A bizarre rewriting of history

I've got a lengthier post in the works, but since Roger Pielke Sr is demanding a response to this I will simply observe that for his new definition of "The Issue That James Annan and Gavin Schmidt Should Focus On With Respect To The Klotzbach Et Al 2009 Paper" he is quoting a paper on...impacts of land use cover change on climate! (the hint is in the title, folks)

However, Klotzbach et al repeatedly and emphatically talked about differences due to CO2 and other atmospheric factors:

The rate of heat loss to space is dependent on several factors, including cloudiness and the local atmospheric concentrations of carbon dioxide and of water vapor (e.g., Pielke, 2002). Under cloudy conditions, cooling is much less. An atmosphere with higher concentrations of the greenhouse gases, CO2 and H2O, also reduces the cooling at night.

Consequently if, for instance, there is a long-term positive trend in greenhouse gas concentrations or cloudiness over the observing site, it may introduce an upward bias in the observational record of minimum temperatures that necessarily will result in an upward bias in the long-term surface temperature record.

Because of changes to the atmosphere over the past century, there are several reasons why we should expect the nighttime cooling in the lower atmosphere to have been reduced. One reason for this is that carbon dioxide concentrations have increased, such that the effect of well-mixed greenhouse gas concentrations on near-surface temperature measurements has also increased. This increase is also expected to be higher for growing urban and industrial locations where carbon dioxide can locally accumulate when the large-scale wind flow is weak. An increase of water vapor over time would have the same effect. Also, an increase of cloudiness has been reported which has the effect of reducing nighttime cooling [Karl et al., 1997].

The term "greenhouse" makes 10 appearances in the Klotzbach paper: "land use" a mere 3. For the much shorter Pielke and Matsui paper, the score is 2:0 in favour of "greenhouse". That's right, the main "issue" of land use is never once mentioned in that paper, which provides the entire theoretical underpinning for Klotzbach et al. (I'll note in passing that the arguments I have made in relation to CO2 and other GHGs also applies equally to cloudiness: clouds do not impose a forcing of the type applied by PM05, so those results are equally inapplicable in that case.)

RPJr adds some emphasis, with It is important to underscore that our hypothesis depends upon (a) the presence of a real warming trend, and (b) (to some extent) an increase in greenhouse gases. So if you accept our arguments, then you necessarily are accepting the presence of a warming trend and corresponding increases in greenhouse gases.

I wonder if anyone is fooled by Pielke Sr's lame attempt to distract from the fatal error of PM05 (and therefore Klotzbach et al 2009 which rests on it)? I'd love to hear from anyone who can argue with a straight face that the real "issue" of Klotzbach et al 2009 (and Pielke and Matsui 2005 on which it rests) was impacts of land use cover change on climate.

For the record, I agree that land use cover change may impact on the climate. But unless Roger Pielke can find some way of arguing that this has changed the net average surface flux by the order of 1Wm^-2 at night, his whole theory is still a bust. And even if he did, it would not rescue his erroneous claims that the trends in temperature due to GHG or the other most significant forcings induce a significant change in the lapse rate in the boundary layer.

But they also laughed at Bozo the Clown

I'm amused to see Roger Pielke Jr playing the Galileo Gambit regarding his (Klotzbach et al) paper:

Had Michael been blogging around the time of Copernicus, he would have explained to his readers that the world is in fact flat, and that Copernicus guy must be wrong, because Michael and all of his Ptolemian friends said the world was flat, so those saying differently must be wrong because they do not jibe with his "coherence network."

Of course Roger wants to talk about politics and tribes, but I'd rather talk about science which is where this disagreement properly resides (IMO). Just to recap briefly:

Pielke and Matsui 2005 claims to have investigated the effect of temperature trends "such as due to increases in the atmospheric concentrations of the greenhouse gases, carbon dioxide and methane" on the lapse rate at night. However, they do this by applying a heat flux to the bottom boundary of the atmosphere. This is not how GHGs (or indeed any of the main climate forcings) act. Thus, their result, cited by Klotzbach et al as: "Monitoring temperature at a single height will produce a significant warm bias when the atmosphere has warmed over time [Pielke and Matsui, 2005]" is simply not valid, and there is absolutely no basis for this belief.

Roger also adds:

"Will Michael's or James' critiques of our work appear in the peer reviewed literature? Of course not (because their critiques are off target and simply wrong)."

