In its April issue, the journal Nature Climate Change published an Opinion and Commentary piece, “Limits to Adaptation.” The authors of the Commentary suggest that the time has come for researchers and policy makers to “begin making progress in predicting and anticipating climate change adaptation limits,” and “to start making plans for managing the consequences of exceeding adaptation limits.” The piece suggests a “third phase” of climate change planning. Phase I, planning for climate change mitigation, began some 25 years ago. Phase 2, planning for adaptation to climate change, began in earnest about 10 years ago. The Commentary authors propose we now start planning for Phase 3, when we cross the “limits to adaptation.” In other words, to use Kevin Costner’s 1995 movie as a metaphor, planning for Waterworld.
The authors argue that climate change poses “acceptable risks” (i.e., risks that we can absorb without new adaptation measures), “tolerable risks” (i.e., risks that can be kept “reasonable” through adaptation measures), and “intolerable risks,” (i.e. risks we encounter after crossing “adaptation limits.”) But how do these terms translate into practice? How many species extinctions are “acceptable risks”? And when discussing “tolerable” and “intolerable” risks, whose perceptions of risk establish the risk baseline? Rich nations or poor nations? Coastal nations or landlocked nations? Natural systems or social systems? The construction sector or the agricultural sector? Businesses or individuals? To be fair, the Commentary authors seem to recognize the complexity of what they are suggesting, pointing to an almost infinite number of adaptation limits that could be encountered, each of which can be analyzed as shown in the figure below.

In the abstract, I don’t question the existence of adaptation limits; their existence seems obvious. But should planning for the “intolerable risks” of crossing a myriad of potential “adaptation limits” be a research and policy priority as the authors propose? That I do question, and explore below several of the assumptions that necessarily underlie the authors’ proposal:
1) That we will not successfully engage in climate change mitigation efforts that prevent us from reaching “adaptation limits.”
2) That we can, through adequate study, accurately characterize adaptation limits in a way that is useful and actionable today.
3) That policy makers and other decision-makers will translate this new understanding of adaptation limits into some sort of problem-solving response.
Each assumption is open to challenge. True, the failure to date of Phase 1 mitigation efforts is responsible for the growing focus on Phase 2 adaptation planning. But does that mean that serious mitigation efforts will NEVER kick in (We’ve discussed elsewhere the Climate Response Tipping Point, the point at which dramatic action against climate change could be expected to become a policy priority). All sorts of analysis points to the fact that we have the technical tools needed to limit climate change, or even to reverse it; the question is whether, perhaps in the face of events that trigger a tipping point in public opinion and policy response, we will deploy those tools at the needed scales.
Moving on, can we really forecast “adaptation limits” in an actionable and policy-useful way? Given the complexity of natural and human systems, sorting out the adaptation limits of rice varieties, vs. the adaptation limits of rice farmers, vs. the adaptation limits of rice exporting countries, quickly becomes a quagmire of assumptions and scenarios. Even if you could sort out answers to all these questions, isn’t it equivalent to studying the temperature at which each of your individual belongings will burst into flame if your house burns down? That’s not the information we use in deciding whether to buy fire insurance. Even more fundamentally, if we get beyond mitigation, and beyond adaptation, what kind of actionable response are we even talking about? Are we talking about disaster relief? If so, we have to ask how practical disaster relief efforts can be if required on an ongoing basis at a global scale.
Lastly, even if we could generate useful estimates of adaptation limits, the next question is whether decision-makers would act on the information. To date, policy makers have largely failed to act to mitigate climate change despite enormous amounts of relevant analysis. Similarly, we’ve hardly scratched the surface of what adaptation analysis has already suggested as prudent (see, e.g., “6 Steps to Managing Your Company’s Physical Climate Risks,” GreenBiz.com, March 29, 2013). The Phase 3 approach proposed in the Commentary relies on exactly the same policy analysis “frame” that Phases 1 and 2 have (unsuccessfully to date) relied upon. If that frame hasn’t generated an adequate risk management response to date, why should we believe that it will when discussing even more abstract and longer-term prospects like “adaptation limits” and “intolerable risks?”
