A report of the Ad Hoc Study Group on carbon dioxide and climate for the National Research Council chaired by Massachusetts Institute of Technology meteorologist Jule Charney estimates “the most probable global warming for a doubling of CO₂ to be near 3°C with a probable error of ± 1.5°C.”

The forward to the 22-page “Charney Report” by Verner Suomi, Chairman of the Climate Research Board of the National Research Council, notes that “For more than a century, we have been aware that changes in the composition of the atmosphere could affect its ability to trap the sun’s energy for our benefit.  We now have incontrovertible evidence that the atmosphere is indeed changing and that we ourselves contribute to that change.  Atmospheric concentrations of carbon dioxide are steadily increasing, and these changes are linked with man’s use of fossil fuels and exploitation of the land.  Since carbon dioxide plays a significant role in the heat budget of the atmosphere, it is reasonable to suppose that continued increases would affect climate.”  Suomi directs a cautionary warning to policymakers:  “The conclusions of this brief but intense investigation may be comforting to scientists but disturbing to policymakers.  If carbon dioxide continues to increase, the study group finds no reason to doubt that climate changes will result and no reason to believe that these changes will be negligible.  The conclusions of prior studies have been generally reaffirmed.  However, the study group points out that the ocean, the great and ponderous flywheel of the global climate system, may be expected to slow the course of observable climatic change.  A wait-and-see policy may mean waiting until it is too late.”  In addition to characterizing the impact of the oceans in delaying observable atmospheric warming, the study explores the impact of both positive and negative feedback mechanisms:  “A strong positive feedback mechanism is the accompanying increase of moisture, which is an even more powerful absorber of terrestrial radiation.  We have examined with care all known negative feedback mechanisms, such as increase in low or middle cloud amount, and have concluded that the oversimplifications and inaccuracies in the models are not likely to have vitiated the principal conclusion that there will be appreciable warming.  The known negative feedback mechanisms can reduce the warming, but they do not appear to be so strong as the positive moisture feedback.”*

*Jule G. Charney and others, Carbon Dioxide and Climate: A Scientific Assessment (National Academy of Sciences 1979),

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Senior Exxon Corporation scientist James F. Black advises Exxon’s Management Committee that CO₂ from the world’s use of fossil fuels would warm the planet and could eventually endanger humanity

At a meeting at Exxon Corporation’s headquarters, senior Exxon scientist James F.  Black advises Exxon’s Management Committee that “
 there is general scientific agreement that the most likely manner in which mankind is influencing the global climate is through carbon dioxide release from the burning of fossil fuels.”  In an updated report to a broader range of Exxon executives and scientists in 1978, Black states that “Present thinking holds that man has a time window of five to ten years before the need for hard decisions regarding changes in energy strategies might become critical.”*

*Neela Banerjee, Lisa Song and David Hasemyer, Exxon: The Road Not Taken, Sept. 15, 2015, Inside Climate News,

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1977

The U.S. National Academy of Sciences releases a report that identifies a global warming trend caused by increased use of fossil fuels, and predicts that global temperatures could rise by 6 degrees Celsius by 2150 due to fossil fuel emissions.

The (NAS) report, “Energy and Climate: Studies in Geophysics,” observes, “Examination of the possible long-term effects of energy use is particularly timely.  With the end of the oil age in sight, we must make long-term decisions as to future energy policies.  One lesson we have been learning is that the time required for transition from one major source to another is several decades.”  The findings, the NAS notes, “should lead neither to panic nor to complacency.”^*

^*National Academy of Sciences, Energy and Climate: Studies in Geophysics, 1977.  (Washington, DC:  GPO, 1977), vii-viii,

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1976

Charles D. Keeling creates the “Keeling Curve,” a simple visualization of the longest continuous record of CO₂ concentration in the world.

A paper published by Charles D. Keeling of the Scripps Institution of Oceanography and coauthors in the journal Tellus, “Atmospheric carbon dioxide variations at Mauna Loa Observatory, Hawaii,” tracks increases in atmospheric carbon dioxide measured at the Mauna Loa Observatory, finding that “the annual average CO₂ concentration rose 3.4% between 1959 and 1971
 Similar changes in rate have been observed at the South Pole and are evidently a global phenomenon.” The Keeling Curve shows measurements dating back to 1958 at Mauna Loa and as it later develops incorporates ice core records to show CO₂ measurements dating back to 1700.^*ÌꎥČő CarbonBrief comments: “With the Mauna Loa measurements continuing today,Ìęthe so-called ‘Keeling curve’ is the longest continuous record of carbon dioxide concentration in the world. Its historical significance and striking simplicity has made it one of the most iconic visualizations of climate change.”^**

