A new “analysis” craze has been sweeping the climate contrarian world of late. Not content with cherrypicking one relatively cool La Nina year (even though 2008 was still in the top 10 in the instrumental record), some of the usual suspects are now using higher-order polynomial fitting in an attempt to illustrate a severe downward “trend” in global temperature.
Chief among them (what a surprise) is Alberta’s very own “fact chucker”, National Post columnist Lorne Gunter (you read that right – LG will not rest until all facts are distorted or removed as seen in recent posts here and here). Roy Spencer (of UAH satellite-derived tropospheric temperature fame) has also jumped on the polynomial bandwagon, and now superimposes a polynomial curve on his monthly update of the UAH record. [Update May 15: Spencer no longer uses the fourth-order polynomial curve in his monthly update]. Can a “scientific” conference on the subject, perhaps jointly sponsored by the Heartland and Fraser institutes, be far behind?
Now it turns out that Gunter, who is mathematically challenged to say the least, has most likely been relying on the wisdom and Microsoft Excel skills of his fellow Albertan, oil industry insider and engineer Allan MacRae (or Allan M.R. MacRae, as he most often styles himself). MacRae is a minor but fast rising star in the contrarian firmament, as we shall see.
I first stumbled across the Gunter curve in a small commentary by Chris Horner at GlobalWarming.org that claimed the Earth has “cooled since George Bush took office.” A barely discernable National Post credit on the accompanying illustration led me to Gunter’s October 20, 2008 column entitled “Thirty years of warmer temperatures go poof”. And there it was in all its awesome majestic stupidity:
The only data set presented was the University of Alabama (UAH) satellite-based lower troposphere estimate, which not so coincidentally, shows less warming than the other commonly cited global temperature data sets. (See some general discussion in the first part of this recent post).
I quickly realized that the “trend line” was a higher-order polynomial, and recalled that Excel had just such a graphing functionality built in (I had often wondered why anyone would use it). Within a few minutes I had reproduced a reasonable facsimile of the graph, using Excel’s sixth-order polynomial trendline, and then just for fun I created the animation that graces the top of this post. It cycles from the usual linear trend line through the various polynomial degrees, each pointing more severely downward at the end point.
And there I left it until a few weeks ago. I had been intending to post on this, but quickly realized that the whole matter had been discussed at length elsewhere. It turned out that Gunter’s column had been posted on WattsUpWithThat.com and had received a thorough going over at Greenfyre’s (which means I need not take on that thankless task again – been there, done that).
Far be it from me, then, to dwell too long on the obvious, but the following points do need to be made:
- By any reasonable long-term measure, global warming has not “stopped” or “disappeared” or “gone poof”, as explained in Tamino’s excellent “What if …” post at Open Mind.
- There is no conceivable justification for fitting a polynomial trend to a temperature time series; it can only be construed as a blatant attempt to mislead by purporting to show a bogus downward trend that has “erased” global warming.
Of course such a curve will change greatly from month to month, at least as the end point is approached. The graph below illustrates this phenomenon.
Here we can see that the end portion has changed upward considerably since MacRae first published his polynomial curve – already a considerable amount of warming has reappeared! As well, as recently as early 2007, the curve was at its peak at the end point. Presumably that’s why this brilliant idea didn’t come up back then.
But where did the curve come from? Greenfyre was led astray by the cryptic credit to Andrew Barr, a National Post illustrator, and mistakenly thought the curve had been drawn by hand. But other sharp-eyed readers, had already concluded, as I did, that the curve had been done in Excel. Somehow, I can’t imagine Gunter (or Barr) downloading data, reformatting it and adding trend lines to it.
But Gunter explicitly stated that “the chart was not produced by Douglass and Christy” (mistakenly attributing the UAH data to David Douglass instead of Roy Spencer). So it was a mystery, until a combination of Googling and luck led me to a blog post by Allan MacRae at icecap.us, which featured this graph as its centrepiece.
This version showed the use of Excel more clearly (dark blue line graph with diamond points being the Excel default). More to the point, the exact same version of data (up to August, 2008) was used, even though Gunter had one more month at his disposal when he published. And MacRae’s comment that “ALL the global warming over the past three decades has disappeared!” eerily presages Gunter’s conclusion that “all of the rise in global temperatures since 1979 has disappeared.”
It turns out MacRae is not new at the climate disinformation game. In 2002, he wrote an anti-AGW piece along with Friends of Science “scientific advisors” Tim Patterson and Sallie Baliunas. “Climate Change is Natural” ran in the Canadian Globe and Mail newspaper on November 19, 2002 (posted at AlbertaResidentsLeague.com). The piece also ran, together with an ardent anti-Kyoto “rebuttal”, in the PEGG, a publication of the Association of Professional Engineers, Geolgists and Geophysicists of Alberta (APEGGA).