So why are we even talking about “adaptation limits”? The Commentary authors suggest that we need to investigate adaptation limits because: “If the capacity to adapt is unlimited, a key rationale for reducing emissions of greenhouse gases is weakened. . .” Is that really the situation we’re in today, after decades of climate change concern? Does any reasonable person believe the capacity to adapt is unlimited? Even setting aside James Hansen’s hypothesized “Venus effect,” the consequences of a significant change in average global temperature, e.g. 8oC, would by all accounts be catastrophic for most social and natural systems. Surely that would be considered “intolerable risk” by any reasonable observer. If so, what’s the real added value of making “adaptation limits” a policy and research priority?
The Nature Climate Change Commentary does implicitly raise three interesting issues not addressed by the authors. First, what actionable conclusions might we suggest today if we wanted to prepare for the consequences of Kevin Costner’s Waterworld scenario (which, presumably, would be considered an example of “intolerable risk,” at least for the majority of the earth’s population that has passed on in the interim)? Is the proposal to research adaptation limits analogous to arguing that we should actively prepare for what could happen if nuclear waste depositories are accidentally opened while they’re still highly radioactive? Is anyone really doing such planning (as opposed to proposing to mitigate the risk of such an event through technological and communications means?)
Second, what do we even mean at a societal level by the term “adaptation limits”? Are Kevin Costner’s webbed fingers and feet in Waterworld an example of successful adaptation, or are the billions of dead an example of failed adaptation and crossing adaptation limits? A curious aspect of defining “successful” or “failed” adaptation is that whoever might ask the question in the future is likely to conclude “yes, we successfully adapted,” simply because they are in a position to ask the question (i.e., they survived). So will the billions of people who didn’t make it on Kevin Costner’s Waterworld simply not matter to the question of adaptation success or failure once they’re gone? Does Waterworld exemplify both failed and successful adaptation? Even this simple example illustrates the intellectual and moral quagmire we are likely to encounter when we start talking about planning for adaptation limits. Instead of advancing the cause of climate risk management, it could become an enormous distraction, and provide yet more grist for the mill of those who argue we don’t need to act now to address climate risks (by suggesting that we need a massive amount of new cost-benefit analysis to determine all of the adaptation limits, analysis that by its very nature e.g. through discounting the future, tends to undercut the priority of near-term risk management). The whole topic of “success and failure” when it comes to societal mitigation and adaptation efforts is a challenging topic that has yet to be widely tackled. That is indeed a priority.
Policy analysis and scenario building are useful tools. But those of us trained in the use of the policy analytic frame need to be able to argue that we are providing added value through its application, leading to conclusions that help advance agreed upon policy and societal objectives and outcomes. The policy analytic frame can fall into the trap of assuming that it is the only hammer in the toolbox, missing the fact that there’s not a nail in sight. Based on our experience with Phases 1 and 2 of climate change planning, launching an “adaptation limits” Phase 3 reflects a misunderstanding of how to best advance the end-game of climate risk management. Before spending time and effort on this new Phase 3 of climate change planning, let’s redouble our efforts to come up with risk-based arguments that effectively motivate decision makers to engage seriously with Phases 1 and 2. Any serious look at potential climate change scenarios in the absence of successful mitigation efforts, and any serious look at adaptation needs in the face of unrestrained climate change, brings us back to the need for mitigation and adaptation at a scale far beyond what we’ve seen so far. If we can’t communicate that fact (which we obviously haven’t), I don’t think that a massive new effort to explore “adaptation limits” is likely to move us in the needed direction. Let’s re-think some of the first principles of the communications and risk-management challenges we face when it comes to climate change. It’s not new and sexy, and it’s not easy, but it’s what we need to do.