No evidence at WUWT - a DuKE, global surface temperature, and statistics

Anthony Watts has a new article on his climate conspiracy blog (archived here). It has the title: "Is There Evidence of Frantic Researchers “Adjusting” Unsuitable Data? (Now Includes July Data)". The answer is NO. Or at least none is provided by anyone. Which raises the question of why the title? You'd think he'd at least make up something to appease the mob. All he has is a mish-mash of temperature data from various sources, including lower troposphere data, and land and sea surface data (combined), and sea surface data, interspersed with gobbledegook from one of his long-winded fans. (And July must be a big deal, even though it's already October!)

The authors are listed as follows:

• Professor Robert Brown from Duke University (aka the batty duke or rgbatduke)
• Werner Brozek
• with one of Anthony's pet Anonymous Cowards known as "Just The Facts" as editor.

In regard to whoever is Just The Facts, he or she is a long time regular. Anthony doesn't like people using pseudonyms. Let me correct that. Anthony only likes deniers using pseudonyms. Any normal person who prefers to comment on climate using a pseudonym is castigated by Anthony Watts. (I think Just The Facts is the same person who also posts at WUWT as justthefactswuwt. But I cannot say for sure. It doesn't matter.)

A note on statistical significance: If you want to skip over the meaningless ramble, you can jump straight to the discussion about what statistical significance means. (Hint: a 'not statistically significant' trend doesn't mean that it hasn't warmed.)

A meaningless ramble from the batty duke

The article is a variation on one you'll see most months at WUWT, which is the denier's take on the various reports of temperature from different sources. The variation this time around is that it includes a lot of conspiracy ideation by the batty duke. (The batty duke earned his name here in part because of his chosen name at WUWT, rgbatduke, and in part because of Lotharsson's suggestion for a collection of deniers - a DuKE of deniers. Think DUnning Kruger Effect.)

Rgbatduke is a physics teacher and novelist at Duke University. He's not done much research, certainly not lately (his CV lists one paper since 2001). He pontificates at WUWT and teaches physics in between, and writes novels. Or the other way around. I can't say what his priorities are. He's getting on in years though by no means ancient. That's about all I know or care to know about him.

I don't know why Werner and JTF (Just The Facts) included his comment, because it wasn't mainly about global temperatures, it started off being about US temperatures and then waffled onto various quite irrelevant topics. He decided that the United States Historical Climatology Network (USHCN) is not allowing for ocean intake valves, or something. Which is a bit weird because USHCN is all about land surface temperature. It doesn't cover the ocean. Rgbatduke is a very longwinded. His first sentence was 108 words long:

Note well that all corrections used by USHCN boil down to (apparently biased) thermometric errors, errors that can be compared to the recently discovered failure to correctly correct for thermal coupling between the actual measuring apparatus in intake valves in ocean vessels and the incoming seawater that just happened to raise global temperatures enough to eliminate the unsightly and embarrassing global anomaly “Pause” in the latest round of corrections to the major global anomalies; they are errors introduced by changing the kind of thermometric sensors used, errors introduced by moving observation sites around, errors introduced by changes in the time of day observations are made, and so on.

On re-reading the above segment, he's not actually claiming that USHCN had anything wrong with intake valves in ships. He's just saying it's like that. How it's like that is because of something to do with global temperature. Which is odd in itself because last I looked, the contiguous USA only took up something like 2% of the earth's surface.

If you try reading his comment a few times, you might come to the same conclusion as I have. That rgbatduke is weaving a conspiracy theory. If you can bring yourself to face the rest of what he wrote, you'll figure out that your first notion was correct. Oh, he tries to wriggle out of it being a full blown conspiracy theory by saying that temperatures are rising because of confirmation bias, which strictly speaking can't be a conspiracy. What makes it fit is that one of the signals of conspiracy ideation is "something must be wrong", particularly, as in this case, in the absence of anything being wrong. In his segment, rgbatduke mostly focuses on:

• His grandson, and how he's not growing because of CO2, he's growing because of something else
• The Dow Jones Industrial Average, and how his grandson isn't growing because the DJIA is going up, down or sideways
• Joe the taxi driver and black swans and two-headed coins, and how he, rgbatduke, sympathises with Joe the taxi driver
• Businesses and shoplifters and embezzlement and courts of law.

