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Attack of the C-Students
, February 25, 2012
This review is from: The Hockey Stick and the Climate Wars: Dispatches from the Front Lines (Hardcover)
(OK, so this piece is a bit long-winded -- but to paraphrase James Hansen, I didn't have time to make it shorter.)
Dr. Mann's book is a gripping read and worth all 5 of the stars that I can give it. Now with that out of the way, I'd like to aim my focus in a different direction from that of most of the reviewers here.
The other reviews here have pretty thoroughly covered the ground I would cover in a standard book review, so I'm going to take a different approach and focus on the attacks against Michael Mann and other climate-scientists (rather than on Mann's book itself). In particular, I am going to attempt to describe, in "plain English" terms as much as possible, just how *incompetent* some of the attacks have been.
In fact, what strikes me most about the attacks directed against Mann and other climate-scientists is not their underhandedness or their nastiness, but their *incompetence*. Dr. Mann may as well have called his book "Attack of the C-Students" ("C" is short for "Gentleman's C", BTW).
So without further ado, let's take a look at 3 examples of such incompetence.
1) The infamous Soon/Baliunas 2003 paper, "Proxy climatic and environmental changes of the past 1000 years":
Dr. Mann describes one of the many methodological blunders in that paper thusly (slightly edited for brevity):
"A fundamental problem with the paper was that its authors' definition of a climatic event was so loose as to be meaningless ... warmth in China in A.D. 850, drought in Africa in A.D. 1000, and wet conditions in England in A.D. would all qualify as part MWP, even though they happened centuries apart".
But that isn't even the worst of it. If you look at the S&B 2003 paper (Google is your friend here), you will find this nugget:
"Anomaly is simply defined as a period of more than 50 yr of sustained warmth, wetness or dryness, within the stipulated interval of the Medieval Warm Period, or a 50 yr or longer period of cold, dryness or wetness within the stipulated Little Ice Age."
So S&B consider periods of wetness/dryness to be indicators of warming during the MWP, but then turn around and equate the very same sort of wetness/dryness periods that just happened to occur a few centuries later (during the LIA) as indicators of *cooling*.
Yes, folks -- you read that right. S&B would literally count a dry-spell as an indicator of warming during the MWP, and then turn around and count that same sort of dry spell as an indicator of *cooling* if it occurred during the LIA instead.
No attempt is made to explain why dry spells should be considered warming indicators in A.D. 1200 and then cooling indicators in A.D. 1400. Folks, this paper really is that bad. If anything, Dr. Mann was too kind to S&B; he did not do full justice to this paper's true awfulness in his book.
And believe it or not, this paper was waved around on the US Senate floor as a refutation of the work of Michael Mann and other climate scientists.
2) The M&M claim that Mann's centering convention caused his processing to generate hockey sticks from random noise:
What M&M did here was to implement a noise model that was "trained" with tree-ring data so that it would produce red noise with statistical properties similar to real "tree-ring data" noise. OK, so that was the plan. But they forgot to do one thing. They did not detrend the tree-ring data first (to remove the long-term "hockey-stick" global warming signal from the data).
As a result, their "random noise" was contaminated with hockey-stick signal statistics!
Dudes -- if you are going to use a noise model that has been "trained" with real data, you have to remove the signal from the real data first! Otherwise, you aren't going to end up with a "noise model"; you will end up with a "signal+noise model" instead.
There are other problems with this M&M claim, but we'd have to start talking about eigenvalue magnitudes/thresholding and such. And the above blunder in of itself is more than enough to invalidate this particular attack on Mann's hockey-stick.
3) The various and sundry attacks on the CRU/NASA/etc. global-average temperature results:
For years, some prominent individuals been attacking the validity of global-average temperature results by leveling charges re: UHI contamination, "dropped stations" skewing global-average temperature results, warming an artifact of homogenization/adjustments, etc. etc.
But it turns out that all of the raw data needed to test the validity of the above charges are freely available on-line (and have been so for years). Ditto for all of the necessary software development and data analysis tools (everything you need really is just a few mouse-clicks away).
Reproducing the NASA global-land temperature index very closely from freely-available raw temperature station data is surprisingly easy. Just run the data through a straightforward area-weighted anomaly averaging procedure (not very hard to code up if you have some programming experience) and you will get results surprisingly close to the results that NASA publishes. No data adjustments or homogenization required -- just run the raw data through what is really just a glorified averaging procedure, right on your laptop -- and you will get results that look quite similar to what the "pros" get.
Confirming that UHI has minimal impact on global-average temperature results is also quite straightforward. First, pick a few dozen "rural" GHCN stations scattered around the world, copy/paste their lat/long coords into Google Earth, and zoom in on the high-res satellite imagery to confirm their rural status. BTW, All GHCN temperature stations are designated "rural", "urban", or "suburban" in the GHCN metadata file, so picking candidate rural stations is easy. (Disclaimer -- due to precision limitations in the metadata format, you don't get exact station locations, but you still get good enough location info to confirm rural vs urban status).
Then run raw data from just those few dozen stations through your basic anomaly averaging procedure. You will *still* get results that are quite similar to the officially published NASA results. That's right -- you can throw out on the order of 99 percent of the temperature stations and still get results similar to what you get when you process all of the stations.
The above exercise will prove two things: (1) UHI has virtually no impact on global-average temperature anomaly results (because you got the same results from Google Earth Certified(tm) rural stations), and (2) the global temperature record is so robust that you can use a tiny subset of the surface temperature stations and still get results similar to what you get if you process data from all of the stations.
Debunking the "dropped stations" claim is also remarkably easy. Once you have your basic area-weighted anomaly averaging program up and running, you can easily add a few lines of additional code to distinguish the "dropped stations" from the stations still reporting data. Then you compute global-average results with and without the "dropped stations". Do that and you will see that the "dropped stations" effect is tiny. Results produced with and without the "dropped stations" will be nearly identical.
A competent programmer/analyst could bang out all of the above results (including coding everything up from scratch) in just a few days.
But those who have spent *years* attacking the global-average temperature results have for some reason been unwilling/unable to perform the few *days* of work needed to test their claims. Keep that in mind when you read about such attacks on the global temperature record.
Those who have been attacking the climate-science community keep insisting that global-average temperature results published by NASA/CRU/etc. are the product of "data manipulation". Folks, this is not "data manipulation"; it's f*&!ing high-school arithmetic! Seriously, folks -- high-school arithmetic and lower-division undergraduate programming skills are all you need to be able to debunk the favorite attacks on the NASA/CRU/etc. global-average temperature results.
So let's wrap this up with a little perspective regarding the CRU and "climategate":
Over 6 months ago, the CRU released the entire raw temperature station data set that was the focus of all the skeptics' FOI demands (and was also the focus of much of the "climategate" fuss). And in the ensuing 6+ months, what have those who were demanding access to that data-set done with it? Well, AFAICT, *nothing*. In over 6 long months, none of those who were demanding the CRU data have bothered to invest the few *days* of work needed to confirm or refute the CRU results, even though all the documentation and software tools needed to confirm/refute the CRU work are freely available on the Internet.
That's right -- the folks who had plenty of free time to file FOI demands, harass climate scientists, and spread conspiracy theories didn't seem to have any time to analyze the temperature data they were demanding, even when the whole data-set was served up to them on a silver platter. Go figure!
To anyone who wants to dispute my claims about the skeptics' lack of interest in doing anything with the CRU data that they were demanding -- in your comments, please include links to the skeptics' global-average temperature computations based on the CRU data.
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