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Despite data being collected for over half a century, despite a President being warned about the looming threat of a changing climate in the mid 1960s, and despite plants and animals now changing their behaviour to fast altering conditions, a few scientists continue to raise doubts regarding climate science and its findings.
Naomi Oreskes sees a pattern. The pattern repeats itself in a string of issues including controversy over tobacco smoke, the dangers of acid rain, and DDT.
Naomi Oreskes tells the story in her book Merchants of Doubt and today on The Science Show we hear Naomi Oreskes in a public address at the University of NSW in 2010.
Robyn Williams: This is The Science Show on ABC Radio National, in which today we meet Naomi Oreskes from the University of California in San Diego. She’s a historian of science and she’s taken on a really perplexing puzzle why did climate science, once accepted by most, and really rather mainstream in the public mind, suddenly become a matter of controversial debate, even a political hot potato? Professor Oreskes has a story to tell. It’s in her book Merchants of Doubt, and it concerns watermelons, green on the outside, red within, and cigarettes, and Star Wars. Naomi Oreskes at the University of NSW.
Naomi Oreskes: Thank you so much, Robyn, for that generous introduction. So in 2005 my Austrian governor announced an initiative in California to commit the state of California to Kyoto level controls on greenhouse gas emissions. When he made this announcement he said, I say the debate is over, we know the science, we see the threat and we know the time for action is now. It’s not every day you get to agree with a politician, but I did agree with my governor. Indeed, I thought he was correct, we did know the science and we did see the threat. And in the mid 2000s it seemed that the American people had gotten the message.
A poll done by the Yale Project on Climate Change working together with the Gallup polling organisation showed that in 2007, 72% of Americans were completely or mostly convinced that global warming was underway. Indeed, 62% of American citizens believed that life on earth would continue without major disruptions only if society took immediate and drastic action to reduce global warming.
Indeed, at that time it did seem as if the debate was over, and even many prominent contrarians had come around and were accepting the scientific evidence. So for example one of these was Frank Luntz, a Republic Party strategist. And in 2006 he said, it’s now 2006. So he was off to a good start, he got the year right! I think most people would conclude that there is global warming taking place, and that the behaviour of humans are affecting the climate, still struggling with this syntax!
Luntz is important. The reason, he explained, was because climate change is a lot less frightening than global warming. He argued that Republican candidates running for office should use scientific uncertainty as a political strategy, that they should emphasise the scientific uncertainty around the issues and insist that there was no scientific consensus. So he wrote, ‘The scientific debate remains open, voters believe that there is no consensus about global warming within the scientific community. Should the public come to believe that the scientific issues are settled, their views about global warming will change accordingly. Therefore you need to continue to make the lack of scientific certainty a primary issue in the debate.’
So we see scientific uncertainty, the legitimate, real, normal uncertainty that’s part of all scientific research, being turned into a political tool. Now Luntz’s position was factually incorrect, the scientific debate was not still open. Indeed, in 2001 the Intergovernmental Panel on Climate Change had written unequivocally, ‘Human activities are modifying the concentration of atmospheric constituents that absorb or scatter radiant energy. Most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations.’ So the IPCC said that in 2001. But in fact the science had actually coalesced earlier than that. In the second assessment report of the IPCC published in 1995, the scientists had written, ‘The balance of evidence suggests a discernible human impact on global climate.’
In my own research as a historian of science, I was interested in the question of whether or not the IPCC reports were an accurate reflection of the rank and file of the scientific community. Did those summaries in the IPCC and in the US National Academy of Sciences and the Royal Society and many other scientific societies who had attempted to summarise the scientific work, were those summaries consistent with what was published in the rank and file, peer reviewed scientific journals?
So in 2003 I did an analysis of the scientific literature and found that through a random sample of 1,000 articles in the ISI, Institute for Scientific Information database, that in fact none of the articles dissented from that IPCC position. In fact, there was essentially unanimity in the scientific community that the balance of evidence did suggest a discernible impact, and that most of the observed warming was likely to have been due to greenhouse gas emissions. I published this in Science Magazine in 2004.
This result surprised many people, but it really should not have. It only surprised us because we had forgotten our own history. In 1992, 193 nations, including the United States and Australia, signed the UN Framework Convention on Climate Change, and when President George H. W. Bush signed the Framework Convention he called on world leaders to translate the written document into ‘concrete action to protect the planet’.
I’ve interviewed a number of people who were involved in the UN Framework Convention on Climate Change, asked them about what happened between then and now. One of them was Gus Speth who served on the Council of Environmental Quality in the Carter administration in the United States, and he said, ‘yes, we thought we were on track to make real changes.’
So what happened? What happened to this political consensus, this scientific consensus, that global warming was discernible? What happened to the UN Framework Convention on Climate Change?
So what I want to do tonight is to give a very brief overview of the evolution of climate science, when scientists understood these different important facts about our climate system,
and then a brief history of the emergence of a political challenge to that science. It’s a story of selling uncertainty to stave off government regulation and to protect the free market, as certain people understood it.
So for a historian of science, the beginning of the history of climate science could start probably most meaningfully with John Tyndall, who was the person who first established the concept of a greenhouse gas. So through a series of experiments in the 1850s, Tyndall showed that certain gases, particularly carbon dioxide and water vapour, had a very distinctive property of being highly transparent to visible light, but rather opaque to infrared. So water vapour and carbon dioxide in the earth’s atmosphere allowed light to come in from the sun, but had a tendency to trap heat. Tyndall understood this is a very important fact about the earth, because without this natural greenhouse effect, the earth would be as cold as the moon or Mars and be a completely inhospitable place for life. So the natural greenhouse gas was basically a good thing.