Well, that's a hostage to fortune if ever I saw one. I will simply remark here that Myles Allen said similar things not so long ago, and I'll have a blog post or two to add on that particular topic shortly :-)

Roger Pielke Sr has also weighed in again, although I really wonder how he expects to benefit by keeping on going on about this. His persistent appeals to his own authority are somewhat undermined by his error of confusing a downwelling forcing at the land surface with a direct warming of the base of the atmosphere. His self-published email to me contains the following:

The P&M paper just looked at the issue as to whether if there was less loss of heat at night out of the top of the boundary layer, even if the loss was the same, would the vertical distribution of the heat loss be uniform between strong and windy nights?

I can't make much sense of the apparent contradiction in less loss of heat at night out of the top of the boundary layer, even if the loss was the same, but a bigger issue is why he claims to have looked at changing the heat loss at the top of the boundary layer when he clearly changed it at the bottom. The distinction is absolutely crucial, and anyone with any sort of knowledge of geophysics knows that thermally stratified fluids can behave very differently when heated from the top versus the bottom. It's a surprising error for an expert in boundary layer meteorology to make. I have emailed him directly and look forward to his explanation on this point.

As for their complaints about tone, well motes and beams come to mind. Not to mention pots and kettles.

Curiouser and curiouser

Down and down into the Pielkeian rabbit hole we go...

Recall that Klotzbach et al observe that the expected (model-based) tropospherical amplification factor of 1.2 is not easily found in a comparison of land surface observations and satellite measurements. They suggest that this is due to a change in lapse rate on calm nights, such that the surface (1.5-2m) temp is warmer than expected, relative to the satellites. There is an underlying series of papers (eg Lin et al 2007, Pielke and Matsui 2005) which discuss boundary layer effects over land at night.

Now I hadn't noticed on my first reading, but the claim that the 1.2 factor applies over land is actually attributed to analysis of the GISS model output by one Ross McKittrick, who one might consider a curious if not altogether dubious authority for this statement.

Up pops Gavin Schmidt a couple of days ago, pointing out that in fact the GISS model output, when correctly analysed, has an amplification factor of just under 1 over land. This result appears to be supported by simple physical understanding and thus probably holds for other models too.

This correction immediately knocks off half of the missing amplification effect that Klotzbach et al was explaining. In the original paper, the difference in trend over land (assuming a 1.2 amplification factor) was estimated as 0.07-0.21C/decade (mean of 0.14), for the 4 combinations of {HadCRU,NHDC} vs {UAH,RSS}. With the correct "amplification" of 1 (it should more precisely be 0.95 according to Gavin's figures) the difference is 0.01-0.13 (mean of 0.07).

Of course in Pielke-speak this "confirm the robustness of our findings to model uncertainties". Actually, in numerical terms it halves the magnitude of the effect, but perhaps this interpretation is just me playing semantic games. It has been interesting to see how much of their result has collapsed, and how rapidly it did so, once their paper saw the light of day. RPSr's original "conservative estimate" of this boundary layer effect being worth 0.21C/decade over land (meaning 0.06C/decade in the global trend, about a third of the overall observed value) now appears to be an overstatement by a factor of three, according to these updated results. Nevertheless, if the remainder of their analysis is valid, this would still be a worthwhile contribution towards improving the compliance of the satellite and ground-based observations, which would bring them more comfortably within each others' respective error bounds.

(I'm still half-expecting someone to pop up and say the whole idea is wrong from start to finish, though.)

Pielkes all the way down, revisited

Remember Pielke and Matsui 2005, Klotzbach et al 2009 and the debate over how plausible and valid their results were? You may recall my main complaint with PM05 (it wasn't my original observation, but I could see its significance) was that they had applied a large heat flux directly into the base of the atmosphere, which is not how GHGs work, but still claimed that their results were indicative of the effects of GHGs. Based on this implausible result, and some observations which were misinterpreted as supporting this theory (but which actually had the wrong sign) Klotzbach et al claimed that about 30% of the global temperature trend might be an artefact.

Well, a new paper has been published in JGR, Screen level temperature increase due to higher atmospheric carbon dioxide in calm and windy nights revisited by Steeneveld et al. (including Roger Pielke Snr as last author). It's a modelling study which investigates how long-term 2m temperature trends (due to GHG increases) should vary with wind speed. Instead of using an analytic equation and implausibly pumping heat into the base of the atmosphere, they have used a realistic atmospheric and radiative transfer model.

