Analysis of James Hansen’s 1988 Prediction of Global Temperatures for the Last 30 Years

by Clyde Spencer, June 30, 2018 in WUWT


There have been articles on WUWT recently, here and here, commemorating the 30 years since James Hansen gave Senate committee testimony about his view of the human influence on climate

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Hansen dramatically emphasized that “The most recent two seasons (Dec.-Jan.-Feb and Mar.-Apr.-May, 1988) are the warmest in the entire record.” This is really a non sequitur. It would be notable if the last point(s) in a long upward-trending series were not the warmest in the series. And, indeed, the 27 seasons preceding the two 1988 record temperatures were all lower than the 1981 seasonal high! (See the next graph, below) Basically, Hansen got lucky again that he had a couple of warm seasons that allowed him to make such a statement to impress the uncritical Senators. Otherwise, he would have had to truncate his graph at 1981 to make a similar claim. He also added an extra season of data to his ‘30-year’ time-series, probably to accentuate the claim. Two seasons sounds more impressive than one season.

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