“Chase after the truth like all hell and you'll free yourself, even though you never touch its coat tails.”
— Clarence Darrow
The hockey season may be in doubt, but hockey sticks are back in the news.
Hockey stick graphs, that is.
For more than a decade, the defining image of global warming has been the “hockey stick” graph, originally mapped by Michael E. Mann et al. back in 1998 and formally adopted by the Intergovernmental Panel on Climate Change in 2001.
It shows the relatively small variance of Earth’s temperatures over the past 1,000 years, ending in a sharp rise over the past century (thus resembling a horizontal hockey stick with the blade pointing up).
The graph is based primarily on proxy data — temperature estimates derived from indirect sources such as tree rings and ice core samples — but actual temperature records dating back to the 1800s are also incorporated.
Many people are under the mistaken impression that the hockey stick graph has been thoroughly discredited. This stems from two things.
First, an independent scientific team (McIntyre/McKitrick) discovered flaws in Mann’s methodology not long after the graph was first published. This led many skeptics to believe it had been disproven. But Mann’s team corrected those errors and still came up with a similar result. In fact, the graph has been replicated several times by other scientists working independently.
The second source of doubt arose when years’ worth of climate research emails and other documents were hacked and leaked to the public in 2009.
A handful of those documents (of which there were thousands) seem to suggest that scientists in Britain and the U.S. were being less than honest about their work. In particular, one British researcher referred to “Mike’s Nature trick” and how to “hide the decline.” The immediate presumption was that Michael Mann was manipulating data to disguise a decline in temperature.
This latter revelation reflects a sad deficiency of the instant-news world we live in. For, while those few damning words were widely circulated by media outlets across the planet, few bothered to follow the ensuing investigation with much vigour.
As it turns out, various internal and external inquiries completely exonerated the scientists. The term “trick” simply meant a “trick of the trade,” and the “decline” was a reference to a well-known problem of diverging data from high-altitude tree-ring data since the 1960s. Apart from the latter anomaly, all other proxy components of the graph conform to actual temperature data. In fact, recent research points to a correlation between the declining tree growth and global warming itself.
To a scientist, accusations of manipulation and dishonesty are extremely serious. It is why peer review is critical in any research, and why results must be independently duplicated.
So, when acerbic, right-wing pundit Mark Steyn, in an online National Review post in July, referred to Mann’s hockey stick graph as “fraudulent,” and compared Mann to Penn State child molester Jerry Sandusky, it would appear by any objective standard that a line had been crossed.
Mann has vowed to sue Steyn. And it won’t be the first time. Last year, he launched a suit against Canadian climate change denier Timothy Ball, for similar reasons.
There are few things nuttier than science on trial in a courtroom. One need only look at the 1925 Scopes “monkey” trial, when attorney Clarence Darrow fought in vain for the right to teach evolution in the classroom.
But this case is about a man’s professional reputation — one the denier community has viciously targeted in an attempt to destroy the most powerful visual image in the climate change arsenal.
If Mann’s legal actions meet with success, it will undoubtedly be a watershed moment.
For now, deniers are jumping with glee at the prospect of Mann’s private work being dragged into the spotlight. They think they’ll uncover a wellspring of incriminating evidence.
If Mann’s academic exoneration is anything to go by, deniers should be careful what they wish for.
Peter Jackson is The Telegram’s commentary editor.
This story has been edited to correct a date.