One of the things I am (not so) fond of saying is that when it comes to climate, I am not really worried about what I do know – it’s the things that I don’t know, and cannot predict, that worry me the most. The climate displays many characteristics of a nonlinear complex system, which means that we cannot assume that any changes in this system will come in a steady manner – even a fast but steady manner. Instead, the geologic record suggests that this system changes in a linear manner (i.e. slowly warms up, with related shifts in sea level, precipitation, wind patterns and ocean circulation) up to a certain point before changing state – that is, shifting all of these patterns rather dramatically into a new state that conveys the extra energy in the atmosphere through the Earth system in a different manner. These state changes are frightening to me because they are highly unpredictable (we are not sure where the thresholds for these changes are) and, at their worst, they could introduce biophysical changes like increased temperature and rates of evaporation and decreased rainfall with such speed (i.e. in a decade or two, as opposed to over centuries) that the rate of change outpaces the capacity of biomes to adapt, and the constituent species in those biomes to evolve. This is not some random concern about biodiversity – people seem to forget that agricultural systems are ecosystems; radically simplified ecosystems, to be sure, but still ecosystems. They are actually terribly unstable ecosystems because they are so simple (they have little resilience to change, as there are so few components that shifting any one of them can introduce huge changes to the whole system), and so the sort of nonlinear changes I am describing have particular salience for our food supply. I am not a doomsday scenario kind of guy – I like to think of myself as a hopelessly realistic optimist – but I admit that this sort of thing worries me a lot.
So, to put this another way: we are running like hell down a long hallway toward an open door into a darkened room. We can’t see what’s in the room, and it is coming up fast. Most normal people would probably slow down and enter the room cautiously so as to avoid a nasty collision with something in the dark. When it comes to climate change, though, our current behavior is akin to running right into that room at full speed and hoping with all our might that there is nothing in the way.
This is a really, really stupid way of addressing the challenge of climate change.
The good news on this front is that we are starting to see the emergence of a literature on the early warning for these tipping points. I had a post on this recently, and now the July issue of Nature Climate Change has a review article by Timothy Lenton on early warning of tipping points. It is a really excellent piece – it lays out what we are currently doing, shows the limitations of what we can do, points to significant challenges both in the science and in the policy realm, and tries to chart a path forward. I think Lenton comes in a bit science-heavy in this piece, though. While he raises the issues of false alarms and missed alarms, he spends nearly all his time looking at methods for reducing the occurrence of these events. This is all well and good, but false and missed alarms are inevitable when trying to predict the behavior of complex systems. Yes, we need more and better science, but we also need to be thinking about how we address the loss of policymaker confidence in the wake of false alarms or missed alarms.
To get to this point, I think we need to be looking to arenas where people have a lot of experience communicating levels of risk and the importance of addressing that risk – the insurance industry. Most readers of this blog will have some form of insurance – be it health insurance, life insurance, car insurance, etc. I have all three. Every month, I pay a premium for a product I sincerely hope I never have to use. I’d rather hang on to that money (with a family the size of mine, it gets steep), but the cost of a catastrophic event in any of these areas would be so high that I gladly continue to pay. We need to encourage the insurance industry (they are already working on this issue, as they stand to lose a hell of a lot of money unless they can get their actuarial tables adjusted) to start communicating their sense of the likely future costs of climate change, and the costs associated with potential state changes – and do so in the same way that they sell us insurance policies. Why do we have scientists working on the marketing of our ideas? We are not trained for this, and most of my colleagues lack the salesman’s charisma that the climate change issue so desperately needs.
It’s time for a serious conversation about how science and the for-profit risk management world can start working together to better translate likely future climate impacts into likely future costs that everyone can understand. Science simply does not carry the weight we need in policy circles – the good data and rigorous analysis that are central to scientific legitimacy are, in the policy realm, simply seen as means to achieving a particular viewpoint, not an ever-improving approximation of how the world works. Until the climate science (and social science) community grasps this, I fear we will continue to talk past far too many people – and if we allow this to happen, we become part of the problem.
Tag: Science
Well, this is interesting . . .
It’s been a while since I focused on the environment side of the whole “global change” thing that this blog is supposed to be covering . . . at least directly. Pretty much everything we do in development is connected to the environment – indeed, of late I have been referring to climate change as development’s Kevin Bacon while at work: I can get you from climate change to a development challenge, or vice versa, in three steps or less. But I have not been writing much on the subject directly.
