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Double Standard on Internal Variability

Posted on 25 October 2013 by John Hartz

The following article is reprinted by permission of its author, Tamino, who originally published it on his blog, Open Mind, on Sept 21, 2013. Click here to access Tamino's original post. 

Masthead Graphic of Tamino's Open Mind Blog

Since 1975, global average surface air temperature has increased at a rate of 0.17 deg.C/decade (estimated by linear regression using either the NASA GISS or HadCRUT4 data sets). But the rate of increase hasn’t been perfectly constant over that entire time span.

As a matter of fact, there’s a 15-year time span during which the rate is notably different. Fifteen whole years!!! By at least one calculation, the difference is “statistically significant.”

Does this mean that global warming is wrong? That the computer models are utter junk? That this whole climate science thing is just a hoax, a nefarious scheme to cheat us all out of tax dollars in order to support the lifestyle of gaudy luxury that we all know scientists wallow in? (Science: money for nothin’ and your chicks for free…)

That 15-year time span covers the years 1992 through 2006, during which the rate of warming was 0.28 deg.C/decade. That’s a lot faster than the warming rate from 1975 to now.


Just a few years ago, when Rahmstorf et al. (2007) compared climate observations to computer model projections, they noticed the faster-than-expected warming leading up to 2006. It was faster than expected and faster than projected by those dreaded “computer models” used by the IPCC. According to the data, global average surface temperature was on a “mad dash” to extreme heat.

How did these evil denizens of global warming react? Did they use that result to push world government based on socialism, so that they could destroy our economy by taxing the super-rich out of some of their hardly-earned riches? Did they run screaming through the streets yelling about how we’re all going to suffer spontaneous combustion by the year 2100?

No. Instead, they attempted to understand the result.

And what explanation, some bunnies may wonder, crossed their minds first? What was their first instinct regarding how this mad dash of global warming might have come about? This:

The first candidate reason is intrinsic variability within the climate system.

Wow. When the data indicated surface warming faster than expected, the first explanation offered by those greedy bastards was natural variation.

You missed your chance, guys. How ya gonna rob the super-rich of all their billions with that?

Since that time, when they failed miserably to capitalize on the opportunity for alarmism, there’s been another 15-year time span when the trend differed noticeably from the trend-since-1975. It covers the years from 1998 through 2012:


The evil cabal of climate scientists are somehow trying to explain this away as simply being “natural variation.”

But the poor, downtrodden “skeptics” are on to them. They know the truth. You see, that extra-fast warming period really was just natural variation, but the extra-slow period is all because the computer models are junk, the whole climate science thing is just a hoax (gaudy luxury for scientists to wallow in), and we’re headed for decades of imminent global cooling.

After all, isn’t that what Curry would say? Didn’t she already say that “natural variability” was responsible for more than half of the global warming since the 1970s — but isn’t she now pushing as hard as she can that “the pause” is proof that we don’t really understand what man-made tampering is doing to our climate? Hey — it’s all just a “regime shift” anyway.

Isn’t that what Watts would say? Maybe not — maybe he wouldn’t blame the extra-fast warming on natural variability at all, he’d just claim that the temperature record isn’t reliable. If it shows extra-fast warming, that is — when the temperature record shows extra-slow warming it’s scientific proof.

It’s kinda like the changes in Arctic sea ice. When it takes a nose-dive like in 2007 and again in 2012, that gets blamed on “weather.” But when it makes an up-tick like 2013 — recovery!!!

I think I finally understand the contrarian approach to science. When data says we have a problem, either it’s just “natural variability,” or the data are either faulty or fraudulent. But whenever data says we don’t have a problem — even if it’s just a single year’s data — voila! Scientific proof.

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Comments 1 to 15:

  1. The "Denial Ratchet" - natural variability only moves in one direction?

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  2. Those attempting to discredit the science are justifiably fearful.

    Science is inexorably increasing the understanding of the unacceptability of the way they want to pursue profit, pleasure, comfort and convenience. Climate impacts are a significant issue, but tere are so many others just like it.

    Democracy where everybody, even the most inconsiderate and intolerant, get a vote, is their last hope. They will do their best to delay the eventually loss of popularity as better understanding develops. They are deliberately attempting to damage the future, but there are few laws against deliberately misrepresenting information (yet). Maybe that will need to be developed. Maybe we need international laws to penalize anyone "who should know better about matters of unacceptable human pursuits of profit, pleasure, comfort and convenience, yet deliberately tries to claim otherwise, or deliberately tries to keep awarenes and fuller understanding from growing".

    The global realization that we are on this one shared planet with a possible future of a few billion years is a "relatively new idea" that cannot be ignored forever. The added realization that the only truly sustainable human activity is activity that does not consume non-renewable resources, and sustainable consumes the renewable resources, means much of the recently developed human activity must end, the sooner the better.

    There will always be some among us who do not care about the future. For the sake of the future every population around our shared world needs to be spotting these kind of people and keeping them from succeeding (in their pursuits that cannot be continued and will ruin the future).

    The battle is more than just the climate. It includes the way consumer products are unsustainably made in unacceptable conditions. It also includes the unacceptable ways that quicker profit from farming is pursued unsustainably.

    As a global collective, the pursuit of short-term gain by any among us has only ever created pain and suffering (always realized too late). The continued efforts to most clearly and completely present the information and understanding about the vast array of unacceptable human activities will ultimately grow awareness, to the detriment of thsoe who do not want the general population to "better understand things".

