This exhibit describes the rise and fall of a large-scale research program on anthropogenic climate change. The program was organized and funded by the U.S. federal government in the late 1970s. The exhibit is based on the papers of William P. Elliott, an atmospheric scientist who was closely involved in the research effort. For more on climate history from the Center for History of Physics, visit The Discovery of Global Warming webpage, created by Spencer Weart.
The climate is changing, and through the combustion of fossil fuels, humans have been driving many of the changes that we experience today. The core scientific claim that humans can and have induced changes in the atmosphere that can be felt on the Earth's surface—a phenomenon known as anthropogenic climate change—has been settled for decades. In 1990, the first report of the Intergovernmental Panel on Climate Change, which is generally recognized as the authoritative scientific body on climate science, stated that anthropogenic factors were indeed changing the composition of the global atmosphere, causing the Earth’s surface to warm. Since then, the IPCC has worked to answer questions such as: how much warming will occur? How will different atmospheric concentrations of carbon dioxide influence global temperatures? What parts of our environment will be most affected by climate change? How will climate change shape global weather patterns? The core science is settled; experts now work to develop the edges of what we know. The possible futures for humanity, the environment, and the global climate have become clearer with every subsequent report.
While searching through the finding aids available on the Niels Bohr Library and Archives website, looking for possible episode material for an episode of Initial Conditions: A Physics History Podcast, I came across the William P. Elliott Papers on Carbon Dioxide and Climate Change, 1975-1996. Knowing a little about the history of climate science and understanding that the first meeting of the IPCC took place in 1988, I thought the Elliott papers seemed a bit early for scientific research on the topic of anthropogenic climate change. Asking myself what did scientists know about anthropogenic climate change in the 1970s, I began looking through the Elliott papers. I was able to reconstruct the history of the Carbon Dioxide Effects Research and Assessment (CDERA) program, a short-lived endeavor within the U.S. Department of Energy to research several topics pertaining to anthropogenic climate change. Despite only operating from 1978-1981, CDERA was a noteworthy undertaking. Perhaps most significantly, CDERA was a research program dedicated to the fairly narrow question of anthropogenic climate change that was funded and operated by the federal government. In its short lifespan, CDERA revealed the close relationship between climate science and climate politics in the United States. Specifically, it provides concrete examples of the divergent ways that the Carter and Regan administrations approached environmental and climate science. The whiplash that the sudden closure of CDERA in mid-1981 produced hit some scientists harder than others, but most noted that a promising young program had been cut down too quickly.
Finally, the memoranda, reports, letters, and journals contained in the Elliott papers give us a glimpse into how scientists themselves understood the changing climate in the 1970s. Some thought it was a dire issue, perhaps the largest problem humanity would face. Others acknowledged that climate change was an issue, but that more research was required before expecting the worst outcome. Still others, like Elliott, believed climate change was a threat but were pessimistic about the possibility of reducing reliance on fossil fuels. He believed that we would simply have to live with the effects of climate change. Perhaps the most striking aspect of the Elliott papers is how remarkably accurate, even at that early stage of research, CDERA's scientists were in predicting the concentration of atmospheric carbon dioxide fifty years later, in our present day. Taken together, the CDERA papers reveal the state of scientific knowledge about anthropogenic climate change in the late 1970s. They are, therefore, worth taking some time to explore. The language that scientists used nearly half a century ago is remarkably familiar, and in some instances, no less dire. We benefit, then, from learning about the cost of scientific and political inaction and reluctance to address anthropogenic climate change in the past, and perhaps we will reconsider making the same mistakes in the present
For the sake of simplicity, this exhibit uses the term “climate scientists” to refer to researchers in many different fields, such as meteorology, oceanography, physics, and atmospheric chemistry. They might have referred to themselves by their specific discipline, but since all were involved in climate research, the term “climate scientist” is the most succinct.
In this letter from March 27th, 1975, Michael MacCracken, a physicist at the Lawrence Livermore National Laboratory, wrote to his colleague Rudolf Engelmann, to express concern that scientists in the Energy Development and Research Administration (ERDA) were not paying adequate attention to the increasing concentration of carbon dioxide in the atmosphere as a result of fossil fuel consumption. The United States had undergone several energy crises since 1970, and in response, according to MacCracken, ERDA and utility executives were pushing for domestic coal to serve as the nation's energy backbone for the next century. MacCracken goes on to summarize the research that had been done on the topic of anthropogenic climate change since the mid-twentieth century, which convincingly demonstrated that the average concentration of atmospheric carbon dioxide had increased from 290 parts per million (ppm) in the 1800s to 325 ppm in 1975. As MacCracken notes, "[w]hile such concentrations are small in an absolute sense and not a direct threat to man, the range of indirect consequences seems large." He concludes "I write this letter to urge that carbon dioxide effects be considered in evaluating energy strategy for the next generation."