The second-to last sentence of their abstract reads:

We find that the screen level temperature response is surprisingly constant for a rather broad range of both geostrophic wind speed (5–15 m s⁻¹) and 10 m wind (2–4.0 m s⁻¹).

Thus the central claim of PM05, which underpinned this entire edifice, is refuted. No doubt this will be spun as a glorious victory, in some quarters...

Evidence for bias in atmospheric temperature trends

Klotzbach et al (including two Pielkes and a Christy) have recently written an interesting paper which, if correct, helps to align the satellite and surface temperature trends. Now I know that the IPCC claimed that these were already consistent "within their respective uncertainties" but it seems to me that the warming ratio of surface to altitude observations is a little on the low side. Recall that climate models suggest a ratio of about 1:1.2 for this, but the observations are close to 1:1. Maybe there is enough uncertainty for the 1:1.2 value to be correct, but it seems to be stretching things a little. I'm not an expert on this, but have been aware of RPSnr's papers on this topic for some time now and I can see the logic in his argument. Although I frequently disagree with the spin they put on things (and there are some red herrings in their work, like the Eastman paper that mt mentions here), I do not reject all that the Pielkes say out of hand. I do, however, note that others have recently objected to some of the work which is cited in this new paper.

So, Klotzbach et al argue that the night time minimum temperature at the surface have, at least on still nights over land, warmed up more than expected (ie compared to a normal lapse rate) due to various radiation-blocking effects. So what does this actually mean?

Well, one thing it does not mean is the main title of RPJnr's post, that the surface temperature trend is overstated. There is nothing in the paper (despite three gratuitous plugs of Watt's photography site) that actually argues for the measured temperature trend being wrong in any way. Rather, the paper explains why the measured trend is a bit greater than would be expected (according to mainstream theory) in comparison to the satellite measurements.

In other words, the satellite measurements are biased low, if one attempts to interpret them as an estimate of the surface temperature trend via the standard 1:1.2 warming ratio. Not that I expect the Pielkes to like that particular interpretation, which is why I put it in bold :-)

Instead, RPSnr is presenting the claim that the surface temperature trend "overstates the magnitude of climate system heat changes". Since it was primarily RPSnr who was pushing the meme of defining global warming through heat content rather than temperature, I don't think the rest of us need to lose much sleep over that one, but I can see why he might be perturbed. Basically all of the downstream impacts-related application of climate modelling is calibrated on temperature rather than integrated atmospheric heat content (tropical storms may be one exception) so all he seems to have shown is that his preferred metric is even less useful than it at first appeared.

Of course being the political scientist that he is, RPJnr is dropping the crucial rider and simply presenting the claim that the trend has a high bias. That transforms the claim from irrelevant to wrong. The warming trend is what it is, and even if part of this is due to heat moving around rather than accumulating, it is still a warming at the surface.

Update.

This is getting rather surreal, which unfortunately seems to be a feature of many exchanges with RPJnr. He is now claiming that his use of the phrase "Global Temperature Trends" was not actually referring to surface measurements at all, in his comment here:

It is fun to play semantic games, especially on blogs. You write:

"The topic of your post is the "temperature trend" and specifically you claim that the surface temperature trend has been overstated."

No. The title of the post is "Evidence that Global Temperature Trends Have Been Overstated". It might have been more accurate to write "global atmospheric temperature trends" but it clearly does not say "surface temperature trend" as you allege. So enogh with the word games, OK?.

Huh? If the supposedly "overstated" "Global Temperature Trends" are not specifically those based on the surface measurements, then at this point I have absolutely no idea what he thinks he is referring to. Unlike Roger, I don't think that it is particularly fun to play semantic games on blogs, so I won't continue further.

Oh, and xkcd, via thingsbreak at init.

Klotzbach ad nauseam 2009

The Klotzbach et al paper (previous here) is finally published, and seems to have kicked off something of a blogstorm again.

As you may recall, when the preprint was first publicised, Gavin Schmidt quickly identified an error in the analysis. The paper looks at the difference in trend between surface and troposphere, and the claim that this points to some previously-unexplained factor (which they ascribe to "bias" in the surface measurements, see below) depends on the "expected" amplification factor of 1.2 which is derived from models.

