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Financial Post
Terence Corcoran: How fossils fuelled the GDP hockey stick
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CP169097874.JPG

The great climate hockey stick trial ended Wednesday in Washington, a libel and science battle between journalist Mark Steyn and climate scientist Michael E. Mann. The jury’s decision sets the stage for debate over free speech and the quality of the climate science used to justify the global campaign to rid the world of fossil fuels.

Missing from the trial, and the ongoing ideological clash over climate change, is another hockey stick, one that economists have been musing about for some time: The GDP hockey stick. While the temperature version under scrutiny at trial plots 1,000 years of speculative reconstructions of temperature history, the GDP hockey sticks deals with harder real data.

The Mann-Steyn trial, outlined here last week and reproduced by steynonline, focused in part on a 1998 graph shaped like a hockey stick developed by Michael Mann. Mann and others claim the graph provides statistical evidence that the use of fossil fuels led to a sharp rise in global temperatures in the 20th century.

The graph, leaving aside problems with the temperature measurement techniques, is one of the major selling points for national and international mega-plans to decarbonize the global economy down to net-zero emissions by 2050.

Missing from policy-making thinking is another hockey stick. Developed by British economist Angus Maddison, the GDP graph posits a thousand years of flatline global growth until the 18th century, when it began a major surge. Through the 19th and 20th centuries, GDP measured in constant dollars per capita began to soar toward $8,000 by 2010 and higher still in later years.

Economic and political debate over the causes of this spectacular gain in average human achievement and welfare has been raging for decades. Maddison, in his 1995 OECD book Monitoring the World Economy, which he expanded on with The World Economy: A Millennial Perspective, in 2001, identified key factors that produced the huge gains, including colonialism, international trade, capital movements, population growth and technological innovation.

Scores of other economists have taken up the GDP hockey stick issue. In a 2013 paper titled Tunzelmann, Schumpeter, and the Hockey Stick, University of Chicago economist Deirdre McCloskey wrote that “The history of the world for tens of millennia before 1800 was, roughly, a flat handle of unchanging real income per head for the average human. Then around 1800 the world reached the business end of the Hockey Stick, and all our joy.” By 2008, the 53 per cent of the world’s population that had lived on less than $1.25 a day in 1981 had been reduced to 22 per cent.