|1990 IPCC Global mean lower atmosphere temperatures|
One scientist who suspected that this analysis was flawed was Stephen McIntyre. Although he initially found Mann co-operative in sharing data and programming, it soon ended. McIntyre teamed up with a professor at Guelph University, McKitrick. Lacking Mann's source program they built a program to do the job. The results were quite at variance with Mann's results. They then played with the program procedure until they could almost duplicate Mann's results. This produced a claim that Mann had not done what he claimed he had done but had invented non-standard procedures. Furthermore, the foxtail bristlecone pines were known to be sensitive to CO2 concentrations and thus their change in ring size could be correlated to CO2 itself and not temperature change.
When the foxtail bristlecone pine data were excluded from the input that alone was sufficient to eliminate the hockey stick shape. When the non-standard procedures were removed a significant change occurred in the values of the Medieval Warm Period. Both were responsible for producing results significantly different from the 1990 results.
McIntyre and McKitrick also produced a set of proxy data that had no trend in the data - simple variation around the mean value. Such a data set combined with an unbiased methodology should have produced minimal change of temperature results. It actually produced the same hockey stick shape produced in Mann's procedure. This in itself means that Mann's results are meaningless. His methodology cannot distinguish between non-trending and trending data. McIntyre and McKitrick asked for Mann's paper to be withdrawn but they were refused.
Then a team from the National Academy of Sciences investigated Mann's graph and concluded that the temperature in the 1990's might be the highest in the last 400 years - not the last 1,000. This sounds like a innocuous response but everyone had already agreed upon this since the 1990 IPCC report. They effectively said there is nothing new. The failure to acknowledge that the steep climb in temperature since 1900 shown by Mann's graph was in fact a stinging indictment of his work. The media failed to understand the import of this.
Chairman of the Committee on Energy and Commerce as well as the Chairman of the Subcommittee on Oversight and Investigations of the American Congress became interested and Dr. Wegman, a statistician, was asked to examine the problem. Concluded that the methodology did not provide appropriate results, that Mann did not have full familiarity with statistical methods or consult with an authority who did, that the community of temperature scientists were very interconnected thus possibly the paper had a vetting that was too friendly and that federally funded research should be shared for vetting and further research, at least after publication if not before. The full report is here http://www.uoguelph.ca/~rmckitri/research/WegmanReport.pdf .
One final conclusion needs to be drawn from all this. There is a mechanism in physics that explains the so-called greenhouse effect and greenhouse gases. There is no controversy that it exists. The biggest greenhouse gas is water composing 75% of the greenhouse effect. Methane is smaller by volume than CO2 but its heating effect is 32 times stronger. CO2 is in effect only the third highest contributor to the greenhouse effect and its effectiveness as a heat source in the atmosphere is now understood to be substantially less than was thought earlier. Human CO2 is only 5% of the total CO2. It is then questionable whether man-made CO2 has anything but a marginal effect within the greenhouse gases.
There is one very large and untested assumption in the UN's IPCC narrative. What are the other contributors to atmospheric temperature change and what is the relationship to the temperature change caused by greenhouse gases. All the atmospheric models treat the Sun's energy as constant and this is known to be false. The Sun's energy variability is also capable of overshadowing the entire heating or cooling affect of greenhouse gases and thus a fortiori that of CO2 and thus a fortiori that of man-made CO2. This is totally ignored by the IPCC.
Where is the case that proves that CO2 variability corresponds directly to atmospheric temperature changes? There are many instances where increase in atmospheric CO2 has produced no change in temperature, including the last 18 years. From 1930-40 CO2 decreased but temperature increased. From 1945-1975 CO2 increased while temperature decreased. Even when there is a positive correlation of the data overall as Mann et al claim, it does not mean that CO2 is the cause. The police force of cities is positively correlated to the crime rate. I think we know that higher crime rates produce larger police forces and not vice-versa. The UN claims that the probability that their thesis is true is now 99%. They have failed still to actually measure with any certainty past temperature changes, to distinguish how much of the increase in temperature is caused by CO2 and how much the increase in CO2 is caused by increase in temperature.
Despite these efforts to have appropriate measuring of the past temperature changes and the appropriate determination of the causes and the probability of a statistically significant effect from CO2 contribution - despite all this - UN efforts to push the war on CO2 go unabated. The publicity machine behind them and their allies in the worldwide system of meteorological bureaucracies and school systems has produced a widespread acceptance of their views. The agenda is very costly both in tax dollars, household budgets and in economic freedom. The gains in controlling people, their businesses and their governments is far to lucrative to consider any lesser mortal than themselves. One day we shall discover the cost of following their agenda.