What do fish, water, and methane have in common?

In previous blogs, I have advocated particular approaches to fisheries and suggested an analogy with climate change. This week, I will describe the analogy more explicitly and make the case for its broad applicability, using water management as an example.

The Pineapple Express

I can talk with at least a little authority on water management systems. While working for the National Oceanic and Atmospheric Administration (NOAA), I had the great fortune to be selected for its Leadership Competencies Development Program. Though I worked for NOAA’s Fisheries Service, the program assigned me to work details in the agency’s Office of Oceanic and Atmospheric Research (OAR), which provides national leadership in climate science and gave me some early exposure to issues I wrote about the last couple of weeks.

OAR also develops new weather forecasting technologies. My mentor for the Leadership Program was Marty Ralph, a meteorological researcher who has played a major role in identifying and describing atmospheric rivers, which rapidly carry warm moist air from the tropics to temperate regions and are responsible for many of the major winter storms that batter the U.S. West Coast. I explained my ideas on managing uncertainty to Marty, and he was interested in having me look at the potential benefits that his research might provide to society. We focused on the Folsom Reservoir, a man-made lake above Sacramento, California.

The Folsom Dam, California

This reservoir is a key water source for central California but also protects Sacramento from floods. Visitors to California’s capital will notice that the buildings of old town are raised above street level, an old technology to confront Sacramento’s great flood risk (second only to New Orleans in the U.S. even with the current dam/reservoir). Managing the reservoir is tricky. The water it contains is extremely valuable from mid-spring through mid-fall, when central California gets virtually no rain or snow. However, warm wet storms have the potential to bring vast quantities of water rushing down from the snow-covered Sierra Mountains. The dam has only so much capacity to release water safely, and so reservoir operators must plan ahead. They risk a flood if they do not release enough water and provide space in anticipation of a storm. However, they risk a water shortage during the dry season if they release too much water. Marty recognized that more accurate weather forecasts could result in better information to guide the choices the dam operators face.

To me, the dam operator challenge sounded strikingly familiar. The water in the reservoir is like fish in the ocean. Let’s call this phenomenon the stock. The decisions about releases are like catch quotas. Let’s call this phenomenon the flow. The dam operator faces two fundamental choices: a target stock level, and rules that govern flow. Both involve trade-offs. Larger stocks of water are good for water supply but bad for floods, just as larger stocks of fish are good for ecosystems but may dampen the productivity of fisheries. More responsive flows will keep reservoirs closer to target water levels and can reduce the chances of a flood, but are more costly in terms of required technology on the dam, greater stress on the riverbed and low-lying development downstream, and lost opportunity to generate electricity (which is done using turbines with carefully controlled water flows). Similarly, more responsive fisheries policies will keep fish stocks closer to target levels and reduce the chance of a stock collapse, but require more management infrastructure and impose economic and social costs of unpredictable incomes for fishing operations and their distribution chains.

Climate change can also be thought of in terms of stock—greenhouse gases in the atmosphere; and flows—production of greenhouse gases. In this context, our current policy can be interpreted in one of two ways. One interpretation is that we have a target stock level that is much higher than current greenhouse gas levels and we are willing to accept the possible consequences of those higher levels. The other interpretation is that we have a target that is somewhere near current levels, but unresponsive flow policies that will allow the stock to grow a fair amount before we gradually adjust it downward. Since we do not fully understand the consequences of much higher greenhouse gas levels, the most accurate depiction of current policies might be one of waiting and seeing. The problem is, if it turns out that high stock levels are as bad as several models predict, we will then be forced into a tough decision between adapting to the new conditions versus enacting expensive or risky responsive policies to bring greenhouse gas levels down quickly.

With all three of these systems—water management, fisheries, and climate—we can make smarter policies by considering stock and flows following a common formula. It involves only a few steps, but each requires specialized knowledge. We need three interconnected models: one of the environmental system of concern, another of the management system, and finally one of the socioeconomic system. The environmental model must describe how stock size will change under various flow rules and consider scientific uncertainties. Similarly, the management model must take into consideration choices managers can make and the degree to which these choices will change flows, including implementation uncertainties. The socioeconomic model must translate uncertainties into risks, and be capable of predictions about stock and flows related to the set of objectives (sometimes conflicting) that various user groups have. In combination, this set of models can then be used to evaluate various policy options and give advice on their relative strengths and weaknesses. This advice can be instrumental in helping people to rationally navigate uncertainties by giving them concrete advice about what options they have to reduce future risks and what they would have to give up to achieve these reductions.

