There is something to be said for disgraced, lying hack Dr. Michael Mann. No matter how often his Hockey Stick Curve™ gets thrown to the dogs, he always seems to bring it back instead of leaving on the dung heap of discarded scientific theory. Rather than pollute his intellectual hygiene with new ideas, he simply recycles the old one and applies it to something else equally ridiculous.
Dr. Mann originally came to prominence in 1998. He and several co-authors published a paper entitled Global scale temperature patterns and climate forcing over the past six centuries in the prestigious scientific journal Nature. In this paper he claimed that temperature records in prior centuries could be reconstructed by studying tree rings. His argument was that tree growth was functionally dependent upon ambient temperature and that this functional dependence could be mapped and reversed. Therefore ancient trees could offer modern scientists insight into what the weather was like when Sir Francis Drake sailed the Atlantic.
This paper purported to show that what climatologists referred to as The Medieval Warm Period wasn’t as warm as experts previously thought. He hypothesized therefore that the recent observed increases in temperature during the 20th Century were historically unprecedented at least as far back as 1400.
This led to a chart on page 783 of the 23 April 1998 issue of Nature Magazine that featured a flat run of temperature from 1400-1900. After 1900, the temperature takes off in what seems to be a nearly-monotonic, increasing, exponential fashion. Someone looked at that chart and imagined a hockey-stick. A meme was born, and Mann gained prominence and great professional success.
The public policy impact of this graph proved monumental. The 2001 IPCC made it the fulcrum of their arguments in favor of increased environmental regulation. Steve McIntyre discussed in 2005 why The Hockey-Stick Graph™ loomed iconic.
The graphic was used repeatedly in IPCC TAR and was one of the most prominent graphics in the Summary for Policymakers. Some governments (and, the Canadian government in particular) relied upon it in their promotion of Kyoto policy even more than IPCC. In the lead-up to adopting Kyoto policy, Canadians were told by their Minister of the Environment that “1998 was the warmest year of the millennium and 1990s the warmest decade”.
Yet the data did not say what Dr. Mann claimed it did. His chart reconstructing the historical temperature record of the last 600 years became very problematic in years prior to 1500. It also seems that Dr. Mann knew his data had holes and chose not to make these facts public. McIntyre’s debunking follows below.
The most questionable IPCC statement about the Hockey Stick is that the MBH98 reconstruction had “significant skill in independent cross-validation tests”. I added bold to highlight the plural—a second level to the misrepresentation contained in this claim. The statement appears to have been written by Michael Mann about his own work. It is now known that the MBH98 reconstruction in the controversial 15th century portion failed the majority of cross-validation tests, including the standard R2 test [McIntyre and McKitrick, 2005a]; the source code provided to the Barton Committee shows that the adverse cross-validation R2 statistics were calculated, but not reported. It is also now known that the MBH98 reconstruction does not live up to its warranty that it is robust to the presence/absence of all dendroclimatic indicators, as the reconstruction depends on the inclusion of bristlecones, a series known to be potentially contaminated as a temperature proxy. Again, this adverse information was known to the authors and not reported.(My bolding for emphasis.)
This should have put Dr. Mann in a similar position to Michael Crichton’s sinister corporate antagonist in Rising Sun. Mann had ascended to tenure at Penn State by this time, and was therefore well neigh untouchable. However, his career as a serious public thinker should have been mercifully attenuated. He was proven wrong and worse still, proven disingenuous. He should have been given a seat in Crichton’s “office by the river.”
But no, Dr. Mann could leave no bad idea behind. He recently went back to Nature Magazine. The magazine was too stupid to protect his reputation and published his latest invention – The Hurricane Hockey-Stick.™
In this effort to scare his way to prominence, Mann piggy-backs onto our fears spawned in the aftermath of Hurricane Katrina. He now claims that modern hurricane seasons are more powerful than any since those between 900-1100 A. D. The Houston Chronicle describes the convoluted time-travel methodologies involved in constructing this pseudo-scientific dog and pony show.
The scientists used two methods to reconstruct hurricane activity from a period when there were no satellites, reliable ship records or coastal residents taking notes. One tack is based on the observation that the powerful storm surge of large hurricanes deposits distinct layers of sediment in coastal lakes and marshes. By taking cores of sediments at the bottom of these lakes, which span centuries, scientists believe they can tell when large hurricanes made landfall at a particular location. The second method used a computer model to simulate storm counts based upon historical Atlantic sea surface temperatures, El Niños and other climate factors.
Fortunately, fewer people are buying what he sells. Chris Landsea of The National Hurricane Center decries what he sees as a fundamental lack of accuracy in Dr. Mann’s work. He compares it to other such work in historical reconstruction and does not say positive things.
“The paper comes to very erroneous conclusions because of using improper data and illogical techniques,” said Chris Landsea, science and operations officer at the National Hurricane Center. In his criticism, Landsea notes that the paper begins by saying that Atlantic tropical activity has “reached anomalous levels over the past decade.”
This ignores recent work by Landsea and a number of other hurricane scientists who found that storm counts in the early 1900s — in an era without satellites and fewer seaborne observers — likely missed three or four storms a year. The addition of these storms to the historical record, he said, causes the long-term trend over the last century to disappear. “This isn’t a small quibble,” he said. “It’s the difference between a massive trend with doubling in the last 100 years, versus no trend.”
Despite continued refutation, in the face of professional scorn, Dr. Mann’s methodologies continue to inform ongoing scientific work. Today’s Washington Post reports that Arctic temperatures are 2.5°F warmer than they should be. The predictable description of methodology follows below.
The analysis, based on more than a dozen lake sediment cores as well as glacier ice and tree ring records from the Arctic, provides one of the broadest pictures to date of how industrial emissions have shifted the Arctic’s long-standing natural climate patterns. Coupled with a separate report on the region issued Wednesday by the World Wildlife Fund, the studies suggest human-induced changes could transform not only the Arctic but climate conditions across the world.
It continues. The lies get recycled, repacked and republished. Rebuke them, debunk them, and make them look like pseudo-sapient lower-order primates and they still won’t cease and desist. The Hockey-Stick Graph™ has all the trademarks of what Goebbels referred to as “The Big Lie.” It can only be hoped that after this current round of falsehoods is debunked, that it will finally die and go away.