Climate legacy of the ‘hockey stick’
There are few more provocative symbols in the debate over global warming than the “hockey stick”.
"The hockey stick was a term coined for a chart of temperature variation over the last 1,000 years, which suggested a recent sharp rise in temperature caused by human activities.
The chart is relatively flat from the period AD 1000 to 1900, indicating that temperatures were relatively stable for this period of time. The flat part forms the stick’s “shaft”.
But after 1900, temperatures appear to shoot up, forming the hockey stick’s “blade”.
The temperature chart originates from two seminal research papers published in Nature in 1998 and Geophysical Research Letters in 1999 by Michael Mann of the University of Virginia, Ray Bradley of the University of Massachusetts at Amherst and Malcolm Hughes of the University of Arizona”