Posted by: bmeverett | August 25, 2011

The Climate Change Switcheroo

I have been working on the climate change issue for well over ten years now, and I have had hundreds of conversations with climate change advocates (“Climatistas”). What strikes me about these conversations is their tendency to present a moving target for argument. As soon as Climatistas start to lose the argument, they quickly switch to a new issue. Here, in brief, is the way these conversations tend to go:

Climatista: How can anyone be a global warming skeptic when the evidence is all around us? Melting ice, increasing storm frequency, struggling polar bears and more frequent heat waves are simply undeniable.

Me: Perhaps, but the Climate Change Hypothesis (CCH) is not that the Earth is warming, which it probably is. The CCH claims that the warming is predominantly man-made and that warming will accelerate in the coming years with catastrophic results. We can’t tell yet if the observed warming is outside the natural range of variation.

(Note: A few years ago, most Climatistas would respond that the historical record shows the clear “hockey stick” phenomenon demonstrating that the warming is faster than anything in the historical record. After the embarrassing Climategate email scandal, however, I don’t hear this one so much anymore.)


Climatista: The science showing the relationship between increasing atmospheric carbon and warming is definitive. Carbon enhances the greenhouse effect and traps heat. There is no scientific debate on this point.

Me: Not true. The heat trapping properties of carbon are indeed well understood, but projected increases in atmospheric carbon would cause only a modest increase in global temperatures of less than 1° C over the next 100 years, similar to what we have experienced over the last century, and not the scary scenarios of 1.5 to 4.5° C predicted by the models. The difference stems from highly uncertain assumptions about non-carbon factors, such as cloud formation. Climate models tend to assume that all non-carbon factors enhance rather than mitigate the greenhouse effect. This might be true, but the point is at least arguable. There are valid theoretical and empirical reasons to believe that the climate system may counteract rather than amplify the warming effects of atmospheric carbon.


Climatista: There will always be some level of uncertainty in the science, but all reputable scientists support the CCH, and we need to rely on their expertise. You, Mr. Everett, are not a scientist and shouldn’t argue with people who are trained in these highly technical fields.

Me: First of all, science works through empirical research, not consensus. A few hundred years ago, there was a consensus that the Earth was the center of the universe. Furthermore, there are large numbers of scientists who disagree with at least part of the CCH. You are defining “reputable” as “agreeing with the CCH”. That’s a tautology equivalent to saying “Everyone who agrees with me agrees with me.”


Climatista: Maybe so, but the real point is that we can’t take this chance. Mankind should not be experimenting with the only planet we have. Whether or not you agree with the science, the consequences are potentially catastrophic and therefore justify taking whatever actions are necessary, even if the probability of disaster is low.

Me: Insurance is inherently a cost-benefit analysis. Everyone takes reasonable precautions against catastrophe. We don’t spend our lives hiding in our basements because there is a finite probability of dying in an automobile accident. Some risks just can’t be mitigated at acceptable cost. The costs of decarbonizing the economy would be so high that it would require government coercion on a scale unprecedented outside of totalitarian countries. Low-carbon technologies are so expensive that forcing them into the market would cause severe and prolonged recessions – or worse. Even if all the western countries were to achieve large reductions in carbon emissions, most of the projected growth is in developing countries, particularly China.


Climatista: Actually, that’s not true. Many studies, including work by the consulting firm McKinsey, have demonstrated clearly that carbon reductions can be obtained at modest cost with very minor economic impact.

Me: Those studies achieve those results by using unreasonably low costs of capital and discount rates. McKinsey, for example, assumes that all capital can be financed through US federal government borrowing at 4% or less. As we have seen clearly in recent days, the borrowing power of the federal government is in fact quite limited. Private investors generally have costs of capital of 12-15%. Extremely risky, high-tech investments financed by venture capitalists often have costs of capital of 20% or higher. If you rerun the McKinsey numbers with realistic capital costs, most of the carbon mitigation steps become prohibitively expensive. Furthermore, when looking at the cost of decarbonization, you must bear in mind that the costs are real and up-front, while the benefits are highly uncertain and far into the future. On a net present value basis, most of these low carbon technologies make no sense.


Climatista: That’s because your economics are wrong. Net present value is the wrong concept to apply to potentially catastrophic events. People should be taught that a $100 initial investment which pays a return $6 a year for 20 years provides them savings of $20. If you use the so-called “net present value” approach, that investment would appear to be a loss.

Me: Net present value reflects the way people actually behave. It’s not an invention of economists. There’s an old joke about the guy who receives a phone call offering both good and bad news. The good news is that he has won the Million Dollar Lottery. The bad news is that the payout is a dollar a year for a million years. This is (at least somewhat) funny because everyone knows that a dollar a year forever is not as valuable as a million dollars in your hand today. What you are in fact saying is that you don’t like the measuring stick because it’s giving you the wrong answer. Instead, you want to design a measuring device that gives you the answer you want. That’s not logical.

Generally, the conversation fades away at this point without any resolution. I have noticed, however, a new switch by some of the more extreme Climatistas to go one more round as follows.


Climatista: You might not consider that logical, but that’s because the basis of your logic is wrong. In fact, the emphasis of the Enlightenment on logic was wrong, and humans would be much better off if we responded to threats viscerally and instinctively rather than wasting too much time analyzing pros and cons.

Me: You’ve got to be kidding.

If you doubt that anyone would actually make that last argument, please check out the article “Ethics and the Economist: What Climate Change Demands of Us” by Prof. Julie Nelson of the University of Massachusetts – Boston, published by the Global Development and Environment Institute at my own beloved Tufts University. You can find this utterly bizarre argument at

Climate change conversations are difficult because Climatistas tend to skirmish and then retreat rather than stand firm and argue any of these points to a conclusion. I disagree completely with Rush Limbaugh when he claims that climate change is a hoax. It’s a hypothesis, and it should be taken seriously. Its supporters, however, will never convince a properly skeptical public of the validity of their arguments if they won’t hold still long enough to have a serious conversation.



  1. I would love to answer to your “arguments” (since I myself am a “Climatista” – it is interesting to hear ever new names people call those who find some sense in climate science), but someone else did it better than I could. For all reading Mr Everett’s blog – read the response and get a picture yourself.

  2. […] to rely on expert’s opinion here). However, I just read a powerful and informed response to Bruce Everett’s post about whom he calls “climatistas” – written by an economist, Frank Ackerman, but […]

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