Published originally in the International Herald Tribune
December 28, 2007
by Daniel B. Botkin
Now that the Bali conference is over and climate scientists have warned us again about the dire predictions of their climate models, a question remains: Will their forecasts come true? Given the current international focus on global warming, you would think that, in 10, 15 or 20 years, many people will want to know whether today's predictions proved accurate.
But, in fact, people rarely look back to see if their old forecasts were on the mark. Foretelling the future has always been difficult and almost always wrong. Charles Mackay, in his wonderful 1841 book "Extraordinary Popular Delusions and the Madness of Crowds," observes that the so-called necromancers of earlier centuries who purported to divine the future were grouped with the worst alchemists. Today, however, computers seem to have undermined our natural skepticism. Many of us put our faith in complex software that most of us cannot understand.
My own experience makes me skeptical of how environmental forecasting is being used. In 1991, several colleagues and I drew national and international attention when we used a computer model to forecast possible effects of global warming on an endangered species. Our computer program forecast that the Kirtland's warbler, the first songbird in America ever subjected to a complete census, would likely face extinction by 2010. Its habitat, jack pine trees, would be unable to thrive in conditions that climate computer programs forecast for southern Michigan, the only place and only trees where the bird nested.
The computer told us these declines should be measurable even in the year we made the forecast. We suggested that measurements of jack pine growth be started to verify the forecasts and to see whether the potential effects of global warming on the diversity of life were actually occurring. People could have started going to southern Michigan to check out our forecasts 16 years ago. Nobody did. I tried to get funding to do this, but no government agency or private foundation was interested.
Even today, amid the furor over global warming, no one is rushing out to verify that it does indeed threaten the Michigan jack pine. (But, happily, independent action by the government, the Audubon Society and private individuals has brought the Kirtland's warbler back from the brink of extinction.)
What could explain the lack of interest in verifying a dated computer forecast? After all, computer forecasts are the basis for the current alarm. Did people perhaps decide that a 16-year-old forecast had to have been based on inferior methods?
But wait a minute. Given the usual progress of science, won't forecasting methods in the future always be better than in the past? What this suggests is that today the primary uses of, and interest in, such forecasts are political, not scientific - that scientists as well as politicians are using forecasts for political and ideological purposes to influence public behavior here and now.
The question is not really whether the forecasts are scientifically valid, but how much impetus they can provide to influence society.
It wasn't always this way. In the 1960s, when research into global warming was just beginning, it seemed impossible that people could change the global environment; the Earth was just too big. Charles Lyell, the father of modern geology, considered the possibility in detail in the mid-19th century and decided it was impossible because the mass of living things amounted to less than a drop in the bucket compared to the weight of all the materials in the oceans, atmosphere, soil and rocks.
In the 1970s, however, scientists began to realize that life had in fact greatly changed the Earth's environment, starting more than a billion years ago. At the same time, evidence was building that burning fossil fuels was increasing the atmospheric concentration of carbon dioxide. In 1957, Charles Keeling began the first continuous measurements to study carbon-dioxide change over time at Mauna Loa, Hawaii. By 1973, he reported at a landmark conference at Brookhaven National Laboratory on "Carbon and the Biosphere" that carbon dioxide showed a definite increase in 15 years, consistent with releases from burning fossil fuels. For those of us working on these issues, the scientific and environmental implications were vast.
Global environmental change began to become a political issue in the 1980s. Climatologists and astrophysicists showed that a nuclear war could put so much dust in the air that disastrous cooling would occur, the infamous nuclear winter. With the end of the Cold War, the focus shifted to global warming. At that time, climatologists explained that their computer models were crude approximations of the real atmosphere and pushed the limit of computer technology, requiring months of computing for a single simulation. You could accept either the results of these crude models or the less-formal projections by the most experienced meteorologists. The primary focus continued to be on the implications of what we knew.
In 1988, in a move that marked a shift to the politicization of forecasts, Congress asked the Environmental Protection Agency to report on the potential effects of global warming. Computer forecasting became much more complex; output from the huge climate models became input into ecological models. My projection for the little warbler was part of that work. The attempt was to be more realistic, but the result was that forecasts became more difficult to verify and also more alarming, thus drawing more and more public attention.
