DISQUS

JeanS-- Stefan edited out the link to my post where we discuss the fishy odor surrounding his document? Heh. (I only edit out links to porn etc.)

David S--
Is the Grinstead extension just a plain straight line? No 'noise'?

Cool! I'll install it and get started. Then I'll be able to go hog wild with equations.

I bet you were wearing alligator loafers as you wrote that. :)

This humidity issue is puzzling because the words in the document really don't seem to match the figures easily available from NOAA. Since the AR4 doesn't include any of their own, and only quotes results from papers, it's difficult to quickly see the basis for the statements in the AR4. This means "off to the library". (Or order the papers from the library.)

It is a puzzlement though.

Hi David--
Interesting comparisons. Definitely, the text doesn't match the appearance of these figures. As the figures are at NOAA, one has to assume they are at least somewhat accepted as meaningful.

That said, having heard mumblings and grumblings about radiosondes for years, I'd be cautious about interpreting any humidity measurements unless I knew the provenance of the data. You'll probably guess what sort of mumblings and grumblings I heard by examining the authors of Dry Bias and Variability in Vaisala RS80-H Radiosondes: The ARM Experience.

The paper cited discusses the problems with Vaisalla equipment used to measure relative humidity and a correction that was eventually developed after problems were uncovered. Luckily, serial numbers of equipment were recorded. ( In one of the grumblings, my husband related that he had been recording these along with the data, and someone non-experimentalist at the table marveled and suggested he must be anal to have thought of that. Jim was astonished at the thought that someone would launch sonds and NOT record the serial number of the equipment! Recording fiduciary information is generally advised in the engineering literature on experimental methods. Anyway, as you see in the paper, if the serial numbers had not been recorded, the correction could never have been retroactively applied. )

Hi David--
Based on the current paper it looks like you need these volcanos to calm down to test the idea in the new paper? In the next one, will you be discussing where things go if they keep erupting?

Anyway, if you get to the point of quantitative predictions, you know I'll compare to data. :)

Right now, it looks like you predict temperature going down, but there is an ozone caveat and you don't suggest a rate. ( I'm asking to make sure I'm understanding correctly.)

Oh no! This supports the theory that the earth is going to explode! (See the bizarre theories of warming I posted just as you were posting. )

I'd hardly call myself the first to note that volcanic activity affect the GMST. But, clearly, if stratospheric volcanos can affect the GMST, and the veiling remains in the sky for a long time, we expect to see big swings in 8 year trend while they erupt. These are absent when they don't-- and that's how the data look.

The Hockey Stick publication seems to have had the largest effect. Sort of like Pinatubo or maybe even Krakatoa. Oddly, An Inconvenient Truth had a lesser effect. But who knows what an opera could do.

This is a rather amazing plunge. I have to admit I'm surprised-- I was expecting La Nina to end, and temperature to move up. (Even with the PDO switch, I still expected up.) Oh well... shows I'm not psychic.

Bob... never mind. I found this:
AMO page.

I also clicked to this link, which is cool:
tool to make maps

Bob Tisdale-- Do you have a link showing current AMOs? I found this:
figure

and this

data.

But the figure only gets to 2000 and the data only gets to 1990.

It's clear looking at figure 1 from Rahmstorf that there was a decision to pin the T=0 point in 1990 from the IPCC projections to some numerical estimate for the "real-underlying" temperature in 1990.

Scare quote intentional because, even if we all agree such a thing exists, then "real" temperature is not the actual GMST from 1990, but something obtained by averaging. It must be estimated based on other data.

Using any statistical method, there is always an uncertainty in the determination of the "real" 1990 value.

David's various tests using different analytical techniques show what has always been obvious: The uncertainty in the determination of the the temperature for the "real" 1990 would result in different positioning of the IPCC projection on that graph. The conclusions could range from all temperatures fall below to all fall above the centerline of the projections.

Where do people get the idea that you compare projections of ensemble average quantities to data points without regard to the uncertainty in determining average properties from the data?

Stefan rebaselined the temperatures which on paper, looks like "sliding" the temperatures all up or down.

The "slide" procedure requires someone to estimate the "true" mean value for the 1990 temperature from the data and pin them. There should be an uncertainty associated with the determination of that mean underlying value. None is stated in that paper. But assuming 11 year centered means give similar sized uncertainties, data could all lie higher or lower depending on that uncertainty.

So, all data lying high or low means nothing unless the uncertainty is reported and doesn't explain the shift. The relative positions could just be an artifact of the re-baselining.

There are other uncertainty issues associated with the data.

If I have correctly understood her results, she finds that the observational record since 2001 is CONSISTENT with continued warming (though probably at a lower rate than the 0.2 C/decade projected by the IPCC). But it does not SHOW that temperatures are continuing to rise, as claimed in the IPCC Report.

Yes. The data I looked at don't rule out continued warming, but they also don't show warming.

So, at best one could say that warming is not ruled out.

Also, evidently, the IPCC thinks it can make statements like this based on 6 or 7 years of data, but those criticizing the falsification insist that one can't make statements like this with 7 years of data. But... well... there ya' go!

