Investigating the Hockey Stick Climate Model EAS Dr. Wang 4/22/08Robert Binion

Problem Michael Mann, et al. have proposed the hockey stick temperature model, which suggests that world temperatures have significantly increased during the twentieth century I sought to analyze temperature data to determine the validity of his assertion that temperatures have significantly increased

Data My data set includes normalized temperature data for the years for both the northern and southern hemispheres as compiled by P.D. Jones from 17 different proxies I used only the most recent 600 years of data because of inconsistencies in measuring techniques before that time period

Methodology I performed a principle component regression using a singular value decomposition method to analyze my temperature data set The regression is used to determine whether the hockey stick model could be a valid model to describe climate changes over the last 1000 years

Methodology After performing the regression on both the northern and southern data, I found the 95 % confidence interval for both slopes and plotted the 95% confidence interval of the fitting line

Results Plot of normalized northern hemisphere temperature data with principle component regression line

Results Plot of normalized southern hemisphere temperature data with principle component regression line

Results 95 % Slope Error estimate for northern data low = high = Actual slope = e e-004

Results 95% Slope error for Southern Data low = high = Actual slope = e e-005

Conclusions Analysis of the data turns out to be inconclusive The regression for the northern hemisphere does have a positive slope to it, which would correspond to the hockey stick model However, the southern data dhows a negative temperature trend Both of the slope error bounds include positive and negative slopes, so neither graph is particularly conclusive We can say that Mann’s results are not statistically vigorous based on the slope error bounds I calculated