Uncertainty About Climate Change (Part II)

Posted by Don Fullerton on Jul 30, 2010

Filed Under (Environmental Policy, U.S. Fiscal Policy)

In my last blog, I pointed out the inherent nature of uncertainties in climate projections, and the long list of reasons for particular uncertainties about the effects of anthropogenic greenhouse gas emissions on the change in future temperature levels, droughts, severe storms, sea level rise, and about measures of economic damages from any such event.  The range of possible outcomes is enormous, but I argued that the uncertainties are not a reason to wait and do more research before enacting legislation to reduce those emissions.  Indeed, the huge range of probability outcomes is a big reason to act now to reduce the possibility of such costly events.

In this blog, I want to expand that point to talk about the various kinds of uncertainties and what to do about them.  I just read an interesting blog by Keith Kloor that lists five kinds of reactions to uncertainty.  I will describe HIS five points, but what they bring to mind for me are the FIVE STAGES OF GRIEF (when a loved one dies, for example).  I’m sure you’ve heard these before:






Well, those approximately label his five reactions to uncertainty about climate change.  First, one could DENY the uncertainty, which might be done to try to further some political agenda.  Those who want environmental protection might say we KNOW that anthropogenic greenhouse gas emissions will cause significant global warming, and therefore we must act to prevent it.  That’s just wrong; we don’t KNOW that global warming will be significant and highly costly.

In fact, “uncertainty deniers” have done a great disservice to their own cause.  The claim that global warming is certain just gives the other side the opportunity to point out correctly that it’s NOT certain!  But that whole argument is irrelevant!  The relevant problem is that global warming MIGHT be significant and highly costly!

Second, one could react by trying to REDUCE the uncertainty, such as through herculean research efforts to make better predictions.  Research might well be worthwhile, and it might help reduce some of the uncertainties, but it will not reduce all of them, and it might introduce new uncertainties that we’ve not yet considered!

Third, one could try to SIMPLIFY the uncertainties, such as to explain in simple terms the complex scientific reasons for the inherent uncertainties listed in my previous blog.  It’s not wrong to try to explain complex uncertainties, and even to fit them into a finite set of categories, but the danger is that such simplification be taken as a replacement for consideration of all the complexities.   The problem is that simplification may in effect minimize those uncertainties.  Anyway, this kind of reaction is somewhat like bargaining: “maybe if we make up simple categories for these complex uncertainties then they might not seem so daunting.”

Actually, Kloor’s fourth reaction sounds even more like bargaining, when he says “Uncertainty detectives – well all scientists should work hard to understand, represent, and reason about uncertainty (. . .). The conflict is when political opponents seize on this uncertainty as an excuse for inaction.”  Now that is a cause for depression!

Anyway, of course, the fifth and final reaction to uncertainty is ACCEPTANCE: “include uncertainty information in rational decision support systems and policies.”  We need to know what is known, and what is unknown, to be able to make rational decisions as a society to adopt policies that can insure us against the worst possible outcomes.  We at least need to make the right tradeoffs between the costs of that insurance and the benefits of reducing those risks.  We need to undertake any available low cost measures to reduce fossil-fuel-fired electricity generation, to increase energy efficiency of vehicles and appliances, to increase alternative fuel use, to build water storage that can help deal with a possible increase in the number of droughts, and to build levees that can help deal with a possible increase in the number of severe storms.

Accepting the fact of uncertainty means giving up the idea of building in those protections because we know things will get worse.  Instead, it means building in those protections because things might get worse, and they might get a lot worse.