2010-09-10 11:18:25blog post on skeptic contradictions (revision 1)
Dana Nuccitelli


I'm writing a blog post on skeptic contradictions and would appreciate some feedback.  John started it to explain the skeptic contradictions database, and I borrowed the bit about WUWT from him.  John in particular, since it pertains to the launch of the contradictions database, let me know if you want to change anything.


A major challenge in conversing with anthropogenic global warming (AGW) skeptics is that they constantly seem to move the goalposts and change their arguments.  As a consequence, they also frequently contradict themselves.  One day they'll argue the current global warming is caused by the Sun, the next that it's "natural cycles", the next that the planet is actually cooling, and the next day they'll say the surface temperature record is unreliable, so we don't even know what the global temperature is.  This is why Skeptical Science has such a massive skeptic argument list.

It should be obvious that the arguments listed above all contradict eachother, yet they're often made by the same skeptics.  As one prominent example, in 2003 physicist and skeptic Fred Singer was arguing that the planet wasn't warming, yet in 2007 he published a book arguing that the planet is warming due to a 1,500-year natural cycle.  You can't have it both ways!

It's a testament to the robustness of the AGW theory that skeptics can't seem to decide what their objection to it is.  If there were a flaw in the theory, then every skeptic would pounce on it and make a consistent argument, rather than the current philosophy which seems to be "throw everything at the wall and see what sticks."

It would behoove AGW skeptics to decide exactly what their objection to the scientific theory is, because then it would be easier to engage in a serious discussion, rather than the current situation where we're basically playing whack-a-mole with the favored skeptic argument of the day, which totally contradicts the favored skeptic argument from yesterday.

Just as one example, you can't argue that the Sun is causing global warming and that climate sensitivity is low.   Solar output has only increased by about 0.1% over the past several hundred years, and the way you determine the associated global temperature change is to multiply the change in solar radiative forcing by the climate sensitivity factor.  So they only way you could argue for a significant solar warming would be if climate sensitivity is high.  You just can't have it both ways - if climate sensitivity is low, it's not just low with respect to greenhouse gases, it's also low to solar activity, orbital variations, volcanic emissions, etc.  And if it's low, then the Sun has caused less than 0.1°C of the 0.8°C warming over the past century.  Similarly, arguing for a low climate sensitivity contradicts the climate has changed before argument for the same reason.  If climate sensitivity is low, it will prevent significant climate changes regardless of the cause, whether they be anthropogenic or solar or some other natural forcing.

If you want to argue that the warming is due to a natural cycle, then pick a specific natural cycle and research it.  Make sure there's a scientific basis to your argument.  For example, don't argue that it's due to a 1,500-year cycle when the planet wasn't warming 1,500 years ago!  But most importantly, don't contradict yourself by claiming that the planet isn't warming the next day.  These kinds of flip-flops are common on Anthony Watts' blog, which had a very schizophrenic six month period:

And that's when he's not arguing that the surface temperature record is so contaminated that we don't even know if the planet is warming.  Or that this same data shows cooling.

Until skeptics start making some consistent arguments, Skeptical Science has set up a page listing all the skeptic arguments that contradict each other in order to make the mole whacking a little easier.

2010-09-10 11:47:55It's impossible for deniers to avoid contradicting themselves


because they would need to have a self-consistent model of the Earth and its atmosphere, compatible with what we know about physics.

They don't.

2010-09-10 13:37:37Another contradiction
James Wight

It’s also pretty inconsistent of contrarians to complain that we don’t understand the Earth’s climate well enough to draw any conclusions, but a few scattered observations of other planets mean the whole solar system must be warming up. We’ve been observing the Earth’s climate for over a century, and are able to study past climates on a number of timescales. If we don’t know peanuts about the Earth’s climate, then we know a microscopic amount about Mars’ and nothing about Pluto’s.
2010-09-10 14:30:34agreed
Dana Nuccitelli
True, very true.  However, we can't fit every contradiction into one blog post.  You should check out the contradiction database - it's huge already.  So I just chose a few common ones.
2010-09-10 17:23:31Prediction of a skeptic comment to this blog post
John Cook


Dana, your logic is correct but I expect you will get a skeptic commenting that climate could be highly sensitive to solar changes via cosmic rays - if cosmic rays do affect cloud cover, this will amplify the solar signal independently of positive feedbacks. Eg - cosmic rays are an amplifier of solar changes but not of CO2 warming. There is little evidence that cosmic rays do affect cloud cover as you well know, having posted about it extensively recently. Nevertheless, that's one argument that I've had to face in my travels.