The background to the new versions of GHCN and ERSST 

There is very little in rgbatduke's comment about temperature. It's mostly about the above topics. He does at one point claims that "NCDC" was looking at sea surface temperatures because they weren't going up as much as the scientists thought they should have. He's wrong, you know. Peter Thorne told HotWhopper readers how ERSST v4 came into being. It had nothing to do with the so-called "pause" (my emphasis):

The driving rationale for this work was entirely internal. There was no external funding or directive involved. While I was at (then) NCDC I arranged (I think via UK FCO funding if memory serves) for Colin Morice to visit NCDC to give a talk on the as yet unpublished HadCRUT4. It was important to know what the new UK effort would look like and that was the only seminar in my time there attended by many senior management. After that it was decided that it was necessary to revisit the SST as well as the land which was already being worked on. Then to revisit the merge and interpolation. Karl et al. is simply a waymark in a long-term process of analysis, investigation, reanalysis and improvement. Which is as it should be. There continue to be efforts to substantively improve the holdings and the analysis methods to strive for the best possible products. And long may that continue as we should strive for best understanding.

At no point in any of the discussions around development of the ERSST product was the effect on the hiatus raised. The driving rationale was actually to better do centennial scale bias adjustments and better recover late 19th / early 20th Century ENSO behaviour. It was also necessary to address the various insights raised in the literature in the intervening decade. Of which the buoy bias viz. ships was obvious and replicated in multiple independent published analyses. It would have been perverse to ignore this and unlikely to have passed muster in peer review had the new product chose to ignore this effect.

ERSSTv4 is published and analysed in two substantive papers which go into great detail to justify and analyse the impact of the changes made. On the land side the ISTI databank is fully documented as is the PHA method across several papers. Karl et al should be considered in combination with these (referenced therein) preceding pieces.

No, there is no evidence of frantic researchers or unsuitable data

As I said, nowhere in the article was there any evidence supporting the title. There was no evidence, nor any hint of evidence, apart from vague insinuations of shady conspiracies, "of Frantic Researchers “Adjusting” Unsuitable Data". Nor did rgbatduke or any of the other authors provide any evidence that the temperature records are biased any which way. You won't be surprised that there are allegations (wrongly) that the temperature record is on balance adjusted to increase the rate of warming. Over the length of the records, that's not so. ERSST without corrections has early temperatures lower than the adjusted ones. Which means that the long term trend is lower than it used to be.

What about UAH adjustments?

One thing, I haven't ever seen an article at WUWT which questions the changes to the UAH temperature record. Deniers only deny one way. They deny that the world is warming. The changes to UAH were in the opposite direction. But not a peep of protest from deniers. They just say how it's the most accurate. They don't admit that if it was so accurate before the change, does that mean it's less accurate now?

So while I'm on the subject, and in keeping with the meandering article at WUWT, why not look at some of the changes to UAH over the years. Below is a chart showing the different versions from 5.5 through to 6.0 beta version 3 from 1979 to 2014. Notice that the chart shows warming over the period.

Data source: UAH

And the chart below shows the difference between the latest beta version and UAH 5.6, which was around for quite a few years.

Data source: UAH

The latest version warms the middle years and cools the recent years. Roy Spencer said on his blog that the new version works out the temperature quite differently to the old version. So when science deniers try to claim that UAH is perfect, ask them which version is perfect. When deniers claim that all the calculations are transparent, ask them where is the transparency? AFAIK, although Roy has promised to make his workings public, he hasn't done so yet.

A note on statistical significance

Before finishing, here are some observations on the reported statistical significance numbers at WUWT. I'll just take RSS as the example. At WUWT it is reported as follows:

For RSS: There is no statistically significant warming since February 1993: Cl from -0.023 to 1.630.