Not all environmental issues have stock and flow properties, but many do. Recognizing this commonality should help us to devise means to use science more effectively when crafting environmental policies.

Next week, I plan to switch gears somewhat. Feel free to suggest topics either by commenting here or by contacting me directly.

Wishing you a Happy 2013,

Josh

Climate change and the art of airplane maintenance

An interested reader sent me a thoughtful email in response to last week’s post on global warming. The reader asked a number of questions and expressed some concerns. I welcome feedback of this sort because it helps me see how my thoughts and attempted explanations are received, and gives me the opportunity to learn from others. In this week’s post I will attempt to clarify and elaborate on some important points by answering questions paraphrased from that correspondence.

Question 1: Even if only a small percentage of models now being used predict very serious consequences of global warming for public health, or drought, or forest fires, or other types of ecosystem damage, or extinctions, etc., doesn't that imply we would be wise to take action on these models just in case they might be right?

Response 1: This question gets at a key attribute of how people respond to uncertainty: what to do about high impact but low probability events? As I have stated before, we are wired to have one of two responses to uncertainty: to ignore it or to overreact. But what would a thoughtful, rational response be? It would depend on the degree of impact and probability of occurrence, but also on the cost of actions to reduce the risk.

As an example, consider airplane design and maintenance. Airplane crashes are rare. Per mile, airline passengers are 50 times less likely to be killed than people traveling by car. When traveling by plane, people tend to ignore the risk of a crash or to be overly troubled by it, e.g., showing far more anxiety then they would if traveling in a car and facing equivalent or greater dangers (since a plane travels more than 50 times faster than a car, the chances of dying at any given moment in each travel mode are more similar). Nevertheless, there is a risk of crashing, and airlines, airplane manufacturers, and government agencies have the opportunity to make rational decisions about how to handle that risk. Why not make an indestructible plane, or as comedian Steven Wright put it, “Why don't they make the whole plane out of that black box stuff?”

Engineers will give you a straight answer to this question, emphasizing impracticality because of the weight of “black box stuff.” I, however, am skeptical that the weight itself is an insurmountable obstacle. After all, a 747 is designed to takeoff at a maximum weight of nearly 1 million pounds, and an Airbus A380 at nearly 1.3 million pounds. It may be impossible to design the entire plane using black box technology, but I imagine that the interior of a 747 or A380 could be gutted and refitted with a small black box-like cabin suitable for just a few passengers who would be protected from nearly every form of harm. The reason we dismiss this possibility is the cost. Operating costs for such a large plane are enormous and usually shared by the hundreds of paying passengers onboard. Not many people would pay 100 times the going price of airfare to reduce already low chances of dying in a plane crash to near zero. Airplane maintenance schedules raise the same issues. More frequent and more extensive inspections would improve safety but would drive up costs. In the end, airplane maintenance schedules represent a rational balance between the two.

This sort of analysis doesn’t encourage the elimination of every risk. Instead it encourages balance. This balance is what we should be striving for with respect to global warming. The real question about global warming is whether the benefits of reduced risks outweigh the costs of taking action today. In order to answer that question, we must highlight scientific uncertainty and examine it carefully with public costs and benefits in mind, which is the approach I advocated last week. I personally believe that we should be enacting policies to address the potential damage from global warming. If we perform and emphasize analyses on climate change like the airplane design and maintenance ones described above, we will disempower unwavering global warming skeptics and foster the development of rational policies.

Question 2: To the scientists I know and admire, uncertainty is a challenge, a focus, and something to highlight. Isn't this what scientists are especially proud to do? What are you implying: that scientists are uncharacteristically uncomfortable with and downplaying of uncertainty when it comes to global warming; that science is easily undermined by self-interest and discomfort with uncertainty in general; or that there is something unusual about climate change that makes it more difficult to study in objective scientific ways?

Response 2: Last week, I focused on an explicit strategy chosen by climate scientists to downplay disagreements among themselves when addressing the public about global warming. In no way does this strategy apply to debates among scientists in scientific arenas. They chose this strategy with the good intentions of breaking out of the dueling expert media formula described last week, and of conveying their genuine concerns to the public. This strategy had a cost, though, in terms of framing the debate about the certainty of global warming’s existence, when I believe a debate focused on the range of possible climate change outcomes and potential costs of avoiding the more extreme possibilities would have been more productive.

