Hockey Stick Is Dead

Published September 29, 2009

One of the most notorious and phony pieces of data underlying global warming alarmism – the “hockey stick” graph – has been shattered in a posting today on the World Wide Web.

In 1998, Dr. Michael Mann, then at the University of Virginia, now a Penn State climatologist, published a paper that purported to show that based on tree-ring information, the Earth’s climate was the hottest period in the last 1,000 years.

The graph is dubbed as the “hockey stick” and becomes famous worldwide. Al Gore uses it in his movie An Inconvenient Truth in the famous “elevator scene”.

In the years since then, Steve McIntyre, a Canadian mathematician and climate realist, attempted without success to win access to Mann’s data and to replicate his hockey stick graph. His suspicions grew that Mann’s tree rings didn’t tell a valid story with a giant uptick at the right side of the graph, implicating the 20th Century as the “hottest period in 1000 years.”

Then last year Mann published another paper in bolstering his tree ring claim in the Philosophical Transactions of the Royal Society, which has a strict data-archiving policy. Thanks to that policy, McIntyre fought and won access to that data just last week.

Having the tree-ring data in complete form, McIntyre replicates it, and plots it, and the infamous hockey stick graph disappears. Not only does it disappear, but goes negative. The conclusion is inescapable. The tree ring data was hand picked to get the desired result.

You can read McIntyre’s full report, complete with re-plotted graphs and some outstanding responses, at Watts Up With That? Anthony Watts’ superb site for commentary on puzzling things in life, nature, science, weather, climate change, technology, and recent news.