MacCracken's letter gives us a sense of the state of climate change science in 1975. Many questions remained, but among atmospheric scientists, there was growing recognition that because the future state of the climate was uncertain, more research into anthropogenic climate change was needed. MacCracken's letter helped spur the creation of the Carbon Dioxide Effects Research and Assessment program (CDERA), a government-sponsored research program into anthropogenic climate change.
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Science is a social activity. Contemporary science, especially as it has been practiced since the late nineteenth century, uses major conferences to gather together experts in a field to discuss research questions, how to fund and organize research, and scientific objectives. In 1976, Elliott and his colleagues thought it would be best to host a conference in order to establish the scientific themes that a federal anthropogenic climate change research program would explore. They selected sunny Miami Beach, Florida, as the venue for this important conference. Surely, no researcher would pass on the change to travel to Florida during the late summer?
The conference organizers agreed on a list of invitees that included the most renowned names in climate science at the time. Among those invited was Bert Bolin, a Professor of Meteorology at the Arrhenius Laboratory of the University of Stockholm, in Sweden. Bolin would later serve as the inaugural chair of the Intergovernmental Panel on Climate Change from 1988 to 1997, which firmly established his stature as one of the leading climate scientists of the twentieth century. In this letter, which was a response to an invitation to attend the Miami Beach conference, Bolin informs Elliott about a similar conference taking place in Hamburg, Germany, two weeks after the U.S. conference. The European conference was sponsored by several international and intergovernmental organizations. The fact that the U.S. and European conferences were being planned around the same time indicates two things. First, that scientists around the world were becoming interested in the question of anthropogenic climate change. Second, that scientists were eager to collaborate across national borders to begin researching a problem of global significance. These conferences can be considered part of the groundwork that would eventually lead to the emergence of the IPCC.
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Taken at Dr. Manabe's office of Geophysical Fluid Dynamics Laboratory (GDFL) / NOAA, located at Princeton University, Princeton, NJ Ctedit: AIP Emilio Segrè Visual Archives.
The image above shows the tentative agenda for the 1977 Miami Beach conference. It provides insight into how scientists at the time understood anthropogenic climate change. We can see some of the themes that interested leading climate experts, including the role of fossil fuel emissions in the global climate system (the first talk), how the oceans and biosphere might respond to increasing carbon dioxide concentrations (the third and fourth talks), and possible measures to mitigate carbon dioxide (the ninth talk).
The seventh talk, titled "The Response of the Climate to Increased CO2," was delivered by Syukuro Manabe. By the time of this conference, Manabe was an established authority on computer models of the global climate. He shared the 2021 Nobel Prize in Physics for his research.
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The records that scientists leave behind can tell historians a great deal about their sentiments regarding the issues they researched. In formal presentations and scholarly publications scientists rely on dispassionate, impersonal language. This reflects and reinforces the status of science as a field of study dedicated to objective truth about nature. This was certainly the case for climate change research in the 1970s, when so many questions remained unanswered. Climate scientists were nervous about appearing to make policy recommendations because they feared being seen as political actors, rather than disciplined researchers. We can, however, sometimes find letters within scientists' professional correspondence that reveal a bit more about how they personally understood the implications of their research.
The letter above provides a glimpse into how Elliott understood the threat that climate change posed. In it, we get a chance to see how Elliott thought about the relationship between climate science and policy. His letter reveals that he was pessimistic about the possibility of undertaking the action needed to mitigate the effects of climate change. Elliott believed the most realistic course of action would be to live with the effects of climate change. "No amount of preaching[,]" Elliott wrote, "will convince the public to lower its standard of living now because people will be a few degrees warmer in 50 years." The only thing that could mitigate climate change, Elliott believed, was a fuel source that provided the same amount of energy at about the same cost. With no such fuel source available, the best that the global population could hope for would be to live with the changes that those extra few degrees would bring.
This exhibit is being published online forty-five years after this letter was sent. Elliott's choice of words rings true today, as we confront the changes already brought on by those few degrees of warming, and as we continue to burn fossil fuels that contribute to the increasing concentration of carbon dioxide in our atmosphere. Elliott's pessimism was apparent when he wrote that "I'm not hopeful that any amount of research will convince the world to mend its way unless substitute fuels are found and even questionable then." We continue to confront that very basic problem today, nearly fifty years after Elliott stated it so clearly in this letter.