Thinking over this history, I see three primary uses of environmental computer forecasts: to understand the implications of what we know (Can living things change the global environment?); to know the future; and to influence public behavior. Only the first can be strictly scientific. The third is wandering farther and farther away from science.
Since proving the validity of long-term forecasts is difficult and the ultimate tests would take years, and since many scientists are alarmed at the dire scenarios, my colleagues are beginning to talk about whether it is O.K. to exaggerate and push forecasts that are not currently provable if the only way to get societies to act is to frighten people. I think it is not O.K. It is a short-term view, and even if it works, it will inevitably debase science and scientists.
Soothsayers have always tried to persuade people that they could predict the future. What is new today is that the incredibly powerful tools of science - nuclear weapons, flights to the moon, computers, iPods - have such huge implications for civilization that they may contain the seeds of their own destruction.
Thirty years from now, we will probably not be interested in today's specific computer forecasts, but we may have lost our faith in science, a deeper and, to me, a more important problem.
Additional information about the Kirtland's warbler forecast:
The scientific paper for the original forecast is:
Botkin, D. B., D. A. Woodby, and R. A. Nisbet, 1991, Kirtland's Warbler Habitats: A Possible Early Indicator of Climatic Warming, Biological Conservation 56 (1): 63-78.
Those interested in the forecasting method can download the computer model of forest growth, JABOWA, from website www.naturestudy.org and play around with it. The software is pretty easy to use, and you can grow your own forest, log it, test it against various global warming climate regimes, etc. It isn't as sophisticated a computer game as you can get today, but it is ecologically realistic and is used in research around the world.
And if you really want to get into the science part of this in depth, there are other scientific papers, including:
Botkin, D. B., and R. A. Nisbet, 1992, Forest response to climatic change: effects of parameter estimation and choice of weather patterns on the reliability of projections, Climatic Change 20: 87-111.
Botkin, D. B. and R. A. Nisbet, 1992, Projecting the effects of climate change on biological diversity in forests, pp. 277 - 293 in R. Peters and T. Lovejoy, (Eds.) Consequences of the Greenhouse Effect for Biological Diversity, Yale University Press, New Haven.
Rick Rendigs says
> Thank you for sending along your IHT article
> entitled “Science and Soothsaying”. I think your point regarding computer
> forecasts and the apparent politicization of the results and their
> upon society is of concern.
> It is unfortunate that many of these computer
> generated forecasts, whether hurricane or global climate change, have
> limited context or places of reference and thus have no immediate
> points of comparison. Given this plus the frenetic level of digesting
> information in this country, the media “spin”, and the fact that many people don’t
> get beyond the headlines or the edited twenty second story “sound bite” in
> the daily TV news segments also leads to a lack of evenhanded information regarding these
> People and legislators are seeking immediate answers
> to these complex environmental problems via computer generated models and
> forecasts. Results from these models should be viewed as but one of a series of tools to
> analyze these issues and the results viewed with a healthy dose of
> As you point out these forecasts may be used to
> influence political and public behavior. I also believe that an additional
> aspect that the results of computer models and the ensuing “spin” by the media may present is to amplify a kind of social fatalism within society as some segment of the public may be
led to believe that they are at a much
> higher risk than they actually are. A chicken little -sky is falling-
> attitude may well develop which may easily skew one’s judgment to any area
> of inquiry.
> Hopefully a renewed balanced and objective disclosure of the implications and results of global climate computer forecast modeling to the public and decision
> by scientists and the media will provide a format from which to
> scrutinize the data and provide a mutual framework to view the risk and
> reward measures of a growing global economy and its potential impacts
> upon the climate and environment.
Jerry Brown says
Very much enjoyed the article . Will be reading the rest of your articles time permitting. I am very much a sceptic on AGW but a strong advocate for environmental and energy change.
Pete H. says
I don’t understand why you think that forecasting is not part of science? The goal of science is to provide models that can provide predictions of future behavior of systems. That is precisely what climate models attempt to do.
I did not mean to suggest that models and theory are not useful. Of course they are, as a basic part of science. And I have developed some of the first successful computer models in ecology and have worked to integrate good models with good data. The problem is not the fundamental role of theory and models in science, but the failures in the attempts to develop and use them.
Great article, thanks very much. One of the problems I see in this AGW debate is not so much one of politicians trying to be scientists (Al Gore), but rather the attempt of scientists to be politicians.
