While scientific evidence of climate change continues to mount and an increasing number of studies point causal fingers at ourselves there is perhaps another way to visualize the risk of inaction or over-reaction. So, since most people can leave ideology aside when it comes to their own health, a medical metaphor, courtesy of Andrew Revkin over at Dot Earth, may be of use to broaden acceptance of the message.

[div class=attrib]From the New York Times:[end-div]

Paul C. Stern, the director of the National Research Council committee on the human dimensions of global change, has been involved in a decades-long string of studies of behavior, climate change and energy choices.

This is an arena that is often attacked by foes of cuts in greenhouse gases, who see signs of mind control and propaganda. Stern says that has nothing to do with his approach, as he made clear in “Contributions of Psychology to Limiting Climate Change,” a paper that was part of a special issue of the journal American Psychologist on climate change and behavior:

Psychological contributions to limiting climate change will come not from trying to change people’s attitudes, but by helping to make low-carbon technologies more attractive and user-friendly, economic incentives more transparent and easier to use, and information more actionable and relevant to the people who need it.

The special issue of the journal builds on a 2009 report on climate and behavior from the American Psychological Association that was covered here. Stern has now offered a reaction to the discussion last week of Princeton researcher Robert Socolow’s call for a fresh approach to climate policy that acknowledges “the news about climate change is unwelcome, that today’s climate science is incomplete, and that every ’solution’ carries risk.” Stern’s response, centered on a medical metaphor (not the first) is worth posting as a “Your Dot” contribution. You can find my reaction to his idea below. Here’s Stern’s piece:

I agree with Robert Socolow that scientists could do better at encouraging a high quality of discussion about climate change.

But providing better technical descriptions will not help most people because they do not follow that level of detail.  Psychological research shows that people often use simple, familiar mental models as analogies for complex phenomena.  It will help people think through climate choices to have a mental model that is familiar and evocative and that also neatly encapsulates Socolow’s points that the news is unwelcome, that science is incomplete, and that some solutions are dangerous. There is such a model.

Too many people think of climate science as an exact science like astronomy that can make highly confident predictions, such as about lunar eclipses.  That model misrepresents the science, does poorly at making Socolow’s points, and has provided an opening for commentators and bloggers seeking to use any scientific disagreement to discredit the whole body of knowledge.

A mental model from medical science might work better.  In the analogy, the planet is a patient suspected of having a serious, progressive disease (anthropogenic climate change).  The symptoms are not obvious, just as they are not with diabetes or hypertension, but the disease may nevertheless be serious.  Humans, as guardians of the planet, must decide what to do.  Scientists are in the role of physician.  The guardians have been asking the physicians about the diagnosis (is this disease present?), the nature of the disease, its prognosis if untreated, and the treatment options, including possible side effects.  The medical analogy helps clarify the kinds of errors that are possible and can help people better appreciate how science can help and think through policy choices.

Diagnosis. A physician must be careful to avoid two errors:  misdiagnosing the patient with a dread disease that is not present, and misdiagnosing a seriously ill patient as healthy.  To avoid these types of error, physicians often run diagnostic tests or observe the patient over a period of time before recommending a course of treatment.  Scientists have been doing this with Earth’s climate at least since 1959, when strong signs of illness were reported from observations in Hawaii.

Scientists now have high confidence that the patient has the disease.  We know the causes:  fossil fuel consumption, certain land cover changes, and a few other physical processes. We know that the disease produces a complex syndrome of symptoms involving change in many planetary systems (temperature, precipitation, sea level and acidity balance, ecological regimes, etc.).  The patient is showing more and more of the syndrome, and although we cannot be sure that each particular symptom is due to climate change rather than some other cause, the combined evidence justifies strong confidence that the syndrome is present.

Prognosis. Fundamental scientific principles tell us that the disease is progressive and very hard to reverse.  Observations tell us that the processes that cause it have been increasing, as have the symptoms.  Without treatment, they will get worse.  However, because this is an extremely rare disease (in fact, the first known case), there is uncertainty about how fast it will progress.  The prognosis could be catastrophic, but we cannot assign a firm probability to the worst outcomes, and we are not even sure what the most likely outcome is.  We want to avoid either seriously underestimating or overestimating the seriousness of the prognosis.

Treatment. We want treatments that improve the patient’s chances at low cost and with limited adverse side effects and we want to avoid “cures” that might be worse than the disease.  We want to consider the chances of improvement for each treatment, and its side effects, in addition to the untreated prognosis.  We want to avoid the dangers both of under-treatment and of side effects.  We know that some treatments (the ones limiting climate change) get at the causes and could alleviate all the symptoms if taken soon enough.  But reducing the use of fossil fuels quickly could be painful.  Other treatments, called adaptations, offer only symptomatic relief.  These make sense because even with strong medicine for limiting climate change, the disease will get worse before it gets better.

Choices. There are no risk-free choices.  We know that the longer treatment is postponed, the more painful it will be, and the worse the prognosis.  We can also use an iterative treatment approach (as Socolow proposed), starting some treatments and monitoring their effects and side effects before raising the dose.  People will disagree about the right course of treatment, but thinking about the choices in this way might give the disagreements the appropriate focus.

[div class=attrib]Read more here.[end-div]

[div class=attrib]Image courtesy of Stephen Wilkes for The New York Times.[end-div]