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On January 20th, 1977, Jimmy Carter delivered the Oath of Office and was inaugurated as the thirty-ninth president of the United States. Carter visibly courted environmentalists during his campaign, who had become an influential voting bloc as their ranks grew during the 1960s and 1970s. Famously, once in office, Carter placed solar panels on the White House roof. Although unable to power anything in the White House, they were serviceable as water heaters, and remained a reminder of the commitments Carter had made to the green voters who helped put him in office.
The solar panels were a small part of Carter's environmental legacy, which was decidedly mixed (see the work of historian Jeffrey Stine for more about politics and environmentalism during the Carter years). Much more of the work to build a lasting environmental legacy for the Carter administration was done behind the scenes. This letter was sent by James Liverman, then at ERDA, to Hugh Loweth, a Director in the Office of Management and Budget, four months after Carter was inaugurated. The scientists who had been busy developing a research agenda for their anthropogenic climate change project likely saw the new administration as a potential ally, and acted quickly to garner support. The letter details the different components of the research program. Liverman argues that such a program could help answer the many questions that scientists had about the effects of fossil fuel emissions in the global climate, which in turn would provide policymakers with the context necessary to make informed decisions.
We see a sense of urgency in the way the letter is framed. Details about the research program are sandwiched between introductory and concluding paragraphs that make the stakes involved clear to Loweth. Liverman summarized the consensus position on climate change among his colleagues when he wrote: "The feeling in the scientific community is that increasing levels of carbon dioxide have a high probability of constituting the most serious impact on the global environment of virtually any of man's activities." He concluded the letter by writing: "The potential global severity of this threat coupled with the enormity of any proposed remedial action requires that we lay the groundwork for what could be the most significant international environmental research program ever attempted." With friends in the West Wing, CDERA was on its way to becoming a fully operational program.
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By late 1978 the scientists and administrators involved in organizing the Department of Energy CO2 research effort had cleared most of the bureaucratic hurdles that stood in their way. They convinced Carter's appointees in the Office of Management and Budget that funding carbon dioxide research was crucial to formulating pragmatic policy. Although scientists at the time disagreed on the scale of the threat that anthropogenic climate change posed, they all agreed that more research on the issue was necessary. The draft plan that Lester Machta prepared shows how they intended to organize their research efforts.
The draft plan breaks down the carbon dioxide program into five "operational components." They were: the carbon cycle, climate modeling, effects, socio-economic studies, and amelioration. According to Machta, the operational components were in logical order; understanding the carbon cycle, especially as more carbon from fossil fuels enters the cycle, could support improved modeling, which would help researchers better understand the effects of increasing concentrations of carbon dioxide in the atmosphere, and so on. The program would also rely on two "oversight functions" which would ensure a proper balance between the program components and maintain a full appraisal of the program to determine its status. The final image, not part of the draft report, shows how the research program would be organized.
Informal portrait of Lester Machta sitting outdoors. Credit: AIP Emilio Segrè Visual Archives, Physics Today Collection
Machta's draft offers a bird's eye view of the Department of Energy carbon dioxide research program. After three years of planning, the program was beginning to take form. Carter's friendly stance towards the environmentalist movement likely helped pave the way for CDERA, as the scientists involved in the planning process found allies in the Office of Management and Budget. The vagaries of presidential elections, however friendly they were in 1976, also threatened the longevity of the CDERA program. A shift in the political winds could bring down the program that climate scientists had worked diligently to build.
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Wallace Broecker, like most scientists working on climate change in the 1970s and 1980s, was hesitant to wade into policy discussions. This did not mean, however, that he was unwilling to reach out directly to lawmakers and keep them informed about climate research. In the letter above, Broecker provides Massachusetts Senator Paul Tsongas with an overview of the climate issue in 1980. Broecker believed that questions about increasing carbon dioxide emissions "should not become an immediate ingredient in energy policy decisions." This was not to say that carbon dioxide emissions should be taken lightly or disregarded altogether. Rather, Broecker makes clear that dramatic increases in atmospheric carbon dioxide would "make a large environmental change which will be noticeable everywhere on the planet." Thus the prudent course of action, as Broecker saw it, would be to redouble efforts to study climate change in order to put lawmakers on firmer ground regarding U.S. energy policy. The political instability that would likely result from mandatory restrictions on coal production and consumption were not justifiable, according to Broecker, given how uncertain climate predictions at the time were.
