This is a guest post by Dave123.

What distinguishes proper skepticism from fatuous doubt? In some part comes down to who is expressing the sentiment. That is, who the person is determines if they are a legitimate skeptic or someone borrowing the title to disguise dismissive rhetoric. I don’t have sufficient training in the necessary physics and math to be a legitimate skeptic about the Higgs boson, the theory behind it or the experimental proof of its existence. I’m never going to have that level of understanding either. So I don’t opine about it. I’m entertained by it, but that’s as far as my engagement with the matter can go.

Too much of what we see called skepticism about climate science is expressed by people who are as unqualified to discuss the matter as I am to discuss the Higgs Boson.

Of course I strongly believe that nearly anyone can study up and learn, and I in no way want to discourage people from doing this. One of the remarks Professor Kemp would make to undergraduate classes in Organic Chemistry at MIT (and I paraphrase), was ‘that this was school, but in real life you have as much time as you need to master a subject’. In my case that still doesn’t mean I’ll learn the Tensor math needed for advanced physics. But in general, with motivation and sufficient time, you can learn nearly anything. That’s why the sites of the Good Guys, like Tamino, Skeptical Science, RealClimate, Science of Doom, and HotWhopper are so important for those of us who continue to study.

For example, having paid handsomely for some post-post graduate on molecular biology that didn’t exist when I was in graduate school in Chemistry, I can read the papers on the HIV/AIDS connection and feel confident in saying that Peter Duesberg went off his rocker in challenging HIV as the cause for AIDS. I know enough about the methods, the cross-checks, etc., to see that the work is well done and trace the consistency across dozens of publications. The anti-HIV ‘skeptics’ can’t do that.

Speaking from my personal authority, having a doctorate in chemistry, having done modeling etc., I can go through a list of propositions that conventional anthropogenic global warming (AGW) theory passes falsifiability tests for starting with my personal performance of infrared spectroscopy, to personally measuring CO 2 , doing isotope measurements, measuring a black body temperature and spectrum in physics lab, and so forth. I cannot replicate and confirm every step, but there are no steps that I can confirm and that do not fit with my training and professional experience.

The overwhelming majority of people claiming to be skeptics about AGW are nowhere close to this level of understanding, much less the understanding of a Hansen, Pierrehumbert, etc. To be blunt, without even a qualitative background they have no standing to be skeptics. They have an incorrect belief, and it is a faith-based thing. They are or course entitled to an opinion and to express it. Protected by law this might be, it however doesn’t make it moral or ethical considering the consequences of AGW.

Now, that’s just the qualitative side. The quantitative side of this isn’t expressed in terms of the language of “skepticism”or “doubt”, but “uncertainty”, and I do not mean Professor Curry’s uncertainty monster either.

Now, the only place I’ve ever seen rhetoric about knowing enough so we can shut up shop and just concentrate on implementing solutions is from hard-core climate science deniers who think they are scoring some kind rhetorical points by making all levels of uncertainty the same. This only fools people (including themselves) who don’t have the background to form opinions on it in the first place.

We can know as a qualitative and paleoclimate supported proposition that continued warming will eventually melt large sections of Greenland and Antarctic Ice sheets. We don’t know enough about ice sheet dynamics to assert that a catastrophic breakup can’t occur, or that accelerated sea level rise beyond current models is out of the question. Every few weeks brings a new paper showing increased cause for concern that things could be worse than what we’ve thought. I’m seeing little to nothing that says the opposite. No shutting up shop here.

If half of the Western Antarctica ice sheet were to slip into the ocean over 10 years that would be a pretty impressive event… and if we had 5 years warning that it was going to happen, that would be 5 years more to cope with what we can’t stop. And none of this is about “skepticism”. It’s about having identified gaps in knowledge, and the creative and imaginative parts of the engine of science being engaged.

I could list other points about climate models: for example we could be able to forecast perfectly the temperature for the next 100 years, and the models still not be able to cope with comparing the effectiveness and/or unanticipated consequences of geoengineering. No shutting up shop here, and again nothing about being skeptical about the dominant knowledge and findings of the global science community about AGW.

Which brings me to my next point: while I’ve done enough modeling to know that models can do great things (sure did for my bank account and my employer’s bottom line). I don’t know enough of fluid mechanics or any number of other components of global circulation models (GCMs) to go in and figure out whether there’s a bug in the code. Or more importantly, a flaw in the reasoning that is translated into the equations, the way I could with my models and simulations. But in this case I think I have a substitute for that kind of investigation that is generally useful, which is the consilience of the model results over the long-term.

What is important here is that there is not a single example of a model that can correctly hindcast and yet offers a pain-free future. None. This isn’t because of a lack of trying as Shell and other oil companies have funding climate modeling for decades at MIT and other institutions. Is there uncertainty about the rate of warming? Sure. But does the area of uncertainty cover any territory that justifies inaction? No. In the April 14th issue of Scientific American, Professor Mann makes that point showing that even the lowest values of earth system sensitivity (ECS) and business as usual CO 2 emissions lead to trouble early.

But unless you’re competent to assess a GCM, you have no standing to have an informed opinion about the varying rates of warming calculated by different models. You must either use my substitute for that competence, devise your own or stand mute. This isn’t something you can finesse with rhetoric.

So to add another difference between a true skeptic and a pseudoskeptic, the true skeptic knows the limits of their own knowledge and competence. The dismissives and climate science deniers think they can somehow find a way around their own lack of knowledge on science subjects and math and come up with a valid answer. They’re wrong, but that doesn’t stop them from expressing this false entitlement at every opportunity.

That leaves one question: do we, the legitimate skeptics, let that go unchallenged and let them bastardize what skepticism is? Of course not.

Dave123 earned a Doctorate in Chemistry from MIT in the distant past. He has worked in the chemical industry ever since in the roles of bench scientist, manager, consultant and entrepreneur in most major sectors. His research has rubbed up against many of the fundamentals of climate science and technology. The development he has led has saved millions of gallons of gasoline equivalents. He believes that after earning a doctorate it is a professional obligation to explicate the science to non-scientist audiences at any opportunity.