As Gavin pointed out, however, the factor of 1.2 does not apply over land (his model's ratio is 0.95) which eliminated half of their effect at a stroke. K09 originally appeared to accept this (see table in blog post) so it was surprising to see that they hadn't bothered to correct this for the final version of the paper. They made several other changes later than that exchange, so it's not like they didn't have the opportunity.

K09 have now replied by claiming that Gavin's correction isn't correct after all, and they "understand" from McKitrick that the original 1.2 value is appropriate for the region they were considering. It is odd enough that they didn't clarify this in the paper, but what is even more bizarre is their repeated claim the different values don't matter, since clearly Gavin's value knocks off half of the claimed discrepancy at a stroke.

Ross McKitrick seems pretty embarrassed by the whole affair. All he did was write an informal email to one of the authors, which he never intended to be made public, and he seems to have been as astonished as Gavin was to find his calculations used as the basis for the analysis in K09. He thinks it was inappropriate for them to have used his numbers, which he now acknowledges are incorrect. His new values are contradicted by Gavin's, and I know who I'd place my money on (McKitrick's numbers imply a global mean factor of about 1.45, far higher than the generally accepted figure, and he's had difficulties with such complex issues as area-weighting in the past). But irrespective of the numbers themselves, it is staggering that K09, having been alerted to the problem by Gavin, didn't bother to check for themselves, preferring to publish the disputed values first and correct (or not) later. Of course this "see no evil" strategy means they have made McKitrick look stupid for the error, and whatever you feel about his contribution to climate science in general it's hard to not feel some sympathy for him in this case. It is shameful of K09 to hide behind McKitrick in this way rather than performing the calculation themselves if they won't accept Gavin's figures.

Distinct from the dispute over those numbers, there are some more rather amusing changes to the paper, in that the interpretation of the Lin et al 2007 results has been reversed. Originally (and repeatedly) touted as supporting the hypothesis of Pielke and Matsui 2005 (and don't forget that Pielke and Matsui were co-authors on L07), it was noted by Urs Neu out that this interpretation of the analysis was based on a sign error. When correctly interpreted, the L07 results actually oppose the PM05 hypothesis, which at a minimum demonstrates that if the PM05 effect really existed, it is not large compared to other local influences.

As a result of this belated realisation, there are some changes to the K09 paper. What was originally written was:

This was documented in Lin et al. [2007] who found from observational data that monitoring long-term near-surface daily minimum temperature trends at a single level on light wind nights will not produce the same trends as for long-term temperature trends at other heights near the surface. For instance, were the data from Lin et al. [2007] to be representative of biases in other station measurements taken at one height, then about 30% of the tropospheric warming during the 20th century reported by the IPCC would be explained as the result of this factor. A warm bias would occur even for daytime maximum temperatures for land locations at high latitudes during the winter when the surface temperature profile remains stably stratified all day.

One might think that correcting the sign error would naturally lead to

This was documented in Lin et al. [2007] who found from observational data that monitoring long-term near-surface daily minimum temperature trends at a single level on light wind nights will not produce the same trends as for long-term temperature trends at other heights near the surface. For instance, were the data from Lin et al. [2007] to be representative of biases in other station measurements taken at one height, then the tropospheric warming during the 20th century reported by the IPCC would be underestimated by about 30% as the result of this factor. A cold bias would occur even for daytime maximum temperatures for land locations at high latitudes during the winter when the surface temperature profile remains stably stratified all day.

But of course they couldn't bring themselves to say that, so instead the paper now reads:

This was documented by Lin et al. [2007] who found from observational data that monitoring long-term near-surface daily minimum temperature trends at a single level on light wind nights will not produce the same trends as for long-term temperature trends at other heights near the surface (although it was a cool bias in that data for the time period and location examined). A warm bias could occur even for daytime maximum temperatures for land locations at high latitudes during the winter when the surface temperature profile remains stably stratified all day.

Funny how this inconvenient result is now relegated to a "time period and location examined" when it was previously hypothesised to be representative of the global picture.

There were no fewer than three other places where L07 was originally cited as being consistent with the K09/PM05 hypothesis, but it would obviously have been too painful for them to mention that their own observations of boundary layer lapse rates contradict their theory. Therefore, these statements have just been deleted.