Broecker broke down the climate issue into four categories. He first addressed sea level rise, writing that "[t]o my knowledge, no one has made even a serious try at modeling the response of existing ice sheets to polar warming. One problem is that there are woefully few people working in the area of ice physics. Another is that our knowledge of the meteorological changes to be expected in the warmed polar regions is as yet meager." On the question of how carbon dioxide might enhance plant growth, Broecker was similarly uncertain. While he acknowledged that atmospheric carbon dioxide acted as a fertilizer, he also claimed that the relationship between the two was unclear. A robust carbon dioxide research program could conduct experiments to assess whether or not significantly increased levels of carbon dioxide in the atmosphere would increase the amount of grain that could be produced on one acre, for example, which, if true, would deal the carbon dioxide question "an enormous complication." Similarly, on the subject of rainfall, Broecker acknowledged that global precipitation would likely increase, with wet areas becoming wetter and dry areas dryer, though "[a]gain in 5 or 10 years a far better assessment will be available." Finally, Broecker pointed out that the potential effects on wildlife were perhaps the least clear. Any energy policies meant to tackle the carbon dioxide question would have to take into account the degree of scientific uncertainty across a range of environmental issues, as well as the economic issues inherent in reducing fossil fuel use for both developing and developed nations. This letter was written forty-two years ago; we have since come a long way towards understanding the role of increasing carbon dioxide concentrations in the global atmosphere and environment.
Given the uncertainties, Broecker urged Tsongas to "put the maximum possible effort toward understanding what the world will be like when CO2 levels become significantly higher." "Only with such knowledge," Broecker continued, "will we be able to make a case strong enough to convince the global community that more CO2 constitutes a sufficient danger to justify legislation limiting the use of coal." (As we saw earlier, Elliott was less optimistic about that prospect.) On this point, Broecker gave CDERA a "B" grade. In his assessment, Broecker draws Tsongas's attention to David Slade, the program manager for CDERA. Slade was a controversial figure in CDERA. Broecker was not alone in his concern about the organization, response time, and management of the CDERA program under Slade. Elliott's personal journals also show concern about Slade's management style and his desire for status within the federal bureaucracy. Of course, Elliott's correspondence and journals also reveal that he considered Broecker to be stubborn, arrogant, and unreceptive to criticism.
Yet, despite their interpersonal squabbles, Broecker, Slade, Elliott, and other climate scientists were united in their desire for a comprehensive research effort on the carbon dioxide question. They might have disagreed about what topics the program should address and how it should be organized, but there was a solid consensus that CDERA and the Department of Energy were doing good work. It was a shock to many, then, when CDERA's funding was sharply curtailed in early 1981.
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On the 1980 campaign trail, Ronald Reagan promised to significantly reduce the budget for the Department of Energy, a plan he put into action soon after his inauguration in January 1981. While the Carter administration had many high ranking staffers who were willing to listen to concerns about the environment and climate, Reagan's administration was hardly sympathetic to those issues. In his personal journals, Elliott wrote that his politics were more in line with those of Reagan, although he was anxious about the appointment of people like S. Fred Singer, the prominent climate change denialist, to a high-level position at NOAA. The Office of Management and Budget under Carter had been more than willing to work with climatologists to establish a research program. Under Reagan, the collaborative and enthusiastic relationship between DoE and OMB quickly evaporated.
Portrait of Wallace Broecker, President of Volcanology, Geochemistry, and Petrology (VGP) Section of the American Geophysical Union (AGU) 1980-1982; Ewing Medal 1979; Revelle Medal 1995. AIP Emilio Segrè Visual Archives, Physics Today Collection.
This letter, from David Burns to Roger Revelle, reveals just how quickly CDERA came to an end. The American Association for the Advancement of Science (AAAS) had worked closely with CDERA before. It was a major source of proposals to CDERA and many of the scientists who had built the program in DoE were affiliated with the AAAS. In this letter, Burns describes an odd phone call he made to David Slade. After receiving word from CDERA that it would be unable to fund any part of a recently submitted AAAS proposal, Burns called Slade to inquire about the decision, which seems to have taken him by surprise. Burns claims that Slade responded with a prepared statement that did little to address his questions. After calling Slade's colleagues, Burns became convinced that the decision was shrouded in secrecy. It became apparent that the new administration was not interested in funding the sort of research that CDERA was conducting. Since the scientific uncertainties about anthropogenic climate change were so apparent, members of the Reagan administration felt comfortable zeroing out CDERA. This was, of course, in direct opposition to the opinions expressed by leading climate scientists like Elliott and Broecker in the past; the scientists believed that because the effects of climate change were so uncertain more research was needed to craft sound policy.
