Thursday, December 27, 2012

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,

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