However, climate scientists are not alone in their struggle with how to portray uncertainty to non-scientists. In fisheries, scientists are often asked to recommend fishing quotas for the next year. This is a daunting task because our current understanding of the status of the fish population is always uncertain, our ability to estimate how many new recruits will be added to the population is even more unpredictable and, in many cases, we are asked to give this advice without a clear idea of how the following year’s quota might be adjusted in response to new information (e.g., not at all versus the rocket science approach). Furthermore, various sectors of society, whether they be different fishing fleets or non-fishing interests, will have different opinions as to what quota, or quota system, will be best.

An example of error bars, shown in red

Typically, fishery scientists will address uncertainties in two ways. First, they will recommend a quota but will bound it with error bars, a graphical technique that shows a range of values likely to contain the correct answer. Error bars are an honest attempt to convey uncertainty. It is my experience, though, that managers often view them skeptically as both an admission that fishery scientists don’t know the right answer, and as latitude to choose any quota value within the range of the bars.

Second, fishery scientists, along with climate scientists and every other scientist I’ve ever met, will talk at length about the uncertainties in their field, but from a scientific perspective focused on the frontiers of discovery. This framing of uncertainty does not translate directly into currencies of relevance to interest groups and policy makers. Whereas scientists often express the need to dumb down the science for policy, in reality it must be translated from the nuanced and complex scientific world to the equally but differently nuanced and complex policy world.

In sum, it’s not that scientists are self-interested or uncomfortable with uncertainty. It’s that they do not have the expertise or do not make the effort to express scientific uncertainty in useful ways for policy makers. In order to craft smarter policies, we need more emphasis in the policy process on bridging the gaps among scientific disciplines and especially the gap between the scientific and policy worlds. Addressing uncertainty more explicitly is a key step in doing so.

With many thanks for these good questions,

Josh

Why uncertainty matters in global warming

On Christmas Eve, I had a delightful dinner with my extended family. My dad was present and we got into a discussion about global warming. He was convinced that the science is stronger than ever, and seemed to suggest that uncertainty was not a real issue. I disagreed. I do not believe the process is an assembly line where scientists make a discovery, obvious policy is drafted, and politicians choose whether to do the right thing. Instead, I believe that the scientific process is complicated by uncertainty and the drafting of policy necessarily must take into account people with diverse interests and opinions. His perspective helped me greatly, though. If I am going to successfully argue for a new approach to issues such as this one, I need to be able to convince smart and concerned people like him.

What’s your favorite explanation for why climate change is such a divisive subject? The corruptive influence of corporations on politics? The self-interest of scientists skewing the results to justify funding for their work? Al Gore? Fox News?

The same basic explanations (plus or minus one ex-VP) are thrown about in frustration during most environmental policy debates. I’ve been privy to many of these through my work in fisheries, marine protected areas, and for the federal government’s National Oceanic and Atmosphere Administration (NOAA). In addition to the Fisheries Service, NOAA runs the Weather Service; the National Ocean Service, which has diverse responsibilities ranging from National Marine Sanctuaries to maintaining and updating nautical charts; and the Office of Oceanic and Atmospheric Research, which develops weather forecasting technologies and is a major player in climate change science. It turns out that the same issues I’ve encountered in fisheries (including the relevance of rocket science) apply to subjects as diverse as managing a freshwater reservoir through unpredictable weather events to addressing climate change.

Recall from last week’s blog that our brains lead us to respond predictably to uncertainty in one of two ways: ignoring it or overreacting. Lo and behold, this may explain the polarization of environmental issues. In virtually every one, there is a side that dismisses the environmental threat and another side that portrays it as if the world will end unless we act decisively and immediately.

Let’s look at climate change through this lens. Isn’t it plausible that people who overreact might be frustrated with the speed of policy development and look for an explanation such as corrupt politics or Fox News? On the other side, might not the ignorers perceive scientists and Al Gore as overblown and look for any signs of bias to challenge their often haughtily emphasized credibility?

Inadvertently, the scientific community has fed the impression of bias. Climate scientists made a strategic choice to downplay uncertainty as a way of getting out of the media pattern of presenting dueling experts (i.e., regardless of his or her credentials, including the opinion of a scientist who argued against climate change). Reputable scientists have stressed that climate change is happening and is caused by humans, and deemphasized any disagreements among themselves about the details. This strategy, of putting up a united scientific front, has had interesting effects. It stopped most of the news media from reporting climate change with dueling experts; but it also made it easier for skeptics to attack the credibility of scientists.

