highlighted in this opening paragraph of an editorial:

Long before geophysicist Michael Mann’s hockeystick graph became the icon for anthropogenic global warming, the US President’s Science Advisory Committee [now known as the President’s Council of Advisors on Science and Technology (PCAST)] cautioned President Lyndon B. Johnson that the continued release of CO2 to the atmosphere from burning fossil fuels would “almost certainly cause significant changes” and “could be deleterious from the point of view of human beings.” The committee’s report concluded that there could be “marked changes in climate, not controllable through local or even national efforts.” In recognition of the 50th anniversary of that first official warning from scientists to policy-makers, the American Association for the Advancement of Science (AAAS), the Carnegie Institution for Science, the American Meteorological Society, and the Linden Trust for Conservation sponsored a 1-day climate symposium on 29 October.

That 1965 report was actually the 23-page Appendix Y4, “Atmospheric Carbon Dioxide,” that accompanied the report Restoring the Quality of Our Environment: Report of the Environmental Pollution Panel. The report’s front matter and its Appendix Y4 have been placed online. Roger Revelle, a name well known to students of climate-science history, chaired the effort to produce the appendix. Concerning that history, a 5 November posting at the blog Skeptical Science emphasized that the appendix effectively "debunked a number of myths that climate contrarians continue to repeat to this day.”

This media report will provide excerpts illustrating that claim, but first, it’s important to recall that climate-science history is an extensive and well-tended field, as seen at the hypertext history site The Discovery of Global Warming.  There historian and site creator Spencer Weart puts the discussion into a wide context. Concerning the then-new scientific findings now being remembered, he wrote:

Gradually the government reacted. In 1965, when the President’s Science Advisory Committee formed a panel to address environmental issues, it included a subpanel of leading climate experts. They reported that greenhouse warming was a matter of real concern. There could be “marked changes in climate,” they reported, “not controllable through local or even national efforts.” That put the issue on the official agenda at the highest level of government—although only as one item on a long list of environmental concerns, many of which seemed more pressing.

It’s also true, though, that climate scoffers often charge that scientists’ climate consensus has been mostly made up, ad hoc, and comparatively recent and that it hasn’t really evolved methodically from sensibly conducted research. That’s why Inside Science News at the American Institute of Physics published and circulated Peter Gwynne’s 2014 article “My 1975 ‘Cooling World’ story doesn’t make today’s climate scientists wrong.” It carried the subheadline “It’s time for deniers of human-caused global warming to stop using an old magazine story as ammunition against the consensus of today’s climate scientists.”

Because some climate scoffers charge that carbon dioxide cannot legitimately be called a pollutant, the heading for Section 1 of the 1965 appendix merits attention: “Carbon dioxide from fossil fuels—The invisible pollutant.” That section contained subsections on “possible effects” headed “Melting of the Antarctic ice cap” and “Rise of sea level,” though neither of those possible effects was presented as likely.

The appendix declared (page 113) that the burning of fossil fuels was “measurably increasing the atmospheric carbon dioxide.” The passage added, “Within a few short centuries, we are returning to the air a significant part of the carbon that was slowly extracted by plants and buried in the sediments during half a billion years. . . . The part that remains in the atmosphere may have a significant effect on climate.” The passage also introduced the greenhouse concept: An “increase of atmospheric carbon dioxide could act, much like the glass in a greenhouse, to raise the temperature of the lower air.”

The next page noted that as of 1965, scientists could not “make a useful prediction concerning the magnitude or nature of the possible climatic effects.” They were, however, “able to say a good deal more than formerly about the change in the quantity of atmospheric carbon dioxide, and about the partition of carbon dioxide from fossil fuel combustion among the atmosphere, the ocean, and the biosphere.” The appendix also offered (pages 121 and 122) some thoughts on the prospect of developing more effective climate models.

