Report: Oil Industry Knew About Dangers of Climate Change in 1954

Leaders of the U.S. fossil fuel industry knew as early as 1954  carbon dioxide pollution accumulating in the atmosphere posed a growing threat to life on Earth, but failed to warn the public. That’s according to new research published by Stanford historian Benjamin Franta in the journal Nature Climate Change. Franta found in the 1950s the American Petroleum Institute commissioned a study by a Caltech scientist which concluded global CO2 levels had risen by 5 percent in a century. It’s the earliest known industry-funded research into climate change, and the findings led in part to a 1965 report by President Lyndon Johnson’s Science Advisory Committee on the threat posed by global warming. Speaking to members of an oil industry conference that year,

Frank Ikard, then-president of the American Petroleum Institute, warned, “This report unquestionably will fan emotions, raise fears, and bring demand for action. The substance of the report is that there is still time to save the world’s peoples from the catastrophic consequence of pollution, but time is running out.” The American Petroleum Institute would instead go on to fund decades of climate change denial while fighting efforts to switch to renewable energy sources.

Early oil industry knowledge of CO2 and global warming

Benjamin Franta Nature

In a seminal 1960 article in the journal Tellus, Charles Keeling reported the concentration of atmospheric CO2 at the South Pole was rising at a rate “nearly that
to be expected from the [global] combustion of fossil fuel.”1

His measurements, begun in 1957, allowed him to start constructing the famous Keeling curve — the continuous, direct record of rising CO2 levels around the globe caused primarily by the burning of fossil fuels.

Yet archival documents show even before Keeling published his measurements, oil industry leaders were aware their products were causing CO2 pollution to accumulate in the planet’s atmosphere in a potentially dangerous fashion.

And when US President Lyndon Johnson’s Science Advisory Committee warned of global warming in 1965, the petroleum industry’s main trade association, the American Petroleum Institute (API), relayed the warning to its members.

In 1954, the geochemist Harrison Brown and his colleagues at the California Institute
of Technology submitted a research proposal to the API entitled “The determination of
the variations and causes of variations of the isotopic composition of carbon in nature.”

The scientists proposed the use of new mass spectrometers to investigate the ratio of carbon-12 to carbon-13 in terrestrial, marine, and mineral systems to understand geological and biological carbon cycling.

The team had already carried out preliminary work, including on tree rings of various ages. “Perhaps the most interesting effect concerning carbon in trees, which we have thus far observed,” the researchers reported to the API, “is a marked and fairly steady increase in the 12C/13C ratio with time.” The results indicated fossil fuels caused atmospheric CO2 concentrations to rise by about 5% over the past century. 2

Brown’s estimate was quite accurate: from 1854 to 1954, global CO2 concentrations rose by 10% (from around 285 to 313 ppm), 3 with about 4% of that from fossil fuels, and the remainder from deforestation and other land-use changes. 4

That same year, in 1954, the Yale ecologist George Hutchinson suggested using carbon
isotopes to measure atmospheric CO2 from fossil fuels.5 However, Brown’s research
proposal, reproduced in Fig. 1 and never before noticed by historians, shows such measurements already had been performed — and reported to petroleum industry leaders.


Fig. 1 | Excerpt of research proposal to the API from Harrison Brown and colleagues in 1954. The proposal informed the API fossil fuels caused atmospheric CO2 levels to rise by about 5% over the last 100 years. Image reproduced from ref. 2, Caltech Archives.

In 1955, the API began funding the proposed research at Caltech under the name Project 53. The project focused on uranium–lead dating, yet work on carbon continued, at least for a time: later that year, the researchers told the API they were using their mass spectrometer to make around 2,300 measurements on CO2 per year. 6 The results were not published.

Others began examining fossil fuel emissions using carbon isotopes in tree rings. Hans Suess, in 1955, gave a low estimate of atmospheric fossil carbon7 of less than 1%.

Suess’ work was expanded in 1957 by H. R. Brannon of Humble Oil Company (now ExxonMobil), who found higher concentrations of 3.5%. Brannon knew of Harrison Brown’s unpublished work, compared results, and found they agreed. 8

A few years later, in 1959, petroleum industry leaders were notified of the danger of CO2 accumulation by the physicist Edward Teller, who warned them of global temperature and sea-level rise by the end of the century. 9

Thus, even before early portions of the Keeling curve were published in 1960, leaders of the API and other segments of the oil industry were informed fossil fuel products were causing atmospheric CO2 concentrations to rise, and that such a rise was
potentially dangerous.

When the danger was brought to US President Lyndon Johnson’s attention by his Science Advisory Committee’s Restoring the Quality of Our Environment report in
1965, the petroleum industry took notice. 10

Three days after the report’s publication, API president Frank Ikard addressed
industry leaders at the organization’s annual meeting, saying, “One of the most important predictions of the report is carbon dioxide is being added to the Earth’s atmosphere by the burning of coal, oil, and natural gas at such a rate that by the year 2000, the heat balance will be so modified as possibly to cause marked changes in climate beyond local or even national efforts.” 11

Ikard did not dispute the links betweenfossil fuels, CO2, and global warming. “The
substance of the report,” he summarized, “is there is still time to save the world’s
peoples from the catastrophic consequence of pollution, but time is running out.” This
communication, reproduced in Fig. 2, remained unnoticed by historians until now.


These archival discoveries add to the growing body of information regarding fossil fuel producers’ knowledge of climate science over time. 12

Such information may assist in understanding the history of climate policy efforts and assessing the responsibilities of fossil fuel producers today. 13

Benjamin Franta
Department of History, Stanford University


1. Keeling, C. D. Tellus 12, 200–203 (1960).

2. Brown, H., Epstein, S., Lowenstam, H. & McKinney, C. R. Te Determination of the Variations and Causes of Variations of the Isotopic Composition of Carbon in Nature: A Proposal to the American Petroleum Institute from the Division of Geological Sciences, the California Institute of Technology (California Institute of Technology, 1954).

3. Global Mean CO2 Mixing Ratios (ppm): Observations (Goddard Institute for Space Studies, NASA, accessed 20 June 2018);

4. Historical Cumulative Emissions by Source (Global Carbon Project, accessed 20 June 2018);

5. Hutchinson, G. E. in Te Earth as a Planet (ed. Kuiper, G. P.) 371–427 (Univ. Chicago Press: Chicago, 1954)..

6. Patterson, C. C., Brown, H. & McKinney, C. R. Progress Report: American Petroleum Institute Project #53 (California Institute of Technology, 1955).

7. Suess, H. E. Science 122, 415–417 (1955).

8. Brannon, H. R., Daughtry, A. C., Perry, D., Whitaker, W. W. & Williams, M. Trans. Am. Geophys. Union 38, 643–650 (1957).

9. Teller, E. Energy patterns of the future. In Energy and Man: A Symposium 53–72 (Appleton-Century-Crofs, Inc., 1960).

10. Environmental Pollution Panel Restoring the Quality of Our Environment: Report 111–133 (President’s Science Advisory Committee, Te White House, 1965).

11. Ikard, F. N. Meeting the challenges of 1966. In Annual Meeting of the American Petroleum Institute 1965 12–15 (API, 1965).

12. Banerjee, N., Cushman, J. H. Jr, Hasemyer, D. & Song, L. Exxon: The Road Not Taken (CreateSpace, InsideClimate News, 2015).

13. Frumhof, P. C., Heede, R. & Oreskes, N. Climatic Change 132, 157–171 (2015).



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