A: No. The “hockey stick” is a reconstruction of temperatures over the past 1,000 years, using tree-rings, ice cores, corals, and other proxies for temperature before thermometer records began. The principal finding of the original paper, by Michael Mann and colleagues, was that global temperature turned up sharply in the 20th century, with the last few decades being the warmest in 1,000 years. Since that paper was published, a number of additional studies have analyzed proxies of past temperature. They all confirm the original “hockey stick” conclusion: the 20th Century is the warmest in the last 1,000 years and warming has been most dramatic in recent decades.
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