No Analogue Climates – An Interview with Professor Jack Williams

Interview by Richard Donohue on August 14, 2007

Jack Williams is Assistant Professor in UW-Madison’s Department of Geography, as well as a Faculty Affiliate of the Center for Climatic Research and the Nelson Institute for Environmental Studies. He investigates ecological responses to climate change through mapping late-Quaternary vegetation history and using the paleoecological record to test earth system models. Williams, along with Dr. Stephen Jackson of University of Wyoming, attracted national attention in the Spring of 2007 when they published their analyses of recent climate model simulations suggesting the possibility of both novel and disappearing climates by the end of the current century. Many media outlets, including NPR and NBC nightly news, picked up the story. I sat down with Professor Williams to discuss the science, media, and politics surrounding this hot topic.

Research Findings

Q: Your research suggests the possibility of both new and disappearing climate zones. What does this mean?

JW: Given these various IPCC [Intergovernmental Panel on Climate Change] climate change scenarios and projections for this century, will these climate changes result in either new climates appearing that are unlike anything we see today or the disappearance of existing climates? We come at these questions as paleoecologists and paleoclimatologists. In the geologic record we see that when there are novel climate regimes that are unlike what we see today, there is a reshuffling of plant species and the emergence of new communities. We call these no analogue communities and no analogue climates because they have no modern analogue. Will this happen in the future and can we predict this? If this is outside the range of experience, can we make predictions for what might happen in this coming century?

That was half of the question with the novel climates.  The flip side was this concern that as certain climates disappeared, species that are endemic to those climates might go extinct. Other people have looked at this but more in an indirect way. They’ve done modeling of species range areas and extinction forecasts. We took a step a step back and asked what climate zones might disappear. That can then be mapped onto different spatial patterns of biodiversity and species ranges.

Q: And you found a high correlation between areas of high biodiversity and climate areas likely to disappear?

JW: We found a couple surprises. One is that depending on how you measure it, there is a fairly large area of the world’s surface that may either have novel or disappearing climates by the end of this century. So that was striking. The other thing is that there is a correspondence between these areas of disappearing climates and areas that people have highlighted as hotspots of biological diversity, or hotspots of endemism where certain species live and nowhere else. We overlay our climate risks map on certain areas of threat and find places where people would most like to preserve or conserve that diversity.

Q: Disappearing climate zones sounds troubling. Is there something exciting about the idea of novel climate zones?

JW: It is opportunity. You can think of it from an ecological perspective: these are new climates with new opportunities for species to move into. Some species will probably do quite well. They will be pre-adapted or poised to move into or exploit these new climate regimes that show up. That’s certainly what we see during the late-glacial period. When we have these climates that are unlike today, there are some species that flourish in those no analogue climates. The problem is that with the long-term forecast it is difficult to say at this point which will be the winners and which will not do as well. There is always this problem of ecological surprises arising from unexpected species interactions.

Q: What led you to studying this?

JW: Broadly, I was an undergraduate geology major and did a senior thesis on devonian coral communities in Ohio-Columbus limestone. I really enjoyed the process of doing scientific research and grappling with the research question, collecting data to test hypotheses. But I could never explain to my friends why I spent my time studying a roughly 400 million year old community that had been dead and gone for a long period of time. So when I was looking for graduate studies I wanted to keep pursuing my interest in earth history and earth systems science, but at a timescale that overlapped with human societies and human concerns. That got me interested in paleoecology and vegetation responses to the climate changes coming out of the last glacial period. That then has increased my interest in twenty-first century climate change. I remember when Jim Hansen gave his first testimony to Congress in the late 80s about how global warming is a real problem. That was right as I was heading into college, so during a prime period of my life I was exposed to these societal messages about environmental concerns. Then things worked out nicely that as I was finishing up my graduate work in the late 90s, global warming was moving up people’s lists of environmental concerns. It’s been a chance of timing and interests merging at the same time.

Q: What is the role of uncertainty in your research?

JW: There is this problem in model testing: how does your model work outside of the conditions in which you designed and built and tested the model. Anytime you extrapolate a line, for example, beyond the range of data, it prompts a question of whether or not you are over-extrapolating. Now, many ecological models are a lot more sophisticated and complex than a simple linear regression, but the same problem holds. At some point you’re going beyond your ability to test the model. There is always this question of how well the model will perform under these no analogue conditions. We’ve argued that one benefit of the geological record is that you can test ecological models and see how well they can reproduce ecological responses to past climate changes.  If they do well, then that’s an argument that they’ll do well in these novel, future climates. But there will always be some sort of greater uncertainty in these areas of novel climates.

Q: You’ve recently invoked a metaphor of mapping unknown terrain to describe your research?