The subsection “Conclusions and findings” opened with an assertion calculated to be striking: “Through his worldwide industrial civilization, Man is unwittingly conducting a vast geophysical experiment.” That experiment metaphor—was it only a metaphor?—had been used before. The opening continued:

Within a few generations he is burning the fossil fuels that slowly accumulated in the earth over the past 500 million years. . . . By the year 2000 the increase in atmospheric CO2 will be close to 25%. This may be sufficient to produce measurable and perhaps marked changes in climate, and will almost certainly cause significant changes in the temperature and other properties of the stratosphere. At present it is impossible to predict these effects quantitatively.

After calling for more federally funded climate monitoring and research, the summarizing subsection asserted, as McNutt and others have emphasized, that the “climatic changes that may be produced by the increased CO2 content could be deleterious from the point of view of human beings.” Then it addressed what’s now called geoengineering:

The possibilities of deliberately bringing about countervailing climatic changes therefore need to be thoroughly explored. A change in the radiation balance in the opposite direction to that which might result from the increase of atmospheric CO2 could be produced by raising the albedo, or reflectivity, of the earth. Such a change in albedo could be brought about, for example, by spreading very small reflecting particles over large oceanic areas. . . . Considering the extraordinary economic and human importance of climate, costs . . .  do not seem excessive.

It also cited a method of causing “cirrus clouds to form at high altitudes” and added that this “potential method of bringing about climatic changes needs to be investigated as a possible tool for modifying atmospheric circulation in ways which might counteract the effects of increasing atmospheric carbon dioxide.”

So what about this appendix from 1965 and journalism in 2015? The potential point for news-consuming citizens isn’t so much that the 1965 document was prescient as that it’s instructive about the long, methodical evolution of climate science—an evolution that some climate scoffers allege has been mostly just contrived. Presumably with the research tools, modeling resources, and climate knowledge available in 1965, climate prescience back then could at best be limited—that is, unless you count as prescient the methodical identification of research desiderata.

At any rate there’s been little press in 2015. The symposium did inspire a posting by one of its presenters, Marshall Shepherd, at the business site But back in 2007, the historian and climate-technopolitics observer Naomi Oreskes cited the 1965 appendix in her Washington Post op-ed “The long consensus on climate change,” which summarized the history of research on climate and carbon dioxide going back to the 19th century.

There was something else this year that the press apparently didn’t pick up. The climate-news blog The Daily Climate aggregates news “from center right to center left.” Back in February, a posting appeared there called “A 50th anniversary few remember: LBJ’s warning on carbon dioxide.” It duly covered the 50th anniversary of the November 1965 document, but it opened by recalling something from earlier still—a presidential speech. The posting makes clear that the speech “mainly focused on all-too-visible pollution of land and waterways, including roadside auto graveyards, strip mine sites, and soot pollution that had marred even the White House.” But the posting opened this way:

It is a key moment in climate change history that few remember: This week marks the 50th anniversary of the first presidential mention of the environmental risk of carbon dioxide pollution from fossil fuels.

President Lyndon Baines Johnson, in an 8 February 1965 special message to Congress, warned about build-up of the invisible air pollutant that scientists recognize today as the primary contributor to global warming.

“Air pollution is no longer ed to isolated places,” said Johnson less than three weeks after his 1965 inauguration. “This generation has altered the composition of the atmosphere on a global scale through radioactive materials and a steady increase in carbon dioxide from the burning of fossil fuels.”

Given that the climate wars grew out of decades, not just years, of growing awareness, and given the allegations and disputes about that evolution, to what extent, if any, should the press report on the history of climate-science awareness?

An answer to that question might include this datum: A 1956 New York Times article headlined “Warmer climate on the Earth may be due to more carbon dioxide in the air” explained the greenhouse effect, warned that economic pressures would force the continued burning of coal and oil, and reported that “a rise in the average temperature of only 4 degrees C. would convert the polar regions into tropical deserts and jungles, with tigers roaming about and gaudy parrots squawking in the trees.”


Steven T. Corneliussen, a media analyst for the American Institute of Physics, monitors three national newspapers, the weeklies Nature and Science, and occasionally other publications. He has published op-eds in the Washington Post and other newspapers, has written for NASA's history program, and is a science writer at a particle-accelerator laboratory.

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