Behind The “Hockey Stick”

The “hockey stick” is a line graph that’s become a superstar. The diagram is embedded at the center of the war between climate change believers and deniers. The Hockey Stick and the Climate Wars: Dispatches from the Front Lines (Columbia University Press) is the story of the graphic told by one of the scientists who created it, Michael Mann, a member of the Penn State University faculty with a Ph.D. in geology and geophysics.

Described as a hockey stick because of its shape, it’s been a target since it appeared in 2001 in a summary of climate change science produced by the Intergovernmental Panel on Climate Change (IPCC). The graphic represents Northern Hemisphere temperatures over one thousand years.

Mann relates the saga of climate change data—how it tells the story of climate change and how it’s been questioned. A note: Mann has found himself in some controversy since publication of this book for allegedly misrepresenting himself as having won the Nobel Peace Prize when it was actually awarded to the IPCC.