Thinking Appropriately About Climate Change

ClimateChange3In his recent State of the Union message, President Obama flatly stated that “Climate change is a fact.” These are fighting words with an influential minority of the American public, and the President may be itching to have this fight.  But saying that climate change is a “fact” is a disservice to the public because it invites people to think about the issue in a misleading and unproductive way.

For one thing, climate change is not all “fact.”  Scientists recognize the tremendous complexity of climate change.  They use supercomputers to crunch billions and billions of numbers to make quantitative models to predict future events and they recognize that some of the model results are more trustworthy than others.  There is near unanimity among scientists about some aspects of climate change, but widespread disagreement about others.  So the President’s statement is oversimplifying.

Simplification is necessary for understanding complex issues.  Psychological research shows that almost everyone thinks about complex issues by applying simple models that relate them to familiar personal experiences.  But simple models can sometimes lead people astray.  What we need are mental models that help us think about complex problems in ways that point us toward choices that will benefit ourselves, our families, our communities, and our nations.

What we need are mental models that help us think about complex problems in ways that point us toward choices that will benefit ourselves, our families, our communities, and our nations.

The “fact” model of climate change doesn’t do this.  It invites us either to stop asking questions (the President’s apparent intent) or, if we want to ask questions, to continue the argument about what is or is not a fact.  If we choose to argue about facts, we will be tempted to adopt a familiar model for determining truth—the one from criminal law, in which the defendant is innocent until proven guilty beyond a reasonable doubt.  This way of thinking is favored by those who oppose action on climate change because it suggests that nothing should be done to change our patterns of fossil fuel consumption until we have near-absolute proof of their “guilt.”

Criminal law provides an unhelpful mental model for thinking about climate change because we are dealing with a mixture of facts, probabilities, and uncertainties; because decisions need not be final; and because there are more than two possible courses of action.  A more helpful model for this kind of situation can be taken from medicine.  Imagine scientists as doctors and yourself as a guardian of the planet, which is the patient.  A panel of doctors has diagnosed the planet with a serious, progressive disease (anthropogenic climate change). The symptoms are not obvious, just as they are not with diabetes, hypertension, or some forms of cancer, but the disease may be just as serious. You have to decide what to do, or to ask your government to do.

In this situation, you should have a lot of questions.  You will want to ask how certain the doctors are of the diagnosis, the likely course of the disease if left untreated, and about the treatment options and their possible side effects. You may want to seek out second opinions, in case the medical team is missing something or has some kind of bias.  This way of thinking is helpful because it prompts us ask the right kinds of questions, think through the consequences of various courses of action and inaction, and consider ways to adapt our actions over time as we learn more.


DIAGNOSIS. Physicians 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, and they know the causes: fossil fuel consumption, certain land cover changes, and a few other physical processes that humanity has helped set in motion, mainly over the past century. 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, though it has its ups and downs, 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. It could be catastrophic, but we cannot assign a firm probability to the worst outcomes, and we are not even sure what the worst outcomes will look like. We want to avoid either seriously underestimating or overestimating the seriousness of the prognosis.  One reason scientists work hard on climate models and debate about them is to improve prognostic skill.

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—things like raising sea walls and improving preparedness for forest fires—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 ore painful it will be, and the worse the prognosis. We may choose an iterative treatment strategy, starting some treatments and monitoring their benefits 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 get people to talk more about choosing a course of action and less about whether climate change is proven fact.

SECOND OPINIONS. We all know that there are scientists who aren’t convinced that climate change is happening or that the causes are human in origin. What should one make of their opinions?  It is always hard to evaluate the technical arguments of specialist communities when we don’t have that expertise.  There are useful ways to assess these arguments from the outside—looking at the scientists’ reputations, their sources of financial support, how they deal with disagreements, and so on.  In my view, these considerations strongly favor believing mainstream climate science over its detractors.  But even without making such assessments, it is worth looking closely at what the detractors claim.  For the most part, the argument is that of the defense attorney:  that guilt has not been proved beyond reasonable doubt.  Even if you believe that, it does not justify doing nothing to keep this defendant in check.

