by Judith Curry
We’re screwed: 11,000 years’ worth of climate data prove it. It’s among the most compelling bits of proof out there that human beings are behind global warming, and as such has become a target on Mann’s back for climate denialists looking to draw a bead on scientists. — The Atlantic, March 9th
We’re not screwed. 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. – Ross McKitrick
The saga surrounding the Marcott et al paper has gotten really interesting over the weekend. Some key posts:
- A series of posts at ClimateAudit
- Response by Marcott et al. at RealClimate
- Fixing the Marcott mess in climate science by Roger Pielke Jr
- The Marcott filibuster at ClimateAudit
Ross McKitrick provides a summary of all this in an article for the Financial Post, entitled We’re not screwed? Excerpts:
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.
Steve McIntyre of climateaudit.org began examining the details of the Marcott et al work, and by March 16 he had made a remarkable discovery (JC note: see original article for details).
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.
. . . contains a remarkable admission: “[The] 20th-century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of glbal 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.
What made their original conclusion about exceptional nature of the 20th century warming plausible was precisely the fact that it appeared to be picked up both by modern thermometers and by their proxy data. But that was an illusion. It was introduced into their proxy reconsruction as an artifact of arbitrarily redating the end points of a few proxy records.
In recent years there have been a number of cases in which high-profile paper 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.
JC comments: This case is an interesting one in the sociology of climate science. Some concerns and questions:
- Are there still no checks and balances in the paleoclimate community (outside of the efforts of Steve McIntyre, JeanS et al.)?
- In terms of the hyping of this story, I am prepared to give Marcott and Shakun somewhat of a pass given that they are recent Ph.D. recipients. Alan Mix and Peter Clark are the senior authors. And the paper was also hyped by a NSF Program Manager. What kind of advice did they give Marcott and Shakun in all this?
- Marcott scored points in my book by communicating with Steve McIntyre, and for some measure of honesty in his response. I wonder how his response landed on RealClimate. Here is a suspicion: Marcott was subsequently contacted by one of the RealClimate principals, providing advice against engaging with McIntyre, sympathy that they are being attacked by deniers, and providing support and a safe refuge on RealClimate.
- I see this as a struggle for the souls of two young climate scientists. Will they (i) decide to care primarily about science, and embrace the values of transparency and public accountability, answer questions about their research, and engage with skeptics in the interest of improving their research; or (ii) do they aspire to Mike Mann-style celebrity and plan to join the RealClimate warriors against auditing and skepticism?
JC advice to Marcott and Shakun: I understand how tough it is for a young Ph.D. scientist to make their mark in academia and obtain a desirable permanent position. Celebrity can be seductive, but engaging with the media is associated with many potential pitfalls. I encourage you to read my essay published a few years ago at DotEarth entitled: An open letter to graduate students and young scientists in fields related to climate research:
What has been noticeably absent so far in the ClimateGate discussion is a public reaffirmation by climate researchers of our basic research values: the rigors of the scientific method (including reproducibility), research integrity and ethics, open minds, and critical thinking. Under no circumstances should we ever sacrifice any of these values . . .
JC advice to NSF and the universities: We are not doing a good enough job in educating our young scientists about the specific ethical challenges faced by scientists working in the climate field. Lets share/generate some wisdom and develop better guidance for dealing with these issues (something for NRC COSEPUP to take on).
JC advice to the skeptical blogosphere: Lets get to the bottom of this, but while doing so I remind you that one element of this is the struggle for the scientific souls of two promising young scientists. Please don’t overegg the pudding and inadvertently send them to the RealClimate refugee and training camp. Cordially invite them to engage, and work with them to try to change the culture in the paleoclimate community.