To me, the most blatant skeptic contradiction is the arguments that "climate sensitivity is low" and "climate's changed before" (an argument for high climate sensitivity). However, when I try to explain that dramatic climate change in the past is evidence of high climate sensitivity, I get a lot of blank stares (have vivid memories of a long pregnant silence after explaining this point to a roomful of engineers). So it's not an easy subject to explain (at least I've found it so).

When you're happy with the blog post, can you go to Author Admin and add the blog post directly into the database. Then let me know and i'll go live with it.

2010-09-10 18:30:59Climate sensitivity paradox



You mention that you've earned blank stares when trying to demonstrate the contradiction between the "low sensitivity" claim and the "climate has changed before" claim.

Maybe this is an issue of phrasing: When I read the write-ups on these two topics, both of them basically argue that the climate sensitivity is about 3, I don't see a direct contradiction between the two rebutted arguments coming up to the surface. Perhaps another way of positioning this: Explain that the "low sensitivity" claim depends on believing that the climate-sensitivity measure is < some value X; and that the "climate has changed before" depends on believing that this measure is > X.

Just a thought.




2010-09-10 21:32:11


Nice.  I have just one quibble -- this is a sentence fragment:  "Like on Anthony Watts' blog, which had a very schizophrenic 6 month period:"

Perhaps revise that to something like "These kinds of flip-flops are common on Anthony Watts' blog, which had a very schizophrenic six month period:"


On second thought, I have a few other words of caution.  First, people will claim that (aside from the Fred Singer situation) the contradictory claims are coming from different people and we can't force all skeptics to agree on a single critique.  Of course most pseudo-skeptics will happily seize on any argument that helps their side, but it's hard to prove this without spending a lot of time tracking down what people have said over time.

Second, and here I'm acting as a bit of a Devil's advocate, is there really anything wrong with a person offering contradictory alternatives?  Let's say you're a chemistry professor and one of your grad students comes to you with some results that seem to contradict some fundamental aspect of basic physical chemistry.  You know their results are probably wrong, but you don't know exactly why.  So you suggest that maybe they used the wrong materials, or they measured something incorrectly, or they failed to maintain the proper temperature or pressure, or they recorded the data incorrectly, or they forgot to add the catalyst, or ... whatever.  Obviously, all of these explanations are contradictory, but that's OK because what you're really doing is proposing a range of alternatives that need to be considered rather than proposing a single coherent argument of your own

In essence, the burden of "coherence" is on those who are actively supporting a specific theory, e.g. the mainstream view of anthropogenic climate change.  Our theory only works if CO2 really is a greenhouse gas and we really are increasing the CO2 concentration in the atmosphere and the assortment of positive feedbacks is strong enough to yield a climate sensitivity > 1 C or whatever and the economic/environmental impacts of climate change are negative enough to worry about. 

The skeptics' advantage is that they "win" if they can break any one of the links in that chain.  Our advantage is that it's a very strong chain; the first two links are rock-solid, the third is at least close to rock-solid, and the fourth is pretty convincing to me but probably the source of greatest uncertainty.


2010-09-11 02:04:11responses
Dana Nuccitelli

John - true, this may illicit comments about GCR or other theorized solar effect amplifications, but then again that's why I've got the link to the "it's the Sun" rebuttal, which covers those bases.  I'll probably add a few more examples, like your "climate has changed before" contradiction.

neal - the contradiction is that if you're arguing the climate has changed signifncantly before, you can't also argue that climate sensitivity is low, because a low climate sensitivity prohibits significant climate changes regardless of the cause, whether it be natural or anthropogenic.

Ned - I'll fix that sentence fragment, good suggestion.  You're right about the links in the chain.  However, if you're arguing "it's the Sun", for example, you're not disputing that CO2 is a greenhouse gas or the physics of AGW, you're simply proposing an alternative theory.  And that alternative theory doesn't work if you also argue that climate sensitivity is low, for example.

2010-09-11 02:29:14all set
Dana Nuccitelli
I'm happy with it, but feel free to change the blog post however you see fit before publishing, John.
2010-09-11 08:59:00


John, Neal and Ned bring up good points but all the same this is a handy primer, thought-provoking and a useful stimulant for critical thinking. I'll monotonously suggest again, no skeptic is going to be swayed by any attempt at correction while "normal" people will see the point of this.

One difference between the hypothetical chemistry professor and a climate skeptic is the typical skeptic's tendency to passionately defend all countervailing ideas even when these ideas are incompatible. We have several examples of such folks doggedly hanging on at SkS.  


2010-09-11 11:31:40



My point is that contradictions are better understood when they are spelled out explicitly, rather than left to be understood implicitly.