Although it was organized only three years prior to this letter, CDERA was an important program. Each of its research themes built on the ones that came before, as Lester Machta pointed out in his 1978 draft plan for the program. Burns notes that the funding denial would deal a dire blow to climate research in the United States. He wrote that "[t]he suddenness of the DoE cut may be a severe set-back to all CO2-climate research....It is the suddenness that affects our own work most severely." Reagan's cuts ensured that CDERA would make little progress on research about the economic and social consequences of anthropogenic climate change.
Burns and Revelle were working on behalf of the AAAS at the time, leading its climate change research program. Revelle was a highly respected oceanographer who had long advocated for more research on carbon dioxide and climate change. He was also politically connected. At the time Revelle received this letter, a former student of his had just started his third term in Congress as a Democratic Representative from Tennessee. That student, Al Gore Jr., would later credit his time in Revelle's classroom as a formative experience that contributed to his activism on the issue of climate change. Burns likely sent the letter to Revelle to see if he could get to the bottom of the secrecy surrounding CDERA's closure. We don't know exactly what happened behind the scenes, but we do know that Gore was quickly made aware of the cuts in funding for anthropogenic climate change research. He held a hearing on the topic just two months after Burns sent his letter. Despite the hearings, CDERA's budget had been fatally compromised. The program would not be reestablished.
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On the 1980 campaign trail, Ronald Reagan promised to significantly reduce the budget for the Department of Energy, a plan he put into action soon after his inauguration in January 1981. While the Carter administration had many high ranking staffers who were willing to listen to concerns about the environment and climate, Reagan's administration was hardly sympathetic to those issues. In his personal journals, Elliott wrote that his politics were more in line with those of Reagan, although he was anxious about the appointment of people like S. Fred Singer, the prominent climate change denialist, to a high-level position at NOAA. The Office of Management and Budget under Carter had been more than willing to work with climatologists to establish a research program. Under Reagan, the collaborative and enthusiastic relationship between DoE and OMB quickly evaporated.
This letter, from David Burns to Roger Revelle, reveals just how quickly CDERA came to an end. The American Association for the Advancement of Science (AAAS) had worked closely with CDERA before. It was a major source of proposals to CDERA and many of the scientists who had built the program in DoE were affiliated with the AAAS. In this letter, Burns describes an odd phone call he made to David Slade. After receiving word from CDERA that it would be unable to fund any part of a recently submitted AAAS proposal, Burns called Slade to inquire about the decision, which seems to have taken him by surprise. Burns claims that Slade responded with a prepared statement that did little to address his questions. After calling Slade's colleagues, Burns became convinced that the decision was shrouded in secrecy. It became apparent that the new administration was not interested in funding the sort of research that CDERA was conducting. Since the scientific uncertainties about anthropogenic climate change were so apparent, members of the Reagan administration felt comfortable zeroing out CDERA. This was, of course, in direct opposition to the opinions expressed by leading climate scientists like Elliott and Broecker in the past; the scientists believed that because the effects of climate change were so uncertain more research was needed to craft sound policy.
Although it was organized only three years prior to this letter, CDERA was an important program. Each of its research themes built on the ones that came before, as Lester Machta pointed out in his 1978 draft plan for the program. Burns notes that the funding denial would deal a dire blow to climate research in the United States. He wrote that "[t]he suddenness of the DoE cut may be a severe set-back to all CO2-climate research....It is the suddenness that affects our own work most severely." Reagan's cuts ensured that CDERA would make little progress on research about the economic and social consequences of anthropogenic climate change.
Roger Revelle in laboratory with equipment. He also is the winner of the Royal Astronomical Society Medalist 1968 and Bowie Medal 1968. Scripps Institute of Oceanography, courtesy of AIP Emilio Segrè Visual Archives.
Burns and Revelle were working on behalf of the AAAS at the time, leading its climate change research program. Revelle was a highly respected oceanographer who had long advocated for more research on carbon dioxide and climate change. He was also politically connected. At the time Revelle received this letter, a former student of his had just started his third term in Congress as a Democratic Representative from Tennessee. That student, Al Gore Jr., would later credit his time in Revelle's classroom as a formative experience that contributed to his activism on the issue of climate change. Burns likely sent the letter to Revelle to see if he could get to the bottom of the secrecy surrounding CDERA's closure. We don't know exactly what happened behind the scenes, but we do know that Gore was quickly made aware of the cuts in funding for anthropogenic climate change research. He held a hearing on the topic just two months after Burns sent his letter. Despite the hearings, CDERA's budget had been fatally compromised. The program would not be reestablished.