The RSS average anomaly so far for 2015 is 0.302. This would rank it as 6th place. 1998 was the warmest at 0.55. The highest ever monthly anomaly was in April of 1998 when it reached 0.857. The anomaly in 2014 was 0.255 and it was ranked 6th.

This could be misleading, with people wrongly thinking that it means the same as "it hasn't warmed", which would be wrong.

Using the Skeptical Science calculator, and just leaving the defaults (moving average 12 months), the results for RSS lower troposphere temperature are as follows from the start year indicated to the latest data:

• From 1989: Trend: 0.120 ±0.109 °C/decade (2σ)
• From 1990: Trend: 0.107 ±0.116 °C/decade (2σ)
• From 1991: Trend: 0.110 ±0.125 °C/decade (2σ)
• From 1992: Trend: 0.113 ±0.134 °C/decade (2σ)
• From 1993: Trend: 0.083 ±0.138 °C/decade (2σ)

As you can see, in all but one of the above cases, the 2σ range is larger than the trend. As you can also see, in all cases the trend is positive. In other words, the lower troposphere is getting warmer. What that means is that, except for the period since 1989, you cannot say with 95% confidence that the warming trend is not what you'd get with random variability. It doesn't mean it hasn't warmed over that period. The data show that it has.

If you cherry pick a year that's much warmer than what is the latest reported, you can get a negative trend. For example, by picking El Nino years as the start date and taking the period to the present, with RSS:

• From 1998: Trend: -0.042 ±0.194 °C/decade (2σ)
• From 2004: Trend: -0.012 ±0.338 °C/decade (2σ)
• From 2005: Trend: -0.034 ±0.396 °C/decade (2σ)
• From 2009: Trend: -0.144 ±0.865 °C/decade (2σ)
• From 2010: Trend: -0.344 ±1.137 °C/decade (2σ)

Notice how the 2σ confidence interval is very much larger than the cooling trend reported for the years above. That means that one cannot say with 95% confidence that the cooling trend is not what you'd expect with random variability.  (Again, you cannot argue that there wasn't a cooling trend over those periods. The data show that there was.)

Stefan Rahmstorf wrote an article at RealClimate explaining the way that "statistical significance" is to be interpreted, when using 2σ confidence intervals. He wrote:

You see a warming trend (blue line) of 0.116 °C per decade, so the claim that there has been no warming is wrong. But is the warming significant? The confidence intervals on the trend (± 0.137) suggest not – they seem to suggest that the temperature trend might have been as much as +0.25 °C, or zero, or even slightly negative. So are we not sure whether there even was a warming trend?

That conclusion would be wrong – it would simply be a misunderstanding of the meaning of the confidence intervals. They are not confidence intervals on whether a warming has taken place – it certainly has. These confidence intervals have nothing to do with measurement uncertainties, which are far smaller.

Rather, these confidence intervals refer to the confidence with which you can reject the null hypothesis that the observed warming trend is just due to random variability (where all the variance beyond the linear trend is treated as random variability). So the confidence intervals (and claims of statistical significance) do not tell us whether a real warming has taken place, rather they tell us whether the warming that has taken place is outside of what might have happened by chance.

As Professor Rahmstorf said, the 2σ confidence intervals are not about whether or not the lower troposphere has warmed. It has. Nor do they have anything to do with measurement uncertainty. What they indicate is the chance of whether the warming is due to random variability. Is it merely the amount of warming you'd expect by chance?

Now the data for RSS for the periods listed up top, show that one cannot say that the warming of the lower troposphere would not have occurred by chance - at the 95% probability level. One cannot argue however, that it hasn't warmed. It has. Below is the SkS chart for RSS lower troposphere since 1979. That shows that the warming trend since 1979 is not pure chance:

Source: Skeptical Science

Looking at the 2σ interval in the above chart, there is a 95% probability that the warming from 1979 to the present is not merely random variability. It's not pure chance. It's no accident that it really is getting hotter. (We're causing it.)

