People who have been following the climate debate closely know that one of the most controversial and key elements of the controversy is the so-called “hockey stick” — a graph of supposed global temperature over the past centuries that ostensibly shows a dramatic increase in average temperature in the last century or so (the upward swoop of the graph at that point is the business end of the stick, with regard to the puck). It vaulted its inventor, Michael Mann of Penn State University, to climate stardom, with associated acclaim and government grants, when he first presented it in the late ’90s. It was the visual basis of much of the hysteria in recent years, from Al Gore’s Oscar-winning crockumentary to bogus reports from the UN’s Intergovernmental Panel on Climate Change (IPCC).

Unfortunately for those promoting the theory (and the potentially economically catastrophic policy recommendations supposedly supported by it), recent events indicate that the last basis of scientific support for the hockey stick may be crumbling. But to understand this, a little background is necessary. (more…)