However, thanks to Garry over at Resilience Science, I’ve just read a really interesting article in Science (and a nice counterpoint to the recent bin Laden ambulance chasing in that journal) by Steve Carpenter and a bunch of others on Early Warnings of Regime Shifts in ecosystems. For years, I have been teaching my students about the challenges of global environmental change, and trying to impress upon them that the part of these changes I find most worrying are the parts that are hardest to predict – the thresholds when particular biophysical systems might make sudden, discontinuous transitions to new states. What has worried me, and I think much of the global change community, the most is the fact that we are not sure where these thresholds are, nor are we sure what it looks like when we approach one. Thus, there is a pervasive concern within the community that we won’t know we’ve crossed a threshold or done something irreversible.
Carpenter and his co-authors, however, tested the hypothesis that “catastrophic ecological regime shifts may be announced in advance by statistical early-warning signals such as slowing return rates from perturbation and rising variance” by artifically inducing a regime shift in an aquatic food web (Carpenter is a limnologist – he does lakes, as it were) while monitoring a nearby similar lake as a control. Their finding: they could see statistical warnings of an impending regime shift for more than a year before it occurred, validating their chosen early warning indicators (chosen from previously constructed understandings of the food web in question, and a bit much to synthesize here).
That there might be early warning indicators, or that the variables chosen by Carpenter, et al served as useful early warning indicators for regime change in this particular system are not terribly surprising. What is interesting, though, is that the authors were able to demonstrate in a real-world (experimental) context (as opposed to desk theorization) that the early warning signals of regime shift are in fact detectable and measurable. Granted, this is for a small, bounded food web – but the demonstration is important in a much wider way. If we can find early warning indicators for regime shift in a small food web, there is no reason why we cannot find indicators for other complex systems – we can find a lot more early warning indicators of the discontinuous changes we fear, and in enough time to possibly address those changes before they occur.
But one big caveat here: this study did not reveal the actual mechanisms of regime shift. As the authors note:
The precise mechanism of the nonlinear transitions is not known for our experiment; it could be one of the processes proposed in the literature, or something else. These early warning signals are expected to occur for a wide class of nonlinear transitions (7). Even though the mechanism is not known, manipulation of an apex predator triggered a nonlinear food web transition that was signaled by early warning indicators more than a year before the food web transition was complete. Thus the early warning indicators appear to be useful even in cases where the form of the potential regime shift is not known.
It seems to me that there is a serious risk of conflating correlation and causation here – that the authors got a bit lucky in this experiment, but that in other systems without an adequate understanding of the mechanisms of change, false correlations could cause us to lose the signal of regime shift in the noise of inappropriate data points. I’m not sure how, or if, they intend to address this . . . but I think they will have to, if we are to usefully apply this to our food-producing ecosystems in a manner that allows us to think about sustainable development and food security in a meaningful way . . .
Geographers had (sorta) found Bin Laden?
Inquiry is dead when the flagship journal Science starts ambulance-chasing . . . but hey, its Osama bin Laden week in all media, so I guess it should be of no surprise that they are running a story on three-ish year old efforts to get a sense of where bin Laden might be hiding. To their credit, the folks at UCLA are hardly crowing – it was a student project, and Thomas Gillespie, the faculty leader of the project openly noted “It’s not my thing to do this type of [terrorism] stuff,” and made it clear that he had no intention of shifting from his biogeographic interests:
“Right now, I’m working on the dry forests of Hawaii where 45% of the trees are on the endangered species list,” says Gillespie. “I’m far more interested in getting trees off the endangered species list.”
I’m waiting for the gentlemen over at floatingsheep.org to weigh in on this particular project – they are much more qualified to comment on the substance of the study. However, I applaud Gillespie for refusing to get caught up in the hype. Sadly, I’m sure some of my disciplinary colleagues will want to trumpet this as an example of how useful geography is, and why it should get more attention. Because, you know, we’ve just recently shaken off the colonial origins of our discipline, where we proved our usefulness by mapping local populations and resources to facilitate their control, and lord knows we wouldn’t want to put that sort of thing behind us. As one of my colleagues in grad school once pointed out (tongue-in-cheek) after listening to some of our colleagues complain about how some engineering and science departments had much larger budgets, “if we were willing to help kill people, we wouldn’t have this problem.”
And people wonder why I get itchy about the militarization of aid and development.