Ten Things Everyone Should Know About Hockey Sticks
Posted by Jeff Id on November 22, 2009
This is an updated repost from a September 11, 2008. It’s was a popular post then but is far more relevant now that we see some of the bias in the recently released files. It has to do with hockey sticks in general but the graphs are from data used in Mann08, a paper by Michael Mann who is a key figure in many of the CRU emails. This post should also answer some questions of the newcomers at the Air Vent.
Most of us have seen a ‘hockey stick’ graph like the one below indicating temperature. It and others like it have been repeatedly used to demonstrate the recent warming of the earth. But how was it created? Certainly there were no thermometers being recorded in 1000 AD.
Number 1 –
This data is considered the powerful evidence of man made climate change. This graph clearly shows it is hotter now than in the past. Scientists often quote the rapidity of the rise in the blade as the reason warming is man made.
Number 2 –
The red line is measured data from thermometers back to 1850. The red temperature data is from the HadCRUT series which was the subject of the legal FOIA requests being blocked by an apparent conspiracy between scientists and government employees in the recently released emails. The source of the data for the red temperature curve is a critical part of understanding man’s role in climate change. The GISS temperature record is a comparable dataset which has massive corrections added right onto thermometer data. The corrections are poorly validated and represent the majority of the warming signal for the past century. Still HadCRUT has a higher warming trend and despite a lack of transparency is more often the curve of choice in global warming publications.
Number 3 –
The rest of the data comes from proxies. Proxies are stand in measurements for temperature employing things such as tree ring width, mollusk shells, various kinds of coral and ice cores.
Number 4 –
There has been no verification or expirament that tree ring widths, mollusks or coral etc. measure temperature. Instead the concept for each proxy started with a basic theory that the trees or other things might change width with temp. The only verification is when the measured data from tree rings “correlates” after “calibration” to temperature. There have been no laboratory verifications of the concept.
Number 5 –
In creating Figure 1, the data from the proxies which match temperature trends are kept, and the remaining data are thrown away. About 60% of the data was thrown away in generating this graph above, the remaining 40 percent that did agree were from a variety of sources (one tree was used, the one next to it was not). Proxies are often very noisy data with little visible signal. See a typical proxy below, selected because it was the first data proxy of the series used to create the hockey stick.
Number 6 –
The retained (accepted) data was scaled (magnified) and offset (up and down) to provide the best fit to today’s temperature measurements. After the averaging, the red temperature line above is glued on the end to extend the blade of the hockey stick.
Number 7 –
The fact that 40% of the data when filtered has some similarity to temperature, is the sole rational for saying that tree ring width, and mollusk isotopes are actually temperature.
Number 8 –
Math techniques called CPS and EIV were used to generate the correlation and scaling of the proxy data for the graph above. A wide variety of other methods which do similar things have also been used.
Number 9 –
Statisticians and scientists have repeatedly discredited the calculations involved. Still ever more varieties are created and the main government branch for global warming Intergovernmental Panel on Climate Change has refused to relinquish this point. This continues despite repeated demonstrations that the statistics seem to be specifically designed to pick out hockey stick shaped proxies from even random red noise data. (see links above).
Number 10 –
Continued acceptance by the premier global warming scientists demonstrates a clear political bias at the top of the global warming community, leaving the world at the mercy of the conclusions of a large power hungry government organization. (this was written in Sept of 2009)
Now that the emails have been released including what appear to be discussions of bending data to fit the pre-determined conclusions, elimination of ‘skeptical’ editors and manipulation of IPCC rules to prevent the points here from being made, the truth of my statement is apparent.
What we can understand now.
This first graph, except for the red line at the end is not temperature, it is not science either but rather it is the output of a cleverly assembled statistical software designed to create hockey sticks. This method and others like it have been used to generate hundreds of hockey stick graphs. The sticks are created by small group of associated scientists with a preferred group of ‘favorite’ proxies using a variety of similar statistical methods. Now that we have these emails from the scientists themselves, it’s easy to see how they keep getting passed through peer review as evidence of global warming.
Proxy based temperatures cannot be trusted to reasonably define temperature history. Basing economic and energy policy on this curve and others like it are the height of irresponsibility.
But it will continue.