In the past – scientific credentials would be RUINED if one attempted down your third path (to influence public behavior).
Today however, it seems as if there are no consequences of making unlikely, unfounded and HIGHLY improbable projections – based upon straightline extrapolations of a) whatever metric (populations / occurrence of birds, trees, fish, men, rain, hurricanes) based upon b) whatever baseline (1970 – present, etc.) of variation in c) whatever causal ‘driver’ (CO2, BTU, SL, Earth ‘temp’, etc.)
Due to how ‘citations’ are counted (more numbers than quality), there is no ‘COST’ to being outrageous. Notoriety USED to be a BAD thing; now it seems that it is rewarded – perhaps even admired.
I would rather see scientists as the ones who inject truth, honor and the long view into this important debate. But in many cases – they’re the zealots themselves.
It is sad to me. My advice is – lets do some great science.
Hello Dr. Botkin,
Really appreciate the courage that you and others share to put ideas into words in interviews and articles open for critique. I just listened to the interview you had with Russ Roberts on Econtalk (3 months ago). So, not knowing where to post my questions for you, I post them here. Forgive me if I seem to parse your words very carefully, but in a larger context I think that scientists have a special responsibility to speak carefully in the complex debate. I will also preface my questions and comments by saying that I understand that participating in an interview is very different from writing, and it is difficult to have your best word choice at the ready. So, I have four questions that I would enjoy reading your response to:
1) You suggest the Thomas et al. 2004 paper is “maybe the worst paper” you had ever read. In hindsight, do you think that it really is the worst paper you ever read, or you may have gotten carried away in a bit of rhetoric that might take away from an intellectual discussion of the weaknesses of the paper? I note that the paper has been cited almost 500 times since publication suggesting it valuable enough for debate, critique, challenge and hypothesis generation by many other ecologists. My question stems from an assumption about the likely audience of economists listening to this podcast. IF you had to do the interview again, do you think you would speak about it in the same terms when trying to convince an audience of the merits or weakness of the paper? Would you use the same terms in front of an audience of ecologists?
2) You suggest that the IPCC goes onto repeat the same claims of this original 2004 paper and the number of times you repeat the statement does not lend veracity to the statement….I will include here the text from the draft summary of the IPCC report for lawmakers as it is very accessible….”There is medium confidence that approximately 20-30% of plant and animal species assessed so far are likely to be at increased risk of extinction if increases in global average temperature exceed 1.5-2.5°C over 1980-1999 levels.”
Your comments in the podcast suggest (perhaps inadvertently)
that the scientists looked at the 2004 paper and repeated the claims of the paper without scouring the available literature for other information about how diversity might be threatened. Do you think that among the “600” scientists that participated in the IPCC report, there was an effort to accumulate other information from the literature, or do you believe that an inappropriate amount of emphasis was placed on this single paper?
3) I think if the format had been a little different in your interview, I would have enjoyed hearing a debate about the difference between a 1.5 degree rise threatening a species pre-human verse post-human. Will the discontinuity in the landscape caused by human disturbance, in essence: fragmentation and disturbance act in concert with a 1.5 degree rise to create greater threats to species than that caused by a 1.5 degree rise without these antagonizing factors.
4) At one point, you suggest that “…we teach science more and more poorly” in a larger part of a comment about your concerns about science education in the face of rising skepticism. So, the question for you here is….”Do you have evidence that we are doing a worse job teaching science then at any other point in time in American history?” …or were your comments more from a personal observation perspective?
Finally a comment….I enjoyed your discussion about the false notion of an equilibrium state in ecology that also pervades a public perception of nature. The concept returned in the discussion of climate change. I think another idea that would have been valuable to discuss here is the notion of what people “value” in their landscape and a desire to maintain (conserve) some semblance of what they knew from their earlier memories. While I think it is hard for people to comprehend that the landscape in a certain area 5000, 500, and 50 years ago was probably very different from the one they are growing up in, and conservation will almost always be in light of what they “value” rather than some true ancient state or true natural state of the landscape. Personally, I find this concept much more worrisome then a false belief in an “equilibrium” state, but perhaps in essence it is the same. Thinking about a perception of the overall “health” of the oceans for example, there is a generational ignorance that develops as chances are what your great grandfather remembers as a kid was a healthy estuary is very different than what you will remember as a child as a healthy estuary.
