FLASHBACK: Twenty years ago today, the infamous “hockey stick” was published in Nature

Twenty years ago today: The infamous “hockey stick” graph that crystalized global warming and ignited the climate wars was published, and became known as MBH98. The science in it was so bad, It is credited with spawning the modern climate skeptic movement.

Michael E. Mann writes in the formerly Scientific American:

Two decades ago this week a pair of colleagues and I published the original “hockey stick” graph in Nature, which happened to coincide with the Earth Day 1998 observances. The graph showed Earth’s temperature, relatively stable for 500 years, had spiked upward during the 20th century. A year later we would extend the graph back in time to A.D. 1000, demonstrating this rise was unprecedented over at least the past millennium—as far back as we could go with the data we had.

Original “hockey stick” temperature graph in Nature, 1998. The Y axis shows the Northern hemisphere mean temperature, in degrees Celsius; the zero line corresponds to the 1902 – 1980 mean. Credit: “Global-scale Temperature Patterns and Climate Forcing over the Past Six Centuries,” by Michael E. Mann et al. in Nature, Vol. 392, April 23, 1998

Although I didn’t realize it at the time, publishing the hockey stick would change my life in a fundamental way. I was thrust suddenly into the spotlight. Nearly every major newspaper and television news networkcovered our study. The widespread attention was exhilarating, if not intimidating for a science nerd with little or no experience—or frankly, inclination at the time—in communicating with the public.

Nothing in my training as a scientist could have prepared me for the very public battles I would soon face. The hockey stick told a simple story: There is something unprecedented about the warming we are experiencing today and, by implication, it has something to do with us and our profligate burning of fossil fuels. The story was a threat to companies that profited from fossil fuels, and government officials doing their bidding, all of whom opposed efforts to reduce greenhouse gas emissions. As the vulnerable junior first author of the article (I was a postdoctoral researcher), I found myself in the crosshairs of industry-funded attack dogs looking to discredit the iconic symbol of the human impact on our climate…by discrediting me personally.

The hockey stick temperature reconstruction from 1999 (blue) along with the data record (red) and the 2013 “PAGES2k” temperature reconstruction (green). ​ ​​Credit: Klaus Bittermann via Wikimedia Commons ​(CC BY-SA 4.0)

In my 2013 book, The Hockey Stick and the Climate Wars: Dispatches from the Front Lines, I gave a name to this modus operandi of science critics: the Serengeti strategy. The term describes how industry special interests and their facilitators single out individual researchers to attack, in much the same way lions of the Serengeti single out an individual zebra from the herd. In numbers there is strength; individuals are far more vulnerable.

The purpose of this strategy, still in force today, is twofold: to undermine the credibility of the science community, thus impairing scientists as messengers and communicators; and to discourage other researchers from raising their heads above the parapet and engaging in public discourse over policy-relevant science. If the aggressors are successful, as I have argued before, we all lose out—in the form of policies that favor special interests over our interests.

Read the rest of Dr. Mann’s “poor me” pleading here (or not)

In the meantime, Climategate happened, along with “Mike’s Nature Trick

by Jean S on November 20th, 2009

So far one of the most circulated e-mails from the CRU hack is the following from Phil Jones to the original hockey stick authors – Michael MannRaymond Bradley, and Malcolm Hughes.

From: Phil Jones
To: ray bradley ,mann@xxxxx.xxx, mhughes@xxxx.xxx
Subject: Diagram for WMO Statement
Date: Tue, 16 Nov 1999 13:31:15 +0000
Cc: k.briffa@xxx.xx.xx,t.osborn@xxxx.xxx

Dear Ray, Mike and Malcolm,
Once Tim’s got a diagram here we’ll send that either later today or
first thing tomorrow.
I’ve just completed Mike’s Nature trick of adding in the real temps
to each series for the last 20 years (ie from 1981 onwards) amd from
1961 for Keith’s to hide the decline. Mike’s series got the annual
land and marine values while the other two got April-Sept for NH land
N of 20N. The latter two are real for 1999, while the estimate for 1999
for NH combined is +0.44C wrt 61-90. The Global estimate for 1999 with
data through Oct is +0.35C cf. 0.57 for 1998.
Thanks for the comments, Ray.


Prof. Phil Jones
Climatic Research Unit Telephone +44 (0) xxxxx
School of Environmental Sciences Fax +44 (0) xxxx
University of East Anglia
Norwich Email p.jones@xxxx.xxx

The e-mail is about WMO statement on the status of the global climate in 1999 -report, or more specifically, about its cover image.

click to enlarge

Back in December 2004 John Finn asked about “the divergence” in Myth vs. Fact Regarding the “Hockey Stick” -thread of RealClimate.org.

Whatever the reason for the divergence, it would seem to suggest that the practice of grafting the thermometer record onto a proxy temperature record – as I believe was done in the case of the ‘hockey stick’ – is dubious to say the least.

Mike’s response speaks for itself.

No researchers in this field have ever, to our knowledge, “grafted the thermometer record onto” any reconstrution. It is somewhat disappointing to find this specious claim (which we usually find originating from industry-funded climate disinformation websites) appearing in this forum.

But there is an interesting twist here: grafting the thermometer onto a reconstruction is not actually the original “Mike’s Nature trick”! Mann did not fully graft the thermometer on a reconstruction, but he stopped the smoothed series in their end years. The trick is more sophisticated, and was uncovered by UC over here. (Note: Try not to click this link now, CA is overloaded. Can’t even get to it myself to mirror it. -A)

When smoothing these time series, the Team had a problem: actual reconstructions “diverge” from the instrumental series in the last part of 20th century. For instance, in the original hockey stick (ending 1980) the last 30-40 years of data points slightly downwards. In order to smooth those time series one needs to “pad” the series beyond the end time, and no matter what method one uses, this leads to a smoothed graph pointing downwards in the end whereas the smoothed instrumental series is pointing upwards — a divergence. So Mann’s solution was to use the instrumental record for padding, which changes the smoothed series to point upwards as clearly seen in UC’s figure (violet original, green without “Mike’s Nature trick”).

TGIF-magazine has already asked Jones about the e-mail, and he denied misleading anyone but did remember grafting.

“No, that’s completely wrong. In the sense that they’re talking about two different things here. They’re talking about the instrumental data which is unaltered – but they’re talking about proxy data going further back in time, a thousand years, and it’s just about how you add on the last few years, because when you get proxy data you sample things like tree rings and ice cores, and they don’t always have the last few years. So one way is to add on the instrumental data for the last few years.”
Jones told TGIF he had no idea what me meant by using the words “hide the decline”.
“That was an email from ten years ago. Can you remember the exact context of what you wrote ten years ago?”

Maybe it helps Dr. Jones’s recollection of the exact context, if he inspects UC’s figure carefully. We here at CA are more than pleased to be able to help such nice persons in these matters.


via Watts Up With That?


April 23, 2018 at 02:55PM

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