JW: I think it came out of being here in UW-Madison’s Department of Geography and having all the cartographers around me. The prospect of novel future climates is very analogous to the spatially incomplete understanding of the world that European mapmakers had during their age of exploration. They drew the limits to their knowledge when beyond a certain point they wrote, “Here there be dragons.” In a temporal sense, it’s the same idea. We are moving a climate system beyond the state of what we have experienced and know. Beyond that point, here there be dragons. There are opportunities and there are risks. To figure out the exact balance of those—what the costs and benefits are—is a real challenge.

Q: Your model points toward predictions. Does your research inquire into the causes of these changes in the climate?

JW: Our research doesn’t deal specifically with the causes at all. However, it’s very common that we get asked this question, so it’s important to make clear that the models we’re working with are climate change scenarios developed for the IPCC. An increase in CO2 and other greenhouse gases during the 21st century are explicitly prescribed in the model scenarios – exactly how much of an increase differs among scenarios. We can say with absolute certainty that in these climate model simulations, the increase in CO2 and other GHG’s are the primary driver of simulated 21st-century climate change. We worked with two scenarios: a high-end scenario and a low-end scenario. The high-end is approximately a tripling of carbon dioxide concentrations from the pre-industrial levels and the lowest is about a doubling. Both are significant increases in CO2. Given these scenarios, we show very large differences in these areal projected extents of these novel and disappearing climates. But what will the real world do? Plenty of theory and data suggest very strongly that the world is warming and that human emissions of gasses are the major driver of the warming seen in the past 25 years.

Science Communication and Policy

Q: How does your research relate to policy?

JW: Our research is a piece in a larger debate about global warming. I think the debate is moving away from, “Is the planet system warming? Are we responsible?” I think that debate is finally ending. It’s taken a long time for that debate to die down, and there are little ripples still. Almost all scientists and most policy makers now accept that the world is warming and human activity is responsible. Now the big question is, “What do we do about it?”

The problem is massive. Everyone uses coal, oil, or natural gas for heating their houses or moving cars around. So moving away from an economy that is almost based entirely on burning fossil fuels is a massive undertaking. There is a debate out there in the policy community about two possible solutions: mitigation-based solutions and adaptation-based solutions. Mitigation-based solutions are the idea that we should reduce our greenhouse gas emissions into the atmosphere and thereby reduce the future climatic changes. Adaptation is the idea that climate change is happing and we have to deal with it. We have to make sure our social and engineered systems are adequate to cope with climatic changes. An example of adaptation would be building higher levees around New Orleans or other places that might be subjected to coastal flooding or storm intensity. Or, in the ecological framework, building networks of nature reserves or helping species move around.

Our work speaks to this debate in a couple ways. One says that in terms of these novel climates, it may be really difficult to plan out where species are going to go because, again, species likely will exhibit unexpected behavior in these areas of novel climates. This will pose a challenge to our planning ability and our ability to help these species adapt. The other piece of it is that if some climates disappear as our analysis suggests that’s a real problem for conservation biologists. One of the things we’re the first to show here is that when these climates disappear, it’s not a regional disappearance from South America. This is a global disappearance. These climates zones that are disappearing do so in a global context. Some species that may be endemic to these climate zones may have nowhere to go in the coming century. For these species, network corridors will not help because there is no endpoint for them to get to. The severity of these risks all depend upon how much carbon dioxide you put in the atmosphere. That really frames this adaptation versus mitigation: you have to do both. You have to do certain conservation-based solutions to climate change. We also have to recognize that at some point these climate changes may be large enough that for some species in some areas, adaptation is not a realistic possibility.

Q: What’s it like being a scientist today and studying such a hot topic, politically speaking?

JW: In some ways I feel a little lucky that I’m coming in after some of the really searing debates when various scientists would be called up before Congress to testify on one side or the other about this issue. I do feel like people are moving more toward a consensus about climate change and the fact that it’s happening now. The question is what should we do about it. How do we balance these potentially massive costs and risks with the potential benefits of climate change? So I feel very fortunate that I’m in a line of work that can make a difference for people, to address their worries and concerns about where our society and where the world is heading. You always hope as a scientist that your work has some broader meaning besides your lab and immediate circle of colleagues. It’s been exciting to be part of a project that has caught people’s attention and has them thinking of these implications for the planet earth.

Q: How about the recent news coverage?

JW: Media coverage is definitely a double-edged sword. It’s fantastic that people are excited or intrigued by the work we’re doing. But there’s always this real risk of the message getting distilled or distorted in some way as it gets spread out. It’s like a game of operator where each time you tell the news or someone reads a newspaper, it gets changed in some way. You must be careful because once it gets out there and it’s reported, you can’t take it back. Your words reach a broad audience, so one must be careful how you choose words. So far, I don’t feel like anything I’ve said has been directly twisted. But in some cases the story has been played up to emphasize the “scare aspect” a little more than I’d like.