There is other data for the surface. Look at GISTemp, for example. Below is comparable data to the years I showed above for RSS. Again from the Skeptical Science trend calculator, just using the default settings.

• From 1989: Trend: 0.166 ±0.066 °C/decade (2σ)
• From 1990: Trend: 0.164 ±0.070 °C/decade (2σ))
• From 1991: Trend: 0.175 ±0.074 °C/decade (2σ)
• From 1992: Trend: 0.186 ±0.079 °C/decade (2σ)
• From 1993: Trend: 0.172 ±0.082 °C/decade (2σ)

All the above periods indicate that at the 95% confidence level (2σ), the warming to the present is not merely random variability.  The trend in all cases is larger than the 2σ confidence interval. (Unlike the lower troposphere, I didn't find any period ending at the present for GISTemp, which had a cooling trend.)

It is not very likely that the surface will warm for extended periods, such as 30 years or more, and the lower troposphere would cool for those same extended periods. It is far more likely that the trend in both would be in the same direction (either warming or cooling).

Anyway, the point of this is that you need to be aware of what people are talking about when they mention statistical significance. It's not whether the world is warming. The world is warming. It's whether or not that warming that we see could simply be the result of random variability. Clearly, the long term warming that we are seeing on the surface is not merely the result of random variability. There is a clear warming trend over the longer term, with confidence intervals indicating that the warming is not simply caused by pure chance.

From the WUWT comments

daveandrews723 says apropos of nothing he read in the article, just a thought he had to get off his chest:

October 1, 2015 at 3:11 am
Fraud, often seen on Wall Street over the years, is apparently not limited to the financial world. This is a sad, dark period for science.

chris y denies the evidence placed before his eyes, and wrongly thinks that the lower troposphere isn't warming. It is.

October 1, 2015 at 10:53 am
One alternative is that the satellite and surface data sets represent reality. Assuming this, I hope that some clever climate scientists are busy figuring out how to modify the current understanding of heat flow in the atmosphere to explain why, for almost two decades, the surface warms while the troposphere does not.
These sorts of ‘ultraviolet catastrophe’ moments in science can lead to tremendous new understanding of our world. 

Brent Walker has a "thought" that has nothing to do with what he read in the article, too.

October 1, 2015 at 3:16 am
There has to be more than ideology behind this. Those who are making money out of this or who intend to make money out of it should be named and shamed. 

Dodgy Geezer asks why WUWT never shows the "raw data". It's probably because the "raw data" also shows that the world is warming.

October 1, 2015 at 3:26 am
Is the raw data being saved? That is the most important thing.
I wonder why – if we have the raw data – we never see a raw data graph…? 

Steven Mosher agrees with Caerbannog (see link), though he says the raw data shows more warming, not less:

October 1, 2015 at 7:06 am
All the raw data still exists.
If you use raw data then the global warming is worse.
The net effect of all adjustments to all records is to COOL the record
The two authors of this post don’t get it.
Adjustments COOL the record..
Cool the record. Period. [snip]

MCourtney, for a change, doesn't go for the regular WUWT conspiracy theory. Instead he's suggesting we set up a duplicate or triplicate planet. Now why didn't the scientists think of that?

October 1, 2015 at 3:27 am
Quite right.
The idea that there must be a nefarious plot for these adjustments to always make the record scarier and scarier… it’s ridiculous.
All that’s needed is the kind of thing that proper science avoids with double-blind trials.
The Greens want to avoid such safety precautions. And that is where we must ask why?
It’s good enough to avoid MMR fiascos so why not to avoid AGW fiascos? 

 There were far too many comments for me to bother reading any more. 216 at the time of archiving. Given that the article didn't live up to the title, and was nothing more than a report of global temperatures with a long, meaningless, wandering, silly few paragraphs from the batty duke in the middle, that's a lot of "thoughts". I think it shows that WUWT has fans and they would dearly love something they can get stuck into. They are a bit sick and tired of hearing how hot it's been getting lately. They don't want to believe it so they don't. Evidence be damned.

Who needs evidence when you're a science-denying conspiracy theorist?