— EXTRA —
» See a  on Vimeo
» reflecting on Keeling’s life

^*Charles D. Keeling and others, “Atmospheric carbon dioxide variations at Moana Loa Observatory, Hawaii,”Tellus, Vol. 28, Issue 6, December, 1976, ; Rob Monroe, “How are ice-core data and Mauna Loa atmospheric data made comparable?” Scripps Institution of  Oceanography, March 20, 2014,
^**Roz Pidcock, “The Most Influential Climate Change Papers of All Time,” CarbonBrief, June 7, 2015,

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1972

The Club of Rome publishes Limits to Growth, a report that predicts that if current growth trends continue unchanged, the limits to growth on the planet will be reached within the next 100 years.

The report , making unprecedented use of computer modeling, summarizes its findings as follows: “1. If the present growth trends in world population, industrialization, pollution, food production, and resource depletion continue unchanged, the limits to growth on this planet will be reached sometime within the next one hundred years.  The most probable result will be a rather sudden and uncontrollable decline in both population and industrial capacity. 2. It is possible to alter these growth trends and to establish a condition of ecological and economic stability that is sustainable far into the future.  The state of global equilibrium could be designed so that the basic material needs of each person on earth are satisfied and each person has an equal opportunity to realize his individual human potential. 3. If the world’s people decide to strive for this second outcome rather than the first, the sooner they begin working to attain it, the greater will be their chances of success.”^* The study is translated into thirty languages and sells 30 million copies, more than any other environmental book.^**

^*Donella Meadows and others, Limits to Growth (New York: Signet, 1972),
^**Bill McKibben, Eaarth (New York:  Henry Holt, 2011) at 90-92.

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1967

Syukuro Manabe and Richard T. Wetherald are the first to use a computer model to explore the impact of increasing atmospheric carbon dioxide on the Earth’s climate

Syukuro Manabe and Richard T. Wetherald publish “Thermal Equilibrium of the Atmosphere with a Given Distribution of Relative Humidity” in the Journal of the Atmospheric Sciences. They conclude that “a doubling of the CO₂ content in the atmosphere has the effect of raising the temperature of the atmosphere (whose relative humidity is fixed) by about 2C.”^* The analysis is “the first to represent the fundamental elements of the Earth’s climate in a computer model, and to explore what doubling carbon dioxide (CO₂) would do to global temperature.”  A 2015 CarbonBrief poll of leading scientists from the Intergovernmental Panel on Climate Change (IPCC) will find this paper most often chosen as the “most influential climate change paper of all time.”^**

^*Syukuro Manabe and Richard Wetherald, “Thermal Equilibrium of the Atmosphere with a Given Distribution of Relative Humidity,” Journal of the Atmospheric Sciences, Vol. 24, No. 3, May, 1967,
^**Roz Pidcock, “The Most Influential Climate Change Papers of All Time,” CarbonBrief, June 7, 2015, ; My acknowledgment to the CarbonBrief survey report for identifying a number of other research articles included in this chronology.

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1965

Roger Revelle contributes to the first mention of global warming in a government report, drawing an analogy between human-produced gases entering the global atmosphere and the effect of glass in a greenhouse

Serving on the President’s Science Advisory Committee Panel on Environmental Pollution, oceanographer Roger Revelle contributes to an appendix to the government report Restoring the Quality of our Environment, entitled “Carbon Dioxide from Fossil Fuels:  the Invisible Pollutant.” Citing measurements by the U.S. Weather Bureau on Mauna Loa Mountain in Hawaii, the report notes that “the data show, clearly and conclusively, that from 1958 through 1962 the carbon dioxide content of the atmosphere increased by 1.36 percent. The increase from year to year was quite regular, close to the average annual value of 0.23%. By comparing the measured increase with the known quantity of carbon dioxide produced by fossil fuel combustion 
 we see that almost exactly half of the fossil fuel CO₂ apparently remained in the atmosphere.” The report concludes that “Within a few short centuries, we are contributing to the air a significant portion of the carbon that was slowly extracted by plants and buried in the sediments during half a billion years
 [A]n increase in atmospheric carbon could act, much like the glass in a greenhouse, to raise the temperature of the lower air.”^*

^*Environmental Pollution Panel of the President’s Scientific Advisory Committee, Restoring the Quality of Our Environment, 1965 (Washington, DC: GPO,1965), App. Y4, 116, .