Different media outlets take on news differently. A two-minute piece on NBC nightly news gives a very different take on the piece than NPR or a newspaper account. They all have a certain audience and amount of time they can devote to a story like this. So inevitably the message gets distilled to varying degrees. In the NBC Nightly News piece my sound bite was literally one sentence compared with longer interviews. On the flip side the NBC Nightly News piece was seen by millions of television viewers and had extensive coverage among the broader public.

Q: Any interesting responses from the public from all of this?

JW: Yes, I’ve kept a file of responses from the public. Most of the responses I get are, “This is really interesting” and are very favorable about it. But there is a subsection of people from whom you get these flaming emails. Wisconsin was called “Moonbat University” by one guy who didn’t like what we had to say. I think a lot of people who were really angry about it were angry with the media coverage, rather than the underlying science. They weren’t going back and reading our original paper. So there’s an off-the-cuff reaction to whatever they saw on television or read in the newspaper.

Q: What is the response from the scientific community?

JW: People have generally been pretty interested in it. In some ways these results are kind of obvious. What we’re really telling everyone is that if the world warms up, the places that are already the warmest become even warmer. While in colder parts of the world, climatic regions start to disappear. But on the other hand no one has looked at it like this before. A lot of times in science there’s a new way of thinking about a problem that lends insight. In this case, the idea of framing it as novel and disappearing climates has helped people think about it in a new way. And in terms of ecology, this idea of novel climates is something many people have known about in the back of their heads, but they haven’t really thought about the implications of that. I think we’re bringing that issue to the forefront. This is a place where our background as paleoecologists forces us to think outside of the bounds of what we see today … imagining the past and ecological systems under very different climatic states than the present. That is a world that most ecologists don’t have to wrestle with on a daily basis. I think this sort of analysis really brings that idea home to a lot of other ecologists.

Challenges, Rewards, and Future Directions

Q: What’s most challenging about this research?

JW: One challenge for me is that this was done as a side project. This was a project of opportunity that came up when I arrived here my first year. Some of the IPPC results were just becoming available to the community. I had some time at that point to get this work going and do some analyses. There’s always follow-up work that would be great to do, it’s just having the time to do it. I have my other research areas that I’m pursuing more vigorously, and now this new area has really opened up and caught fire. Now the question is how much do I drop other stuff to pursue it. It’s always a matter of having limited time to pursue research and how to juggle research and different projects.

Another challenging thing was that when this paper got published and people started calling in for interviews, it was fantastic getting all this attention. But there was about a week of my time, just returning people’s phone calls. Reporters are obviously working on a very tight deadline so when they call you should try to get back to them that day. That easily took a solid week out of my schedule, plus more time following up on that since then. At the same time of course, I feel very lucky to have had an opportunity to communicate my work to a broader audience.

Q: What has been most rewarding about this research?

JW: What’s been most rewarding about this has been doing some work that is of relevance to a broad sector of both other scientists and the community at large. I think a lot of us are used to working on a topic that’s of very great interest to ourselves and other specialists in our field, but the opportunity to reach out to a broader community is rare. That’s been very rewarding. At the same time in climate change science there’s always this balance between doing cool science and being impressed by the results and the potentially staggering implications if these are valid forecasts for the next century.

Q: What’s it like doing this research now at UW-Madison?

JW: UW-Madison is a great place to pursue this work. There are many other great scientists on campus and a lot of people who are committed to changing the world in a positive way in terms of improving environmental quality and reversing or slowing down the effects of global warming. There’s a really great cadre of scientists here at UW-Madison Department of Geography, Center for Sustainability and Global Environment, Center for Climatic Research, and other people affiliated with the Nelson Institute all interested in these different dimensions of climate change. Climate change is such a complex subject that having people who are trained as atmospheric climate modelers or biologists or economists or rural sociologists is invaluable.  All the different human, social, and physical dimensions of climate change are all studied here on the UW-Madison campus. It’s a great community of people to work with. And then the students who come through are really great students, motivated to be good scientists and good environmentalists. So I get a really good mix of people coming in to the take my courses or work with me on these issues. Madison has been a fantastic place to pursue this kind of work.

Q: What is the future direction of this research?

JW: I’m continuing to pursue a lot of work into the Late Glacial, which is maybe 15,000 to 9,000 years ago as a model system, as a prior period of time when carbon dioxide concentrations were changing very rapidly and climates were changing very rapidly.  We have some periods of abrupt transitions when species were rapid to migrate quickly across landscapes.  I’m collecting new pollen records to document the vegetation changes across this transition. We are funded to look at this from a network of sites from Tennessee to Minnesota. I have help from Jacquelyn Gill and Leila Gonzales, who are two of my current graduate students. The other part of it is doing some model development and testing. Can we use current generations of ecological models, apply them to try to reconstruct these vegetation responses of these Late Glacial no analogue climates?  And then do they work? And if they do work again, that gives us some confidence that they may work in a twenty-first century context. We are in that stage of model development and testing the paleological record. The next step will be the application of this model to the twenty-first century.