It is particularly curious that the contribution of Urs Neu (who corrected this sign error) is nowhere acknowledged. Perhaps he requested that his name was not mentioned, but otherwise this omission sits uncomfortably with (in particular) RPJr's willingness to throw accusations of plagiarism around at others.

Yet another error is the repeated mis-attribution of comments from Santer et al (2000) as coming from Santer et al (2005). The significance of this is that back in 2000, there was still a rather large discrepancy between satellite observations (and specifically between the UAH analysis and the expected tropospheric amplification), for which people put a lot of effort in to trying to think up plausible explanations. Of course a large part of this discrepancy was fixed, when it was discovered that another sign error in the UAH analysis had understated the trend (BTW, anyone notice a pattern here?), largely reconciling the problem. By giving the wrong reference, K09 gives the wholly misleading impression that many scientists in 2005 disagreed with this reconciliation. In fact, Santer et al 2005 (and accompanying papers) was this reconciliation!

So it seems we have a hypothesis about a significant decrease in lapse rates in the boundary layer which even were it true, has no real impact on predictions of climate change but anyway is (a) not supported by any theoretical calculations (since the PM05 calculation is simply inapplicable), and (b) actually opposed by the observational evidence on lapse rates that the proponents themselves have analysed (as L07 had a sign error). It seems that only one thing has remained a constant amongst the blizzard of errors and bluster, and that is Roger Pielke Sr's unshakeable beliefs that the surface temperature record is wrong, and that the fact that his nonsensical "research" on this has been ignored by the scientific community is evidence of some conspiracy to cover it all up. Perhaps this is what "Pielke Climate Science" means. I prefer the traditional approach.

Pielke and Matsui (2005) revisited

So, a whole lot of hot air has passed, and maybe the dust is starting to settle. Mt noted that the Klotzbach et al work is "Pielkes all the way down", and several references have been made to the Pielke and Matsui 2005 paper which underpins a lot of this work. Mention of this prompted a distant memory, so I checked my mailbox (amazing the power of computers to recover old memories these days). I also re-read the PM05 paper more critically, in light of its current relevance and the previous emailed comment.

Well, well. That was...enlightening.

PM05 examines the near-surface lapse rate that arises on calm and windy nights, with a simple one-dimensional analytical model. They further calculate the changes in lapse rate as the cooling rate varies.

In all this work, they apply the radiative cooling at the surface, even though they explicitly portray this forcing as being representative of the effect that arises from a change in GHG concentrations. Standard climate theory holds that the radiative forcing is applied the top of the atmosphere - indeed this is the level at which the forcing is defined. It is simply wrong to claim that a doubling of CO₂ will generate a forcing of 3.7Wm^-2 at the surface, for example.

The startling impact of this odd application of "bottom of the atmosphere" forcing is apparent from their Table 1. A change in this "forcing" of a mere 1Wm^-2 leads to a temperature difference of a whopping 1.5C (at the 2m level) over a single calm night! This is the simple result of applying 1Wm^-2 of cooling to the fairly shallow layer at the bottom of the atmosphere, which has relatively low heat capacity due to its shallowness.

Consider a simple thought experiment. Start with a pre-industrial atmosphere, wait for a calm night, and instantaneously double the CO₂ level. According to PM05's interpretation of GHG forcing, this will result in a temperature rise of about 6C (compared to the unforced case) in the space of 12 hours. This simply doesn't pass the sniff test, not by a million miles. It's not just wrong, it's several orders of magnitude wrong!

Remember, PM05 is the celebrated theoretical underpinning for this entire night-time warming edifice.

For the standard approach, check out this article which compares various radiation models. Here's their plot of depth-varying warming rate due to an increase in GHGs (from 1860 to 2000 values) holding everything else constant:
Note the warming rate is basically uniform in the bottom 200hPa of the atmosphere, in stark contrast to the PM05 assumption that the forcing acts at ground level. Thus, a large increase in GHGs generates a warming rate of about 0.04K per day across the boundary layer, as compared to the Pielkian ~1K over a single night (depending on wind speed).

This paper (pdf here), co-authored by all the big names in the field, ("The radiative effects from increased concentrations of well-mixed greenhouse gases (WMGHGs) represent the most significant and best understood anthropogenic forcing of the climate system.") has essentially the same plot in their Figure 12. There does not appear to be the slightest bit of debate over this subject.

So I don't think that the PM05 calculations can have any relevance to the response of the lower part of the atmosphere to changes in GHG forcing.