    Keep up the "Good Work".

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  3. Willard Tony is Anthony Watts?

    Aunt Judy Judith Curry from Climate etc?

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  4. I have come to the conclusion that arguing with deniers is like reasoning with two year olds. It is an utter waste of time! All we can do is to repeatedly put up the evidence in a form that the layman can understand. It will not be long before the evidence becomes self evident. This has already started. Flooded subways in New York and bushfires in the middle of spring in Sydney are two tiny examples of many more. These purely 'natural' events should get the locals thinking! How many more 'natural ' events do we put up with before we hit irreversible tipping points? Bert

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  5. I agree with Bert. When "debating" (a bit risable) in a public forum the purpose is that perhaps other bods who are impartial but interested will browse through there and hopefully find my arguments more convincing, it is never to "change the mind" of whoever you are (ahem) "debating" with in a public forum. But it might be different with you more highbrow types,  perhaps you were debating without the quotes with Prof. Muller a few years back.

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  6. Fwiw, and if anyone is interested, "Tony" answers Tamino with more graphs and actually takes the high road (comparitively). Good read if you are actually interested in the science and not the stone throwing. 

    Link not needed, those with interest will know where to look.

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  7. hank_ @6, you and I will have to disagree about what constitutes a "Good read if you ar actually interested in the science".  Essentially Tisdale's argument comes down to the claim that 1990 was not "especially hot" because it was in the upper 27th percentile of temperature residuals rather than in the upper who knows what percentile, for he never says what percentile he would consider "especially hot".  So, he is quibbling about words and trying to hide the fact behind a barrage of graphs, mostly irrelevant.   It may be good science by Tisdale's standards, but it is not good science.  Indeed, from my point of view it is not science at all, just "sciency talk".

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  8. The "high road"? ROFL. Tisdale's word salad is a perfect fit for the venue where it is published, nothing more...

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  9. Well after picking myself off the floor, perhaps the way to discuss this constructively would be you, hank, what it was that impressed you about the piece and what made you think that it discussed actual science. 

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  10. Note that 1990 was the hottest year on record at the time.  The only reason it's now "not especially hot" is because of the global warming that's occurred over the subsequent 2 decades.

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  11. And this is the problem... there is a segment of the population for whom complete nonsense is automatically held to be 'good science' if it states what they want to believe. There are still many people who think, 'McIntyre proved that PCA always produces a hockey stick shape'.

    Similarly, people otherwise capable of basic reasoning somehow lose the ability to understand the simplest concepts of statistical analysis (e.g. 15 year trends in lower atmospheric warming a few years apart give radically different results, ergo these trends are obviously too short to be indicative of the long term impact) when there is any 'refutation' at all... no matter how meaningless.

    Too much credit is given to the few skeptics capable of performing actual scientific analysis... because none of their science supports the nonsense they spread. The fact that Pielke senior, Curry, Lindzen, Christy, Spencer, Muller, and various others have conducted actual scientific research with valid methodologies and repeatable results does not excuse the fact that they have also made blatantly false statements to advance various beliefs which they cannot substantiate scientifically. After someone at the LA Times said that they don't print letters from climate 'skeptics' containing false information various other papers stated their policies. The Denver Post stated that the matter is still in doubt and it would be "editorial arrogance" to dismiss the views of "properly credentialed experts" like Spencer and Curry. The quotations from these two are particularly galling because Spencer's is outright false and Curry's deliberately misleading;

    The fact that these sometimes scientists have not been sufficiently called out and denounced for their false claims means that they will continue to be given equal (or greater) time by many segments of the press and provides cover for the Tisdale's and Watts's to push climate denial into the realm of fantasy and nonsense.

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  12. It's obvious in which direction global temperature is headed. Just look at the mean of 1941-1958. That should be long enough a period to permit predictive certainty. We need to start burning more fossil fuel to stave off the impending ice age!

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  13. Christopher Gyles @12, it is wise to clearly mark ironical statements as such on the internet.  Otherwise you will find your irony popping up in "skeptic" mouths as serious argument.

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  14. CBDunkerson @11

    I could not agree more regarding your comments about the skeptics (or maybe they should be called contrarians - aren't all good scientists skeptics?). Having recently redirected my physics/math background to climate science I had to wonder about well-established figures such as Lindzen - being an MIT prof - also being against the mainstream science view about climate change and its causes. Further research showed that he hypothesized about how global warming was occurring due to a ‘cloud iris’ effect rather than GHG and that subsequent examination by others showed no support for his hypothesis. Maybe it’s a case of 'There's no way I could be wrong, it has to be them'. Losing face can be tough - even more so for well-known people. So the intelligent contrarians may never admit what the majority accept, which is a pity, because they lend credence to the contrarian point of view. Some of the others take an adversarial point of view for the publicity it gains them, some because they simply don’t have the background and/or training to understand the physics involved – and either don’t realize that or don’t want to admit it. In any case, one cannot reason with such people, and they are, quite frankly, best ignored!


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  15. " In any case, one cannot reason with such people, and they are, quite frankly, best ignored!"


    Rght up to the time these unreasonable and unreachable folks/sources/institutions are called upon by the MSM, for the "balance" they provide, regardless of how false it is. It is then we--us based in rational, data-driven thought processes--*have to* not ignore them, but once again, ad nauseam, rebut their lack of background of what they profess expertise in. Lindzen and Freeman Dyson are some of the most guilty of this, and it puzzles me to no end.

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