A central figure in the controversy over human-caused climate change has been “The Hockey Stick,” a simple, easy-to-understand graph Mann and his colleagues constructed to depict changes in Earth’s temperature back to 1000 AD. The graph was featured in the high-profile “Summary for Policy Makers” of the 2001 report of the Intergovernmental Panel on Climate Change (IPCC), and it quickly became an icon in the debate over human-caused (“anthropogenic”) climate change. Mann tells the ongoing story behind the Hockey Stick, using it as a vehicle for exploring broader issues regarding the role of skepticism in science, the uneasy relationship between science and politics, and the dangers that arise when special economic interests and those who do their bidding attempt to skew the discourse over policy-relevant areas of science. In short, he attempts to use the Hockey Stick to cut through the fog of disinformation that has been generated by the campaign to deny the reality of climate change. It is his intent, in so doing, to reveal the very real threat to our future that lies behind it.

Michael E. Mann is Distinguished Professor of Atmospheric Science at Penn State University, with joint appointments in the Department of Geosciences and the Earth and Environmental Systems Institute (EESI). He is also director of the Penn State Earth System Science Center (ESSC).

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