MacRae was identified by the Globe as “a professional engineer, investment banker and environmentalist”. As Frank Magazine sardonically observed at the time he “sounds like a real ecologist, eh?”
From ZoomInfo and other sources, I’ve pieced together a slightly more elaborate resume of MacRae’s “scientific research” in the Alberta oil patch going back twenty-five years:
- 1984-1996: Canadian Occidental Petroleum (including involvement “in the management of the Syncrude, OSLO and PCEJ oilsands projects” from 1984 to 1991, according to his 2007 Alberta royalty review submission).
- 1996-200?: Consultant, working “with a major US-based multinational on international oil acquisitions”
- 200?-200?: President and CEO of Odyssey Petroleum (see ZoomInfo cache)
- 200?-????: CEO of Aterra Energy Corporation (see FindArticles cache)
In the intervening years, MacRae wrote a few letters to the editor, listed here along with other writings. But in 2008, MacRae stepped back into the contrarian big leagues. A correspondence with Roy Spencer led to MacRae being acknowledged as a major inspiration for Spencer’s, um, unorthodox ocean-driven CO2 hypothesis, as outlined at WattsUpWithThat:
Even though I have been playing with the CO2 and global temperature data for about a year, it was the persistent queries from a Canadian engineer, Allan MacRae, who made me recently revisit this issue in more detail.
MacRae’s own blog post hypothesizing CO2 rise as an effect of rising temperature (rather than as a cause) appeared at icecap.us in February, 2008. That led eventually to full induction into Marc Morano’s infamous list of “international scientists” who “dissent over man-made global warming” (2009 edition):
Professional Engineer Allan M.R. MacRae of Alberta, Canada, authored a scientific analysis critical of man-made global warming in 2008. “The IPCC’s position that increased CO2 is the primary cause of global warming is not supported by the temperature data,” MacRae wrote on February 5, 2008. Variations in atmospheric CO2 concentration lag (occur after) variations in Earth’s Surface Temperature by ~9 months. The IPCC states that increasing atmospheric CO2 is the primary cause of global warming – in effect, the IPCC states that the future is causing the past. The IPCC’s core scientific conclusion is illogical and false,” MacRae explained.
Since MacRae has also identified such a recent steep downward trend in temperature, I suppose we’ll see a similarly steep decrease in atmospheric CO2 any month now. Or not.
Be that is it may, it does seem that Spencer’s new-found fondness for polynomial fitting the UAH temperature series was very likely inspired by MacRae. Spencer’s October 11, 2008 update at Climate Research Newsdid not have the polynomial curve, but in November, there it was. However, Spencer’s polynomial fit is only fourth-order, not sixth. Presumably this is considered somehow more sober and “scientific”, albeit at the cost of making less warming “disappear”. Spencer’s explanation of the curve (now at his own drroyspencer.com website) is interesting:
The smooth curve in the graph is a fourth-order polynomial fit to the data, which smooths out the large amount of monthly variability in the data and helps reveal the underlying ‘trends’. (There is no claim that this curve has any predictive power for the coming months or years.)
Of course, in the official UAH data archive the only trend published is the conventional linear least squares fit. It still stands at +0.13 deg C per decade, somewhat less than RSS and the surface data sets, but significantly positive. Surely its omission from Spencer’s monthly updated chart is an oversight that will be rectified shortly. Or perhaps not.
Spencer’s caveat about “predictive power” is apparently not shared by MacRae, who back in October threw all caution to the winds:
Furthermore, the best fit polynomial shows a strong declining trend. Are we seeing the beginning of a natural cooling cycle? YES.
Perhaps, then, this would be a good time to extend MacRae’s polynomial curve and compare its awesome predictive power to the simple linear trend that has been made to disappear. Poof, indeed!
Oops. Recent UAH observations are close to or even above the linear trend, while the polynomial curve appears to project another ice age within a few years.
Anyway, now that the true source of the polynomial curve has been revealed, perhaps the National Post would like to update the Gunter column with an appropriate credit to Allan MacRae. Credit where credit is due and all that. If journalistic professionalism or ethics are not motivation enough, Post editors should spare a thought to poor Andrew Barr, who has unfairly taken much of the blame for the statistical travesty.
After all, all the hapless illustrator did was pretty up an ugly graph. The phrase “putting lipstick on a pig” comes to mind, somehow.