Michael Crichton, author of the blockbuster Jurassic Park and a medical doctor by training, wrote a novel that presented real data about climate change, raising doubts about the science. State of Fear is a poorly written story with a thin plot, but is interesting because of the political reaction it generated. The novel made a splash in conservative political circles and garnered Dr. Crichton an invitation to testify before the US Congress as an expert witness on climate change, despite criticism by trained scientists of the novel as distorted. Yet, a united front only passes muster if it is truly united. By presenting selected data and highlighting underlying real scientific disagreements to the public, Crichton and others have been able to challenge the united front and damage the credibility of climate scientists in the process.

Let’s look at more examples that highlight the fragility of scientific credibility. There was a huge uproar about a 2007 report by the Intergovernmental Panel on Climate Change. The report included a misstatement that the Himalayas could lose their glaciers by 2035. That assertion came from a media interview with a scientist rather than a scientific journal (which peer reviews scientific claims prior to publication), and is most likely false. However, this misstep was the exception rather than the norm in the report, which was literally thousands of pages long. Nevertheless, it generated a huge amount of media coverage and no doubt fueled skepticism. In similar fashion, one of Al Gore’s claims of the evidence of global warming was receding glaciers on Mount Kilimanjaro. While it’s true that the glaciers are melting, recent studies have shown that the cause is more likely deforestation than global warming. As expected, skeptics are having a field day and presenting this new information as if it disproves global warming entirely.

What an unfortunate mess given the state of the science. Scientists collect new data and learn more about climate change every year. If you are interested in a good review of the current evidence, albeit one designed to make a global warming believer of you, check out the website Skeptical Science. Of particular relevance to this blog is a discussion of climate change models. As the author points out, there are uncertainties in predicting the future. However, among the many potential climate change scenarios that have been predicted, data from the past 20 years have generally been on the warm side of things. Despite the growing strength of evidence, though, the US public has remained wary. Opinion is gradually shifting towards seeing climate change as a real concern but as recently as 2010, a major poll indicated that nearly half of all Americans thought the threat was exaggerated. I am convinced the skepticism comes from the strategy of emphasizing scientific consensus. In fact, I will go so far as to claim that, in doing so, scientists have failed to give the public and politicians the information that could actually be useful in choosing how to move forward.

What is it that we need? We need a better sense of what risks we are facing and how much sacrifice will be necessary to reduce them. This theme is one I’ve addressed in an earlier blog about the US cod fishery. The key from scientists is a clearer picture of the uncertainty surrounding climate change. Even if scientists generally agree that climate change is occurring and is influenced by human activities, they do not agree on what the world will look like in 50 or 100 years. Under a scenario with no new policies, estimates of temperatures in 2100 range from mild to catastrophic. If the Earth warms only a couple of degrees, the costs will be fairly benign. Some people, particularly in low lying areas, will suffer. However, the benefits of reversing those changes may not be worth the immediate costs that would be associated with cutting our carbon emissions. If the Earth warms 20 degrees, though, we could easily be looking at an apocalyptic future. In that case, which is a realistic possibility, the future benefits would almost surely be worth even major costs of acting today. The actual outcome could be anything between these extremes. Thus, we are in a situation where we have to choose among gambles, but we don’t get useful information because the debate is about whether global warming is real rather than the odds we face.

Yet there is progress, albeit work that does not often get much publicity. Robert Lempert, a senior scientist at the RAND Corporation, has been exploring robust policy strategies—ones that will work across a range of possible warming scenarios. These have commonalities with the fisheries lessons I learned by working with a rocket scientist. More directly related to the strategy I suggested above, economist William Nordhaus has worked extensively on models that allow the analysis of policy options by pairing climate science, including its uncertainty, with economics. The uncertainty matters a lot: the prudence of immediate and decisive action depends greatly on how much weight is given to the potential for catastrophic outcomes. Educated people may disagree about the details of such analyses but at least this approach moves us in the right direction.

Climate change is a serious issue. When the media begins presenting stories that talk about risks and the costs of reducing them, we will be on track for global solutions. Until then, scientists can do their part by emphasizing uncertainty in a constructive manner, and non-scientists can help by demanding this sort of information.

Please share your thoughts in the comments section. I invite you to respond to this post, propose subjects for future posts, or just say hi. I’d love to have this blog evolve into a dialog.

Best regards,

Josh