Opnieuw statistische manipulatie door klimaatalarmisten

Hoe de klimaathype weer wordt aangewakkerd door de firma list en bedrog.

Eerder schonk ik aandacht aan een nieuwe temperatuurreconstructie van Marcott et al, die de gediscrediteerde 'hockeystick'–grafiek van Michael Mann et al weer nieuw leven leek in te blazen. Verschillende media kwamen daarop weer met nieuwe paniekverhalen – ook in Nederland.

Een aantal prominente klimaatsceptici - bij ons Rob de Vos - kon na een paar dagen al uitleggen wat er mankeerde aan deze nieuwe grafiek. Ook Ross McKitrick heeft zich in de discussie gemengd. Onder de titel, 'We’re not screwed?', schreef hij in de Canadese 'Financial Post' daarover onder meer het volgende:

Left, global temperature variation over the past 11,000 years based on analysis of fossils from 73 sites around the world, with addition of 20th-century temperature records, from the Marcott et al. Science paper. At right, the same graph without the current temperature records. Sources: left, Science; right, Roger Pielke Jr..

What scientists and media said last month

— The Atlantic, March 10

The modern rise that has recreated the temperatures of 5,000 years ago is occurring at an exceedingly rapid clip on a geological time scale, appearing in graphs in the new paper as a sharp vertical spike.

— Justin Gillis, New York Times, March 7

“Rapid” head spike unlike anything in 11,000 years. Research released Thursday in the journal Science uses fossils of tiny marine organisms to reconstruct global temperatures . It shows how the globe for several thousandscof years was cooling until an unprecedented reversal in the 20th century.

— The Associated Press, March 7

What we’ve found is that temperatures increased in the last hundreds years as much as they had cooled in the lst six or seven thousand. In other words, the rate of change is much greater than anything we’ve seen in the whole Holocene.

— Shaun Marcott, Oregon State University, co-author of A Reconstruction of Regional and Global Temperature for the last 11,300 Years, media interview, March 7

In 100 years, we’ve gone from the cold end of the spectrum to the warm end of the spectrum. We hever seen something this rapid. Even in the ice age the global temperature never changed this quickly.

— Shaun Marcott, Oregon State ­University, quoted by Associated Press, March 8

What that history shows, the researchers say, is that during the last 5,000 years, the Earth on average cooled about 1.3 degrees Fahrenheit — until the last 100 years, when it warmed about 1.3 degrees F.

— press release, National Science Foundation, March 7

The rate of warming in the last 150 years is unlike anything that happened in at least 11,000 years, says Michael Mann of the Pennsylvania State University in University Park, who was not involved in Marcott’s study. ...

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On March 8, a paper appeared in the prestigious journal Science under the title A reconstruction of regional and global temperature for the past 11,300 years. Temperature reconstructions are nothing new, but papers claiming to be able to go back so far in time are rare, especially ones that promise global and regional coverage. The new study, by Shaun Marcott, Jeremy Shakun, Peter Clark and Alan Mix, was based on an analysis of 73 long-term proxies, and offered a few interesting results: one familiar (and unremarkable), one odd but probably unimportant, and one new and stunning. The latter was an apparent discovery that 20th-century warming was a wild departure from anything seen in over 11,000 years. News of this finding flew around the world and the authors suddenly became the latest in a long line of celebrity climate scientists. The trouble is, as they quietly admitted over the weekend, their new and stunning claim is groundless. The real story is only just emerging, and it isn’t pretty. ...

The new, and startling, feature of the Marcott graph was at the very end: Their data showed a remarkable uptick that implied that, during the 20th century, our climate swung from nearly the coldest conditions over the past 11,500 years to nearly the warmest. Specifically, their analysis showed that in under 100 years we’ve had more warming than previously took thousands of years to occur, in the process undoing 5,000 years’ worth of cooling. This uptick became the focus of considerable excitement, as well as scrutiny.

One of the first questions was how it was derived. Marcott had finished his PhD thesis at Oregon State University in 2011 and his dissertation is online. The Science paper is derived from the fourth chapter, which uses the same 73 proxy records and seemingly identical methods. But there is no uptick in that chart, nor does the abstract to his thesis mention such a ­finding. ...

According to the scientists who originally published the alkenone series, the core tops varied in age from nearly the present to over a thousand years ago. Fewer than 10 of the original proxies had values for the 20th century. Had Marcott et al. used the end dates as calculated by the specialists who compiled the original data, there would have been no 20th-century uptick in their graph, as indeed was the case in Marcott’s PhD thesis. But Marcott et al. redated a number of core tops, changing the mix of proxies that contribute to the closing value, and this created the uptick at the end of their graph. Far from being a feature of the proxy data, it was an artifact of arbitrarily redating the underlying cores.

Worse, the article did not disclose this step. In their online supplementary information the authors said they had assumed the core tops were dated to the present “unless otherwise noted in the original publication.” In other words, they claimed to be relying on the original dating, even while they had redated the cores in a way that strongly influenced their results.

In een persoonlijke e-mailwisseling met Steve McIntyre, gaf Marcott toe:

“[The] 20th-century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes, and therefore is not the basis of any of our conclusions.”

Now you tell us! The 20th-century uptick was the focus of worldwide media attention, during which the authors made very strong claims about the implications of their findings regarding 20th-century warming. Yet at no point did they mention the fact that the 20th century portion of their proxy reconstruction is garbage. ...

In recent years there have been a number of cases in which high-profile papers from climate scientists turned out, on close inspection, to rely on unseemly tricks, fudges and/or misleading analyses. After they get uncovered in the blogosphere, the academic community rushes to circle the wagons and denounce any criticism as “denialism.” There’s denialism going on all right — on the part of scientists who don’t see that their continuing defence of these kinds of practices exacts a toll on the public credibility of their field.

Lees verder hier.

Men zou denken dat klimaatalarmisten na de onthullingen van Climategate toch wat voorzichtiger en serieuzer zouden opereren. Maar dit voorbeeld bewijst maar weer eens dat ze nog steeds op de oude manipulatieve weg voortgaan.

Wanneer komt daar nu eens een einde aan?

Hebben onze kwaliteitskranten inmiddels al gerapporteerd over de kritiek op Marcott et al en diens bekentenis: “[The] 20th-century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes, and therefore is not the basis of any of our conclusions.”?

Nee natuurlijk! In hun onbenul hebben ze zich voor de zoveelste keer laten misbruiken als onbezoldigde apostelen van het broeikasevangelie.

Voor mijn eerder DDS-bijdragen, zie hier.