This presentation is brought to you by Arizona State University’s Julie Ann Wrigley Global Institute of Sustainability, and a generous investment by Julie Ann Wrigley. How should we think about responsibility for climate change, and can we use that to help us think about the question Anne posed at the very beginning to guide action in moving forward? So responsibility implies knowledge. Now, legally, in most cases, ignorance of the law is not an excuse. But most of us do tend to think that people can’t be held responsible for what they don’t know. If we didn’t know that climate change was happening, then obviously, it wouldn’t make sense to say that we were responsible for what we had done. And indeed, the heart of the tobacco prosecution was the evidence that industry knew of the hazards of its product and conspired to deny, conceal, and confuse people about those hazards.
So knowledge matters. It matters to us both ethically and morally, and it matters legally. What the tobacco industry did was both wrong and illegal because scientific evidence had demonstrated the harms of tobacco use. And so it is relevant to be reminded of what we know about climate change and how long we have known it. So I thought I’d take a few minutes here just to recap some of the historical work that I and others have done on the history of climate science, just in case any of you are still wondering if we really know for sure. Because in my experience, even I’ve served on a nonprofit board of an environmental group fighting climate change, and on our own board, we have someone who, in a taxi ride, said to me, well, so tell me how we really know that climate change is happening. So I’m not going to take it for granted that everybody is 100% convinced. So we’ll just spend a few minutes on that. So like any story in the history of science, there are a lot of different places we could start. But a convenient place to start is with the work of John Tyndall, who is the scientist who first established the idea of something being a greenhouse gas. And in a series of experiments done in the 1850s and ’60s, he showed that both water vapor and carbon dioxide have the distinctive and important property of being relatively transparent to visible light but relatively opaque to infrared radiation. So light comes in and heat is trapped, and that warms the planet.
Around the turn of the century, a number of scientists started thinking about what the burning of fossil fuels meant in terms of the greenhouse effect. Because it was well known that when you burn fossil fuels at that time, it was mostly coal you release carbon dioxide to the atmosphere. And so the Swedish geochemist Svante Arrhenius was one of the first to suggest that burning fossil fuels could lead to climate change. And he did the first calculations that we know of what the effect of doubling atmospheric concentration of CO2 would be, and concluded that it would warm the average temperature of the globe by 1.5 to 4.5 degrees centigrade, which is not different too different from what we believe today. Now, he was Swedish, so he thought global warming would be a good thing. By the 1930s, the issue had gotten taken up by a number of other people, including Guy Stewart Callendar, who was the first scientist to compile measurements of carbon dioxide in the atmosphere and to suggest that CO2 was, in fact, already increasing. And in the United States, E. O. Hulburt, a physicist at the Naval Research Laboratory, who did the first modeling of what the effects of doubling carbon dioxide would be. 1940s was World War II.
Of course, a lot of scientists were diverted. But in the ’50s, scientists came back to the question of climate change particularly this man, Gilbert Plass, who worked on the physics of carbon dioxide heat absorption. Plass addressed a question that had already been raised at that time and still comes up today in a lot of doubt mongering literature, which is the question of how much effect can carbon dioxide really have when there’s only 390 parts per million of CO2 in the atmosphere, and there’s so much more water vapor. And water vapor is a greenhouse gas, too. So why would a little bit of CO2 make a difference? Well, Plass explained why in the 1950s. He showed that the absorption bands for CO2 are distinct from the absorption bands of water. So even though it’s true there’s much more water in the atmosphere, it’s also true that carbon dioxide plays a significant role, and that even modest amounts of CO2 have a significant impact on the radiative balance of the atmosphere. Two people who were influenced by Plass’ work were colleagues well, not colleagues, because I wasn’t there then, but we think of them metaphorically as being colleagues professors at the University of California, Hans Suess and Roger Revelle, who in the 1950s began to argue that because there was this important effect of CO2, that scientists should begin to systematically measure the carbon dioxide in the atmosphere in order to determine whether or not it was really increasing and whether or not that increase was having an effect on global climate. And they proposed that this issue, this question should be taken up as part of the research for the International Geophysical Year, which began in 1957, ’58. And that work was taken up by this man, Charles David Keeling, who began his lifelong work on carbon dioxide during the International Geophysical Year. All of you have probably seen this graph. It’s now known as the Keeling Curve. It’s probably the most widely reproduced graph now in the history of Earth science. Dave started these measurements in 1958. He continued them until his death a few years ago. The work is still being done by his son, Ralph Keeling.
And we now know, based on his very careful measurements, that carbon dioxide has increased by about 30%, 35% since before the Industrial Revolution. And we see this very steady, inexorable rise. The ups and downs are the seasonal variation, but overall, a very, very, very clear trend. So we know that carbon dioxide has increased. What most people don’t know is that as early as 1965, some politicians were aware of this issue. And in 1965, President Lyndon Johnson, in a special message to Congress, noted that 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 already by the 1960s, Dave Keeling had showed that CO2 was rising. So this is the bit of the Keeling Curve that Lyndon Johnson had available to him. Well, there we go. So here’s what we had in 1965. So already, a few parts about five parts per million increased. And Lyndon Johnson incorporated this into a speech in 1965. By the 1970s, the idea of a social cost of carbon was beginning to emerge as well. And there are many examples of scientists beginning to talk about it. One that I like that I think is particularly clear in 1978, Robert White, the first head of NOAA, wrote about this in a special issue of the Journal of Oceans and Climate, in which he said we now understand that industrial waste, such as carbon dioxide released during the burning of fossil fuels, can have consequences for climate that pose a considerable threat to future society. So in a nutshell, this is it. It’s industrial waste. It’s carbon dioxide. It comes from burning fossil fuels. It has consequences for climate, and those consequences are a threat to society. That is the climate change, the CO2 problem in a nutshell. And then he says the scientific problems are formidable, the technological problems unprecedented, and the potential economic and social impacts ominous.
Moreover, by the late 1970s, we also see the word “consensus” being used by scientists to describe the emerging agreement that climate change is likely to occur. So in 1979, the National Academy of Sciences concluded that 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. And they went on to say the close linkage between man’s welfare and the climatic regime within which his society has evolved suggests that such climatic changes would have profound impacts on human society. So again, it’s not just that they think the climate may change. It’s also that they understand that human societies have evolved in a very narrow window of climate conditions. And our society, our infrastructure, is built to accommodate a certain range of climatic conditions. And if those conditions change, we may not be prepared to deal with them. And I think the kind of flooding that’s going on in the Midwest right now is a very clear example of that. And so finally, the Academy concluded in a classic scientific double negative, if carbon dioxide continues to increase, we find no reason to doubt that climate changes will result and no reason to believe that these changes will be negligible. Now, again, one of the questions that I’ve always been interested in is what I would call the uptake or traction question. Just because scientists knew something doesn’t mean that the public at large or the government or politicians understood or knew about this. But actually, there’s a lot of evidence from the 1980s of discussion in political circles about what this scientific evidence means. And this is just a little tidbit that I found in Roger Revelle’s paper. But it was actually a copy of a bill that was introduced into Congress in 1988, the National Energy Policy Act. And the goal of this act was to establish a national energy policy to reduce the generation of carbon dioxide and trace gases as quickly as is feasible in order to slow the pace and degree of atmospheric warming. And I thought this is really great, because all those guys in Congress who are gridlocked, they don’t need to write a new bill. They could just get out, dust off the National Energy Policy Act of 1988, and it’s all there. The work has already been done for them. This presentation is brought to you by Arizona State University’s Julie Ann Wrigley Global Institute of Sustainability, for educational, and non-commercial use only.