Realize I’ve written a lot here….if you have time, I look forward to hearing your comments about some of these questions. Thanks for having the courage to put your ideas into the public discourse.
Reply to Patrick:
I very much appreciate the thoughtful, nicely stated comments about my interview with Russ Roberts on Econtalk — available on the web for anyone who wants to hear it. This is the kind of discussion — polite but raising interesting questions — that I hope my website will stimulate, and that I think is important (and often missing) from public information about difficult environmental issues.
Patrick is correct in saying that it is more difficult to be precise in one’s statements during a live interview than in writing. Still, having agreed to do the interview, I take responsibility for what I said. So to answer Patrick’s questions:
Yes, unfortunately, I do consider it to be the worst paper I have ever read in a major scientific journal. There are some close rivals, of course. I class this paper as I do for two reasons, which are explained more fully in the recent article in BioScience:
Botkin, D. B., Henrik Saxe, Miguel B. Araújo, Richard Betts, Richard H.W. Bradshaw, Tomas Cedhagen, Peter Chesson, Terry P. Dawson, Julie Etterson, Daniel P. Faith, Simon Ferrier, Antoine Guisan, Anja Skjoldborg Hansen, David W. Hilbert, Craig Loehle, Chris Margules, Mark New, Matthew J. Sobel, and David R.B. Stockwell. 2007 “Forecasting Effects of Global Warming on Biodiversity.” BioScience 57(3): 227-236.
First, the paper uses a theory that is inappropriate and illogical for the question. Second, the data on which the calculations are based — the areas of the world’s biomes — are crude, lacking estimates of measurement error. My textbook Environmental Science: Earth as a Living Planet has a chapter on the scientific method in which I state that “a measurement without a statement about its degree of uncertainty is meaningless.”
As I discuss in another scientific article, where we report actual valid measures for the biomass of the boreal forest biome of the world and northern hardwoods biome of North America, even the scientifically valid estimates we made have an error of more than 20%. And we show that biogeographers have not agreed on the total area covered by a biome, differing by as much as 100% in their estimates. So when Thomas et al. discuss comparatively small changes in biome areas, these small changes are less than the known errors and therefore do not discuss a statistically and scientifically valid distinction.
For more information, see Botkin, D. B. and L. G. Simpson, 1990, Biomass of the North American Boreal Forest: A step toward accurate Global Measures: Biogeochemistry 9:161-174; Botkin, D. B., L. G., Simpson, and H. J. Schenk, 1992, Estimating Biomass, Science Letters; and Botkin, D. B., L. G., Simpson, and R. A. Nisbet, 1993, Biomass and Carbon Storage of the North American Deciduous Forest, Biogeochemistry 20: 1-17.
Patrick: IPCC statements about extinctions: IPCC presents a number of versions of its most recent reports, some for journalists, some overview statements, some detailed reports. The statement about likely extinction rates varies among these.
I am not privy to the IPCC report process, as I have not been involved in it. Some of my colleagues have, but I do not feel qualified to give you any insights into how much scientific literature was used. The point I make in the interview is that the IPCC summary statement is very close to the Thomas et al. statement.
This is very much worth discussing and investigating, and I would welcome a forum where this could happen.
I have taught full courses in ecology and environmental science at Yale University, the University of California, Santa Barbara (where I was chairman of the Environmental Studies Program), and George Mason University; participated in a well-known summer course in ecology at the Marine Biological Laboratory, Woods Hole, MA; taught ecology as a visiting professor at the University of Notre Dame, including a summer field course at a field station; and for two years taught a field course in ecology at the University of Michigan’s Douglas Lake summer field station. I have taken students on ecology and environmental field trips; and have been a lecturer on these topics on several ocean cruises. Over four decades, I have given talks at many major universities in the United States and elsewhere.
It is my personal experience that students seem less well prepared and less knowledgeable now than in the past. For example, at one university where I was a visiting professor, I was warned by a faculty member that the students would not ask questions, and even worse, would not answer questions asked of them. They just sat silently until the class was over. They showed no interest in learning to understand science, just to “get through.”
Colleagues confirm my concerns about the teaching of science.
A leading textbook in ecology makes it easier and easier for the student to memorize information, but in doing so challenges the student less and less to try to think for oneself.
The statistics suggest that students are doing more poorly in science and math.