Paul C. Stern

Paul in Iceland cropped

Paul C. Stern is a senior scholar with the Board on Environmental Change and Society (formerly the Committee on the Human Dimensions of Global Change, which he directed from its inception in 1989) at the U.S. National Research Council/National Academy of Sciences. His research interests include the determinants of environmentally significant behavior, particularly at the individual level; participatory processes for informing environmental decision making; processes for informing environmental decisions; and the governance of environmental resources and risks. He is a fellow of the American Association for the Advancement of Science and the American Psychological Association. He holds a B.A. from Amherst College and an M.A. and Ph.D. from Clark University, all in psychology.

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Photo credit: NASA Goddard Space and Flight Center 

Paul C. Stern first wrote about a medical metaphor for Climate Change on the NY Times Dot Earth Blog.


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3 replies
  1. Miner49er
    Miner49er says:

    Here’s how to think about anthropogenic climate change. It is a hideous lie. Human use of fossil fuels and carbon dioxide have no material effect on climate. Carbon dioxide is in nearly perfect balance in nature’s ecosystem.

    CO2 is a benign, colorless, odorless gas that is necessary for life–not a pollutant. Nature quickly recycles all natural and human CO2 emissions into carbonate rock, where it remains trapped for tens of millions of years. It does it better than humans could, and for free. That means we can use all the fossil fuels we want, without affecting climate.

    Coal power is reliable, affordable, scalable and clean. Natural gas is too valuable to use for power generation, and numerous value-added users will soon price it out of power generators’ reach. Nuclear power is too costly & dangerous, and cannot make it without subsidies. Renewables will collapse after subsidies are withdrawn because of “green fatigue”. Like it or not, coal will be the only remaining viable option, and that’s good for everybody.

  2. Bob Perkowitz
    Bob Perkowitz says:

    There’s a lot of good in this piece, but the concept of discrediting facts and reality as useful tools in talking about climate change is profoundly misguided.

    Real Americans know that science is fungible. Every time they read about science of anything, it’s refuting other science. Are mammograms dangerous or will they save your life? Opposing sides have opposing scientists. Next year or next decade, the science will be different. If there is scientific consensus, why would we have to always argue this point?

    The only things that are real are ‘facts’ – things that you can see with your own eyes. Seasonal, weather patterns are changing, temperatures are rising, farmlands are drying up…

    Saying that “… saying that climate change is a “fact” is a disservice to the public because it invites people to think about the issue in a misleading and unproductive way.” is an out of touch with reality comment. Thankfully Obama and his team think otherwise.

  3. Kent Pitman
    Kent Pitman says:

    It might be nice if society had been brought up to think this way, but changing the way society thinks would take longer than we have before utter environmental catastrophe–assuming we are not already within that and just not yet seeing its worst effects, which many of us think is so.

    The politics of the matter preys on people who have very little experience with any of these models. All they hear is “fact” or “opinion”. Answering “opinion” is to render the entire subject something on which they are experts because they know they themselves can have opinions. At that point, the denialists are laughing their way to political success because as long as it’s a war of opinion, nothing will move forward.

    A critical quality of a leader is “decisiveness”. This should not be confused with either authoritarianism or any kind of denial that the world exists in probabilities. Rather, like the leap of faith that triages the wave height of an analog signal into the essential ones and zeros of a digital world, it transforms a world of metaphorical analog “we have not decided” into a metaphorical digital world of “we will behave as if this is decided”.

    It is a leader’s job to take the messy world of probability and get you out of it. It is the leader’s job to tell you that something is fact even sometimes when he knows it’s not, taking the risk onto himself of being wrong. It’s the leader’s job to say that something can be done, because wars are not won nor monuments built by yelling “this might be possible, then again it might not”. To say that he may not be definitive is more than to state the obvious, it’s to further discount a discounting that is already expected, and really to undermine the ability of the leader to lead.

    You might wish leaders inspired and led differently, but that’s a much bigger problem. You can’t solve it by changing the paradigm only for Climate without making people think there is something fishy about Climate that is different than all other things. The only thing different about Climate is that those who are professionals doing serious research are quite consistently saying there is no debate here.

    In fact, I think Obama makes many errors about Climate including his support of natural gas (and implicitly fracking) and his failure to screen out Keystone. I’m not at all an Obama apologist. If anything, he too little understands the severity and urgent timeline of the problem, he doesn’t overstate it. But I think he was right to say that Climate is a fact. Language is rarely perfectly precise, but that use of that word in that context was quite defensible.

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