Well, it had struck me that the uncertainty in correct location of the smooth line had to be high, and particularly near the end point. So, it would appear that if Ramhstorf7 had given the slightest consideration to uncertainty, they would have seen that they had no clue where the non-linear fit went through the data!

Peter--
I specifically examined the AR4 projections, which project higher values than the TAR. So, that's part of the difference. But there are puzzling things about Rahmstorf 7. The paper is very brief, and the analysis method explained in a rather cursory fashion. Ultimately, the method is "Fit a fancy curve, slide the data "up" to the 1990 predictions match the fancy curve in the year 1990, eyeball, tell people how it looks to you!"

That's pretty much it.

David--
Does the method describe how to estimate the uncertainty in the "mean" value around the trend line?

I'm puzzled about this because the Rahmstorf7 method involves: Fit, slide (to the match 1990's average to the IPCC zero point) and eyeball.

You are discussing the fit on the endpoint. But uncertainty in the "slide" amount should normally be discussed in a paper like Rahmstorf. If I estimate uncertainty in means calculated using an 11 year centered average, that uncertainty is also enough to significantly affect the later "calibrated eyeball" comparison of the observations to the projections.

Gosh... R won't call you? And Tamino suggested that I was silly to ask my readers a question about his paper. Evidently, I should have just picked up the phone and called! :)

That last paragraph: Of course. :)

I saw that flattish spot in the sea level rise in the graphic in Roger Pielke's paper. I immediately went to the AR4 to see if I could find any concrete predictions, but they must have just decided that predicting sea level rise is impossible. (I found predictions for thermal expansion rates but not the overall rise.)

David--
Out of curiosity, can you get an uncertainty estimate for the "true mean" near 1990?

The reason I ask is the procedure in Rahmstorf is to rebaseline (that is shift) all the temperatures to the "mean" temperature at 1990. (The TAR just sets the baseline at 1990 to zero, and includes no data. So, you see, it's set to the entirely unknown and unknowable "true mean temperature" for 1990.)

To do the eyeball method of data analysis, Rahmstorf finds one specific temperature, then shift the whole shebang up. No uncertainty is attributed to the shift. However, if I were to say the 95% uncertainty in the mean was 0.1C or so, (as consistent with estimating based on a 11 year centered mean) and shift up or down a different amount, we get different results using the "calibrated eyeball test" used in Rahmstorf.

David-- Thanks for looking at this. I am very puzzled by that Rahmstrof paper on so many levels. I've been trying to do some rather simple minded things-- but using the figure that I actually find in the TAR "Scientific Basis" (the document they cite as providing the IPCC predictions!

If you can make heads of tails of Rahmstorf, more power to you!

David,
On the one hand, someone might accuse me of confusing weather and climate. However, all that happens with shorter data sets is that the uncertainty in estimates of any metric describing climate increases.

I am also willing to admit here are difficulties in short records in and of themselves. There may be very long trends in climate -- including multidecadal ones like the PDO. The existence of these cuts against both your analysis and mine to some extent. But, it also cuts against using data from 1975-- we should include several full complete PDO cycles to average out that effect. The most recent half cycle seems to have lasted 30 years, right? Do we need 120 years to fully describe the baseline climate uninfluenced by GHG's?

This isn't an easy issue.

That said, in principle, the climatologist in the IPCC considered the possibility of any switch in PDO and incorporated its effect into their uncertainty intervals for trends.

What's interesting is that, currently, it's rather difficult to find any reasonable criterion for selecting a "start" point that permits the IPCC projections to survive. The only thing that can bring those in line with the data is for temperatures to rise, and pronto.

Ohhh!!! We are all starting to get the same results.. different ways! (This is the upside to minor disagrements.)

Way cool. :)

Hi David,

I don't mean to suggest 10 years is cherry picking per se. But, since my goal is to apply a hypothesis to the IPCC projections, 10 years is cherry picking in this instance. I think it's best to pick a start date based on when they made their projections. Their projections are for 2001- on. So saying the post 2001 projections don't match earlier trends doesn't mean much. The IPCC's own projections indicate that the trend is supposed to increase in time. So, in a sense, the trend was supposed to be less than 2C/century before 2001.

Otherwise, of course we can gain insight looking at 10 year trends, bearing in mind that we must be cautious about what it means for one particular trend to fall below some statistical threshold. (But I think you already know this, and I doubt we disagree.

David-- What are you using for spam filtering? I find using Akismet, spamkarma AND bad behavior plugins all at once does help. (There is an Akismet extension for SpamKarma, so it's no long either or.)

Yes. It's a fair test. Admittedly, we expect a lot of scatter in one year. Still, it's interesting to see everyone's predictions. (My prediction is going to be ... wrong!)

I was busy all last week and missed the excitement-- but my blogs rank got bitch-slapped too. Do I have any PPP posts on it? No. Do I have any Smorty ads? No. Review me? No.

Well... I think my bitch slap my prove this: Google can't identify paid links!