For all these reasons, I believe that science is in general being taught less well. There are, of course, wonderful exceptions at certain colleges and universities. Two come to mind especially: my experiences as a guest lecturer at Amherst College, and at the College of the Atlantic, where the students were well prepared, enthusiastic, inquisitive.
My book Discordant Harmonies: A New Ecology for the 21st Century discusses this idea and its importance to human society, to conservation and management of natural resources, and to our perception and appreciation of nature.
Mike Lunsford says
This is an interesting discussion.
Please help your fellow scientists to see how important their public comments are to those who hear them. We tend to put a good deal of credence in what our respected scientists say, particularly in matters of broad concern like global warming.
The difficulty society faces in understanding and properly responding to adverse, human-induced changes in the biosphere (such as global warming) may, in part, be caused by the seeming disconnect between science and governance. While science is enhanced by ongoing questioning and critique, governance often requires timely decisions based on the best available, but often limited information.
The vast majority of even the best educated citizens cannot presume to be able to critique the methodologies and conclusions in the increasing number of studies being published on climate change. We must, by necessity, look to the credentials of person/s and organization/s who interpret this science, and to the scientific community itself for its peer review in order to judge the accuracy of conclusions.
When the IPCC issues a report, supported by hundreds of esteemed scientists, which reveals the potential for enormous and long-lasting implications for mankind, the precautionary principle requires us to act with caution and prudence.
You may agree that general, unspecific critique of the science underlying reports on climate change is a disservice to society because it tends to cast doubt about the authenticity of the problem. It seems to me that peer review and public dialogue concerning the quality of a particular study is most useful when it is specific, revealing why a certain conclusion is unwarranted.
Those of us who spend our time trying to ensure government decision making is informed by sound science and analysis need some modicum of agreement within the scientific community on matters of such consequence. While absolute certainty may not always be possible, we need some basis on which to act responsibly.
If science is to be useful in a broad social context, the listening public needs to able to put the comments and conclusions of scientists in proper perspective. For instance, in the normal course of peer review, a qualified scientist questioning a particular thing in a study on some aspect of global warming doesn’t mean that scientist disagrees with the general proposition that global warming is occurring. But to not put such comments in that broader context when addressing the public, may lead some listeners to believe the commentator is questioning the premise of climate change.
If ever there were a time for us to err on the side of caution, and speak the plain truth about the science of climate change as we presently understand it, it is now.
Isaac Schumann says
A wonderful post, I whole heartedly agree with you and the above commentator about the often problematic mix of science and politics. It seems to me (I am a microbiologist so I don’t have much experience with modeling or climate science, apologies) that the main purpose of climate models would be to increase our understanding of the global climate, not to predict the future. I could therefore envision a model that did a poor job of predicting the future, but was nonetheless very informative; whereas if a model were to accurately predict the future yet we were unsure why this was, it would not be a very informative or useful. My point is that the models are useful to science as a method to understand complex systems, whereas they are only useful in the political sphere for what they say about future and its implications to politics.
Another thing I would appreciate hearing your thoughts on, in my readings concerning the politics and science of global warming, i almost always get the sense from the political commentators that our understanding of the climate and climate change is very good and the only relevant discussion is over how bad things will get. My understanding is that our knowledge of the global climate is quite limited, yet there is definitely a tendency (as the above commentator mentioned) to project certainty and confidence when discussing climate change in the political sphere. The recent tone of the debate has particularly alarmed me as it has become increasingly heated and personal. In my opinion, people who are threatened by climate change, evolution, etc… will ALWAYS use the legitimate uncertainty of science to unreasonably discredit its findings, this seems to me to put even more emphasis on the need for scientist to put forth deliberate, sober and factual explanations for their work; as opposed to making assumptions and simplifications for the public debate.
Thank you so much for writing this blog, I recommend it to everyone I know.
Thank you so much for writing this blog
Environmental Issues says
I am believe that if we know that we are taking carbon material that is underneath the earth and has been there for as long as we know. And millions and billions of individuals are sucking it out of the ground and pumping it into the air that we are altering the normal pattern the Earth would go through. Do volcanoes and other natural phenomena contribute to climate change? yes. But humans are playing their role and we need to change.
If not for climate change but for health reasons, pollution is a killer, and we haven’t figured out cures for cancer or tumors yet. I am a believer that climate change is one of the most important environmental issues humanity will face.