## Super-simple hockey stick explanation.

January 31, 2010

I have been reading over the blog posts of Steve McIntryre and Jeff Id and others about the nuances of various constructions of the hockey stick.  I’ve been examining the archived Mann08 data at the NCDC.  This is my attempt to boil down hockey stick construction to its bare-bones, expressed as five essential steps:

Step 1. Gather time series.
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Step 2. Select those time series that fit the instrumental (measured) temperature record of choice. Assume that since these time series match the instrumental temperature record in some way, then they are, in fact, temperature proxies.
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Step 3. Combine the chosen proxies in some fashion and note, not surprisingly, that the combined proxies match the temperature record (duh!).
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Step 4. Call this thing made from the combined proxies your temperature reconstruction, and therefore assume that the combined proxies are also a match for the temperature that occurred prior to the temperature measurement records.
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Step 5.  Note that the reconstruction shows that the temperature prior to the instrumental data is relatively flat.  Make the important conclusion that the temperature prior to the instrumental record changed very little.

Defenders of hockey stick constructions will point out my naïvety with an endless list of nuances and subtleties involved in each of these steps.  But keep your eye on the puck.  The following picture illustrates the difference between my simple steps and their more nuanced approaches…

It’s important to examine those details and nuances at some time and place.  But sometimes they are simply a smokescreen.  Keep your eye on the hockey puck.

Coming soon to ClimateSanity: the Amazing Multiplying Proxies.

1. This spoof of climate science may be of interest:

http://climaterealists.com/?id=4960

2. In the complicated graphic, step 2 doesn’t go to step 3 and step 3 goes to itself. Not sure if that was intended.

BTW, I think your list of steps is an accurate, albeit general, description of the process. I think step 2 is the biggest problem.

3. […] Sanity « Super-simple hockey stick explanation. Amazing multiplying hockey stick proxies February 3, 2010 In my previous post I wrote […]

4. […] Tree-rings: Proxies for Temperature or CO2? February 15, 2010 Recall step 2 of the  five super-simple steps for building a hockey stick: Step 2. Select those time series that fit the instrumental (measured) temperature record of […]