The first person to suggest that changes in the greenhouse gas concentration could change the climate was this man Svante Arrhenius, a Swedish geochemist. Arrhenius was the first to suggest that by burning fossil fuels, mostly coal, we were adding additional carbon dioxide to the atmosphere above and beyond the natural CO 2 levels, and that this could change the climate through an increase in the absorption and trapping of heat in the atmosphere.
Arrhenius did the first calculations of the potential effect of doubling carbon dioxide, and calculated that doubling CO 2 would lead to an average global temperature increase of 1.5 to 4.5 centigrade. Arrhenius was Swedish, so he thought global warming would be a good thing! The first person to suggest that it might be a bad thing was Guy Stewart Callendar, a British steam engineer. In 1938, Callendar was the first to suggest that global warming was actually possibly already underway. He compiled some of the early measurements of CO 2 in the atmosphere from mostly in Europe, and in a publication in the quarterly Journal of the Royal Meteorological Society suggested that temperature might in fact already be beginning to increase. That was in 1938.
In 1939 war broke out in Europe, Callendar became involved in war work, as did many other scientists in various different disciplines. The issue was not really revisited in a serious way until the 1950s, when it was taken up by a number of scientists in Europe, the United States and here in Australia, and most particularly by two men, Hans Seuss and Roger Revelle, both professors at my university, the University of California in San Diego.
In 1957, Suess and Revelle published an article in the peer review journal, Tellus, in which they suggested that mankind was performing a great geophysical experiment, by taking carbon dioxide that had been stored in rocks over the course of hundreds of millions of years of geological history, and returning a very significant amount of that carbon dioxide back to the atmosphere over the course of only a few decades. This argument was also made by a number of people including Bert Bolin in Sweden, who later would work on acid rain and also found the IPCC.
So Revelle’s argument in 1957 was not that global warming was necessarily already underway, but that we needed to pay attention and track the issue. One of the most important ways to track it would be measuring the amount of carbon dioxide in the atmosphere to see if Callendar was correct, that it was actually already increasing. Through the International Geophysical Year in 1957 58, he obtained funding for the beginning of this project to measure carbon dioxide in the atmosphere.
The person who undertook that work beginning in 1958 was Charles David Keeling, who began the systematic measurement of carbon dioxide as part of the International Geophysical Year. This became Dave Keeling’s life work. He continued it until he died just a few years ago. For this he won the National Medal of Science in the United States, awarded to him by President George W. Bush, and he produced what is now known as the Keeling Curve, which today is probably the single most reproduced time series data in the history of science.
What Keeling was able to show was that there was a systematic seasonal variability of carbon dioxide associated with photosynthesis, summer in the northern hemisphere where most of the land masses are, and by 1965 Keeling had already concluded that there was in fact a detectable increase in carbon dioxide in the atmosphere. This result led to the US President Science Advisory Committee writing a report with an appendix written by Revelle and Keeling, in which they made one of the early specific predictions of what the impact of increasing carbon dioxide might be. In 1965, they wrote, ‘By the year 2000 there will be about 25% more CO 2 in our atmosphere than at present, and this will modify the heat balance of the atmosphere to such an extent that marked changes in climate could occur.’ So that was in 1965.
Now it’s often said that politicians never listen to scientists, but that’s not always true. In this case, Keeling and Revelle’s report landed on the desk of President Lyndon Johnson, and in 1965 in a special message to congress Lyndon Jonson declared, ‘This generation has altered the composition of the atmosphere on a global scale through a steady increase in carbon dioxide from the burning of fossil fuels.’ So if anyone says nobody knew, nobody could’ve know, we simply know that that’s not true.
There’s a lot of science that then begins to develop at this time, as the US government and other European governments and others begin to invest money in climate science research, but the most important is that this scientific insight coincides with the development of digital computing. By the late 1960s and early 1970s we see the rise of computer modelling and the construction of the first general circulation models, to model what happens to the atmosphere when you change the amount of greenhouse gases in it.
There was soon an emerging consensus in the expert community that given the rise of CO 2 that Keeling had documented, sooner or later warming would be expected to occur. This consensus was expressed by numerous different scientific bodies in many parts of the world. But one of the most concise summaries came from the US National Academy of Sciences in 1979, who wrote, ‘a plethora of studies from diverse sources indicates a consensus that climate changes will result from man’s combustion of fossil fuels and changes in land use’.
This is a very interesting quote, because sceptics love to say that science is not about consensus. They like to quote Galileo saying that ‘science advances by the work of heroic individuals’, and of course sometimes that’s true. Heroic individuals have played a role in the history of science. But it’s interesting to me to see here the National Academy of Sciences using consensus as their word, their category, to summarise what it is that scientists believe they know at this moment in time. What they know is that climate changes will result, that this will happen, from man’s using fossil fuels and changes in land use. We’ve also seen some sceptics complain that the scientific community has not paid enough attention to land use changes, but we see it right here in 1979.
Robyn Williams: You’re listening to The Science Show on ABC Radio National, Professor Naomi Oreskes at the University of NSW.
Naomi Oreskes: So scientists had a consensus that global warming would occur, but what they did not have a consensus about is when this would happen. In fact, the when part of the question was quite contested,
and there was a big difference of opinion among scientists right in the 1970s about how soon any of these changes might actually become detectable.