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1957

American oceanographers Roger Revelle and Hans Suess demonstrate that CO₂ levels in the air have increased as a result of the use of fossil fuels

Roger Revelle and Hans Suess of the Scripps Institution of Oceanography publish “Carbon Dioxide Exchange Between Atmosphere and Ocean and the Question of an Increase of Atmospheric CO₂ during the Past Decades.” From measuring carbon content in wood and marine material, the authors conclude that “most of the CO₂ released by artificial fuel combustion since the beginning of the industrial revolution must have been absorbed by the oceans. The increase in atmospheric CO₂ from this cause is at present small but may become significant during future decades if industrial fuel combustion continues to rise exponentially.” The authors observe that previous estimates about the amount of warming that would be attributable to increased CO₂ releases have not taken into account feedback mechanisms that can enhance warming: “
 [A]mplifying or feedback processes may exist such that a slight change in the character of the back radiation might have a more pronounced effect. Possible examples are a decrease in the albedo [reflection of solar energy] of the earth due to melting of ice caps
”^* The authors note that this emerging human impact on the planet is unprecedented: “Thus human beings are now carrying out a large scale geophysical experiment of a kind that could not have happened in the past 
 Within a few centuries we are returning to the atmosphere and oceans the concentrated organic carbon stored in sedimentary rocks over hundreds of millions of years. This experiment 
 may yield a far-reaching insight into the process determining weather and climate.”^*

^*Revelle, Roger, and Hans E. Suess. “Carbon Dioxide Exchange Between Atmosphere and Oceans and the Question of an Increase of Atmospheric CO2 during the Past Decades,” Tellus 9 (1957): 19-20.

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1956

The New York Times publishes a summary of the Gilbert Plass paper headlined “Warmer climate on the earth may be due to more carbon dioxide in the air”

The New York Times summary of the Gilbert Plass paper concludes:  “Even if our coal and oil reserves will be used up in 1,000 years, seventeen times the present amount of carbon dioxide in the atmosphere must be reckoned with.  The introduction of nuclear energy will not make much difference.  Coal and oil are still plentiful and cheap in many parts of the world, and there’s every reason to believe that both will be consumed by industry as long as it pays to do so.”^*

^*Waldemar Kaempffert, “Warmer climate on the earth may be due to more carbon dioxide in the air,” New York Times, October 28, 1956,

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1956

Canadian physicist Gilbert Plass publishes a lucid explanation of “carbon dioxide theory” to account for “the general warming of the climate that has taken place in the last sixty years”

Physicist Gilbert Plass of Johns Hopkins and colleagues publish “The Carbon Dioxide Theory of Climatic Change,” to account for “the general warming of the climate that has taken place in the last sixty years” in the journal American Scientist. The article questions: “What is the reason for the recent temperature rise that is found throughout the world? Will this trend toward warmer climates continue for some time? The carbon dioxide theory may provide the answer.” After citing various other theories for warming, Plass notes: “Although the carbon dioxide theory of climatic change was one of the most widely held fifty years ago, in recent years it has had relatively few adherents. However, recent research work suggests that the usual reasons for rejecting this theory are not valid.” Evidence demonstrates that “[t]he infrared absorption properties of carbon dioxide, water vapor, and ozone determine our climate to a large extent. Their action has often been compared to that of a greenhouse
 [A]s the amount of carbon dioxide increases
 the outgoing radiation is trapped more effectively near the earth’s surface and the temperature rises. The latest calculations show that if the carbon dioxide content of the atmosphere should double, the surface temperature would rise 3.6 Celsius…” The article goes on to discuss the impact of fossil fuel combustion:  “Recently
 man has added an important new factor to the carbon dioxide balance
 [C]ombustion of fossil fuels is adding 6.0 x 10⁹ tons [tonnes] per year of carbon dioxide to the atmosphere at the present time and the rate is increasing every year. Today this factor is larger than any contribution from the inorganic world. Thus today man by his own activities is increasing the carbon dioxide in the atmosphere at the rate of 30 per cent a century
 Even if there may be some question as to whether or not the general amelioration of the climate in the last fifty years has really been caused by increased industrial activity, there can be no doubt that this will become an increasingly serious problem as the level of industrial activity increases. In a few centuries the amount of carbon dioxide released into the atmosphere will have become so large that it will have a profound influence on our climate.”^*

^*Gilbert N. Plass, ,Ìę, “Carbon Dioxide and the Climate,” American Scientist Vol. 44, No. 3 (July 1956):302-316; reprinted in American Scientist, January-February 2010,

Photo:

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